Super knowledgeable man! I really enjoy the vids!! Thanks to you I'm going to properly troubleshoot my fuel pump and injector on my 2014 RMZ 250 that won't start. Hopefully I find something similar to what you have found in the past and I get it fixed up in a timely manner!! Keep posting, I will keep watching!
Awesome man! And thanks so much for watching. Yeah dig into that rmz and see whats happening. I would check the pumps PSI first. If its been sitting forever it might also need a new injector or at least flush the current injector. Let me know what you find if you don't mind and if you need any help.
@@UpAllNight91 Awesome! I actually put 5V through the pump last night just to see and it did turn on. Now I need to check the actual pressure with a 12V. I will try to keep you updated but I don't have as much time to work on it as I'd like.
@@sergiomz21 I did fix the issue. The fuel pump tested fine using the gauge from Harbor Freight. Turns out my issue was the electrical connector (pigtail) coming from the Fuel pump going into the wiring harness. Loose connector was the issue. I re-installed the wires and used clear silicone to hold them in place. Started first kick ever since.
It looks like it was running too lean to me. I have a 2023 YZ125 and am running a 65 pilot, leaner oem needle number 2 position and a 172 main. I mix Blendzall green label 28:1. No spooge, crisp throttle response and strong power everywhere. I run 1 step colder plug for the sand tracks to keep the heat down. I’m also at 4,500 feet elevation.
Nice. I haven't had the chance to jet a 2022 or newer but based on feel it feels it could be rich. But I wouldn't know till I've had the chance to swing it both ways and see how she handles it
Any update to the jetting? Currently 68 pilot, leaner needle (NYEF-3), 158 main. Much better power over stock for me in Texas, 65degrees, less than 1000ft. About to put a Apex head with SX/XC dome. They recommend 48 pilot, richer needle (NYCF-3), 172 main. However HP development recommends the opposite basically, stating they got much better power with 70 pilot, NYDF-2, and 155-158 main and lost power with the JD or Apex jetting. I’m sure the Apex head with change things but I’ll be surprised it’s that much different.
@@tcoll1233 I now have a 60 pilot, 175 main and back to the oem needle in the #2 position for the colder temps. It looks like for me I’ll only have to swap needles for temp swings. My bike pulls hard and runs clean. Check out my channel.
@@tcoll1233 no updates on the jetting. The owner "Braden" has been just running it as is. I'm sure down the road when he's ready to change a pipe or head then I will be getting in her and jetting it but as of now it's stock. Which as you know is no the best jetting lol. I would expect Apex head to need leaner jetting than stock on the main due to the tighter squishband. There is a chance that my wife might be getting a 22 or 23 soon. If she does then I will digging in head first and dialing her in to a T. Fingers 🤞. Where you able to dial in a stronger mid range out of her yet?
Hello. Hard racing on a forged piston. I would say 10 to 20 hours on a 125. I would start with 15 hours. If it looks good maybe move it up to 20. If it looks worn then move it down to 10 hours.
The amount of knowledge you have is quite noticeable with how quickly you ripped that thing apart lol. Quick question: my buddy has a 2023 yz125. We were riding today and he dropped it in the water and now it feels like compression is down and it won't start. We pulled the plug, tipped it up to drain the exhaust and checked the air filter. Do you think it needs a top end rebuild? Only has maybe 10 hours on it. What should we look for and what tests can we do to figure out what's wrong with it?
Hello. I would surely open the motor and at minimum clean the piston, ring, and crank area. A new piston would be best though as well. What happens is when they are flooded in water the water that goes through the air filter can bring dirt through the filter with it. You would think the filter oil would collect the dirt but when the filter is soak with water it doesn't catch the dirt. Most likely you have some dirt in the motor keep the ring from getting a good seal.
Still loving your videos! Hey I am curious to where you got the piston kit. Will the 21 piston work with it? I see on rev zilla they put them all together as there the same. Motorsport doesn’t have it and says 21 doesn’t fit. Any help you can give me would be great.
@@UpAllNight91 the only choice was pro lite. The weird thing was buying the wrist pin bearing they only had 125x. What’s up with that. I got it anyway. I hope that’s ok. Kinda weird they sell a piston then not do the bearing huh? Let me know what you think on that. Thanks bro
Well i got 24ish hours on my 2023 yz125 and now im scared to ride it after seeing this… thanks for the video im definitely ordering a wiseco piston now. Im 195lbs and im not easy on it so im guessing im long overdue?
@@UpAllNight91Hey man, I just put a new piston in my bike, but i did not really pay attention to the ring being completely aligned with that little groove. I did when installed the ring, I rode the bike up and down my street and did a little trail ride… What happens if the ring isnt aligned correctly and do you think im good if i rode it and nothing happened?
@@austinsilva5054 If the ring end gap is not aligned with the ring gap pin on the piston, the ring can snag a port and it will mess up the cylinder. That being said its really really hard, almost impossible to slide the cylinder down on the piston is the ring in not aligned on that pin. I think you will be ok if you didnt have to force the cylinder on however I like peace of mind so I would pull the cylinder off and check to be safe.
Any update to the jetting? Currently 68 pilot, leaner needle (NYEF-3), 158 main. Much better power over stock for me in Texas, 65degrees, less than 1000ft. About to put a Apex head with SX/XC dome. They recommend 48 pilot, richer needle (NYCF-3), 172 main. However HP development recommends the opposite basically, stating they got much better power with 70 pilot, NYDF-2, and 155-158 main and lost power with the JD or Apex jetting. I’m sure the Apex head with change things but I’ll be surprised it’s that much different.
Strange apex would recommend richer jetting. Usually a tighter squish enjoys leaner jetting, mainly in the main jet. I haven't had a chance to tune in the 202e, currently he's just running it stock and as you know stock on that bike surely leaves something to be desired. But there is a good chance my wife could end up with a 2023 here shortly and then I will be digging into that one and see what I can get out of her. Still trying to figure out why apex recommends richer on the main, unless they where getting pinging out of it with pump gas, only thing I can think of
@@UpAllNight91 not sure. Haven’t gotten a chance to ride. I did crank it and warm it up. New top end and the apex head, with the 48 pilot and 172 main and it seems crisp, much crisper off the crack of the throttle and doesn’t seem to load up as much. I will do a plug chop on the main and adjust from there. Matt did say the main is a little rich for safety and they will adjust more as they get feed back from around the country. I expect to end up around 168 main here in Texas at 300-900ft altitude but we will see. I asked a guy about his 2023 and he was running 50 pilot and 172 main also, standard needle, in the mountains of Arizona, like 6-9k altitude but said it’s cuz he’s wide open on flats all the time
@@tcoll1233 Yes I have always noticed the tighter squish on first startup and blipping. Surely crisper. Sound much more like a race bike. 168 sounds about right for that attitude and head. She should do good 👍
Crazy what you found in there! What mix were they running? I run 30:1 with motorex cross power 2t I’m at 25 hours or so on my 22. Loving it! Unfortunately unable to ride because a torn cartilage in my knee. Thanks for the videos!
Back riding again and still mixing gas hauling ass 30 to one went back to Yama lube 2R and I had the bigger main jet in it was running rich but I went back to stock 160 and I haven’t tried messing with it going leaner because if it needs anything it’s a piston and rings. I’m at 39.3 hours. Does the air filter always being clean help prolong top end life?
In reference to you recommending wiseco pistons over the stock cast piston, do you also recommend the same for 4 strokes? Thanks in advance for the advice.
Hello. Most of the oem pistons on these modern 4 strokes are good. Brands like Yamaha have a special coating on the wrist pin that slows down the wear on the upper rod bear race. After market pistons like wiseco don't have wrist pins like this. For the most part I suggest OEM pistons for the 4 strokes.
It's normal. I believe it's just the stator making power. Totally normal though and nothing to worry about. I actually think they sound cool when they make that sound lol
Did you ever do a vid with a crank case flush. My lad's bike has done exact same as this on his 2023 yz 125 and want to know best way to flush crank case without taking the motor out. Did u tip the bike upside when flushing it? Thanks Stu
Hello. Below I provided a link where you can download your service manual for free from yamaha. I'm about too put together a video on ring end gap but the jist of it is you should never have to file down a ring on a nickel plated cylinder. Notice in the manual it shows you how to check and if its out of spec to just replace it. Meaning they are only worried about the ring end gap being too large and not worried about it being too tight because they are pre cut perfectly from the factory for the cylinder. Here is the link to the manual download library.ymcapps.net/library/om/app/index.html?baseCode=6150&langId=02
I have a 22 yz 125 with roughly 130ish hours on the stock piston and ring. I run 40:1 which is what probably helped with the longevity of the top end. But time has come too replace it before it does go boom. What piston size did you go for?
Hello. If replacing with a stock type piston I suggest using what size your cylinder is. Like if its a B use a B. I have a video on pistons maybe it can help. Here is a link ... ua-cam.com/video/sAeSBuNQILY/v-deo.html
They come with holes in them if its needed. I think the days of us having to drill our own holes are gone. Anymore all the pistons I see already have the holes in them for the bikes that require them
@@UpAllNight91perfect lol so that means mine is good especially on the 2022 Yeo thank you for mamiing this video cause I did everything you said to do on it and the rebuild came out beautiful my bike feel so much better
Not sure what the purpose of that coating really is, when I removed my reed cage I noticed the coating on mine was worn off after just 3 hours of run time. Maybe it helps with an easier break in?
Yeah that coating on my YZ250 wears off the very bottom and top edge really fast. I read literature from wiseco and they claim its designed to wear where is needs to wear and stay where it needs to stay to help with noise. But I don't know. Guess it doesnt hurt anything being there, or not lol
@@TheWhole36 I like to do 3 heat cycles. Running it on the stand till the radiators are nice and hot (but don't over heat it). Letting it cool down for 15 minutes between heat cycles. Check the coolant. Then first ride make it a shorter ride, about 8 minutes or do. Easy ride. Come back in check the coolant again. If alls good then shes good to rip into!
Really enjoying your channel. Thanks for the content. I noticed in your build videos that you don’t bother with measuring ring gap. Is it important on these bikes? I use to not measure and never had a failure when doing it that way. Curious as to your thoughts on it.
I've heard you should measure gap after machining cylinder. He was just changing piston and there was no size change so I don't think it was necessary. But I'm curious to hear author's opinion on that as well!
I'm not a expert on cylinders and pistons so I could be wrong but from what I have gathered through the years is a cast iron sleeve being bored out needs to be bored to match the piston and the ring gap checked to insure alls well. When I send cast iron sleeve cylinders off to be bore the machine shop always request I also send the new piston with it so they can get it just right. However with nickle plated cylinders they are machine so well and accurately that they are the exact size that fits the piston and rings perfectly. One of the benefits to this that was really noticed when it first came out in like the late 80s was a racer no longer needed to do as much work to freshen up a top end, just remove the cylinder and drop in a new piston and rings. I think machining in general as gotten so much better these days. I remember when they would only sell engine cases as a set and it was advised to always use a matching set of cases. However these days they will now sell you just one case half and there is no need to worry about matching cases because the machining is so accurate that they are all cut out identical for the most part. I think the same applies to pistons and rings in these nickel plated cylinders. They have everything machined out pretty much perfect right out the box these days. I could be wrong, but I havent had any problems tossing rings in nickel plated cylinder, it always comes out ok and lives long (as long as all else is ok lol)
The pro x piston is very similar to the OEM piston. It is also a cast piston. Its good for a cast piston but a forged piston is still going to be the stronger choice.
It will need the nitrogen released to take the shock apart to replace the bumper. Which means you will need to fill it back up. Most your motorcycle shops will fill it with nitrogen for about 25 to 75 bucks (depending on how they want to charge). So you do all the work, and when done take it in to have it nitrogen charged. I had to do it like that for years before I was able to get my own charging equipment.
Hi and Happy Thanksgiving to you and your family! After repairing it, I would like to ask you why the engine sounds very strange? I think some of the mean bearings or conrod will blow soon. Take care!
Hello. That may be just how the camera picked it up. In person she sounds normal and the bike has had probably 10 to 15 hours put on her since the video and she's doing OK. Gotta just be howbthe camera picked up the sound. Happy Thanksgiving to you too! Hopefully you have a good weekend of riding ahead and thanks for watching and commenting!
Don't get a new head, send it to HP development, their cut heads are amazing, then Jet it...simple. It'll run better and you can get the cylinder ported aswell for the price of a new head, itll be a ripper...they did my lorettas bikes, a 125 and 250F with their 'national' package. I put 3500 into my 125 engine, it cracked 40hp in a 125. Thinking about boring it and put a longer connecting rod, which takes some case mods. They also have a deal with wiseco for their own pistons that allows for different porting than what the stock one will allow.
Hello. There is no need to file a ring end gap on a stock YZ125 cylinder with a stock or a wiseco piston. Sure it doesn't hurt to check but if using a wiseco be sure to use the ring end gap specs for the wiseco ring (not the OEM ring). I actually made a video covering this pretty well if you are interested. Here is a link ua-cam.com/video/5wdMNpgAAYo/v-deo.html . The head, we replaced with a stock head (its not my bike). I myself on my bikes have been using heads rechambered for race fuel for years now. I usually cut my own heads so I can tune there right to where I want them. But I agree, the head mod is surely the best bang for the buck
For sure 30 hours is too much. Yeah that pipe wear is odd. But truly doesnt have more that 30 to 40 hours, so he must just be riding it funny to be wearing that pipe that quickly. We put a hour meter on it at around 10 to 20 hours use and the meter now reads 20 hours. For me the best part of the wiseco piston (or any forged piston) is that they are not known to break easy, even if ran way to long. I have seen compression drop to near zero from running a wiseco too long but its still in one piece
@@UpAllNight91 Yamaha must have cheaped out on the paint for the new pipes. My 2009 yz 125 with the stock pipe had almost no wear after 250+ hours. My 2022 yz 125 looks almost like the one in the video with just 20.
95% sure somebody didn't break that bike in and just started ripping it. 0 oil in the power valve and on the head. Gotta ride a fresh bike lightly for about 5 hours or else this happens
The OEM piston is the achilles heel of Yamaha 2 strokes. I see guys replacing top ends with OEM pistons and I just cringe. Nothing worse than blowing up your new bike after 20-30 hrs. I've used Vertex but you prefer WiseCo Chris?
@@UpAllNight91 splitting the case and going into the guts of it wasn't necessary this time, in your experience how easy is it for broken pieces of top end to find there way into the bottom end.
@@aaronbligh3619 it happens. And sometimes there is no other option but to split the motor and clean it out. Sometimes they get logged down in the bottom. I try to just keep this from happening in the first place by using forged pistons.
@@UpAllNight91 excellent I understand now, 05 -19 are the same bike and have your approval. I love yz 125 . I'm 42 and still have the most fun on this bike. Just out of curiosity what's your thoughts on the 2000 model yz 125. Sorry I know your busy. Appreciate you taking the time.
@@aaronbligh3619 the 2000 is the same as the 2017 to 2021 in every way. From brake rotor size, to suspension, to engine. I think the 2017 to 2021 is the best of the 2005 to 2021 yz125's. I still own a 2021 and its a amazing bike. Its still competitive with the 2022 and newer YZ125. You have a great bike, A underrated bike in my opinion. I actually did a review comparing the 2021 to the 2023 if your interested its in my video listing
Yes the standard vertex is cast. But they do make some forged pistons for some models. You gotta look hard for them but they are on their web site I think. I had to install them in a racers KTM 125 that would only run vertex lol
Yeah. I think its kinda a balancing act. The stock piston being cast is better for people who don't warm a motor up at all. The forged pistons need to be warmed up. So I think they are trying to choose the path of least failures with the average buyer. Average being doesn't know much or have much experience and will start it up and run it hard before it even warms up
I would not buy wiseco there junk namura is what i use really good only 50 bucks cheaper better il never use wiseco mine broke 16 hours never ever again
@@UpAllNight91 ok im look into a different piston then I need a strong one cause I ride in this guy's property it's big an I keep bike wide open in all gears run bike hard I think that's how I melted wisco piston ring I want say I'm flying threw this field an deer are everywhere I all most hit one came out nowhere then me an my dog basset hound were chasing them I got get bike out shop I miss these times I called shop they think it's o ring in carb I don't think it's that cause I put same kind brand new bike did same thing I told them I dropped off new carb they can take parts off it I just want my bike back
I'm so glad I've found this channel. I love videos you make. Knowledge you share is very valuable, thanks!
That's awesome man . I really appreciate you taking the time to watch these!
Super knowledgeable man! I really enjoy the vids!! Thanks to you I'm going to properly troubleshoot my fuel pump and injector on my 2014 RMZ 250 that won't start. Hopefully I find something similar to what you have found in the past and I get it fixed up in a timely manner!! Keep posting, I will keep watching!
Awesome man! And thanks so much for watching. Yeah dig into that rmz and see whats happening. I would check the pumps PSI first. If its been sitting forever it might also need a new injector or at least flush the current injector. Let me know what you find if you don't mind and if you need any help.
@@UpAllNight91 Awesome! I actually put 5V through the pump last night just to see and it did turn on. Now I need to check the actual pressure with a 12V. I will try to keep you updated but I don't have as much time to work on it as I'd like.
If you don't have one,, Harbor freight sells fuel pump gauges for like 25 bucks. She should have 45 to 55 PSI to run decent for the most part
Did you fix this? I have 2013 rmz 250 same issue
@@sergiomz21 I did fix the issue. The fuel pump tested fine using the gauge from Harbor Freight. Turns out my issue was the electrical connector (pigtail) coming from the Fuel pump going into the wiring harness. Loose connector was the issue. I re-installed the wires and used clear silicone to hold them in place. Started first kick ever since.
Another great video!!
Thanks!
It looks like it was running too lean to me. I have a 2023 YZ125 and am running a 65 pilot, leaner oem needle number 2 position and a 172 main. I mix Blendzall green label 28:1. No spooge, crisp throttle response and strong power everywhere. I run 1 step colder plug for the sand tracks to keep the heat down. I’m also at 4,500 feet elevation.
Nice. I haven't had the chance to jet a 2022 or newer but based on feel it feels it could be rich. But I wouldn't know till I've had the chance to swing it both ways and see how she handles it
It’s definitely way too rich on the pilot and a little lean on the main
Any update to the jetting? Currently 68 pilot, leaner needle (NYEF-3), 158 main. Much better power over stock for me in Texas, 65degrees, less than 1000ft. About to put a Apex head with SX/XC dome. They recommend 48 pilot, richer needle (NYCF-3), 172 main. However HP development recommends the opposite basically, stating they got much better power with 70 pilot, NYDF-2, and 155-158 main and lost power with the JD or Apex jetting. I’m sure the Apex head with change things but I’ll be surprised it’s that much different.
@@tcoll1233 I now have a 60 pilot, 175 main and back to the oem needle in the #2 position for the colder temps. It looks like for me I’ll only have to swap needles for temp swings. My bike pulls hard and runs clean. Check out my channel.
@@tcoll1233 no updates on the jetting. The owner "Braden" has been just running it as is. I'm sure down the road when he's ready to change a pipe or head then I will be getting in her and jetting it but as of now it's stock. Which as you know is no the best jetting lol. I would expect Apex head to need leaner jetting than stock on the main due to the tighter squishband. There is a chance that my wife might be getting a 22 or 23 soon. If she does then I will digging in head first and dialing her in to a T. Fingers 🤞. Where you able to dial in a stronger mid range out of her yet?
Great video, thanks for sharing.
Can I ask how often you would change the forget piston? Assuming it was used for hard MX practise and racing.
Hello. Hard racing on a forged piston. I would say 10 to 20 hours on a 125. I would start with 15 hours. If it looks good maybe move it up to 20. If it looks worn then move it down to 10 hours.
I’m getting a new OEM cylinder for my 2007 yz125, would the standard 54mm pro lite piston work for it
Or should I wait for the cylinder to come in and measure the bore?
If its a new OEM cylinder then it will be ok to go ahead and order a stock size piston. It will fit perfectly!
And can't go wrong with the forged wiseco piston. Great piston
The amount of knowledge you have is quite noticeable with how quickly you ripped that thing apart lol.
Quick question: my buddy has a 2023 yz125. We were riding today and he dropped it in the water and now it feels like compression is down and it won't start. We pulled the plug, tipped it up to drain the exhaust and checked the air filter.
Do you think it needs a top end rebuild? Only has maybe 10 hours on it. What should we look for and what tests can we do to figure out what's wrong with it?
Hello. I would surely open the motor and at minimum clean the piston, ring, and crank area. A new piston would be best though as well. What happens is when they are flooded in water the water that goes through the air filter can bring dirt through the filter with it. You would think the filter oil would collect the dirt but when the filter is soak with water it doesn't catch the dirt. Most likely you have some dirt in the motor keep the ring from getting a good seal.
@@UpAllNight91 thanks for the reply! Will definitely try to get it apart this weekend!
@@flatbedder yes. The sooner the better. Because if any water is hanging out in the crank area it can rust the bearings.
Thanks!
Ahh thanks brother
Awesome way to warp the cylinder head! But good job bro..💪
Thanks!
I have the same bike and I have a similar issue I need to get my bike repaired would be possible to get in contact with you.
Hello. You can reach me at upallnight91@hotmail.com
Ur a badass mechanic dude all I can say
Still loving your videos! Hey I am curious to where you got the piston kit. Will the 21 piston work with it? I see on rev zilla they put them all together as there the same. Motorsport doesn’t have it and says 21 doesn’t fit. Any help you can give me would be great.
Hello. 21 is surely a different piston. I ordered the 2022 piston from rocky mountain ATV. You can also order directly from Wiseco on their web page
@@UpAllNight91 I didn’t see an order cart on wiseco page. I will try there. Thanks for the help mate!!!
@@UpAllNight91 got it on the way!!! Thanks so much bro! Got two of them coming!
@@brandonmitchell8846 Awesome right on! Great pistons! Did yall go pro light or racer elete?
@@UpAllNight91 the only choice was pro lite. The weird thing was buying the wrist pin bearing they only had 125x. What’s up with that. I got it anyway. I hope that’s ok. Kinda weird they sell a piston then not do the bearing huh? Let me know what you think on that. Thanks bro
Well i got 24ish hours on my 2023 yz125 and now im scared to ride it after seeing this… thanks for the video im definitely ordering a wiseco piston now. Im 195lbs and im not easy on it so im guessing im long overdue?
Oh yeah, 24 hours is about due for a broken piston on the YZ125 with a stock piston. Surely get a wiseco in there ASAP and all will be well!
@@UpAllNight91Hey man, I just put a new piston in my bike, but i did not really pay attention to the ring being completely aligned with that little groove. I did when installed the ring, I rode the bike up and down my street and did a little trail ride… What happens if the ring isnt aligned correctly and do you think im good if i rode it and nothing happened?
@@austinsilva5054 If the ring end gap is not aligned with the ring gap pin on the piston, the ring can snag a port and it will mess up the cylinder. That being said its really really hard, almost impossible to slide the cylinder down on the piston is the ring in not aligned on that pin. I think you will be ok if you didnt have to force the cylinder on however I like peace of mind so I would pull the cylinder off and check to be safe.
Any update to the jetting? Currently 68 pilot, leaner needle (NYEF-3), 158 main. Much better power over stock for me in Texas, 65degrees, less than 1000ft. About to put a Apex head with SX/XC dome. They recommend 48 pilot, richer needle (NYCF-3), 172 main. However HP development recommends the opposite basically, stating they got much better power with 70 pilot, NYDF-2, and 155-158 main and lost power with the JD or Apex jetting. I’m sure the Apex head with change things but I’ll be surprised it’s that much different.
Strange apex would recommend richer jetting. Usually a tighter squish enjoys leaner jetting, mainly in the main jet. I haven't had a chance to tune in the 202e, currently he's just running it stock and as you know stock on that bike surely leaves something to be desired. But there is a good chance my wife could end up with a 2023 here shortly and then I will be digging into that one and see what I can get out of her. Still trying to figure out why apex recommends richer on the main, unless they where getting pinging out of it with pump gas, only thing I can think of
@@UpAllNight91 not sure. Haven’t gotten a chance to ride. I did crank it and warm it up. New top end and the apex head, with the 48 pilot and 172 main and it seems crisp, much crisper off the crack of the throttle and doesn’t seem to load up as much. I will do a plug chop on the main and adjust from there. Matt did say the main is a little rich for safety and they will adjust more as they get feed back from around the country. I expect to end up around 168 main here in Texas at 300-900ft altitude but we will see. I asked a guy about his 2023 and he was running 50 pilot and 172 main also, standard needle, in the mountains of Arizona, like 6-9k altitude but said it’s cuz he’s wide open on flats all the time
@@tcoll1233 Yes I have always noticed the tighter squish on first startup and blipping. Surely crisper. Sound much more like a race bike. 168 sounds about right for that attitude and head. She should do good 👍
Crazy what you found in there! What mix were they running? I run 30:1 with motorex cross power 2t
I’m at 25 hours or so on my 22. Loving it! Unfortunately unable to ride because a torn cartilage in my knee. Thanks for the videos!
They are running 32:1. yamalube 2R. Bummer on the knee, hope you get healed up fast!
@@UpAllNight91 thank you I hope so too. Bum knees are no good!
Detonation u think beat the bearing out of it? That be my guess
The pits in the top of the piston will tell the tell. If they look like material dings or detonation
Back riding again and still mixing gas hauling ass 30 to one went back to Yama lube 2R and I had the bigger main jet in it was running rich but I went back to stock 160 and I haven’t tried messing with it going leaner because if it needs anything it’s a piston and rings. I’m at 39.3 hours. Does the air filter always being clean help prolong top end life?
In reference to you recommending wiseco pistons over the stock cast piston, do you also recommend the same for 4 strokes? Thanks in advance for the advice.
Hello. Most of the oem pistons on these modern 4 strokes are good. Brands like Yamaha have a special coating on the wrist pin that slows down the wear on the upper rod bear race. After market pistons like wiseco don't have wrist pins like this. For the most part I suggest OEM pistons for the 4 strokes.
@@UpAllNight91 thanks very much for the advice.
What is that "turbine " whining sonud the motor makes? mine makes the same. Some bikes make more, others less. /Tomas from Sweden.🙂
It's normal. I believe it's just the stator making power. Totally normal though and nothing to worry about. I actually think they sound cool when they make that sound lol
@@UpAllNight91 okej, thank you sir❤
Thanks for the awesome video. Can you kindly provide the part number for the Wiseco piston.
Yes, Wiseco 899M05400
I think the wrist pin bearing went which then caused the piston to break
Yeah, me too.
Can you show the WD40 flush?
The job is already done but the next one i get i will include that in the video for sure. Thanks!
Did you ever do a vid with a crank case flush. My lad's bike has done exact same as this on his 2023 yz 125 and want to know best way to flush crank case without taking the motor out. Did u tip the bike upside when flushing it? Thanks Stu
By any chance do you know the ring end gap. I’ve looked and can’t find it, I got a 23 125 but it should be the same. Thanks
Hello. Below I provided a link where you can download your service manual for free from yamaha. I'm about too put together a video on ring end gap but the jist of it is you should never have to file down a ring on a nickel plated cylinder. Notice in the manual it shows you how to check and if its out of spec to just replace it. Meaning they are only worried about the ring end gap being too large and not worried about it being too tight because they are pre cut perfectly from the factory for the cylinder. Here is the link to the manual download library.ymcapps.net/library/om/app/index.html?baseCode=6150&langId=02
@@UpAllNight91thanks
Yes Sir!
I have a 22 yz 125 with roughly 130ish hours on the stock piston and ring. I run 40:1 which is what probably helped with the longevity of the top end. But time has come too replace it before it does go boom. What piston size did you go for?
Hello. If replacing with a stock type piston I suggest using what size your cylinder is. Like if its a B use a B. I have a video on pistons maybe it can help. Here is a link ... ua-cam.com/video/sAeSBuNQILY/v-deo.html
Man I really don’t remember if my piston had exhaust holes did you have to drill those or the piston comes like that
They come with holes in them if its needed. I think the days of us having to drill our own holes are gone. Anymore all the pistons I see already have the holes in them for the bikes that require them
@@UpAllNight91perfect lol so that means mine is good especially on the 2022 Yeo thank you for mamiing this video cause I did everything you said to do on it and the rebuild came out beautiful my bike feel so much better
That's always good to hear! 👍
Not sure what the purpose of that coating really is, when I removed my reed cage I noticed the coating on mine was worn off after just 3 hours of run time. Maybe it helps with an easier break in?
I had to laugh when I noticed it, like "they seen me coming"
Yeah that coating on my YZ250 wears off the very bottom and top edge really fast. I read literature from wiseco and they claim its designed to wear where is needs to wear and stay where it needs to stay to help with noise. But I don't know. Guess it doesnt hurt anything being there, or not lol
Vi did break stock piston on my sons yz125 2022 at 22hrs.
It broke cylinder and head to.
Ouch, bummer
I’ve got a yz 125 01 just blown what’s the best piston for it?
I like wiseco pistons myself. Its forged and very strong. Also a hair lighter than OEM type pistons. And priced well.
What’s the best way to run the bike in after a new top end?
@@TheWhole36 I like to do 3 heat cycles. Running it on the stand till the radiators are nice and hot (but don't over heat it). Letting it cool down for 15 minutes between heat cycles. Check the coolant. Then first ride make it a shorter ride, about 8 minutes or do. Easy ride. Come back in check the coolant again. If alls good then shes good to rip into!
@@UpAllNight91 how long roughly for each heat cycle
@@TheWhole36 on a 125. About 5 good minutes each cycle is good.
Really enjoying your channel. Thanks for the content. I noticed in your build videos that you don’t bother with measuring ring gap. Is it important on these bikes? I use to not measure and never had a failure when doing it that way. Curious as to your thoughts on it.
I've heard you should measure gap after machining cylinder. He was just changing piston and there was no size change so I don't think it was necessary. But I'm curious to hear author's opinion on that as well!
I'm not a expert on cylinders and pistons so I could be wrong but from what I have gathered through the years is a cast iron sleeve being bored out needs to be bored to match the piston and the ring gap checked to insure alls well. When I send cast iron sleeve cylinders off to be bore the machine shop always request I also send the new piston with it so they can get it just right. However with nickle plated cylinders they are machine so well and accurately that they are the exact size that fits the piston and rings perfectly. One of the benefits to this that was really noticed when it first came out in like the late 80s was a racer no longer needed to do as much work to freshen up a top end, just remove the cylinder and drop in a new piston and rings. I think machining in general as gotten so much better these days. I remember when they would only sell engine cases as a set and it was advised to always use a matching set of cases. However these days they will now sell you just one case half and there is no need to worry about matching cases because the machining is so accurate that they are all cut out identical for the most part. I think the same applies to pistons and rings in these nickel plated cylinders. They have everything machined out pretty much perfect right out the box these days. I could be wrong, but I havent had any problems tossing rings in nickel plated cylinder, it always comes out ok and lives long (as long as all else is ok lol)
@@UpAllNight91 Thanks for your response and it explained things very well. I look forward to your next video!
Thanks!
Pro X pistons are good too right?
The pro x piston is very similar to the OEM piston. It is also a cast piston. Its good for a cast piston but a forged piston is still going to be the stronger choice.
So the bumper on my yz125 shock is damaged so I was thinking of buying a new bumper and fit it myself can I do this without nitrogen
It will need the nitrogen released to take the shock apart to replace the bumper. Which means you will need to fill it back up. Most your motorcycle shops will fill it with nitrogen for about 25 to 75 bucks (depending on how they want to charge). So you do all the work, and when done take it in to have it nitrogen charged. I had to do it like that for years before I was able to get my own charging equipment.
It’s a pain not having the tools for the job I’ve never done shocks before but not afraid of getting my hands dirty
Yeah I know. I collect tools as I can afford and need the best I can.
Hi and Happy Thanksgiving to you and your family! After repairing it, I would like to ask you why the engine sounds very strange? I think some of the mean bearings or conrod will blow soon. Take care!
Hello. That may be just how the camera picked it up. In person she sounds normal and the bike has had probably 10 to 15 hours put on her since the video and she's doing OK. Gotta just be howbthe camera picked up the sound. Happy Thanksgiving to you too! Hopefully you have a good weekend of riding ahead and thanks for watching and commenting!
Don't get a new head, send it to HP development, their cut heads are amazing, then Jet it...simple. It'll run better and you can get the cylinder ported aswell for the price of a new head, itll be a ripper...they did my lorettas bikes, a 125 and 250F with their 'national' package. I put 3500 into my 125 engine, it cracked 40hp in a 125. Thinking about boring it and put a longer connecting rod, which takes some case mods. They also have a deal with wiseco for their own pistons that allows for different porting than what the stock one will allow.
You didn't check ring gap...good way to seize an engine quick. I've had to file rings with that exact piston.
Hello. There is no need to file a ring end gap on a stock YZ125 cylinder with a stock or a wiseco piston. Sure it doesn't hurt to check but if using a wiseco be sure to use the ring end gap specs for the wiseco ring (not the OEM ring). I actually made a video covering this pretty well if you are interested. Here is a link ua-cam.com/video/5wdMNpgAAYo/v-deo.html . The head, we replaced with a stock head (its not my bike). I myself on my bikes have been using heads rechambered for race fuel for years now. I usually cut my own heads so I can tune there right to where I want them. But I agree, the head mod is surely the best bang for the buck
Did you split the cases and get all the aluminum out of the crank
No. I opted to just a good flushing and blowing out.
How much did your YZ 125 for?
Hello. This is not one of my own bikes. Its a friends bike, he bought it new from a dealership. Not sure what he paid for it.
same happened to me after testing like 12mth
Bummer. Hopefully you replaced it with a forged piston. Keeps that from happening again
What's up with the gloves?
Saves my hands. Don't have to wash between jobs either. Just swap gloves and move along
30+ hours on the stock piston is just asking for trouble. Looking at the wear on the pipe, that bike has 30+ hours atleast.
For sure 30 hours is too much. Yeah that pipe wear is odd. But truly doesnt have more that 30 to 40 hours, so he must just be riding it funny to be wearing that pipe that quickly. We put a hour meter on it at around 10 to 20 hours use and the meter now reads 20 hours. For me the best part of the wiseco piston (or any forged piston) is that they are not known to break easy, even if ran way to long. I have seen compression drop to near zero from running a wiseco too long but its still in one piece
@@UpAllNight91 Yamaha must have cheaped out on the paint for the new pipes. My 2009 yz 125 with the stock pipe had almost no wear after 250+ hours. My 2022 yz 125 looks almost like the one in the video with just 20.
I know, that paint doesn't hold up on the 22 for sure.
95% sure somebody didn't break that bike in and just started ripping it. 0 oil in the power valve and on the head. Gotta ride a fresh bike lightly for about 5 hours or else this happens
The OEM piston is the achilles heel of Yamaha 2 strokes. I see guys replacing top ends with OEM pistons and I just cringe. Nothing worse than blowing up your new bike after 20-30 hrs. I've used Vertex but you prefer WiseCo Chris?
Yeah the OEM piston just doesnt hold up well.. I like the wiseco. Been using them for like 25 years. Does vertex make a forged piston for the YZ's?
There's no way you know there's no metal in that bottom end . Take that risk with your own bike but not someone elses. Pray 🙏 well said
Not sure what your asking but this bike has over 100 hours on it since this video and alls been well.
@@UpAllNight91 splitting the case and going into the guts of it wasn't necessary this time, in your experience how easy is it for broken pieces of top end to find there way into the bottom end.
@@aaronbligh3619 it happens. And sometimes there is no other option but to split the motor and clean it out. Sometimes they get logged down in the bottom. I try to just keep this from happening in the first place by using forged pistons.
@@UpAllNight91 excellent I understand now, 05 -19 are the same bike and have your approval. I love yz 125 . I'm 42 and still have the most fun on this bike. Just out of curiosity what's your thoughts on the 2000 model yz 125. Sorry I know your busy. Appreciate you taking the time.
@@aaronbligh3619 the 2000 is the same as the 2017 to 2021 in every way. From brake rotor size, to suspension, to engine. I think the 2017 to 2021 is the best of the 2005 to 2021 yz125's. I still own a 2021 and its a amazing bike. Its still competitive with the 2022 and newer YZ125. You have a great bike, A underrated bike in my opinion. I actually did a review comparing the 2021 to the 2023 if your interested its in my video listing
Nice 💣
👍😆
You don’t measure squish ???
Geez I should have. I will when the new head comes in from backorder
Vertex is also cast
Yes the standard vertex is cast. But they do make some forged pistons for some models. You gotta look hard for them but they are on their web site I think. I had to install them in a racers KTM 125 that would only run vertex lol
Full strip down , no way would i risk bottom end damage, your behind with work that's unfortunate but you can't cut corners bro
Dude... cover that hole up with a rag while you take that top end off....
bearing broke the piston
That was my first thought too. But I have seen so many of these OEM pistons break that its hard to say
As much money you pay for them bikes they should not be like that should be better quality
Yeah. I think its kinda a balancing act. The stock piston being cast is better for people who don't warm a motor up at all. The forged pistons need to be warmed up. So I think they are trying to choose the path of least failures with the average buyer. Average being doesn't know much or have much experience and will start it up and run it hard before it even warms up
Hey I know that bike... Thats Vigina Boys bike.
Yup v boy
I would not buy wiseco there junk namura is what i use really good only 50 bucks cheaper better il never use wiseco mine broke 16 hours never ever again
I only broke one wiseco ever, it was in 1999 on the 89 CR125 that was the wrong size for the cylinder.
@@UpAllNight91 Okay how are the namura pistons ? Ur thoughts
@@michaelgarland579They work for the price but they are are cheap and not very strong.
@@UpAllNight91 ok im look into a different piston then I need a strong one cause I ride in this guy's property it's big an I keep bike wide open in all gears run bike hard I think that's how I melted wisco piston ring I want say I'm flying threw this field an deer are everywhere I all most hit one came out nowhere then me an my dog basset hound were chasing them I got get bike out shop I miss these times I called shop they think it's o ring in carb I don't think it's that cause I put same kind brand new bike did same thing I told them I dropped off new carb they can take parts off it I just want my bike back
@@michaelgarland579Right. Mikuni carb? They have a rubber seal that does go out.