Seller Scammed Me On This Rare 2-Stroke Dirt Bike (First Ride)
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- Опубліковано 2 лип 2024
- I rebuild a 1982 Yamaha yz125 dirt bike and take it for the first ride. #Yamaha, #DirtBike, #Fix,
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Several previous commenters have touched on the likely issue(s). The bore is way oversize from stock. The port edges originally are chamfered to prevent catching the ring. Likely when it was bored (or honed, see below) the chamfer was eliminated and not recreated. Also ports can only get so wide before the ring falls into them no matter what you do - that's why at a certain point an exhaust bridge is implemented. The ports in this cylinder have likely widened due to the degree of overbore, making the chamfer situation worse.
It is likely the cylinder is out of round and may also have straightness issues, especially if most of the oversize was created with a hone rather than boring bar. The amount of material a hone removes is affected by the amount of cylinder wall it contacts - so the bore will grow in areas of the cylinder that have a lot of port area, and thus less wall area, hurting straightness even if it is still round. I've not seen this wear the rings funny, but it sure will place an upper bound on compression and therefore power.
It is also possible the power valve is contacting the ring, but I think you'd have ugly scars on the piston if that was the case.
Overall you've been pretty lucky to this point in not evaluating cylinder straightness and the crosshatch and roughness your honing technique produces. I'd recommend picking up a dial-bore gage so you can measure precisely and slowing your drill way down when you hone to achieve a more optimal crosshatch angle. It's also non-trivial to create the proper roughness with a hand hone, even a Sunnen portable one, much less brake-cylinder hone types. Luck only goes so far.
You can also get a better feel for roundness and straightness with a telescoping gage and appropriately-sized outside micrometer, but you can probably pick up a used dial-bore gage of adequate quality about as cheaply as a good set of snap gages and outside micrometers. Dial-bore gauge is the way to go, it's much quicker and more precise.
This all comes from a guy with a lot of 2-stroke engine building experience, including a lot of cylinder measuring and honing.
I M GUESSING IT NEEDS ANOTHER DIFFERENT CYLINDER AND NEW PISTON AND RING.
@@shartne A new cylinder is probably going to be cheaper than re-sleeving this one. But by the time you buy a new piston too, it might be close. Definitely need a new ring. This sort of calculus depends on if you have a quality machine shop nearby that charges reasonable rates. But I agree a fresher cylinder with matching piston and ring is a more straightforward fix than remedying this one's ills. By the time you get to 3mm over you are in sketchy territory.
This guy hones!
Time to step up your game, get the bore guage and do the measurements and practices as he described. Win!
Yup I've been saying this all along. He's been putting new pistons in out of round cylinders for years now
Not sure what a snap gage is but checking for roundness and taper of the cylinder bore is standard practice in automotive. If this cylinder was honed oversize by hand its hard to imagine it can be round and free of taper. The other thing Joe does is check ring gap in one location and assume it is the same up and down the cylinder, bad assumption. Still low compression doesn't explain all the symptoms Joe talked about so I am waiting to see final solution.
Bottom line if you want to be a good engine builder you need micrometers and the ability to measure accurately at 10,000 th of an inch. Both piston and cylinder need to be checked in multiple locations to find problems and confirm piston size matches the bore size.
At this stage your patience is the stuff legends are made. Well done
he's a great example for young people his age
Seller watching this just laughing
I am shocked at how much patience he has had with motors lol.
@@user-sg5ws7zw5h definitely, me and my room mates started to do this stuff after watching his videos
The youtube revenue helps with that immensely
I would put my money on the fact that when you honed the cylinder you didn't chamfer the ports when you hone a cylinder you're essentially making the edge of the port sharp you need to take a Dremel and round that edge so that when the ring slides by it's not like a razor going past the ring all the time it's a nice smooth transition that's I would say 95% sure that's what caused it these older bikes are a little less forgiving if everything's not right they'll start breaking down quick
LISTEN TO THIS GUY!
The unintentional razor's edge is shaving the piston ring. Excellent hypothesis.
That was my first thought. Only thing that could shave down that ring that fast
I thought as long as the port width rule was followed and the rings are pinned then it didnt matter and shouldn't be a problem?
Could not have said it better myself. That was my train of thought as well.
Bore gauge to check roundness in cylinder and check power valve for any signs of contact. The only things I can think of.
A bore gauge is pretty expensive. You can use just normal Mics, and telescoping gauges to do the same thing. Bore gauges are better for production though, (and probably a tiny bit more accurate if both are used properly), as they are faster, and take less skill to use. Neither are used to check the power valve. But you have 36 likes anyway. That is how sharp the new generation is. You did not have a machine shop in your HS like I did though, (and a life long machinist here because of that HS shop), as they were pulled out of our HS after 1981, when our federal government gave our free enterprise to communism in china. You see how we were ripped off?
The big difference between a telescoping gauge and a bore gauge is telescoping gauges to not give you numbers, so you measure them after you sweep the bore, and measure them with the OD mics. The bore gauge gives you a direct reading, where a telescoping gauge is called a "comparison gauge". That is what may give the bore gauge a bit more accuracy. But if both are used properly, only by about +or- .0001"
Dont come on here rambling on and belittling the younger generation for trying new things and learning to work on their own bikes you weird old man! Get outta here go have a nap. Ffs@EarthSurferUSA
@@EarthSurferUSAThe commenter recommends a powervalve check as an additional suggestion, its not linked to the bore gauge measuring/cyl ovality.
@EarthSurferUSA Still doesn't service manual specify allowable out of round, taper and piston to bore clearance? I don't know of any high schools with an automotive machine shop, not too many community colleges either. I went to Ferris State College in Michigan where they offered a certificate program in Automotive Machine. There were not many places offering anything similar. So if your high school offered that, I am jealous.
I agree it is a mistake for schools to not offer shop classes but that is your local school board not federal government. My opinion, we need to get apprentice programs established to teach trades like plumbing, electrical, auto repair, etc. These are good paying jobs, people in short supply. You shouldn't have to go to college to get these skills.
Thank you youtube at least diy folks can watch a video.
I have a 1982 Yz250, its been in the garage for several years because i cannot find parts for it. 82's were one year only and didn't share many parts with the 83s or 81s. Good job Joe your patience paid off.
Go back and look at the sequence where you drained some fuel into the clear container. There appears to be no mix in the gas.
That’s the same thing I noticed
After seeing him drain that, I immediately was like, "yeah, it's clean fuel with no oil mix."
Ya I thought the same thing it looked like straight gas he may have grabbed the wrong can ?
"look how big that gap is" ..... I've said that once or twice in my life. LOL
Is it in ?
Like throwing a hotdog down a hallway
Big is subjective.
Oh, you're a welder?!🤣
@@christopherprisco8690 1/4" 7018 ain't fillin those gaps. lol
This the junkyard special Yamaha you can see these everywhere with so much potential
Badass bike man! I've been watching you for years now youve taught me so much and I now have my own small business at 16!
Good for you. I love private business and it is a thrill to build one IMO. But, if this guy is all you learn from,---buy books. I see stuff he does wrong (he cuts corners) in any of his vids. You and this kid are at a disadvantage though. Before we sent our free enterprise to communism in china starting in the early 80's, we had machine shops in our High Schools, and replaced with arts and crafts or gender studies. I learned a lot more after HS in colleges. I hope to bring machining back to a school in our area and teach it, and entice kids to start their own business also, (after they get some experience). The last thing you want to do for your business,--is do shoddy work. It will bite you and may put you out of business, Good work will allow you to grow much better. You can do what this cat does not, and find a shop manual for the bike on line, so you can know what you are doing. Good luck man. I am excited for you. I enjoy the freedom of my own business also. I Port/stroke little 2-stroke engines for a living now, and made more money than I could with 2 engineering degrees and employed by somebody. But I do the best retail work in the world with a great distributor (sends me new stuff to modify, and he sells them all over the world.), and that made me the most popular in the world. I get new customers from a competitor, who does shoddy work, all the time. My customers never go to him. Enjoy your business, and getting great at it. It makes all the difference in the world. Doug in Michigan.
PS: What does JOB stand for? "Just Over Broke". :)
Interesting pfp
Stolen comment bot 🤡 Stolen from a kid, no less.
Really? you have your own business? On onlyfans? That's your business? Get lost bot!
I know you want to keep the cost down, but I noticed it on a couple of videos now
Normally if you change to a new sprocket you should do the front and back and a new chain.
Now you run a worn and stretched chain on the new back sprocket which will ruin the new sprocket a lot faster.
But again I understand you want the cost down.❤
I agree u are 100 percent right I just did mine on yz125 2003 I bought steel sprokets on ebay for 34 bucks for both an bought new chain at bike store 74 bucks so
sprocket wont last a month change all or none!!!!
An old chain on a new sprocket is the least of his worries right now pin head .
This dude drains gas from one bike to the next. He’s broke af🤷♂️
@@DirtDiggerDanHere whats his worries than no it all
Joe I love your videos I am an Australian who has been building and riding bikes for nearly 50 years. Two respectful requests, because I love watching what you do my friend. One never, ever, ever use a shifter, when you can use a socket, or spanner. Two never, ever use multi grips to remove a spark plug, see rule one. Rule three! Three never trust a seller Joe. You have great skills, love watching your videos. Your Aussie fan Skippy!
Dude, you are an experienced bike mechanic! Why are you making rookie mistakes. Clean the darn brakes before replacing. ALWAYS check the cylinder bore roundness, especially when you can't trust the seller! You're letting me down, I love the channel.
Doesn't need to he just looks at it and knows if its ok lol
pro's measure amateurs guess.
Don’t drink before you comment just saying, it’s never good, if you’re hooked on the the stupid brakes that he actually fixed and you’re being stupid about it then it’s all on
You my brain has 29 psi 38:03
Don’t drink before you comment just saying, it’s never good, if you’re hooked on the the stupid brakes that he actually fixed and you’re being stupid about it then it’s all on
You my brain has 29 psi
like he cares about what some asshole on the internet thinks
@danielbrinkman8069 Asshole? I am not. He makes a living from UA-cam. People look to vids like this for education and they should be correct. This guy cuts corners that should be exposed for rookies.
My man. You need to start and measure the bores. Get you a good mic and inside snap gauge to get a pretty good reading. And if you can afford it get a dial bore gauge with the mic. Once set to the dimension you need. You can use it to determine out of round , taper in the bore.
He doesn't check bore size or wear with a micrometer , over 90 thousands ring gap looks like it's either really wore out or maybe .5mm over size be my guess it's the later of the two if it has been bored an the power valve is for a stock cylinder it could be hitting the piston
As much as he does this stuff you would think he'd learn instead of making the same mistakes on stroke cylinders all the time, sometimes he throws a bunch of used eBay parts together an says everything's just perfect bite's him in the ass every once in a while lol
@@lawerncemiller6557look at his inventory. He can’t sell anything he’s touched 🤷♂️
@lawerncemiller6557 Lately, he's had §|-|¡Ť luck. It seems like everything he tries to fix these days goes completely to hell. The tranny in the QuadRacer, the nasty bog on the 1995 CR 250 (still a mystery) nothing seems to be going his way.
He's a shade tree mechanic without the tree, don't expect precision, cleanliness, or proper tools. He is entertaining however and makes em run eventually. For how long, well, that's another story =)
I had one of those back in 94 and boy did it suck, mine run pretty much just as bad as yours.. was bad crank seals and someone’s "creative" welding of the crankshaft that was the big problem on mine. Sold it and bought a CR 93 instead. :)
You riding that thing triggered my memories of it.. It would run "ok” for a while until it warmed up and then boouhhh boouuuhh bööööuooohhh, young as I was I would clean the carburettor because I thought it was the culprit and every time when I put it back together it would run ok again... until it warmed up and I would repeat the process. haha
I had one as well, my friends call it the curse
I would inspect the power valve for contact abrasion from ring. Also, you might check cylinder squareness with a good straight edge.
I had a yz 80, same year, bored 20 over - that was an angry bike, whipping around sand pits as a teenager was a dream.
Bore could be out of round and you may need to chamfer the ports! Definitely invest in a bore gage!
Every time i watch a video of Joes. I learn so much. Even though he thought he knew what the problem was. He still went down the checklist checking possible but unlikely causes and ultimately narrows it down to only being a couple possible culprits. Joes never to cocky to assume he knows the problem.
DUDE YES! I've been waiting for this for months!!! I know you were let down about the state of the bike back when you got it, but I guess we got the parts we needed and now she's gonna RIIIIIP around the field!!!
Many people today have no moral compass and therefore are liars, cheats and thieves NOT scammers (too nice a word).
Do NOT trust what people say, instead, CHECK OUT THE CAR, TRUCK, MOTORCYCLE, ATV etc. BEFORE BUYING!!!
The old adage of BUYER BEWARE is paramount in today's world.
GREAT CHANNEL!!!! (My take on what's wrong......bad metallurgy in the ring, Chinese junk?)
but then he can't make these great videos on how to fix all the things wrong with it, and also make mad youtube revenue
You just described every democrat in history 😂, thank you!
@@machinesnmetal Very true!
@@christopherquarry6234 Yes, I did and you're welcome.....lol
With your skills and knowledge you need to develop a ten point system to evaluate every new purchase. If the seller won't allow the inspection, just assume there scammers
No such thing as a scam when you buy a bike that doesn't run, it's just risky business...
Then he wouldn’t have millions of views. 🤷♂️
Brilliant as always, i never miss a new video 👍🏻👍🏻👍🏻👍🏻🇬🇧
@ 3:55 You are suppose to use a pin, that is put in that little fork at the end, and into a matching hole in the cylinder casting,--to hold that power valve actuator in place while you tighten the nut. Since you did not do that, the power valve is not "clocked" correctly. I thought you knew what you were doing?,---for all of us to see. lol
I noticed that also.
Yeah, I thought that fork end was meant for something.
Absolutely correct sir!
Once you lock it that sets your base adjustment
i dont know why a person would just assume and throw it together like he did.. was driving me crazy
thanks to your devotion there are a good number of vintage bikes running around that would have ended up in the junkyard or sitting on the side of someones house until they where worthless. good job! and i know the feeling of rebuilding a bike only for it to shit its internals out into the oil pan shitty feeling but i know youll get it.
If cylinder is over bored... Yes stock pv will be an issue. You need to check cylinder for egg shaped
Jeez, talk about not giving up. BRAVO for your patience and knowledge, in that order
I think it is the edges of the ports cutting the ring.
Makes sense. Need a chamfer on them to prevent this.
A ton of great info in these comments Joe!! My suggestion is the next level of your engine building.. incorporate a leakdown test. Pressuring the engine and leave it for a period of time.. lose pressure obviously there is a leak! Enjoy all your content brother! 💪
I doubt you will see this comment but your videos have helped me so much with learning about bikes. I have a job repairing bikes now thanks to you.
I had same thing happen to a new to me Banshee. After tearing apart I figured it was combo of cheap rebuild and the wrist pins on both pistons was very very tight. Good luck.
Check the edges of the ports. Some uncertain cylinders become sharpened and can catch the ring. I’ve taken a Dremel very carefully with a sanding bit to work it smooth.
Get some ID telescoping gauges and check the cylinder for out of round and straightness. Great channel!
Bro , What a collection of bikes you have.
I have two honda ATC'S , and a xr200 but your videos of two strokes make me want to buy another project.
Good videos , watching from New Zealand.
Well done after all the hard work.
I bought a 2 year old 1982 YZ250 in 84 for $850.00, (the first used bike I ever bought as a kid making $1.00/hr part time.), and was making $4.00/hr when I bought this bike, and $4.00/hr when I bought a new 1986 YZ250 in 86 for $2,300, and a new mini truck for 7 grand with a payment plan, (first time for a car, and bike, I think). The evil FIM 1986 production rule, (Yes, it was the FIM, not the AMA as taught. The FIM stopped factory bike development in the USA,--because we won the MXofN 5 times in a row by then,--and still won it for another 8 on production based bikes. Yamaha was the manufacture spear head for that rule, saying they could not afford to make works bikes. But they still make them for Europe today, along with the rest of the factories), tripled the cost of a bike in about 5 years. The 4-stroke forced on the industry by a dictatorship called the EPA has almost tripled the cost again.
when you bore a cylinder,you should grind the valve too,sorry for my english,i,m a frenchie from the north of quebec,,you doing alway,s agreat job
It is a two stroke engine, it has reed valves, but you definitely don't grind them
@@quakermaasDoesn't this one have an unusual valve system instead of reed valves, & that is a reason, that this bike is special?
I believe he was talking about the power valve being to close to the piston if the cylinder has been bored over
@@andyjidas you have understand me very well,i do the same on my 2 stroque sea doo engine few year ago
@@andyjidas Aaaah my bad, I understand now and completely agree. I was actually thinking the power valve could be clipping the rings, I just didn't put two and two together.
Happy Days Joe Has Posted 🔥🔥🔥
10:15 You’re supposed to do the initial loosen from the back, not turn the countersunk head first. Also on assembly it’s a good idea to put blue lock tite on both the threads and the countersunk head tapered surface.
Probably why the power valves weren’t hooked up properly when you bought it, I’d say the rings hitting them are the problem
this guy will make it work again i remember seeing this type of bike as a kid always wanted one but life goes on
I had this bike, got it with no engine. It was sent to a shop to be rebuilt and the engine disappeared. I ended up cobbling a 73 LT100 engine in it and it worked out okay. Not nearly as fast or powerful as it was but it was still fun to ride. The biggest challenge was switching the sprocket to the other side, motor mounts were pretty easy. I have a UA-cam of it posted if you want to search for it.
The ring could wear down like that if the ports are not chamfered correctly or as you said it hits the power valve. Also you should check that the ring sits all the way in the piston or it sticks out.
Joe, lots of good suggestions, you should also always check for bore "taper", check the ring gap at the top of the stroke, in the middle, and at the bottom of the stroke, a cylinder can look great with no scratches, but be worn out of spec in roundness, or taper...Rich in Sacramento
I raced KT100 Yamaha karts for 8 years and did all my own work. Snap gauges, sunnen hone to produce round honing results were a must have. I never had a problem with even very large over bores, although the KT has a port bridge. I'd definitely check the port chamfers. Agree with others that power valve would show marks on the piston.
Great content - can't wait to see the solution.
You can definitely run into problems with this combination. We used a Sunnen portable hone on so many KT100s I can't count. While it is true it will produce a round bore, the size of that bore eventually is not constant over the length of the cylinder. Lower in the cylinder where there are ports the hone will remove more material and the cylinder is no longer straight. It's a lot easier to see this with a dial-bore gage, consistency over enough measurements to reveal it is always a challenge with a snap gage.
We had motors on 52.10-52.15 mm pistons with .003-.0035" clearance above the exhaust port exhibit ring seal problems that we sent to Mark Dismore at CKS to bore them to restore straightness. They had to go out to 52.40-52.50 mm to get them straight top to bottom, essentially ending their stock-class lives as the biggest Yamaha piston was 52.35 and the Wiseco and Burris pistons (which were made in larger sizes) were junk.
Stand-up Sunnen honing machines were better in this regard as the stones are longer and you have better control moving the cylinder rather than the hone, but you still need to bore as much as possible and hone just enough to finish and crosshatch the bore properly to maximize compression and power. Nothing ran as well as a new cylinder at their original 51.97, .98 or .99 mm sizes as they were the straightest.
We built open KT100s with 55+ mm bores, which you definitely wanted done with a boring bar. That's how I know what happens at 3mm over - the port area, timing and angles all changed just from the boring operation. Of course these were then fully ported for this application, but they changed quite a bit just from the bore.
We also built multitudes of Briggs and Strattons, along with controlled stock and Unlimited reed and rotary valve Komet, Parilla, KTM, DAP, Atomic and Atlas engines. Of all these the KT100 was the most efficient and cost-effective, and to my mind one of the best engine designs of all time - debuting in 1972 and still in use to this day.
We still have the Sunnen portable hone - along with a basement full of trophies and plaques from tracks and series all across the nation.
Great answer. Sounds like you have deep experience - I'm assuming you are in the Midwest with the Dismore CKS comment. I ran in CA and had good relationships with PKS and HRE. I ran at the same tracks at the same time as Scott Pruett, Ronnie Emmick, the Hartmans and the Arakis in both sprint karts and Road Race karts. If the IKF had left well enough alone and not allowed the Italian PP engines in, I would have raced far longer.
@@rcodepaul I raced with thousands of people, but Ron Emmick was the best. I still remember his absolutely dominant runs at the '85 IKF Grandnationals at Adams Raceway in Riverside. He won at least 2 classes that weekend with the then-new Elite chassis, DAP power, Goodyear tires and a precision I never saw before or since.
We started in the southeast running 4-cycles on dirt in the early '80s, moved to the Phoenix AZ area, then SoCal, and eventually back east. We ran club and local dirt and roadcourse stuff, the IKF Region 7 series, and the WKA B&S Dirt National series for years, along with any money races we could find. We built engines for ourselves and always for a large number of other racers to fund our efforts.
Our Yamahas were good enough that we ran them successfully against the Italian PP stuff. I was a pretty big guy back then and used to overcoming power/weight ratio disadvantage. I just had to slim down some and get closer to the weight limit to continue winning once the DAP, TKM and Komet PP products debuted. We also ran open-modified Briggs and a lot of controlled-stock stuff, with first Komet K55s and K78's, and later DAP TA80R, TT-75 Parilla, and the awesome Atomic PCR93 reed.
We later had absolutely incredible Unlimited rotary valve engines - a trick Komet K299 B-bomb with a K30 cylinder Dismore helped us build and a KTM 135. The B-bomb was just amazing - its 50+ horsepower made the 365lb kart and driver package as fast as a sprint car and a real challenge to hook up on dirt.
I retired after 20 seasons and am at this point an old man - but will never forget the crucible that is racing and the glory I enjoyed on my best days, beating all comers on national stages. Nothing teaches confidence like racing, and I would have become much less without that and its myriad of other lessons.
@@user-ln7mk3yl4n Totally agree on Ronnie Emmick. I don't know what happened when he went to Europe to race - maybe that's when his dad fell ill? I don't know but I think he had the gift and could have been our Max Verstappen. Dreams dashed for sure. My brother just sent me a video of Ronnie driving a dual kart at Bakersfield, so I'm glad he's still kicking. I'm assuming he is participating in the vintage kart stuff. Your quote that you "will never forget the crucible that is racing and the glory I enjoyed on my best days". That really sums it up. We designed our own roadracing chassis and it was fast. It was a mashup of a Hartman and an Emmick. It had Emmick RR spindles but an enclosed axle like a Hartman. We put a very narrow porch on it for aero, made the whole kart as narrow as the rules allowed, pushed the driver forward for almost completely neutral handling. I won the 1985 Winternationals at Willow Springs in the PVAL class by a huge margin, lapped half the field. Then threw on weight and nearly won Expert against Tommy Nields, Kel McIntee and others. I placed 4th with a broken slippy pipe cable. Coulda woulda double win in one day. I ran in NorCal and SoCal including Infineon/Sears Point, Laguna Seca, Riverside (before it closed) Willow Springs. Then I broke everything I owned at the 85 Grandnationals, then the rule change and I left the sport. I'm long separated, but still miss it all the time.
@@rcodepaul I never got the chance to run any laydown stuff, but did attend an enduro race at Firebird International in the Phoenix area in the mid-80's. The superkarts were awe-inspiring and the speeds KT100s produced on the front stretch, which was most of the 1/4 mile dragstrip, were very impressive. I got to witness a lot of slippy-pipe chaos, so I can appreciate your plight.
Your remarks on the design of your laydown chassis are interesting. We built our first sprint chassis and in that timeframe (1980) tires were still fairly hard and narrow designs with a substantially rearward weight-bias were still common. But by the mid-80s tires got very sticky and frame and track widths increased substantially, with the weight bias moved forward as much as possible to create front bite to prevent understeer. The Emmick Elite was a prime example of this trend. I guess the aerodynamic imperative of enduro racing made a narrow design still advantageous, where we were already running 44-46" rear track widths on sprint karts for asphalt racing. The sanctioning bodies soon had limit this to 50".
We moved back east and were back on dirt by the late 80s, first running our last Invader roadrace kart and then a custom Invader Gary Nelson built for us with narrower rear frame rails for the dirt application. Offset designs started to dominate dirt races and we were soon furnished several by a friend who built them nearby and wanted to promote them. We were able to win WKA Dirt Nationals events for him and were one race from winning the Yamaha series title in '97 before getting taken out in the first turn of the final race that year.
Even though it's been 24 years since my last race I also miss it dearly. I still vividly recall most of the many tracks I raced and drive them in my mind and dreams. Racing does more than leave a mark on its devotees, it shapes them through highs and lows we never knew existed - and will never forget.
Patience you have, so many "expert" comments..add my 2 cents, powerbelt needs to be ground down, rubbed against piston rings. Cylinder could be egg shape..both items you suspect. Why would the power valve bracket have an unused notch on end? Something not right with it. Enjoy your videos, needed these 40 years ago when my atv's and dirt bikes broke. Had dealer repair them.
Notch is there to make an adjustment usually you put a 3mm drill bit through the notch and into the cylinder thats sets the base point then you take the slack out
Thanks for info@@elodmihaly6665
How does this guy not have sponsors? Great content!
I used to own that exact bike, power valve has to be adjusted correctly. That locknut needs to be lose, and the arm has a pin that fits in cylinder for correct spot. If I find a link I will send it to you. And yes coolant always leaks. I had a custom radiator made by Fontana Radiator. Once you get it running better , it has a lot of topend low end sucks.
The price of good drama, and content
My friend has one of these, it took him months trying to get a seal for the coolant, where the radiator is mounted behind the front number panel, and was very expensive too
Wow ,that's a shame I was hoping to see that classic running.
Great video
You need a legit set of internal bore calipers to measure cylinders from multiple spots to get an idea of its true shape. Just because it measures well with vernier calipers from a few spots and doesn’t have any bad scratches, doesn’t mean it’s good.
Joe, if you got a new Wiseco piston it will show a tolerance to the powervalve in the instructions for you to measure and trim off powervalve if necessary. I also saw many comments about port chamfers which should also be checked.
Wow I'm a big fan you always get too the bottom of or the problem great looking at you're videos bro I'm learning from you alot
You need to invest into a cylinder leak down tester. Great for testing cylinder leakage and also for crankcase leakage. I use one when building chainsaws. Valuable tool, believe me.
Brings back bad memories of my 1982 YZ250 crapping out on me right off the starting line. I was pissed. I sold it after that. And yes, the design that has coolant flow through the frame stem is a terrible idea. In the case of my bike, the engine crapping out was due to a bad porting job done my yours truly. Back in the day, you could get port modification suggestions directly from your Yamaha dealer. I took that info, did it myself and opened up the ports enough that the piston ring broke. In original congfiguration, the bike had two rings. The Yamaha mods suggested using only one ring, which my port mods damaged.
Could the cylinder be out of round?
Everyone talks about Joe putting new pistons in egg shaped cylinders but other than that he is one hell of a diagnostics bike mechanic. Hes a smart dude if i was him i would buy a bore mechine and learn that craft since he builds tons of bikes a year
No doubt he's an experienced and capable mechanic. His electrical diagnosis are first-rate. But real machine work, and even the understanding of when it's required, comes at a much higher cost in dollars and time. Good enough equipment to properly bore and hone cylinders is very pricy, and there's a big learning curve in using it. While that would be great to have considering the volume of work Joe does you really need to understand when the cure is to find somebody who already has that equipment and experience and recognize when sending stuff out if needed.
As another poster mentioned, another cylinder is really the way to go in this case, assuming any are available at a reasonable price. But however you fix this I think you end up with a pretty pricey '82 YZ125.
I seen it to Joe. Add in 2 ounces of ATF transmission fluid to you fuel mixture it'll clean and clear out the clogged up baffle silencer.,an screen inside of the entire exhaust system that way to for yah on it. Run the whole tank of fuel out riding it then just add in fresh mixed fuel to it again and ride some more.
A little sanding with p36 on the drum makes braking much better. Enjoy your work. Thx
If the cylinder has been bored maybe the piston is flopping around or could be hitting that power valve but the power valve only goes in a certain way I'd say something with the cylinder bore
When I was 15 I had an 82 yz 125 only it was white and red, I loved that bike 🍻
Ring may be catching the ports or your bores out of round . Try measuring top ,middle an bottem in ypur bore..or your crank could be coming apart ..good luck
He must be part Native American...he was staring at the Exhaust Smoke Signals alot!! 😂
🇨🇦🤓🤟
That sucks Joe smh. Through your struggles, we learn haha. THANKS!
When you took the head and barrel off did you not notice all of the water mixed with the oil mix? the crank was a big clue. Before reassembling I noticed that you didn't clean and level the head and barrel surfaces and the grooves for the rubber seals need a really good clean out, there is no way to get a good seal left like that. Chain, I agree with others, either change all or change none, not just the rear sprocket. Another thing is that the rear wheel brake has got a big chunk broke from the brake liner which can cause your rear wheel to lock up if the brake shoe's catch, needs hub replacing, and why clean the inner brake surfaces, to get the rust out, LOL, and not clean the brake plate before fitting new shoe's. All good entertainment as always, Thanks for making me smile. Buy the way, when a bike is not running properly, please don't try thrashing it hoping it will get better, it wont, it will get worst.
I’m wondering if you run the three stone hone down the barrel lightly and articulate the power valve to see if there’s any contact marks. It will also show you high spots on the cylinder.
The comments on 2Vintage are priceless. Very good information, sometimes not relevant to the situation, but... still a lot of old heads in here teaching good stuff.
I don’t buy used junk anymore only new dirt bikes I’m to old for that stuff,😂😂😂😂
@@kevinbushey1879 Nice, got any bikes you want to get rid of? I have the old part down, just not the 8-12 grand each year for a new bike.
yep. many good trains of thought in comments. Definitely look into the linkage on power valve. it appears that the u shaped end is in correctly assembled and conflicts with cover. gasoline looked without oil. not sure if you chamfered the ports correctly. probably not the issue as you have great skills. Definitely the oversize and maybe a correction the valve blade. this bike is going to make you stronger. all in all great diagnosis. all the best from the west.
2vintage - They should put Your "1982 Yamaha yz125 dirt bike" video series, on Wikipedia as an example of "Murphy's Law In Effect". Big Thumbs Up.
Glad you moved the chain to on top of the roller.
My favorites are where you just get boxes of random parts along with the project vehicle 😀
The ring cutting is from the ports not being chamfered. I have a core top end if you want it. Cylinder and PV parts. Yours for the cost of shipping.
I would identify the narrow areas on the ring and mark them with a flow pen then put the ring back in the cylinder, and clock the ring gap according to the locating pin on the piston. That should give you an idea what feature in the cylinder is chewing at that ring, or get a new ring, put it in the bore, and check with a light for any gaps which would mean the bore is out of round.
My all-time favorite motorcycle. Sorry to hear you got scammed.
incorrect bore job maybe allowing pv to hit. place a straight edge vertical in cylinder see if pv scraps it?
If your ports are sharp or have burr on them, it explains where the ring went. As it wore away, the end gap got bigger. Good luck.
Great content as usual. Would love to see a Suzuki lt80 on the channel. I don’t think you have ever had one on before
That tiny chode piston was hilarious, plus that guy acting all surprised was the cherry on top.
I had a 82 yz250, which I loved. When I got it, I did a top end. The cylinder was slightly cone shaped by measurement and had to be machined including the powervalve.
The design of two seals with a rubber seal/washer to separate the hot and cold coolant was poor at best.
Joe that clutch lever is the straightest lever I've ever seen, I think you need a different lever with a little curve to it bud 😉
From what you are showing with the ring wear, it wore in the back on the intake side and the front on the exhaust side. Maybe it is the bore, but it could be not enough oil in the gas mixture and/or running too lean. Try a reputable piston ring company, drain all that fuel out and put new mix in it. I've also found it good to run a higher oil to fuel ratio during break in period.
No shop foreman today. Where venni? Love that little dog. 😂
Vintage I could use you more than ever rn I’m going to pick up an ltz250 for my gf it’s ticking and has a chatter I think I can get away with doing timing and it will be running like new but I’m nervous the guy road it like this quite a bit I guess we’ll find out what this toppys lookin like at noon lol
Love the looks old school bikes 80s 90s I’m amazed bro how meany bikes you got and they keep on coming lol good luck ❤ David from Scotland 😊
I absolutely love your videos!! I used to work on my own bikes, way back in the day. I was wondering when you drain some of the gas out from the petcock earlier into a cup the gas look very straight looking as far as color. I didn’t see any color unless you’re running a clear All and there? Is it possible that there was no premix and it ran too hot?. Thanks again for some awesome videos.🙌🙌
Likes how he revs it with a new piston and stone cold
He revs the nuts off every cold start up, can't seem to help himself.
@@al4904 😆
By using used piston oil rings in them and coolant got in there from the bypass of coolant leaking seals and back flow of coolant through the cooling system will allow coolant to flow back into the cylinder jug.
It takes a lot of balls for someone to scam you like that considering how big your channel is !!! I agree with a the comments check bore for roundness and sharp edges on your ports . Looks like a good fun bike otherwise I cant wait to see it run !!
Put some love and attention into this bike it will pay you back - Bikes like this need a full break down and restoration no cutting corners
That radiator on the handlebars gets me 🤣 I’m all for trying new things but just a little bit of R&D should have showed them that wasn’t the best place to put that.
Joe took one for the Team on this one 😂
Sorta..Yes, he got burned by the liar of a seller but he made 3 really good videos of Joe putting this thing back together....more than pays for the trouble..Magic of YT..great videos.
Cylinder in out-round. Its needs to be bored or replaced and you need to properly clean the top of cylinder and head to ensure a proper mating surface. Pitting and corrosion is not good, needs to be properly sanded or machined. Check those surfaces with a straightedge to ensure a flush mating surface. Love the bike though, that’s a gem I would keep!
Great video mate. Some of the comments are a bit harsh though. If i had 1/10 of your knowledge and patience, id be proud. 👍
Sharp ports will cut the rings, sometimes the powervalves need to be ground back after the cylinder is bored. Chamfer all ports
Win a few, lose a few (liars suck; sorry about that seller) but, really good content! Hopefully that makes up for it!
It can only be two things - Power valve (But not likely), or out of round cylinder due to previously running with over sized rings and undersized pistons - Needs to be replated or re-sleeved - $140 job - One of these bikes is going for $3,000 in Hillsboro, Oregon though, so you shouldn't loose money on it. motosporthillsboro
Check the cylinder. It's not round anymore. Great content by the way!
"What the heck?" Straight gas buddy!!
Whew! This one reminds me of the ATV you bought from the Grandpa & Grandma who only drove it around to do Gardening stuff.
and Then this Bike's previous owner claims it was running?
then you take the Head off and the Piston is clanging around in the Cylinder like the Clapper in a Bell!
Guess you should have asked the guy as a response to his answer, When did you last see this motor run?
And this Engine looks to be worn out. If this Bike could talk?
Oh Goodie! Looks like you'll be soon buying some Tools to measure the Bore and more.
I love buying New Tools!
Great Channel though.
Sounds like my neighbors RM 80 that he bought for $900. Luckily it was STD bore and I was able to have it bored .005 over and put a OEM .005 over piston in it without grinding down or replacing the factory dual stage power valves. Water pump and crank seals failed and burnt up the crank bearings and scored the cylinder near the exhaust port. It still ran but had no power.