How to Redo your Top End: Yamaha Moto 4 Top End Rebuild on Yamaha Moto 4 YFM225 YFM200 DX - Part 2
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- Опубліковано 13 січ 2021
- / wrekkedoffroad / @vermontlife www.buyjimmyabeer.com/
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Lot's of learning happening as I put this back together. I make a few mistakes with the order of operations that could have saved time and discover the wrong way to install a timing chain tensioner.
This is a longer video with more raw footage but if you're picking apart a Moto 4 it's worth watching to learn from my mistakes. Hopefully it will save you time on your build.
In the end I get the motor back together and crank it but find there is more work to do.
The specific ATV I am working on is a 1988 Yamaha Moto 4 YFM225.
Used in this Video:
New Cylinder Piston Gasket Kit Fit For Yamaha Moto-4 225 YFM225 1986-1988 - amzn.to/39MOfHl
Screw Thread Gauge | Metric and SAE | Recommends Drill Bit & Tap Size - amzn.to/39uX48p
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#Vermont
#VermontLife - Розваги
Thank you for your videos I just wonted to say that I have had the parts for awhile and untill i watched your video I didnt have to knowledge that you provided I just finished it and it runs perfectly enjoy your property looks peaceful
That’s awesome to hear! Thanks for letting me know.
This comment is very reassuring
You don’t know how much you helped me
You don’t know how much you helped me thank you agin
Glad to hear it. I just this process again on a YFM350ERW and tried to capture more of the process. I'm pumped to hear you're maintaining another old YFM. These things are still great machines.
Thank you so much
Thank you for real for real
What kit did you use? Have the same year/make/model I have to do that on
I popped a link in for it in the description. Hope that helps.
i live in vermont also i have 2 moto 4s
Did you reuse the o-ring for the base of the cylinder? Kit did not come with one and the original is much too thick
Oh boy, I'm not sure I can remember at this point. If I had to choose though I'd reuse the existing if it's in reasonable condition rather than risking not using one or using one that seems to large. Good Luck.
Does anyone know if the 225 cylinder rebuild kit would work on my yfm 200?? Just bolt on kind of deal like normal installation?
I've heard no from folks. Never researched it myself though.
Where would the piston be in the jug for the timing chain??
Hi Jay, are you looking to be sure you are at top dead center for timing? Let me know goal for the question and I’ll try to help get you dialed in.
which mark did u use the one before the t or after the t
Are you referring to the other timing marks on the stator? There are also markings for advanced and retarded timing but you would want to be right on that T line.
I have the same bike. I’ve had issues with the timing. How do you set the timing so it is on the top dead center of the compression stroke after you’ve taken off the cam chain? Or does it matter if you line up the T and the mark on the car chair sprocket?
You’ll need to line the T and mark up for timing to be correct. Note that with a slightly stretched timing chain you may be a have a link before TDC (advanced timing) or a half link behind TDC ( retarded timing). You ‘should’ be fine either way. To line things up take out the tensioner and the screw holding can chain sprocket. With a little work you can get the sprocket into the right place on the chain and press the sprocket back on. Note that there will be a cutout on the sprocket that presses over a protrusion on the shaft behind the sprocket. You can easily spin the shaft to line up for the sprocket so everything presses on. That’s a lot to digest. If you’re still struggling let me know.
@@VermontLife that’s the problem. I’ve done this, set the mark to T on the cam chain sprocket lined up with the top. It used to run rough. I’ve done some jet work on the carb to set it to original jets.
It’s backfiring through the carb, but not starting.
I’ve got spark, good compression. I’ve adjusted valves multiple times to factory settings. I’m at a loss. Unless the jets are still wrong? But I bought the original jets. Any ideas?
@@bleckybob Interestingly I just went through the same thing. Backfiring through the carb led me to adjust the timing to retard it one tooth. I had replaced the valves, lapped them, set the gap, replaced the timing chain etc. It was still backfiring through the carb and kicking back the motor quite bad when it would try to fire. Retarding the timing helped get it starting consistently. I should also say to make sure you're not overly lean etc. (If you get it running try riding with the choke on, does it get better etc.) If you're cranking hard the plug is going to get pretty fouled too. I had to pull the plug and clean it in carburetor fluid to get good spark again it was so dirty from me cranking. So check you still have solid spark :). I'm running a 45 pilot and 122.5 main with 2.75 turns out on the air screw which was the oem setup and that's working for me.
@@VermontLife I’ll try that! I had it running a while back and then it would run for about 20 seconds an then die oks the fuel was clogged and even then it would only run on opening the throttlez. Choke doesn’t seem to do anything. Now I can’t get it to fire at all. Good spark, good compression,
I was playing with the timing and noticed that the valve sprocket only points up every other revolution of the flywheel. Can setting it 180 degrees help? And when you say retard by one tooth, is that setting the notch to the right or left of the mark on the cam sprocket? Would I set the sprocket to the F mark instead? I’m just at a loss.
I’m gonna try messing with the carb some more and see if I can’t get it to do something.
Another weird thing is it kicks back on me really hard and yanks the starter cord handle out of my hand. Very weird. It messed up the one way bearing on the starting motor so I had to replace the assembly.
This bike has put so many gray hairs on my head. I’m so deep into parts, that I’m about ready to just scrap it out
Kicking back hard and backfiring out the carb are signs of timing too far advanced. The F is the point at which the plug fires. Moving TDC closer to the F mark advanced timing. This can lead to the intake valve still being open when it fires and can lead to the kick back. (Ie it is trying to spin the motor backward). Four strokes will hit TDC twice. Once on what is called the overlap stroke and once on the compression stroke. Make sure you’re setting TDC at the compression stroke. ( stick a screwdriver down the spark plug hole gently to see where the piston is or pull off the intake valve cover. TDC mark that comes up after the intake valve closes is the compression stroke. I hope that helps a bit. You’ll get it.
Can you replace the guides without pulling the head
I have replaced the guides on a Yamaha Big Bear 350 by removing the flywheel and installing from the bottom. The 225 is quite similar so it may be worth a shot to look at. On the Big Bear I had to drain the oil and pull the flywheel and stator. Then take the timing chain cover off and remove the timing chain. (Also take off the timing chain tensioner.) At that point I was able to replace the guides. I was doing this to replace the timing chain without removing the head. Good luck. It worked.
could this top end work with a 1987 Yamaha yfm 200?
I believe it can. I haven’t tried but from my research so far preparing to replace the top end on one of my yfm200 quads it seems that it will and will be easier to find and lower cost. If you find out for sure let me know.
Did anyone find out I'm wondering the same thing. Does anyone know if the 225 cylinder rebuild kit would work on my yfm 200?? Just bolt on kind of deal like normal installation?
@@truckergilligangilligan5877 NO, it cannot work just by bolting it on. At least not without modifications that would be tricky to engineer. I've seen you post this question to a number of videos so let me provide the REASONS why it won't work once and for all. Basically, the 225 engine is not the same as the 200. The 200 specifications are:
"... a four-stroke, air-cooled single-cylinder SOHC engine with a bore of 67 millimeters and a stroke of 55.7 millimeters. Bore and stroke on the engine is 2.63 by 2.12 inches.""
Compare the above specs for the 200 engine to those for a original replacement cylinder sold by Labwork on Amazon:
"The cylinder Bore is 71.00mm
The Stroke is 58.00mm, The cylinder Displacement is 229.6cc / Compression 8.7:1
Fit For : Bear Tracker 250 (1999-2004), Timberwolf 250 (1992-2000), Tri-Moto 225 YTM225 (1983-1986), Moto-4 225 YFM225 (1986-1988) & Moto-4 250 YFM250 (1989-1991)"
I'm not an ATV mechanic but when the bore diameter is bigger and the stroke is longer, even by a tiny amount, there would need to be adjustments in the timing, which is controlled by a timing chain mechanism. Essentially, the exhaust and intake valves must open at the precise times and close correctly PLUS the spark must fire at the appropriate point in the cycle. Those three settings would all need to be different to make the larger 225 parts work with a 200 cc (actually 196 cc) engine.
That said, it would be possible to obtain a little more horsepower (likely 1 to 2 hp) by simply boring out the original cylinder in the 200 engine. That too would require some additional actions, such as using an oversized piston. Honestly, the small gain that is achieved in horsepower between the two different engine sizes is no where near enough to justify all the work and expense to modify the smaller engine. An engine swap would be a better decision, perhaps with a 250 engine for the 200.
The small 200 Yamaha quad, which I own in a 1985 version, is a low powered machine and was always intended to be. If there is a need for more horsepower, the best solution is to get a bigger quad. There's just not much way to boost the horsepower of a small 200 cc ATV motor to a much higher level that is economical or sensible.
Yes, there are ways to increase the horsepower output of an ATV engine, or any engine for that matter. You could probably figure out how to hook up a cylinder to run the beast on nitro fuel if you wanted to but why do that? It just doesn't make sense. It's like trying to find a way to make a tack hammer do the work of a sledge hammer. If you really need more horsepower what you need is a bigger hammer!
Thanks for the great insight. I appreciate the great detail.
Don't you think it was important to explain how to get the piston inside the cylinder...? In the video it magically jumped on....
Good call out. So far I've been lucky. No special tools. I slide the head over the top of the piston and compress the rings with my fingers. I'll try to get some shots in another video. (I'm rebuilding a YFM350ER now and just started doing the valves and head so an opportunity is in my near future.)
HOW DO U REMOVE THE CAM CHAIN BOLT TO GET THE SPROCKET OUT>??!??!?!?!?!?!?!?? i DONT HAVE A IMPACT GUN AND IVE BEEN TRYING TO GET THIS STUPID THING OUT ALL DAY!!!!!!!
How about an impact drill? You might also be able to get it by putting a socket wrench on it and giving it a quick wrap with a dead blow hammer to break it out. One more risky trick is to put a screwdriver shaft between the chain and sprocket teeth so it can’t rotate. Not a great idea but with a little patience and caution I have done it successfully. Good luck.
@@VermontLife Yeah I barrowed a impact from a friend and it still wont come off.... I have tried everything I dont think it has ever been taken off or its just stuck on there.
i had the same problem removing that cam sprocket bolt. what i did after struggling was; i got the chain and tensioner back on, then i held the bottom magneto bolt in place while i reefed hard on the cam sprocket. the part i overlooked was the chain on the bottom, on the crank. it was not on properly, then when it fired up for about 20 seconds the chain slipped off and i got scared because the sound was horrendous. but the chain just slipped off the bottom. i had to start over. it has been running healthy for the past 10 months.
Put a wrench on the bolt where pull start is and hold it
are you selling it ?
I’ve held onto this one. It’s fairly small but has been a capable little quad. My only beef with it is the dual rear shock setup Yamaha used on this year model. The shocks are undersized and don’t have good rebound damping.
Hello, I am subscribed to your Chanel and I do watch your videos, I have a 1986 moto4 YFM200DXS and I need a lot of help, when I took the stator cover of the idler gear #1 fell out now I need to get it back in, can you PLEASE HELP!!! I can send you pictures.
I might be able to do you one better. Sites like bike bandit.com have all the assembly pictures. If you were to lookup your quad on the site under oem and find pictures that show that case half you’ll be able to see exactly where and how that gear goes in. I’ll take a look and see if I have pics. (I think I do on the yfm350er build videos I did). Keep in touch.
www.bikebandit.com/oem-parts/1986-yamaha-moto-4-200-yfm200dxs/o/m146913#sch215031 That link should bring you directly to the oem parts and assembly diagram. Part 1 is the #1 idler gear. It will show you position and how to assemble the parts around it. Good luck.
@@VermontLife THANK YOU SO MUCH!!!!!!!!! Your the best!!!!!!
@@VermontLifeTHANK YOU SO MUCH!!!!! Can you send me your email or I can send mine so, I can send you the pics.
Thanks for spending your time to reply to my message.
Is there any way I can give back to you, im already subscribed.
That’s great, for me I’d just love to hear you get it running for your grandson. I believe my email is listed on the ‘about’ channel page.