2001 YZ426F for trails...

2 replies to this topic
  • achildofthesky

Posted January 26, 2007 - 12:16 PM


Hello again all. I finally am coming up on a big chunk of free time and seriously weighing the possibility of getting a YZ426F, bought (supposed to be a 2001) initially to part out, running and set up as a big honking "play" bike.

Currently, the machine has been taken down to the engine in the frame with the wheels, forks and shock still there, but that is about it. It is complete. It doesn't run but has prodigeous compression. In a previous post I asked about the kickstarter not turning the engine over, but with the comp. release pulled in it does, albeit a somewhat stiffly. I have yet to open the engine and was hoping to do so in the next week. I reckon at the best it could use a piston and rings and possibly a valve job and at the worst??? I don't want to go there yet. If the trans is buggered the deals is off anyway...

Anyhow, I figured that seeing how it was picked up for less than a song and a good night out on the town, I am seriously considering getting the beast up and running provided it can be done VERY economically. I'd like the result to be a general purpose woods and trail bike. Now I realize that this bike is certainly not a top choice for this but, dang, if it does run or can be made to run for < say $3-500.00 I can deal with a fair degree of compromise. Any thoughts on this?

Feel free to call me a doofus for considering it or what ever. I have worked extensively on 2 strokes pretty much all my life, from spark plugs to splitting the cases but have 0 experience on the guts of 4 strokes. Should I bother? Just part it out and take the cash and buy a running bike? I do have a decent tool kit and don't mind digging in the chitterlins' of a bike. But the cost IS a big deal right now. A really big deal.

I don't have many biking contacts here in NW AArghkansas and could use a bit of show and tell help if I can find it.

I believe that these have plated cylinders. Please correct me if I am wrong. But if the bore is knackered then I will have to either find a used, good one or perhaps it is possible to have a machine shop strip the plating, hog it out, then replate. Again, correct me if I am off base.

Given the huge compression and lack of metal on metal contact turning the engine over, I reckon that the valve seat and valve sealing surfaces are at the least passably good.

If I proceed, I will need a rear exhaust section/muffler (trashed), right radiator (looks like it might leak due to a fall), right side numberplate (cooked a bit due to the beat muffler), bars (I have new spares), grips and tires. I would take the frame apart and paint it and do a full service on all the greasable points and check wheel bearings, steering head bearings and the like. From what I have read here by you generous folks about the YZ450 autodecompress cam benefits this would be a necessity for starting ease.

Please feel free to fire away and should there be a cheap source of the parts needed fro this project outside of Ebay, please clue me in. I figured that with all the thumper experience here, I could get some straight and enlightening answers. Thanks for the space and I look forward to your posts...


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  • YZ426F Rider

Posted January 26, 2007 - 01:18 PM


chitterlins? Lol...

I'm by no means a master mechanic but I would think that if you have good compression that you can't be too far away from getting it fired up...are your getting spark?

The 426 makes a great play bike...heck, I stil race mine. IMO, I would at least get the bike running and take if for a short ride to see how it runs before deciding whether to part it out or not.

If your radiator is not leaking you might be able to have a radiator shop straighten it out...there is a guy near me that does that. If you are spiltting cases on two strokes then you have the skills to get after a valvetrain. Find a service manual for the bike...they are very, very helpful.

Ebay will be your best bet in finding a replacement silencer. Good luck with everything!

  • jimbob69

Posted January 27, 2007 - 12:37 AM


You said it turns over with the decomp lever pulled in, but STIFFLY turns over???

By no means should it be stiff, Sounds like a big end rod bearing to me.
cranks run about 280 on thumpertalk eom parts.

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