rebuilding 00' 426 motor, high wear items?

5 replies to this topic
  • Guest_BrandonV_*

Posted April 08, 2005 - 08:23 AM


My 2000 is getting a 'freshen up': bored jug, 97mm wiseco, 450 cam and anything that should be replaced/checked will be.

I will be replacing all these parts:
Piston (rings, pin, circlip,)
Cam chain
Cam chain tensioner
ex. cam with 450 cam
What else should I replace? How about the cam chain guides?

What do I need to check for excessive wear?
The bottom end was rebuilt back in 01' or 02' and it got new 2nd & 3rd gears, shift fork and 01' clutch update. Is it time to split the cases again?
I seized the motor last weekend and although I'm failr certain the lower end is okay, I only want to do this once and might as well do it now.



Posted April 08, 2005 - 09:53 PM


i seized my motor back in november and it was my bottom end. bearing on the big end of the rod. i replaced all the bearings in cases, had the crank and rod rebuilt, hi-comp piston, hot cams auto-decomp exhaust cam, and clutch fibers. my first trip out it locked up again. this time it was the clutch basket that grenaded and caused the motor to lock up because a large chunk got wedged in between two gears. so then i upgraded to a hinson and also added a K&N and a SLP power pack. ive ridden it since and it seems to be fine. i would just say go over anything that could go out. dont make the same mistake that i did and have to do it twice.

  • Guest_BrandonV_*

Posted April 09, 2005 - 07:20 AM


Sorry to hear about that! I had the same thing happen with a 250R Honda way back when. I appreciate you telling me though, thanks!
I didn't plan on upgrading the clutch components, but it is cheap insurance.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • mkporn

Posted April 09, 2005 - 09:03 PM


Pay close attention to the timing chain sprocket on the crank..... Replace the guides. Take some good measurements of the valves......

  • mkporn

Posted April 09, 2005 - 09:05 PM


Take a good look at the rist pin area. I have seen several with gaulling on the rod...

  • Fastest1

Posted April 11, 2005 - 01:09 PM


Also replace either the whole crankshaft to a 2001 model due to the splines instead of a keyway for the counterbalancer gear. You can just replace one half of it if you want. The key on the 2000 is known to fail. Cheap insurance.

Related Content


Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Is the 2016 GYTR Yamaha YZ450F too fast? by Fryboy

Dirt Bike   Special Interest Forums   Pro Racing
  • * - - - -
  • Hot  241 replies

Need help by Goforaride

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  68 replies

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  106 replies

yz400f throttle bog by yz400fmaniac

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • * * * * *
  • Hot  28 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.