need to knwo things about my 426f

5 replies to this topic
  • redneckk

Posted October 28, 2008 - 12:14 AM


Ok ive got a 2001 and had a couple questions and hopesomeone can help me lol i know lots about cars and that stuff but im knew to bikes..... ok first question should my oil be really dark after only 3 short rides? and what can i do to change that? also it smokes a bit at start up? is that normal for these bikes? thanks

  • matt4x4

Posted October 28, 2008 - 04:36 AM


A bit of Smoke at startup is normal IF you use the choke, no choke, no smoke.
If you get smoke without the choke it's either bad valve stem seals or rings - I'm leaning towards rings since my bike did it a little bit and replacing rings fixed it.

Oil - dark - that's all in how you perceive it - your clutch is also using the oil, so I find it gets dark pretty fast, however, on the dipstick, I find it isn't noticeable - only when you drain it into a container and look at it then.

  • grayracer513

Posted October 28, 2008 - 06:08 AM


Typically, a puff of oil smoke on start up that goes away pretty much as soon as the engine starts is caused by oil coming past the valve guide seals. Rings will leak oil in while running, not while it sits.

Darkening of the oil can mean a lot of different things. I can mean that the oil has started to oxidize, or has been exposed to heat beyond its normal capacity. It can also be a result of contamination by debris, especially if you are really hard on the clutch. Or, it can simply be a matter of the particular oil blend behaves. It does not necessarily mean anything at all. You might try a good synthetic, like Amsoil MCF or MCV, or Mobil 1 Racing 4T.

However, 3 rides is long enough for the oil to be in there. You say short rides, and by that, I'm not sure what you mean, but my ride days run anywhere from 1 to as much as 4 hours of run time, and I change oil after two or three ride days, no matter what.

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

Posted October 29, 2008 - 12:07 AM


thanks i feel better now lol i think it might just need new valve seats aswell as a good tune up... ive got a awsome local shop that ive been dealing with for awhile. but i dont want to hav to rebuild it yet lol next season

  • grayracer513

Posted October 29, 2008 - 05:19 AM


... i think it might just need new valve seats aswell as a good tune up...

Valve SEALS, it may never need new valve seats.

  • USED YZ426F

Posted October 29, 2008 - 06:23 AM


What color is the smoke on start up?

If it is black (or very dark) and goes away after a couple of seconds it would indicate that you are running rich (normal with the choke on).

If it is blue (or gray) and goes away after a few seconds, it would tend to indicate you are burning oil, probably from worn valve guide seals (a pretty easy fix).

Related Content


Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

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

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

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.