98 overheating

1 reply to this topic
  • Lance_Blair

Posted June 23, 2001 - 11:22 AM


I just added a bigbore kit and new crank (RB) and am having overheating problems. I found oil in the water after a desert race. Replace the WP seals and bearing and the Radiator cap. Found oil in the water. Inpected head and base gasket. No apparent problems. Going back to water pump. Ordered a new impellar and shaft. Someone sujested jetting. Not real good in this or any other area to be honest. Missed a race today because I can't figure it out. Not real happy! Any ideas or experiances in this area?

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

Posted June 24, 2001 - 06:53 AM


Did you retorque the head bolts after it ran for a while? I don't know about these gasgets specifically, but on some other rebuild jobs I've done it's not unusual for you to have to retorque a short time after installation; usually after the first run or after break-in. It's also not unusual to blow a head gasget because of overheating. If this problem persists then you may want to remove the head and check the head and the top of the cylinder to be sure that they are both still flat (not warped). A warped head will cause a leak.

Actually now that I think about it, are there any pressurized oil passages which run between the cylinder and the head on this motor? It may be all external oil lines, in which case I doubt that a leaky head gasget could cause oil in the water, though it may still cause water in the oil if the leak is near the space where the timing chain runs.. Maybe Hick will chime in with some advice, he seems to know this motor pretty well.

Related Content


100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 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.