01 yzf 426 ?

my buddy has an 01 yzf 426, and the problem we have been having with it seems to be over heating. The head pipe glows red we replaced the water pump impeller and the gaskets , and it still seems to be over heating would a rejet be what it needs?


Head pipes glowing red is normal...the metal is very thin takea very little heat to glow

Does it do any of this while you ride it, or only when you let it idle for a while?

Yes while riding it loses coolant , we also replaced the radiator cap .

Hows the radiator fins look

How much coolant does it lose when riding ?

Also is there any discolouration when you change the oil ?

Finally, please tell us what jetting is currently installed

The coolant goes past the fins , so the amount it loses I'm unsure of as well as jetting

I have an 01 yz426f, and my bike pukes at idle and trail riding. I just ordered an overflow bottle for a wr426f. I think this will be a huge help. Fairly east to mount and route hoses.

Oh, and this is my second 01 426 and they both glow red hot at the header, and spit out coolant

The red header and coolant discharge are only normal if the bike is left to idle for longer than 45-60 seconds, or if operated at very low speeds, such as fighting up through a tight, twisting trail. Otherwise, it should not overheat, and jetting won't make it do that unless it's so far off that it also runs poorly.

If filled full while cold, then run to normal temperatures and cooled back down, you will normally see that the coolant level has dropped to the tops of the tubes due to expansion while hot. More than that, and you have either a heating problem or a leak. The radiators need to be clean both internally and externally. There is a possibility that the head gasket may be leaking as well.

Wouldn't you lose power if the head gasket was fed up

Not necessarily. Depends on how much it leaks.

Last night I bought header wrap from advanced auto and wrapped the header, cost 30 dollar's, I think this is going to be a huge help along with the WR overflow tank. If I ride this weekend, I will let you know...... IMO, the main reason they run hot b/c the header is super close to the radiator and hoses,carb setting can have some Affect to, but the main problem is the ever glowing pipe.

Oh, and I will be trail riding, as expected mine runs hot in the trails not at the track

Edited by johull

I went trail riding this past weekend, after installing the coolant bottle, and header wrap, my bike ran all day without overheating for the first time ever. I am extremely happy with the results. If anyone wants pictures of my bottle install or wrap please email me for pictures at jolynnhull@Yahoo dot com

well after lookin into this turns out my buddy put his seal in wrong on the impeller shaft, lol so a new one is on its way, and we also put header wrap on it thanks for all the replies

i have a 01 426 and i just checked the valve shims and after putting it back together it has white smoke comeing outta the breather tube what is that from and it doesnt wanna idle wich is y i tore into to begin with

Edited by vajayjay1

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