Alright my buddy has an 400ex he bought from a kid he knows. I guess its a bored to a 426, with a weisco 426piston at 12.6:1 compression. Gots the cam work and such. Anyways I am pretty sure its the Base gasket that is leaking. I guess its the lowest gasket in the Topend gasket kit. Which im wondering If i can get a stock gasket kit or do we need to order a kit for a 426. I am not sure where to find these gasket kits. Also since we are in the engine were going to check the clearence and such on the piston and probably replace the piston rings since we are in it. Where would I find these rings too?

 

for the rings: you need to know what exact piston you have in the bike. then call up that manufacturer and order a new set of rings for it.

for the base gasket: you can use the stock base gasket. if it doesnt' fit exactly right, just cut it out so it does. this is a paper gasket, not a metal one so you can cut it to fit properly.

 

Would the whole Topend Gasket kit for a 400ex work on the 426? Or do I need to buy the kit for the 426. Wondering if the headgasket would fit or not.

 

if it is a true 426 then why bother getting a stock kit.....the 426 kit is made for a 426 engine so that would be the logical answer to your question. it would be like buying a screw too big for the hole you have so now you have to make the whole bigger instead of just buying the correct screw in the first place.....common sense dude.

 

Well because I can get a topend kit for about 20 dollers and have it here tomorrow. I havnt been able to find a kit for the 426 yet.