My buddy just bought a 02 400ex. Its got a yoshi slip on and thats it for the performance. He was wanting to do a 440 kit and my question was who makes the best kit? Are there other mods that have to be done like headwork or anything like that. And is the 440 even the way to go? is there another kit that is better? Im open to any comments and we havent even took this thing apart yet we were just trying to get some ideas before we did.

 

search this site for the 440 mod you will see they have nuttin but problems.i hear the 416 or 426 kit is much more reliable

 

440 kit POS.Head gaskets,and overheating.If his heart is set on the 440 then buy a 400$weisco kit off of ebay.416 or 426 are the most reliable way to go.

 

im glad i found this site lol where would the best place to buy the 426 or the 416 kit be?

 

try ebay

 

leave it a stock motor all your doing is not makeing it reliable

 

I recommend that you stay away from the 440. They will cause you alot more problems than they are worth. Although, the 416, and 426 are supposed to be really good. You can also go stock size and put a high compression piston in this will also give it more power.

 

I recommend that you stay away from the 440. They will cause you alot more problems than they are worth. Although, the 416, and 426 are supposed to be really good. You can also go stock size and put a high compression piston in this will also give it more power.

 

I recommend that you stay away from the 440. They will cause you alot more problems than they are worth. Although, the 416, and 426 are supposed to be really good. You can also go stock size and put a high compression piston in this will also give it more power.