engine mods without replacing major parts

[400EXracer74]

are there any engine mods i can do to my 400 without replacing anything big. maybe a timing key or something little liek that. I dont want to do anything major cuz i will probably get a CRF 450 in the next few years.

[44oEX]

well the bets mod is a pipe and filter and re jetting.

But if you really want something simple put a filter and rejet. and then make a couple holes in the air box lid.

[400EXracer74]

ive already put on a new fmf powercore 4 pipe jetted it, put in a k and n filter and completely removed the air box lid thats sick, but other than a head pipe is there another thing to do?

[cals400ex]

you may consider this big but it is your best route. a high compression piston and a drop in cam. this will dramatically increase power. you can even go with a stock bore or a 406 high compression piston, both will perform great. if you get a service manual and do the work your self, you will spend under $400 and that even includes taking the cylinder to a shop and having them bore it and getting new gaskets.

[44oEX]

yeah hi comp piston and cam is the next step up

[400EXracer74]

do you have to get it bored for that cuz thats something i dont want to deal with.

[44oEX]

well you can but if you don't want to you can get a hi compretion stock size piston

[400EXracer74]

does that make a good difference?

[44oEX]

yes a piston and cam will help alot. a bore would be a big help also tho

[K_Fulk]

Degree key

[BLEEDRED]

do you have to get it bored for that cuz thats something i dont want to deal with.

It's no big deal.

Tearing down the top end is easy with a clymer manual. And you always have us here on this site to answer any of your questions. I love my 440 and I did all the work myself with the exception of the machine work.

[blue416ex]

do a 416 kit in it do a cam and bore the sleeve to .80 and your at 416 ccs very simple and powerful mod if your willing to do the topend just make it 10 x more powerful and go with the 416