Hotcams (:

[2003TrX400eX]

Was burnin oil a few weeks back, decided to put that problem to an end. Took the head off the cylinder, rings and piston are fried. Thinkin about throwin a hotcam in there. If i do, is it going to drain my gastank quickly when i ride? I got the stock size piston, no major motor work.

Thanks.

[JOHNDOE83]

Your gas usage will be fine....lol.

Thats a odd question for a cam thread...:blah:

[Stickman400]

The only thing that will drain your gas quicker is if you bore it to a 440 or bigger and add an '04-'05 450R carb. These 400s are pretty easy on gas in stock form or slightly modified. I noticed I started using gas a little quicker when I added my 450R carb., but it's still easily managable.

[2003TrX400eX]

Thanks guys. Just started getting into the major motor work on these things lol.

[CJM]

If the piston is trash your gonna need to bore up one size anyways. I bet the cylinder sleeve is out of round.

Id do a 85.5mm piston with 11:1 compression. Combined with a stage 2 hotcam its alot mroe power and it doesnt really waste too much more gas. I can ride hard all day when I had that setup and only need to fill after 4+ hours.

[hybridracer686]

I agree 11:1 and stage two are great upgrades to any 400ex. mine runs pretty strong even with stock exhaust.:D

[2003TrX400eX]

Do i have to bore to go to a 11:1 piston?

[b0rn c0nfused]

I think you can get a stock bore 11:1 but if it was burning oil you need to bore it or buy a new sleeve to fix that problem.

[2003TrX400eX]

The cylinder is fine though?

[CJM]

Originally posted by 2003TrX400eX
The cylinder is fine though?

The only way to know for sure is to have it measured. BUT this is a rather moot point b/c if it was burning oil theres at least an 80-90% chance its done and needs to be bored.

See my original recommendation for an 85.5mm piston aka 402. Boring it for the next larger size will ensure that you dont have any issues later.

Slapping some rings in there might fix it or it might not-do you really want to take it apart again?

[2003TrX400eX]

Well i honed the cylinder and put a new piston & rings in it.

[CJM]

Originally posted by 2003TrX400eX
Well i honed the cylinder and put a new piston & rings in it.

Did you check the ring gaps? If not, if the piston rings and all slid in there easy its worn, it should be a tight fit.

Good luck man.

[2003TrX400eX]

Well i honed the cylinder and put a new piston & rings in it.

[2003TrX400eX]

no it was a pretty tight fit. when i pulled the head off, the rings were like stretched and the piston just had some wear on the head.

[CJM]

Well if you start burning oil gonna hafta do the job again and bore the sleeve.