Possible build coming up, what to do?

[Zakradu398]

So being a poor high school kid, I've been tossing around the idea of buildingth 400ex. Well today, I noticed while I was in neutral and would rev up, it would puff some black smoke :scary: guess it could use a rebuild. As far as the engine goes, I want a 416 since they are damn reliable. I need some input onto where to go with the motor. I ride trails and harescrambles a few times a year just for fun so I don't need a national built motor. Need to keep it on 93.
11:1?? 10:1 and +6?? Which brand
also, where should I send the cylinder the be bored? Would also like a port/polish.
I will also get some new vavles while it's apart since they're cheap. Also should I get a cAm?? Thanks.

[trx400exrider14]

11:1 is the highest with Pump,you will really benefit with a new hotcam too. Stage 1 2,just preference. +6 is not good with high compression pistons,+3 is about the way to go on it.

[Zakradu398]

If I go with an 11:1 I'm not gonna do a key to stay on the safe side. Also, does a cam add comp.?

[CJM]

Originally posted by Zakradu398
If I go with an 11:1 I'm not gonna do a key to stay on the safe side. Also, does a cam add comp.?

No key for 11:1 or you need to run 100+ octane. Cam doesnt add compression, it adds power by changing the way the machine delivers the power. You want a stage 2 cam with an 11:1 piston.

[eprovenzano]

While you have her down, I'd replace the timing chain with one from a CRF450.

[Zakradu398]

I planned on the 450 chain, just forgot to add that but thanks.

Anyways, where to send the cylinder for boring/port that isn't gonna cost an arm and a kidney

[B.C.#11TRX400EX]

I'd send it to like GT THunder or C&D Racing, or just buy a engine kit like Curtis Sparks 416cc Engine Kit (thats what i'd do)

thats just my thinkin

[Zakradu398]

Curtis sparks would be nice if I had 1200 dollars laying around plus 6$ a gallon for gas since it's 12.5:1 comp.