Porting the head....

[YELLOW_TRX400EX]

ok i got a 400ex with stage 2 cam the spark key and a slip on i was thinking to take the head off and port the intake and the exhaus. should i do it ??? another thing was to shave the head a little bit .how much should i shave? is it going to get way too hot??? is ts possible to make a 3 angle valve job? is all of this worth the time? thank for any help ..................

[Ntensweapon]

Those are all very good mods, I wouldn't recommend doing them yourself though. There is more to port and polish that getting a dremel and hogging out holes. You can actually cause more harm if done wrong. It takes special tools to do 5 angle grinds. Shaving a head needs to be done within tight tolerances. I'd find a proven race shop in your area and take it there.

You could take your pipe off and grind the welds down inside. That would be something easy to do with minimal tool.

Try a free flow air filter like a uni, remove your airbox lid and install an outerwear lid cover. You may have to rejet for this especially if it hasn't been jetted since you slip on.

[drew416ex]

X2, its worth it, but dont do it yourself. If you want to bump up the compression a little, you can just remove the base gasket instead of shaving the head.

[YELLOW_TRX400EX]

hey drew where did you bought those +1mm intake valves??

[drew416ex]

they are kibblewhite valves. They are way better than stock. My stock valves would always be a little warped when I would rebuild, but I havnt had that problem with these.

[rideracelivemx7]

always wondered this, what's involved in doing over sized valves? bigger seats? guides? what's the performance gains if any at all. you feel them?

Originally posted by rideracelivemx7
always wondered this, what's involved in doing over sized valves? bigger seats? guides? what's the performance gains if any at all. you feel them?

On a bigger displacement motor like your 440 you can see some really great gains. On a smaller bore its not as great of a gain but I hear people with 416's having it ported and polished and they claim to have a nice gain in power. Stock bore I dont think it would be worth it.

[rideracelivemx7]

I miss that 440 lol thing was fun. but I got a crf450 that's my new money pit. stroking it. porting it 350$ port 12:1 conmp piston and stage 2 cam. can't wait. it destroys my 440 stock