I'm looking for power out of my 400ex. I'm already getting all the other mods I was just wondering about the valves. Anyone know?

 

Aaron10,
i've heard that a three angle valve job is the best mod to have done.im sending mine to tc-racing for a few mods.he's not really that expensive but i've heard that he's not the quickest as far as turn around goes,but im in no hurry,have to split my cases for my broken shift shaft..good luck.

 

the 3 angle along with porting the passageways will help..

 

there is a new valve for the 400, that has little swirl marks on the bottom for better fuel and air mixing. also make sure you get your valves lapped for better seating and that should help your horsepower along with the 3-angle valve job.

 

Actually my honda service manual says not to lap honda valves as honda coats them with a super hard coating to prevent valve damage due to non-leaded fuel. It states that lapping "honda" valves will remove this coating and result in almost imideate valve falure.-Dunno about the aftermarket ones though. Just thought id share what my manual says.

 

JRM, does the service manual say anything about carb adjustements on the stock carb? I will be getting a manual in about a month. Does it give every little detail about the ex?

 

Talked to local shop and they said that a 3 angle valve job is a waste of money cause it comes from the factory already done. Basically all it is making sure all the valves are all at the same angle to the head. This is just what I was told he said I should not pay for what is already there.

 

Mine is a climber manual, it just shows how to replace jets and adjust the air screw and do the plug color check. My experence shows that hondas are jetted a tad lean, so one number larger on both pilot and main helps (unless you live above 4,000FT)