How much does a 3 angle valve job help a 300ex? Does it add hp? i also have porting

 

I'm not sure how much it would help on a single cylinder motor but i've had it done on 4 cylinder street bikes(5 angles). I don't think it makes as much difference as porting does because as soon as you run it, you get some carbon build up that gets in the way anyways...I'm sure oversize valves would be the ultimate. I'm also not sure if it actually takes away from the valve-to-head mating surface, if it does that would mean shorter valve life.

 

Whoever did your porting should have done a 3-angle valve (actually, seat)grind at the same time, since you get almost as much increase from the VG as from the porting.

If it wasn't done, I definitely recommend it. The downside is, if you've been running the engine more than about 6 months, you'll probably have to spring for new valves again when they do the valve grind.

Reason? Honda valves are stellite coated, once the coating is worn off (happens pretty quickly), you can't grind them at all -- they just cup really fast. That means if someone removes the used valves and does the 3-angle grind, they won't be able to re-seat the old valves and have them not leak.

Hope this helps.

 

How do you like the porting?