Has anyone tried any chamber mods?

[69zandar]

Has anybody tried to modify the combustion chamber on a 400ex, I have my brothers apart for a hone and rings ( or possibly a bore i havent had it checked yet ) and while doing some cleanup porting i noticed that the intake valves seem to be partialy shrouded by the ridge of the chamber. This is an 89mm cylinder so i was thinking of doing a little blending around the intake valves. I know on my small block chevy heads the intake valves have been shifted toward the centerline of the bore to avoid shrouding . I know it will have an adverse affect on compression but we are adjusting that also with some milling. Any input on that would be a help. Thanks:chinese:

[sc400ex_rider]

i polished my combustion chamber to a mirror finish. i thought the same thing when i had it apart, there is some shrouding and a sharp edge close to the valve. i have a 85MM piston so i didnt want to get into the head gasket mating surface so i left it alone. when i polished it i did take some of the sharp edge off. i dont think you would feel the difference but every little bit helps and all the little thing make for a good running engine.

[69zandar]

I agree , if you add up all the little things it does make a difference! I thought about rounding off that edge at the very least too, try and keep sharp edges at a minimum to help fight off detonation. Maybe ill work over the intake area just a little more and then have the thing milled some. Does anybody know if they make an adjustable cam gear?

[brokenmike]

falicon cranks makes a adjustable cam gear. $34 + shipping. check them out



http://www.faliconcranks.com/

[Wheelie]

GT Thunder has an adjustable cam gear.

[soyo]

unshrouding will help at low lifts. but dont take to much off. put the cylinder on and mark where the cylinder walls are on the head as a guide to not go to far and flow on top of the cylinder!

as far as adjusting the gear just notch out the stock one a little.

make sure you check valve to piston clearance after milling! how much are you thinking about milling?