<< Why are only the intake valves experiencing the tuliping? The exhaust valves handle most of the heat. Im sure my combustion temps are much higher sice my mods. I will have to try and rejet before Wednesday. >>



In addition to being smaller the exhaust valves are made to take more heat then the intakes.
Your sig says you ported the head, did you install larger valves or just open and clean the ports?

If you run out of shim sizes to use you will need to either replace the valves or have the tip of the valve stem ground .020&quot;. Both will require removal so you might as well replace them. Of course this is after you figure out why your comb chamber temp is so high.

 

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<< Why are only the intake valves experiencing the tuliping? The exhaust valves handle most of the heat. Im sure my combustion temps are much higher sice my mods. I will have to try and rejet before Wednesday. >>



In addition to being smaller the exhaust valves are made to take more heat then the intakes.
Your sig says you ported the head, did you install larger valves or just open and clean the ports?

If you run out of shim sizes to use you will need to either replace the valves or have the tip of the valve stem ground .020&quot;. Both will require removal so you might as well replace them. Of course this is after you figure out why your comb chamber temp is so high. >>



It was a thorough cleanup with matching and narrowing of the valve guide boss. The head still retains the stock valves and there was no sign of tuliping at that time. That was about 20 hours of ride time ago.

I got the motor running again and drilled a larger jet. It definitely needed more fuel. It runs much stronger on the top end, but it runs pig rich in the low rpms at WOT and makes it pop and run a little rough. I guess I have reached the limits of the stock carb. Time to invest in a bigger carb.

Thats a great suggestion about griniding the valve stem. When I pull the head nextt ime I will check to see if there is tuliping and possibly just have the stems ground down. Are the intake and exhaust valves made of the same material? Do they make SS stock size valves?

 

Call Ron Woods (949)645-0393, I think he has SS valves in stock sizes. I know he has oversized SS valves to go with your porting work [img]i/expressions/face-icon-small-wink.gif[/img]

 

hey rockey, i can tell a small difference in lowend power after shimming. we ride at livingston ky., big rock in maysville and we're taking a trip to silver lakes michigan labor day weekend, you should join us

 

last summer i lost a little on my times,so when we pulled it down i had two bent exhaust vales and the valves seats were nicked around the edges.

 

We're you able to determine the cause of the bent valves? I mean i'd guess they must've hit the piston, but why? That's a bummer dude. Did it damage the cam too?

 

no,
i didn't mess the cams up.i guess i did it by over reving a few times.i thought there was enough clearance that it wouldn't do that.i don't know. maybe someone else knows why.i ran those cams for a while before changing.