hand lap valve

why fight it? if you got a 6 inch c clamp and a little
know how, break those valves down and take them to you local machine shop. I found they charge very little
to grind a face, and then you put em back in and lap em. this saves tons of time, money, and energy. local
machine shops are less likely to turn you away too
if you bring em stuff with quick turn aroun and pay cash.

Did you click on "Topic" instead of "Reply"?
I'm not sure what you are replying to.

But as far as lapping the valves go, it seems pretty senseless to grind them unless they are bad enough to require grinding, and I'd rather spend the $10 or so for lapping compound and a stick with a suction cup and know it's done right, than spend the $50 or so at a machine shop and hope they did it right.

It would be my opinion that just grinding the valve face would be a waste of time and money. If the valves need refacing the seats certainly will not be flat and will also need to be ground. Grinding the face only will require a considerable amount of lapping to get them to properly seal.

thats what i thought. im not saying grind the face
into oblivion, if you got a good machine shop tell em you just want to nock the skin off. some things you coulod lapp all day and never get straight. bump em a time or two and move on mostly exaust any way. according to redline cycle intake are less likely to go bad. go figure exaust being were all the explosions
take place.

Clean the valves first too. Then all they have to do is grind them. You walk in our place with clean valves, we will peobably do it for while you wait.

By the way, putting the valves in a super accurate valve machine is the most accurate way to tell if the valve is slightly bent. If so, it will usually grind out. Something all the lapping in the world can't fix.

Jay

With valves, its almost alwys the seat that is slightly mushed and needs the skin off, then lapping is a snap. You can look at a valve and can easily tell if it has its normal angle. I agree with steel that lapping yourself and pressure testing will ensure your going to get all the compression out of your rings. Some shops may not lap the valves. If you look at the seats in the head and see sharp crisp angles, you can lap the valves right in. If not, have them cut very lightly. Way you dont lose so much clearance as the new valve will sink into the seats farther. If u have a problem with clearance during assembly, can change shims, but there are times when this does not give u enough clearance. The answer then is grinding the stem,just have a set of keepers and a retainer on hand and by installing them onto the valve while holding it in your hand, u can check to see that the stem is still above the retainer. If a valve starts grooving while lapping it may be bent. Then take it to the shop and ahve them try to gring it. When they swing the valve over and against the stone it will skip on and off the stone if it is bent. This can be seen and heard the instant that contact is made. Knowing these things can save u much time and effort.

Post edited by: nads.com, at: 2006/03/26 00:23

I lapped and lapped and lapped, thought what am i doing? took em out, drove em down to the machine shop and the guy let me follow him back. set em up about half a minute, nnocked the dust of charged me 25.00
got home lapped em in in about 30 min, assembled
bike and wow like a good shot of herion, 195 psi across the board. he did say one exaust was slightly
off kilter and grinding would never take that out. you do what you want to but for me ill lap em in after a little grinding.

dont ask me for gas money.