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how to relap valve seats with Ti valves?

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yes no laping it will kill them. Dont cut your own seats unless you have a nice kit and lots of practice. I have a newway kit that ran about 700 bucks. usually cheeper to have a shop do it.

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The seats should be lapped just use an old valve or if a shop is doing it the should have lapping valves.

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No, you do not lap the seats. You cut them and have a perfectly flat, angled surface.

Lapping with an old valve will cause the seat to have an uneven surface that coincidently will perfectly match the old worn out valve and not the new one.

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The seats should be lapped just use an old valve or if a shop is doing it the should have lapping valves.

This is wrong. The purpose of lapping is to form the angle of the seat and valve together. If you use an old valve, you cut an old worn angle in the seat, and your new valve will not seal well, and may wear out prematurely. Don't lap seats with ti valves at all. Just have them recut.

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Listen experts it's not the wrong way to do it. I have worked in a shop for several years and all we do is cylinder heads. I understand why you lap valves, to mate the two surfaces. You need to grind the old valve to the correct angle.

There's no such thing as a perfect cut valve face surface and seat angle. That's why lapping exists! If you can't do it the correct way (which is to lap because they coat the valves) you should at least lap them with a lapping valve.

Argue all you want I actually do this for a living unlike 99.99% of everyone here

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Listen experts it's not the wrong way to do it. I have worked in a shop for several years and all we do is cylinder heads. I understand why you lap valves, to mate the two surfaces. You need to grind the old valve to the correct angle.

There's no such thing as a perfect cut valve face surface and seat angle. That's why lapping exists! If you can't do it the correct way (which is to lap because they coat the valves) you should at least lap them with a lapping valve.

Argue all you want I actually do this for a living unlike 99.99% of everyone here

With modern 3 angle valves and seats, the ti-valve will cut into the freshly cut seat creating the proper seal. Lapping to a differen valve, whether it has been cut or not will not create as effective of a seal as a properly cut seat with a brand new titanium valve. Stainess steel valves are different, they can be lapped (and it is better to lap them, as they do not have a hard enough surface to act like a titanium valve). I'm sure your shop does not work with titanium valves much, and if they do then they must have a lot of frequent repeat customers.

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He is correct a laping valve should be used. Just not the ti valve. Even with the 3 angle cutters the carbide that cuts them still leaves a bit the grinding and cutting marks. The laping makes a nice smooth surface for your valve to sit on. It is the same thing as a stelite coated valve.

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maybe you should spend more time actually working on engines instead of posting in forums.

My shop works on the fastest cars and bikes in the world. I don't need to name drop but we do all the cylinder head work and repairs for multiple top fuel teams. ......and oh my god they all use titanium valves and we lap everything!!!

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maybe you should spend more time actually working on engines instead of posting in forums.

My shop works on the fastest cars and bikes in the world. I don't need to name drop but we do all the cylinder head work and repairs for multiple top fuel teams. ......and oh my god they all use titanium valves and we lap everything!!!

Top fuels get new valves every race, that is a few minutes of running. Titanium valves have a very thin but very hard ti-nitride coating, anything that can compromise the integrity of the coating may destroy your valves. They will work great for a few hours, but that is it, you will never see 100 hours out of the valves, period. You may not want to name drop, but I will, Jesse Williams of Williams motor works, who makes titanium valves and engines that have won many national championships, has said many times never to lap titanium valves, just have the seats cut.

To make comments about me working on my bikes just shows your ignorance to how I build and maintain my equipment.

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Allow me to name drop: Kevin Cameron. He has a wee bit of experience in the field. In my conversations with him, we've dicussed this and he's showed me the effects of Ti valves that sat on lapped seats Vs. one that did not. The unlapped ones were still serviceable long after the lapped ones were shot.

Just becauswe you work in a place that builds drag engines does not make you an authority on motorcycle engines. I know little about drag engines nor would I ever profess to be an expert. Apples and oranges. Drags and MX.

I do, however (as does KJ790) know motorcycle engines. I have over 35 years experience, some of which working for Yamaha factory.

However, if you wish to lap your Ti valves, by all means, go ahead and do so.

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This will be a never ending debate.

Yamaha factory does indeed lap their valves, but they have the resources to replace valves more frequently. And they feel it's the way to go. I'm not going to tell them not to, it's their choice. But there are downsides to it that goes beyond just wearing out the valves coating.

I am against lapping valves for numerous reasons.

The first and foremost, you think you are making the seat more concentric by lapping? Not even close. When done on a reputable seat cutting machine the pilot is tight in the guide. When lapping... guess what... the guide and valve have clearance... so you are just lapping to a floating dimension.

The old misconception to the seats being "rough" from a profile cutter. Yep, it's true. The coating is harder than the seat... so the seat conforms to the valve after 15 minutes. That's why 4 strokes make their best power after a 15 minute break in.

Other points... a lapped seat will show less flow on a flowbench most of the time.

A lapped seat will deteriorate quicker than a non lapped seat in a racing application.

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I totally agree with williamsmotowerx. I thought the manuals were just written by tech authors that hadn't been re-schooled. The O8 and previous Yamaha service manual actually suggests using a light lapping compound and working untill the valve face and the valve seat are evenly polished. They also suggest using a coarse lapping compound when replacing a valve and valve guide. They must have little reguard to the cost of valves. I also do MX race heads and engine rebuilding for a living. Many of the OEM Ti valves don't seem to be hard faced or coated. We cut the seats using the newest Rottler SG7 seat and guide machine with tooling for these types of seats. I will on occation use 800 grit with Ti valves if the cutting bit left any chatter marks or if the vacuum test is slightly off. Every manufacturer uses different seat materials that cut differently and some even have hard and soft area's after heated and need some additional surface lapping after cutting. Aftermarket valves usually have a special vapor applied nitrate type coating on the stem and sometimes a different under coating on the valve face. If needed I use a freashly cut dummy valve to lap the seat as not to ruin the coating on a new valve. In a perfect world every seat cut would be 100% matched to its valve mate. Concentricity to the guide axis is a lot more important and can only be acomplished with modern high dollar machinery. I wrote an article in TT under engines in the TT article section. NOTE: After a very short time of running the valve will seat itself on a good quality cut seat without lapping. I'm just a freak when it comes to seeing good valve seat vacuum readings.

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I know all about lapping due to spending about 30 years in titty bars from NYC to LA.

A good lap dance is a wonderful thing when done by a skilled professional. A BAC of .10 or better is a must as well.

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I know all about lapping due to spending about 30 years in titty bars from NYC to LA.

A good lap dance is a wonderful thing when done by a skilled professional. A BAC of .10 or better is a must as well.

lmao nice post bro

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I know all about lapping due to spending about 30 years in titty bars from NYC to LA.

A good lap dance is a wonderful thing when done by a skilled professional. A BAC of .10 or better is a must as well.

lol 👍:worthy::busted::blah::D:doh:

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