Why me?

Who can tell me why my new complete GYTR ported head assembly has leaky valves (I & E leak down is excessive)?

Has the head been run? What method are you using to test how well the valves are sealing?

needs a valve job. Send it to someone reputable, TUF, PR2 etc. Shouldn't cost much.

I'd be pissed too. A $1500 head should not have leaking valves. Are you testing them on the bike with a leakdown tester, or off the bike with solvent?

Leakdown @ TDC with the cams in, leakdown @ TDC with the cams out, leakdown @ BDC with the cams out; all well over 15% leakdown. Valve clearance wasn't what I was expecting from GYT, either, intake clearances are out of spec, exhaust are in the middle.

Leakdown @ TDC with the cams in, leakdown @ TDC with the cams out, leakdown @ BDC with the cams out; all well over 15% leakdown. Valve clearance wasn't what I was expecting from GYT, either, intake clearances are out of spec, exhaust are in the middle.
KJ asked "has it been run?", and you gave no answer. It's a pertinent question. Smart builders will never lap titanium valves, and in the case of the GYT-R head, which, like it or not, is a production assembly rather than custom work, it's likely that the head started and finished with new valves and a head off the shelf, making the matter of sealing just about exactly like a brand new bike.

Run the engine for an hour and test it again. There should be a significant difference.

Valve clearance cannot be accurately set on the bench each and every time it's done. With a seasoned casting, it's a bit more likely, but the clearance can only be accurately done with the head torqued in place. It doesn't really surprise me that they'd be off a little.

Leak down testers are not made to a particular standard like a pressure gauge would be. 3 different testers will usually yield 3 different results, and it's only useful if used repeatedly on the same engine, or on several engines of the same type, so that some meaningful comparison can be done.

Yup, like Gray said, I've seen many freshly assembled heads leak before they are run. Once they are run for a few minutes they tend to seal up. If it is still leaking after you have run the engine for a little bit then there is something wrong.

I like to use a black marker to check the valve seat contact area in relashion to the valve face. This way doesnt affect the machined surface or valve. Color the seat/valve face and lap by hand by slowly turning with medium pressure.

Yup, like Gray said, I've seen many freshly assembled heads leak before they are run. Once they are run for a few minutes they tend to seal up. If it is still leaking after you have run the engine for a little bit then there is something wrong.

Very true... they will pound thier own seat and seal lol.

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