No, actually after port job I sent the head to have the seat and guide replace ? Also they put in +1 intake valve. Since then I installed the kibblewhite valves spring kit and installed the head back. Does weak springs cause reversion?
Just a guess here, but were the valves set right. If gap was to tight, or valve had pressure on it early it could open while exhaust gases are still in chamber. But that should of been noticeable with a backfire or something every know and then.
Can it be reversion? I'm using a stock kawa 1000cc zx-10 muffler adapted to a full barker pipe (i just exchange the muffler)because of noise regulation (92 db max) so if it can flow a 175hp bike what's the deal with a 700cc 50-60hp bike ? Is pulse can be something i overlooked?
no its either a bad seat seal or your valves were to tight valves should be lapped after cutting to ensure a good seat. theres a few special ones with certain coatings you shouldnt lap but almost everything its good practice
take the head off and poor some gas into the intake ( a good bit) see if it leaks past valves same with exhaust. Compression test will tell you, you have a leak but not where and small minor leaks may be hard to tell if you dont have other numbers to go off of, also you need to make sure the decomp is not a factor
Forgot about the lapping. I used to put air in the cylinder thru a homemade chuck and screw into plug hole. It would put 100 psi in the cylinder when I had to change springs on chevy heads. It turned out to be a good tool to find out where my motor was bleeding off pressure if I had a problem. Should work on just about anything else I would think. If intake valves are leaking, air would come out intake, same with exhaust. And same with crankcase.
Hey Eric I have been riding my bike very hard for about a tank today and the zx-10 muffler exploded!!!! Damn, so I going back to my barker muffler...so I thinking of reversion... Anyway I will pull the head cause if i'm buying the 106-x1 cam I will have to clay for valves clearance. What about the cam you're working on?