I was going to answer "check if valve seal has left the guide".
Clean the head and replace all seals just for sure.
I have never seen a loose valve seal when using the seals included in the gasket kits.
- Is this happen more with KPMI red Viton seals?
I saw one seal last year that has lifted, it sat loose on guide. Kibblewhite 5mm stem kit.
Some of the bronze guides had a little bit play. Not enough to take it apart but definitely not good enough to assemble again. A little bit more than 25.000 km.
Too rich and too lean jetting might have helped to shorten the guide life.
I used another refurbished ported head (K2 style) with stock guides, F2 34mm inlet valves and 28mm KPMI ex.
Chamber volumes 23.7- 23.8cc (old head 24.4cc)
I cranked up the compression with that head giving 101whp, before max 93whp.
Billet block, JE 71.25 mm ordered from Dynoman, around CR11:1 since chambers were bigger.
I changed cam too, from RC295 profile to Megacycle 125-75.
I have another head ongoing, new stock guides I believe is better on a street bike. KPMI 33.5/28.5 mm valves.
Same chamber volume as my 101whp head. But thinner base gasket this time will increase compression a little bit more.
Lets see if it will give more on the wheel. 105whp and keep the good torque my 101 head gave is my goal.
Or even better, surpass Mike's +106 whp, the value to beat!!
My cheap compression tester showed 197.5 vs 202.5 PSI on last head.
(Old head had around185-190PSI thicker head gasket)
If compression is higher with next head, more power might be around the corner.
Hopefully no pinging.
Cure then is to replace head gasket from 0.75mm to my old 1mm MLS.
The chambers will get a good squish area to avoid it, hopefully it will become true.
I might get the head this week. I'll update my K6 build thread.
Good thing with MLS, use again, again..... Some spray were Viton is worn. I'll use Loctite 3020 after recommendation from my nearby shop.
