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Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 12:44 pm
by spookefoote1956
As most of you know I binned the Thorspark and got a mag from our beautiful spares dept. Lovel blue spark. The Beast will not fire and the compresseion was low, less than 50 psi.
The pictures show the head off and oil going to the head
Put fuel in the head and the valves appear to be seated well
Valve springs are in right, small over large
Piston rings aren't broken
Slight scoring on the barrel
I'm now at the end of my knowledge and skill base so don't know where to go now. Any thoughts?
Big love, Chris
Woes.jpg
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 12:58 pm
by g80csp11
try turning head upside down with valves and springs still fitted . put in spark plug and then fill combustion chamber wit paraffin . does it drop level and run out of one of the ports . if so the valves are not sealing
A good starting point
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 1:25 pm
by spookefoote1956
I think that's what one of the pictures is showing?
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 1:27 pm
by SPRIDDLER
Valve lifter cable too tight holding the zorst valve off its seat?
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 1:37 pm
by CharlesDP
I had my mag rebuilt, it had a lovely spark, BUT under compression it had no spark, I asked a different person to check it out and they said that it was rebuilt incorrectly so had it rebuilt again, what I am saying is do not assume that just because it sparks on the bench it always sparks when fitted.
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 1:55 pm
by dave16mct
Just a thought Chris, are the rings exactly as they came out of the barrell because they gaps are all in line. They should be spaced at 60 degrees apart.
PS are you going to Farmyard Ales on tuesday night?
Dave.
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 2:19 pm
by spookefoote1956
Morning Dave. The rings were at 120 to each other. I moved them round for the photo. Might see you at FYA on Tuesday.
I've just measured the ring gaps Top 0.017, Middle 0.016, Bottom 0.013 Still not up to the permissible which is supposedly 0.03
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 2:51 pm
by dave16mct
Sorry I meant 120 degrees (honest!). Isn't it 3 thou per inch gap?
Dave.
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 3:01 pm
by spookefoote1956
This is what I got from the 56 Manual
Ring Gap.jpg
Re: Where do I go, where do I go, where do I go now?
Posted: Fri Jul 29, 2022 3:19 pm
by spookefoote1956
My current piston is a JP. The more I'm reading about them the less I like.