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You may have fractionally bent some valves, probably exhaust ones given the after fire in the pipes, and as the calves heat up the stems expand a fraction, but enough to cause intermittent sticking. That is only a theory, but knowing how easy it is to damage valves fitting the rockers in the 350/400/500 and 550 fours, it certainly warrants further investigation if the head is coming off again. The affected valve seats may show signs of burning as a result, but not much as it has not been ridden much since this started Sent from my POT-LX1 using Tapatalk
Quote from: hairygit on September 10, 2019, 08:54:54 AMYou may have fractionally bent some valves, probably exhaust ones given the after fire in the pipes, and as the calves heat up the stems expand a fraction, but enough to cause intermittent sticking. That is only a theory, but knowing how easy it is to damage valves fitting the rockers in the 350/400/500 and 550 fours, it certainly warrants further investigation if the head is coming off again. The affected valve seats may show signs of burning as a result, but not much as it has not been ridden much since this started Sent from my POT-LX1 using TapatalkThanks Hairy useful input, one question is you say how easy it is to damage the valves etc. What are the big care points when refitting. May be some clue as to what I have done !!Also what do you mean by valve "calves"
Quote from: paulbaker1954 on September 10, 2019, 09:00:37 AMQuote from: hairygit on September 10, 2019, 08:54:54 AMYou may have fractionally bent some valves, probably exhaust ones given the after fire in the pipes, and as the calves heat up the stems expand a fraction, but enough to cause intermittent sticking. That is only a theory, but knowing how easy it is to damage valves fitting the rockers in the 350/400/500 and 550 fours, it certainly warrants further investigation if the head is coming off again. The affected valve seats may show signs of burning as a result, but not much as it has not been ridden much since this started Sent from my POT-LX1 using TapatalkThanks Hairy useful input, one question is you say how easy it is to damage the valves etc. What are the big care points when refitting. May be some clue as to what I have done !!Also what do you mean by valve "calves"Sorry, bloody auto correct crap that I can't turn off in Tapatalk, it should have said as the VALVES get warm and expand, the stems start sticking in the guides.Sent from my POT-LX1 using Tapatalk
I find it much easier when trying to source a valve seat leak to fill the tract up with petrol rather than the combustion chamber, you get more in and it's far easier to see the leakage as you can look directly at the valve seat whilst it's trying to leak past. This was how I lapped valves in, I'd just hold the stem with a tap wrench and see if any petrol leaked past, if the seals good it wouldn't leak past even with lower pressure exerted on the valve seat. I liked using petrol as it was easy to obtain and it was very easy to spot as it leaked past.
Quote from: Oddjob on September 10, 2019, 12:31:12 PMI find it much easier when trying to source a valve seat leak to fill the tract up with petrol rather than the combustion chamber, you get more in and it's far easier to see the leakage as you can look directly at the valve seat whilst it's trying to leak past. This was how I lapped valves in, I'd just hold the stem with a tap wrench and see if any petrol leaked past, if the seals good it wouldn't leak past even with lower pressure exerted on the valve seat. I liked using petrol as it was easy to obtain and it was very easy to spot as it leaked past. In most situations I would 100% agree on that one Oddjob, but if the stem is fractionally bent, so little that it only gets sticky when the stem is at running temperature, it may not have damaged the seat enough to see any leakage. Also, if the bend is so minor it probably wouldn't show lapping valves in if there is any clearance in the guides.
Paul, by any chance did you take the bike to Hammer and Tongs in Warrington?For some reason I'm not convinced the valves are the problem, not sure why, just a gut feeling, something in my head keeps saying it's a gasket problem, again, I'm not sure why but I can't shut the damned voice in my head up. I'll be happy if it is a valve problem, at least then I can tell the voice to shut the hell up and stop bothering me. Am I going mad? it's a possibility.
Oh dear Paul....you have done well so far retaining your sanity over this problem 😀 Did you back off the tappets fully and hold the tappets up with elastic bands when you fitted the rocker cover?