Hi,
So the 'rattling tools on the bike lift' problem was solved but there was still a rattle. So back to basics. What had I done to the engine?
New oil pump, head overhaul and new exhaust.
First to check was back lash in the timing gears - nothing really but checking with a stethoscope had indicated more noise from the pinion on the electronic ign. drive and there was a bit of wear so a replacement was probably a good idea anyway and it was a bit lighter than the one I took off.
Next, although highly unlikely to be the problem, was the new pump so quickly put the old one back but no change and then put the new one back on again.
Moving up the engine, the next thing was the head and I do not want it take it off. I had also noticed that the tail pipe was quite oily - this symptom was new to me so a bit baffling. Had I not cleaned the drain holes by the exhaust valves and oil was building up and being sucked down the valve guide? No, they were clear.
So next check the valve clearances and at first I gave myself a good talking to as one of the inlets was incredibly slack. So turned the engine and 'boing', the valve seated and the clearance was OK.
The valve was a bit sticky in the guide and was not closing properly every time hence the rather disconcerting noises. So after checking that there was plenty of oil getting through by using a 'squirty' oil can on the end of the rocker feed I gingerly filled ther carb with fuel and started the engine and ran it for few minutes with a bit of 'stickyness' still evident. So a few more gentle cycles of start, run at a fast tick over and then stop. I could see plenty of oil was getting up there as I still had the rocker cover off. It seems OK now but a few more tentative gos tomorrow to get it a bit hotter before boxing it all up again. If all OK then I will be a happy bunny otherwise the head will have to come off.
Dave.
I would worry that as soon as you gave it any stick the valve would seize in the guide, contact the piston, and cause all sorts of mayhem.
Hi,
This is a possibility but as it my wife's bike and she has strongly suggested that I just bight the bullet and take the head off. As you suggest even if I get it working OK on the bench it may nip up under proper use. So head off this afternoon.
Dave.
Hi,
Once the head was off and spring removed the valve slid nicely under gravity against the oil with no feeling of a tight spot but had it very lightly 'diamond honed to give a minute amount more clearance so that should be that.
Just a question of fitting valve guide seals or not?
Dave.