wallo Posted October 5, 2014 Report Share Posted October 5, 2014 So, still got the metal on metal noise after the bike has run for around 10 minutes. I sat looking at the engine tonight waiting for a eureka moment and maybe I had one. Have a look at the picture, could it be that as the oil heats up it just flows downhill to the inlet rocker and doesn't bother to flow uphill to the exhaust rocker? The oil starvation from the exhaust rocker then creates the noise. Quote Link to comment Share on other sites More sharing options...
wallo Posted October 5, 2014 Author Report Share Posted October 5, 2014 Maybe the picture is there now? Quote Link to comment Share on other sites More sharing options...
naichuff Posted October 5, 2014 Report Share Posted October 5, 2014 looks like the pipe is flattened (starving oil supply) at the bend where it enters the banjo connector stopping the flow Both my BSA B31 and two AJS's the rocker feed starts below the barrel base on the same system (oil return side) as your engine so uphill should not be a problem 1 Quote Link to comment Share on other sites More sharing options...
dadof2 Posted October 5, 2014 Report Share Posted October 5, 2014 Its longer than I care to remember since I worked on this type of engine but in general the separate flow to each rocker should have a restriction in it so it can't take all the oil coming up the single feed. This forces equal amounts of oil to both rockers (or camshafts) irrespective of oil viscosity or gravity. I know of some car engines where people have failed to replace these restrictors resulting in oil starvation to parts of the valvetrain. Perhaps something similar is your bikes problem Quote Link to comment Share on other sites More sharing options...
sirdabalot Posted October 5, 2014 Report Share Posted October 5, 2014 Not sure what your engine is, but the British singles and twins I owned had pressure fed rocker assemblies, using one feed pipe teed off to feed both rocker shafts (looked like that in your pic). Start it up and loosen one banjo nut, oil should come out, tighten it up and repeat on the other. If good. Look elswhere, eg loose tappet, broken valve spring, snapped rocker shaft, missing or broken rocker shaft sidethrust springs/shims. Quote Link to comment Share on other sites More sharing options...
japes1275 Posted October 5, 2014 Report Share Posted October 5, 2014 That's a C15 head. I can't see any kinking or flattening of the pipes and I can't imagine the oil not being able to flow up that little rise if it's just managed to get all the way from the bottom of the engine. Have you got a copy of Rupert Ratio? Might give you some ideas. If not then try asking on b50.org forum, some very knowledgable BSA unit single chaps there. Quote Link to comment Share on other sites More sharing options...
b40rt Posted October 6, 2014 Report Share Posted October 6, 2014 Nothing to do with valve lifter ? Quote Link to comment Share on other sites More sharing options...
davetom Posted October 6, 2014 Report Share Posted October 6, 2014 My C15 makes similar metallic noises after 5-10 mins. I put it down to the piston, I just carry on warming it up, or ride it and the noise disappears. Quote Link to comment Share on other sites More sharing options...
wallo Posted October 7, 2014 Author Report Share Posted October 7, 2014 Thanks for the posts. So the latest status is: Oil pipe feed is working fine I was straightened the pipe and checked that oil is still flowing when the noise starts. I have checked the clearence between the stator and the pick ups which if fine. I have noticed though that when the noise starts I start to see air bubbles in the return pipe, any thoughts? Quote Link to comment Share on other sites More sharing options...
naichuff Posted October 7, 2014 Report Share Posted October 7, 2014 The return side of the oil pump is bigger than the feed side so it will draw air once the crankcase is flowing properly My cub and BSA do this as they both have clear plastic oil pipes If not the oil is not being supplied to the engine or it is filling up It take a minute or two for the air to appear as the oil will drain to the bottom while the engine was stopped Quote Link to comment Share on other sites More sharing options...
wallo Posted October 13, 2014 Author Report Share Posted October 13, 2014 So, I think I know the issue now after a chat waiting at sections yesterday. The general consensus was that the liner was moving when hot so when i got home I fired her up and kept the barrel cool with compressed air. She ran for 30 mins, with no noise. Turned off the air and the noise started after about another 10 mins of running. Putting the air back on the barrel stopped the noise :-) So just need to figure out how to stop the liner moving now. Quote Link to comment Share on other sites More sharing options...
jon v8 Posted October 13, 2014 Report Share Posted October 13, 2014 Good to see you out on a decent bike yesterday Ken,give yer 30 quid for it when you get fed up with it ! My advice is to take the barrel and piston to South Cerney Engineering and take their advice.Whoever bored the barrel to take the liner didnt get the correct amount of interference.I dont think I'd want to trust Loctite or similar to hold it,plus it wouldnt be good for heat transfer.An oversize OD liner fitted correctly is the best way forward I think,with the bonus that the heat transfer would be much better. Quote Link to comment Share on other sites More sharing options...
wallo Posted October 13, 2014 Author Report Share Posted October 13, 2014 Cheers Jon, I've arranged to go there early doors tomorrow. The Matchless is riding like a dream, the shorter wheelbase has made a massive difference just need to get the turning circle sorted (new yokes need the tank pushed back a little). See you at the Bath Classic on Sunday :-) Quote Link to comment Share on other sites More sharing options...
wallo Posted October 24, 2014 Author Report Share Posted October 24, 2014 All sorted, hybrid engines are a pain. The liner was hitting the head, all sorted now, happy days. Just need to get a log book, anyone got a V5 for sale? 1 Quote Link to comment Share on other sites More sharing options...
rusty ken Posted October 26, 2014 Report Share Posted October 26, 2014 Cheers Jon, I've arranged to go there early doors tomorrow. The Matchless is riding like a dream, the shorter wheelbase has made a massive difference just need to get the turning circle sorted (new yokes need the tank pushed back a little). See you at the Bath Classic on Sunday :-) Quote Link to comment Share on other sites More sharing options...
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