SOHC.co.uk Forums > CB500/550
Wont exceed 4,500 rpm then stalls and wont restart - on route to MOT
notobikeparkingtax:
--- Quote from: totty on April 24, 2010, 03:31:05 PM ---I set the tappets when I first bought it 350 miles ago, could they cause these symptoms?
--- End quote ---
Sure could. If they're too tight then at higher revs either the inlet or exhaust valves might not be closing completely - causing lack of compression.
Worth checking, supposing there was a spot of carbon on one of the valve seats last time you checked them, giving a false reading ? How long will it take, 30 minutes ? How long have you spent on it already ?
And yes, valve clearances close with wear, and camshafts do flex.
rigwit:
clean float chamber out sounds like a dropplet of water which will be picked up and resonate at a certan flow /revs also clean out your inline fuel filter as if any water droplets in with petrol you could go 1 to 1,000 miles b4 it happens again one of those annoying probs that come and go ...........
totty:
I hope to get some time to work on it this week end. I'm going to work in order of easyness - check fuel filter and drain carb bowls, check tappets, relay coil feed, adjust needles and re sync. Hopefully one of those steps will sort it out.
K2-K6:
Hi Anoyone checked the air filter? just run it with it out for a test to see effect (had a filter do this on another Honda and I could not beleive the effect was so defined, took me ages to sort). Not sure of the intake on the 550 but friend had 400/4 and put overtrousers over air box intake under seat and caused similar probs once. It'll be interesting to find out what it is, shame we can't get you more help.
Have you done a plug inspection on all cylinders when it's running hot to give you an idea of mixture?
What is the psi reading for compressions on each cylinder?
If you start it from cold, run for 30secs, switch off and touch the header pipes to see if all are similar temp tells you if they are all firing straightaway.
Check through the fuel tap to make sure there is no blockage in any passageway
BTW fuel always comes from the bottom of the tank when on reserve!! I've always run everything I've owned bike/car to as near empty as I can (what's the point having range if you don't use it) and never ever used additional filters. My theory is you might as well run anything that could be a problem out so it will never accumilate things you don't want in there. On that note, if you don't use it down to the bottom do you have a tank cleaning schedule? to get out the mythical junk.
totty:
Hi,
I tried without the airfilter and checked the plug colours, the airfilter made little if any differance and the plugs looked good but that was some time ago and I've replaced the ignition system since. Also tried pulling the choke on when it bogged, but the choke doesn't stay on when the revs are up and in that rev range power delivary is a too bit unpredictable and rough for 1 handed riding.
I don't recall the compression readings and i can't find my notes but they were all within 5%.
I've twice found that number 4 didn't heat up imediately, but I then made a point of checking on most startups and it hasn't done it since.
The fuel flow seemed good when I let it flow into a can.
I don't normaly aim to drain a tank or have a cleaning schedule, but I have drained and rinsed out this tank.
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