SOHC.co.uk Forums > CB500/550

550 breaking down intermitant

<< < (2/3) > >>

K2-K6:
As Z110r says you seem to have covered the obvious and know what to look for, you could do some simple tests along his suggested topics of kill switch etc by when it happens again stop and switch it off with the kill switch then operate the switch a few times, restart and see if it has any effect, then do the same with the ignition barrel swicth if no change.

You can run with a wire direct from battery pos to coil to elimniate loom faults but you'll have no emergency switch-off while doing it so make a join you can pull out if you do.

Old trick but useful, take off tank and run motor in pitch darkness (tarp over you and bike can be useful) you'll be able to see any HT leaks that could be there and crossing to earth.

Check cylinder psi to make sure that's eliminated.

andy_c101:
K2-K6 could be on the right track.
I had a previous bike, and only when i was working in the last few minutes of daylight did I notice blue sparks jumping from plug cap to cylinderhead. It turned out to be the plug cap; the internal spring clip, that clips onto the plug, was badly corroded and cracked.

duzatun:
thanks for all the feedback lads
 as i did try another set of coils with their own caps didnt think it could be caps but im goint to check this out anyway you never know the remote possabilities that the other set being second hand could have a faulty cap stranger things have happened.
 and will check out the kill switch and a direct pos wire to coil never thought of that.
If the problem was their all the time it would be easier to find but as it does it intermitant makes it harder
 some times when its happened ive gone straight home so i can check it out but by the time i get home has stopped playing up.
One of those problems when i find it i will never forget these symptoms in the future.
 I will report back on tests i do
cheers

K2-K6:
Sporadic problems are always difficult to find out as you don't really know what you've done to make them stop so can't absolutely pin it down straight away.

It's just possible if the HT leads are leaking at all then if the same age it could be on both sets, more than possible with the overall age of these things I guess.

I was unable to diagnose an RD250 that didn't run and we went through most things with no success so someone else had a look at it and changed the fuel as a last resort, bingo straight away it started then the owner told me he'd put something like 50p of diesel into the tank wrongly before then adding petrol, it started and drove home but when cold it just wouldn't fire, you have to try and cover off almost everything to get there sometmes!!

It'll be interesting when you get it sorted to see what it was.

metalcatfish:
This might seem a bit weird but here goes anyway. In running similar setup but with 130 main jets. Fuelling is spot on. However do get horrid misfire in a cross wind.
I spoke to an old british bike expert and he reckons I was right thinking a cross wind would affect the fuelling. I know its weird, but I can run straight on a road with high hedges either side in the fens hit a patch of road with a break in the hedges or open motorway, add in some good cross wind and hey presto, runs like sh*t!

Navigation

[0] Message Index

[#] Next page

[*] Previous page