SOHC.co.uk Forums > CB500/550

tickover problem

<< < (3/3)

mickwinf:
well I spent a few hours stripping carbs, everything internally very clean, the only thing I could see wrong was the floats were a bit twisted so I spent some time straightening them out and reset float hights. Re-fitted with new rubbers so definitely no air leaks. Now It is better and will tick over for longer but still will suddenly drop revs and stall. will try again tomorrow!

fisjon:
If your carbs were ultrasonically cleaned as one unit it is possible that the fuel connector seals may be perished. Rubber or plastic placed into an ultrasonic cleaner can degrade very quickly. If they were original fit then they wouldn't take long to disintegrate. Also the core plugs can dislodge and/or fall out completely if the fluid was being used at the 60-80 degrees recommended by the cleaning fluid manufacturer. I have found a few in my bath and have resealed them back into the carbs with resin. Another thing I have found is two lots of rubber seals in the air screws and sometimes no flat washer to go between the spring and air screw seal.

If the engine slows down gently before conking out then it may be fuel flow, but this would be apparent at higher speeds so if your bike runs good except for tickover and conks much without warning then it is probably electrical. As the engine slows down the electrical output is marginally reduced and there may be a gremlin due to a faulty regulator or a bad earth somewhere on the bike that is affecting the spark train. All it takes is for a momentary loss of spark and the motor will hunt and stall.

I fitted my CB650Z with a Boyer unit, totally ripping out the Honda stuff and the bike absolutely refused to stall. The spark was like an arc welder! I used a plug on the side of the engine to test it when I first fitted it and I have never seen a spark so bright. It also make a cracking sound and frightened the s**t out of me.

Food for thought

mickwinf:
Carbs were stripped prior to ultrasonic cleaning and all new rubbers fitted afterwards. I hadn't considered electrical but will check it out. It is better but not perfect yet.

Navigation

[0] Message Index

[*] Previous page