Motorcycle Repair: CBR 600 Idle missing when engine is hot, shively ohio, plug caps

Question
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Followup To
Question -
Hi Mark,

The problem is that when my CBR 600 FY 2000 (carb model with 23,000 miles) gets fully hot (the radiator fan activates intermittently), the idle becomes irregular and sometime stalls while sitting at the lights. Other times it stalls (or almost stalls) when when accelerating from idle. When the engine is below that temperature, the problem
isn't there.

I've been struggling with this problem for almost 2 years now, mostly because I do most of my riding in cold weather for relatively short journeys. I've had this into the shop a couple of times and either they say that they've "fixed it" or can't see the problem, however the problem keeps occuring.

I've not touched the carbs and everthing is stock. On the weekend I had the airbox off and looked at the air filter, it looked ok, and plugs, they all looked normal and all the same. I replace the plug caps with a set from another CBR FY without any improvement.

With the warm weather upon us, I'd like to try to get rid of this worry once and for all.

Any help gratefully accepted.
Thanks
Pat Mosco
London UK
Answer -
Hi Pat,

Can you tell more about what repairs the shop performed? Any parts replaced?

I return tech files by email. There was no email address with your question as requested and explained in my instructions. Include your email addy with your reply. We'll go from there.

Respectfully,
Mark Shively
Ohio, USA
(descendant of Manchester County, UK)


Thanks, Mark, for your quick reply.

The shop hasn't replaced any parts that I am aware. The first time they said it was a pinched fuel line, the second time they said the spark plug cap wasn't full on, the third time they said they couldn't see anything wrong (presumably because they didn't run it until it was hot enough).

Another bit to add, I don't know if it's related, today I rode into work in the worst rain and traffic I've seen in a while and the bike stalled twice and nearly stalled another. The engine temperature gauge read well below the temperature i normally have these problems. It could be something else, but I really don't know.

BTW, interesting your family come from Manchester, I seem to meet more Mancunians than any other region.

Thanks
Pat Mosco
t_rick_e@hotmail.com


Answer
Pat,

The recent rain stalling may be related to water shorting.

The over-heating problems may be one or more of the following:

Defective thermal switch
Defective fan switch
Defective conductor wires or connectors
Loose conductor wire or connector
Defective fan motor
Improper coolant mixture
Air in the cooling system
Defective thermostat
or other

I'll send tech files to your email addy.

Respectfully,

Mark