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04 CBR 600rr won't start when hot
Bump for an old thread
I'm bumping this thread because there may be some folks, like myself... who buy a relatively unused 03/04 cbr600rr from an original owner... who tells you about the "bike wont' start when hot" story that he never got resolved.. and just worked around it by sitting and waiting 20 minutes if/when it happened.
This thread is full of so much information, but most of it is downright rubbish. So for anyone who HAS THIS PROBLEM, where the bike starts fine when cold, yet barely cranks and won't fire when HOT, let me clarify the simple fix.. so you don't go down the garden path as posted above in the thread.
1. Starter. First off, this is riduclous to think that the starter gets hot and won't turn. Whomever came up with that, is just dumb.
2. Stator. These bikes have stators that do fail. This has NOTHING to do with the symptoms you would get.
3. Grounds. While maintaining clean grounds is important, this has nothing to do with a voltage drop due to crappy grounds.
4. Battery. This is NOT happening because your battery is crap. Your battery may be crap BECAUSE of the problem, but it's NOT THE CAUSE.
This problem occurs EXCLUSIVELY and WIHTOUT QUESTION as a result of the REGULATOR RECTIFIER. The unit works fine when cold, but does not function correctly once it's hot as hell. When that happens, the bike doesn't maintain enough current back to the battery to keep it fully charged. After extended heat and ride time, the battery is to the point when you turn the bike off, that it does not have the umph to turn the starter.
The bike cooling down and running has nothing to do with the engine, the starter, or the starter cooling down. It has to do with the battery sitting for a bit and the voltage and amperage spiking as it always does when it sits, if it's been discharged down somewhat.
I had to laugh when I read the crap over the internet about this problem. Some folks are as dumb as rocks - and others try to make some complex problem out of one that - if you simply grab a basic multimeter, allows you to figure it in 1 attempt.
Carry on. The answer is now here for everyone to read that may need some assistance.
DO NOT BUY A HONDA OEM REG/REC. Get one from Rick's motorsport.. they are about $150 bucks and designed specifically to be more resistant to temperature due to the CBR location. Installation is about 20 minutes, get some dielectric grease.. and cut back the wire housing to split the two leads for easier and cleaner installation.
Starter motor... what a joke... roflmao.