General Category > General Discussion
Bike hard to start when it’s hot???
bobrebos:
--- Quote from: Jack Straw on May 18, 2022, 05:58:31 PM ---I encountered hard hot start problems on a few bikes. Every time it's been coils, and, every time the problem coils checked out OK with basic multi meter testing. Go figure, eh.
--- End quote ---
:thumb:
Chuck in Indiana:
--- Quote from: Jack Straw on May 18, 2022, 05:58:31 PM ---I encountered hard hot start problems on a few bikes. Every time it's been coils, and, every time the problem coils checked out OK with basic multi meter testing. Go figure, eh.
--- End quote ---
You need to put the coils in the oven and warm them up.. then check with a multi meter.
A bad plug can mimic a failing coil.. don't ask me how I know. :evil:
Wayne Orwig:
--- Quote from: PJPR01 on May 18, 2022, 12:56:57 PM ---As has been stated several times and recommended by numerous folks, when it’s hot you’re likely to be getting some level of vapor lock. Open the gas cap and let it vent a few seconds and try again…
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Very unlikely. That fuel pump is submerged under liquid fuel. That pressurizes the entire system down stream from there. Even if the tank does not vent properly, the pump will typically keep pushing out fuel. Very difficult to get a vapor condition in a system with a submerged pump. Now in the systems with the external pump sucking on the lines, that is very common.
pressureangle:
--- Quote from: Perazzimx14 on May 19, 2022, 08:21:19 AM ---Unless the sparkplugs have 150,000 miles on them or were fouled by poor fuel or oil burning they are not the problem. Modern sparkplugs are not the crappy AC Delco's of the 1970's. They last a looooooooog time. If they are iridium you'll get tired of the bike before they are worm to the point of needed replaced.
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There's a clear misuse of terms in this thread.
Vapor lock is when the fuel boils within the system, and displaces liquid fuel at the engine entry point.
Tank vacuum is when the pressure in the tank becomes too low to feed the carbs or pump. Seems unlikely in an EFI system, but still to be verified.
PJPR01:
--- Quote from: Wayne Orwig on May 19, 2022, 08:16:34 AM ---Very unlikely. That fuel pump is submerged under liquid fuel. That pressurizes the entire system down stream from there. Even if the tank does not vent properly, the pump will typically keep pushing out fuel. Very difficult to get a vapor condition in a system with a submerged pump. Now in the systems with the external pump sucking on the lines, that is very common.
--- End quote ---
From personal experience on my 08 Norge, it's behaving exactly as I've described - I understand the above statement, however opening the gas cap, relieving the pressure and the bike runs fine again immediately, so....This only occurs on extremely hot days, and not very often. Which sounds like what Bob is experiencing. Either way, it's one alternative for him to explore...hopefully he finds the root cause.
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