A friend of mine just bought a 2012 R6 with 12,000 miles on it and is having issues with a specific starting issue that I can’t figure out. When the bike is cold/sitting it cranks right up no issue (not on tender and overnight) When the bike is hot and you shut it off then restart shortly after shutting it off it cranks right up no issue. When the bike is hot and it sits for an hour or two bike “lugs” starting like the battery is weak/almost doesn’t start. If the bike sits in the sun for that hour it’s worse. This is not a happened “once or twice” problem it’s consistent with this specific scenario and I can’t figured out what’s wrong. Only thing I keep coming up with is the rectifier (in stock location under tank) is staying hot and causing the issue. Any help is appreciated thanks
I would be led to believe it is the battery starting to die. Have him pull it out and take it to almost any auto parts store and have it tested.
Battery is good I tested it myself. I’m still going to have her replace it anyway because its 3 years old and well they are cheap enough just in case because I tested the battery while the bike was cold.
A kinked vent or vapor lock will not cause a slow crank situation. Those are no or stumbling start with fast crank. Not a rectifier issue. That has nothing to do with cranking. Either your battery is crap, which is most likely or the starter is crap. Starters can suffer from heat soak, which can increase their internal resistance when hot and then will crank slowly. Get a new battery first.
Cool thank you. I didn’t know that with the starter. It makes sense. I’m going to get her to replace the battery and see if that fixes the problem. The only reason I was thinking rectifier was it was the only thing I thought would be affected by heat minus the battery. Never thought of the starter getting heat soaked ether Thank you
especially if a lithium, testing em is iffy. Even with the preferred load tester.. as suggested, i'd try a known good battery first. Had a couple over the years that load tested good, but in real world needed replaced. And in 10 years of racing the same 2 bikes and a variety of 4 motors at a time.. i've changed 2 starters. it can go bad as it's nestled right down in there in the heat of the motor all the time.
Mine starts fine when cold. After it gets hot from a track session, it cranks like normal but will take longer to start (more cranking) and sometimes, when it starts it shuts right off. I usually give it a little gas to help it. Or I have to crank it again and hold the starter longer. Any ideas?