Total Motorcycle Community Forums

Bought the bike earlier this summer and had no problems until it started getting cold. Now the bike won't start at all. Took it into the local Yamaha dealer and they said the battery wasn't holding its charge so they replaced it. The problem persists, I'd rather not take it back to a shop that didn't correct the problem the first time. This is my first bike and I'm inexperienced (though somewhat mechanically inclined) so I'm not sure what else would cause it. Thanks!

If I have learn one thing here on the forum this is it. Check you vaccuum hose to the petcock. It may be fitting loose due to the drop in temperature.

if the new battery wasnt charged for several hours with a motorcycle specific charger it wont be much better than the one you replaced if any.

Does the engine turn but fails to start????

A little more information since I couldn't be specific in my original post. The bike starts fine on warmer days, so I'm almost sure it's temperature related. Secondly, I'm pretty sure it's not electrical because I do have a motorcycle battery charger and I had charged both the new and old batteries.

I'll check the hose to the petcock tomorrow to see if that is the problem, what should I do if that is the case?

When it's very cold (say less than 45 degrees) the starter will crank but it won't turn over at all. When it's just cold (maybe 55 degrees) it might turn over but it will die immediately. Tries to start after that point will be just like when it's very cold.

I got it started today when it warmed up a bit, to say 55 degrees. I rode it to school, finished my classes, and went out to start it. I pulled the choke out since it hadn't been ridden in a few hours and it started and ran for 2-3 seconds then died (I probably could have given it a bit more gas and it would have been fine but I wasn't paying close enough attention).

Another tidbit: the bike runs great in warm weather, no problems at all... but in the cold weather, if i can get it to start, it hesitates every once in a while... could that be a symptom of the aformentioned hose to petcock?

Thanks again

If the hose is cracked or fits loose replace it with a simular hose that will do the job. When you say the starter will crank but it will not turn over you mean it will not start, right. However, the engine is turning but not starting. Good luck.

Are you using the choke? And is it opening the 4 chokes on the Carbs? Make sure the cable isn't or didn't slip in the clamp. Try moving it to full choke and then back off a little. NO throttle then crank it over.

Alright, after reading some of your suggestions and other posts on the forum I thought it might be a vacuum problem. Lo and behold when I set my petcock to PRI it has started twice in the cold with no problems. I hope this finally identifies my problem and I can get it fixed eventually, but for now I'll start it on PRI switch to ON after. Will this do any damage to the bike on the longterm? I probably won't have a chance to work on it until December. Thanks.

If you run it on prime don't forget to turn back to on when not in use. If the carb floats or the needle are not holding the fuel off completely you may accidently leak fuel into the engine.

I am having the same cold start trouble on my 1990 Yamaha Radian YX600. I have checked the vac hose on the fuel valve and it is in good condition. When cold, the engine fires only at closed throttle and will not fully start and run. If I attempt to give it more gas it quits firing.