I've got a new to me 1990 GS500E that does not appear to like starting up in cold weather (~20-30 Degrees F) on full choke, with a full tank of gas, and a fully charged battery. Any ideas as to how I would get the bike to start reliably in cold weather? The bike has been re-jetted, fitted with a K&N Air Filter, and a Vince and Hanes SuperSport exhaust.
Rejet it.
For me, shaking the bike back and forth on a cold cold day seems to help get it up and running pretty well.
Make sure the jets are correct, mixture screws,and check the valves. And do start with fresh plugs also....good luck!
IF its been sitting for a period of time and you dont think its a jetting problem. Try turning the petcock to "PRIME" for a second or two, then turn it back to "ON". Now hold the starter and let the motor turn. If it doesnt start after about 10-15 seconds than let go of the starter. Do this in intervals until it starts. If the battery is fully charged and fuel and spark is there, it should start no matter hot or cold.
Again unless there is a jetting prob. This is a good way to find out i guess.
Good Luck,
Barry.
It's could be jetting, battery, or valves. From what you've already posted, I'd bet your valves are out of spec. This can make the bike run like a nightmare. The bike will stall at idle unless full choke is applied even after 30 minutes of riding.