After installing some cobra slip-ons and proper jetting on my 07 Roadstar I thought every thing was great… but now … the bike runs great except when she’s cold. If I have to get to highway speed before she’s warm … she misses and backfires like crazy until I back off and ride slow for a couple minutes and then she’s fine. I got stuck and had to run some E-10 a couple tanks back; could it possibly be moisture from that nasty stuff our legislators forced down our throats here in Oregon?

Do you have the stock air box still? If you do the proper jetting would be to leave the jetting stock. These bikes are cold blooded. We need to know what you have for jetting for starters.

redrain



How long ago did it run great and what happened since?

It may be bad gas. Try draining out some from the tank into a glass jar and check it out for water. If there is water, drain it out until clear and also drain some out from the reserve too.

Do you choke when starting, warming up and beginning your ride?

Does it backfire out the exhaust or intake???

Rayjay wrote:
It may be bad gas. Try draining out some from the tank into a glass jar and check it out for water. If there is water, drain it out until clear and also drain some out from the reserve too.

When checking for water; drain with the valve on reserve! The main feed is an inch or so off the bottom of the tank; the reserve is the rest right to the bottom.

Clifford

Ethanol in gasoline won't cause any problems, it's all you can buy in Virginia and I've been running it for years.

Thanks to everyone who responded to my question. I am running a stock airbox. I first tried to run with the stock jetting and it was a nightmare ... backfired to holy ---- and not good on power so I ordered a jet kit from Cobra and installed it. I was very pleased with the difference at first more power and no backfiring, but a few days later when taking off for work in the morning I experienced the problem. The jets I installed were the ones recommended by Cobra … a 175 main with their needle and the pilot that came in the kit, I drilled out the PMS and pulled the screw out to 3 turns as recommended. It was set at 2 turns from the factory. I just got home from work and thought and checked to see if one of the leads to my fuel heater had vibrated off but that was not the case. I will go back out to the shop when I go off line and check for moisture. Again THANKS for the response!!!

Also ... I choke when I start for a few minutes ... when the rpms come up I back off on the choke after a few minutes I take off ride slow for a mile or so before getting on the highway. Choke seems to have no effect on the poor running conditions and the bike runs great when compleltly warmed up. The backfiring is through the exhaust mostly but is quilled when I slow down for a minute or two and resume highway speed. The only other issue I have with the jetting is the milage.

Clifford ... I checked for bad gas ... it was fine. Now that I think about it ... when rejetting I cought myself with my thumb on the float. It could be that I knocked it out just enough that it would hang up at first and keep the inlet needle valve from dropping at when getting up to main jet rpm until the fuel level dropped enough to free it from the inlet seat. When the engine gets hot metal expands and it's not a problem ... I hope that's it. Tomarrow I'll pull the carb off and see.

OK ... day later after further investigation it appears that the last thought is it. When I took off for a ride this morning before getting on the highway I forced the float to drop by turning off the gas and letting run till the motor died. At that poing I opened the pet-cock and started the motor got on the highway and opened it up... DID NOT faulter ... so now I guess I adjust the float.