Good day all. I am a owner of a 03 roadstar. The problem I am having is when the outside temperature is less than 40 degrees ( in 30s) my bike will backfire and miss so bad it wants to quit especially when I crack the throttle. As the engine warms this does not change. The RPM will drop so low at idle the bike will quit. This only happens when the outside temperature is below 40. Above 40 degrees it runs like a top (all good). When I start out with the outside temperature in the 30s it will buck and snort but as the outside temperature (not engine temperature)gets warm the bike will purr like a kitten. Please help, do not want to be a fair weather rider.

Mr-G, hello and what all do you have on your bike as far as performance mods? Maybe we can sort something out, post any and all you've done with your motor.

Bulb pipes and yes it was rejeted. thats all I can say or know

Normally I'd say that your bike is to lean.... usually, colder weather leans out a bike more, warmer weather richens it up... but at the same time, I didn't think anyone could lean out their bike more than mine and still get it to run... mine will start even when it's 17 degrees with the choke on... takes the engine 10 - 15 to warm up...

Do you need to use the choke every time you start your bike?

When you bike idles normally do it sound like it's just barely running... stock set up on the idle is fast 900 RPM... might need to bump up the idle in the cold...

have you changed your spark plugs lately... often the cold weather amplifies problems we don't see in the summer... I'm changing my plugs this winter I've got 9500 miles on mine (only 7 months old), but has been rejetted...

~D<br><br>Post edited by: davehrn, at: 2006/02/02 09:40

Yes on new plugs and all that good stuff I.E. diessambly of carb. Oh. The work is being done by yamaha mechanics. Have to pull choke to start and when it is below 40 degrees it will fire as normal but the longer it run the RPM will keep dropping until it wants to quit. RPM will range from 1300 to a point where I can't read it on my tach (needle whipping) It doesn,t idle the same RPM most of the time, even above 40 degrees

sorry I couldn't help... sounds beyond my abilities ~D

So it only run bad if the temp is cold?

Otherwise it may be that you have some crud in you fuel line or carb that's restricting the flow.

Doc

As I read this problem, I was wondering, if you leave your choke on at all during the early part of your cold weather riding. My understanding is that every time you start your bike you are to use your choke. It sure makes things easier on the bike and it always starts up quickly with no throttle. I live in Phoenix, but we get some cold mornings, in the 30's. I have just used the choke for about ten minutes, (just pulled out a little) and this helps a great deal.

Clearly what you are experiancing is not a good thing and should be taken care of.

Chookie

That's correct Chookie.

Ideally, if the bike is cold you should have to pull the choke to start it. How long you need to keep it pulled out depends on how cold the air temp and how lean the bike.

If you can start a cold bike without the choke, it's setup too rich. At about 70 F, it takes me about 1-3 minutes but at 40 F it takes at least about 5 min.

Doc

I own an 05 Roadstar Midnight with a stage 2 kit, Vance &amp; Hines Slash cuts, rejetted,pro hypercharger with addl. scoops, dynatech 300 ignition, and a crankcase vent. I had to have the idle upped to almost 1000rpm, adjust the jetting and with the addition of the crankcase vent I am able to rocket thru 70mph in 2nd gear with no break up, I am proud to say that I live in Pittsburgh, home of the Championship Pittsburgh Steelers, and I ride anytime above 30 degrees as long as the roads are clear. I had the same problem until I understood the carb better. At the temp your talkin about, full choke for 3-5 minutes then throttle the the motor a few times to clear the engine out then go to half choke for the next 7-10 minutes. Remember the choke is there for a reason,,, to richen up the mixture to help it warm up... but the engine can load up fairly quickly if you don't watch yourself, ie. backfire and sputtering. Make sure the mechanics richen your bike up a little, tell tale sign, when you turn the engine off after hot do you hear a spin back of the motor??? if so you are running way to lean. hope this helps?!
Michael