Cold Starting Problem M900

[ChrisK]

Hey all, I know there's a lot of info on this from doing a search on the forum but I'm having difficulty finding an answer for my question...

I just purchased this bike (98 M900) about 3 weeks ago now and that whole time it has started and run great. Normally, when starting it after it's been sitting over night I'll have to use the fast idle lever all the way open and just let it idle for a few minutes before I get on and ride.

This morning, I tried to start it in the coldest weather I've had it in since I've owned it. It was about 40 F this morning. Went through the same procedure I normally do but couldn't get the bike to start. It would crank and crank and crank for about 30 seconds and then quit cranking all together. I'd let it sit for a minute or two and try it again and it would do the same thing all over again but result in a very loud backfire? Never did get it to start. Advice?

[PhilB]

Yeah, they are cold-blooded at best, and when it is really cold, they really don't respond well.  When I lived in san Diego, this never came up, but when I moved to New Hampshire last year, I found the same thing -- just wouldn't start if it was about 40F or below.  I wound up having the local shop upgrade the starting circuit -- went to 4 ga wire from the battery to the relay, and from the relay to the starter, and added a direct ground line from the starter back to the battery.  Along with switching to a lighter oil in the winter, that solved the problem.

PhilB

[Dellikose]

I've had mine crank and fire down to freezing...which I found is where it's too cold to enjoy the ride.

As for what Phil has recommended, Demo Times offers a wire upgrade kit. I don't have it installed, but it looks like a solid deal.

http://www.desmotimes.com/product193.htm

[Autostrada Pilot]

I have the desmotimes (Powerlet) kit and it worked wonders on my bike.  Warm weather, cold weather, the bike just kicks harder and starts faster than ever before.  Best $30ish spent ever.  My 1999 M900 still struggles a bit around 40-45* (I don't ride below 40*) even after being in the garage (not heated).

My ground cable was about 1" too short, but Powerlet was great to work with and took care of it quickly.

[Howie]

Your bike has a choke,  more accurately a cold start enrichment device since there is no choke plate, not a fast idle lever.

My bike stars up well in temperatures well below freezing.  Anyway, I suspect your problem is either electrical (weak battery, excessive starter control resistance) or fuel (carb never rejetted, idle mixture screws still at factory US emissions settings), a combination of the two or just in need of routine service.

Start with getting your battery load tested.  OK, if it cranked for 30 seconds in the cold it is probably good, but check it anyway.  Then go to the starter control circuit.  There should be no more than .2V aver any wire or connection or .5V for the whole circuit.  Don't forgrt the grounds.  Here is a how-to:  http://www.autotechnician.org/starter-voltage-drop-test-explained-in-plain-english/  Needless to say,upgraded cables would fix the problem, but I'm of the "if it ain't broke, don't fix it" school and it should start with stock cables in good shape.

From the factory, the carbs were set very lean, bad for cold starting and running.  Turning the idle screws out 3 turns from seated, or if you have access to an exhaust analyzer, 4-6% CO w3ill help with starting.

When was the last service done?  Cam belts should be changed every 2 years or 12K miles, whichever come first.  Valve clearance should be checked every 6K miles.  Brake and clutch fluid every year or 12K.  New spark plugs never hurt.  While you are at it, if the tires are over 5 years old, consider new ones.

[ChrisK]

Thank you for the tips, guys.

The bike was just serviced a couple weeks before I bought it. I bought it from a friend so I know that it actually was completely serviced. Whether or not the guy doing the servicing knows about the idle screw settings and whatnot is another story...

I'll look through the wiring and see if I can notice any red flags.

Again, thanks for the input.

ALSO, I went back at work and the thing started at the first push of the button... 25 F warmer.

[ChrisK]

Just an update on this:

I determined the battery that was in the bike was losing its effectiveness. The previous owner said it was a Ballistic battery but I don't know as if he knew what that actually meant. The battery was actually a Bikemaster - while it was probably a good battery new, I think the overuse of a battery tender by the PO ruined it.

SO, I purchased an actual Ballistic 12 cell battery.

Changed the oil to 5W-40 full synthetic for the winter.

Adjusted the O2, idle, and synchro screws on the carb.

Haven't had a single issue since. It was around 30 degrees F this morning and it started up after about 5 seconds of cranking. Couldn't be happier.