Mark's observations about gas are relevant, but I think if it was just gas, we'd see it on most other bikes on a much more consistent basis. My KLR's never exhibited this problem even after sitting for very long periods.

I think there's something about the combination of the stock CV carb and the KLX250 that's not a good match when cold. I'm not sure why that would make sense when you consider that basically the same carb is on the kickstart KLX300, and it's not horribly hard to start when cold. This still leads me back to something not supplying enough fuel at startup, and this is usually just the choke circuit. Engine vacuum pulls the fuel through the system, so maybe the 300 just produces more startup vacuum than the 250 as delivered. I'll bet the KACR is basically identical between the two engines, so I don't really think that's the issue. Aren't the cams basically the same too?

Well, here's the ultimate solution that addresses a whole lot more than just difficult cold starting...a pumper carb. After living with one for several months now, I even hate the idea that I didn't do this swap a lot sooner.

 

So, TNC, if you think its a vacuum thing, could GC take his shop vac to the muffler and pull a vacuum on the engine and see if it starts any easier? Not much of a permanent solution, but perhaps to confirm or rebut this concept.

Suck start that *****.


.

 

Fuel injection should be on your next bike, mine too.
But for now I'm going with a stronger battery and maybe a lighter oil for the cold.
This bike does suck to start, unless it's warm out, really warm.

 

Vacuum on the exhaust paints an interesting picture but what the hay, try it.

The lightest oil listed in the '09 manual is 10W-30 with an operating range of -10 to +30 celcius. I guess they not expecting anyone operating this bike below -10C.

go cytocis, post a thread re the Calgary mc show if it's worthwhile.

 

Fuel injection on a trail bike will end the option to bump start with a dead battery. Not a good option out in the outback.

Is the starter having a hard time turning the engine over, if not going to lighter oil in it for the winter such as 0w30 or something is not going to help much.

Drill the choke jet out more or get a pumper carb, you can add fuel by turning the throttle.

If your only getting 80psi, the heat from low compression is not helping. Removing the Kacr would increase combustion chamber temperatures to help ignition.

 

The new breed of 4 stroke trials (not trail) bikes have fuel injection and NO battery.

Ride on
Brewster

 

Dang!...well, I guess I can scratch off that new trials/touring bike I was thinking about...windshield, trunk, and full fairing.

Brewster, I swear I heard one of the guys at the shop I used to work at say that one or more of the new Kawasaki KX's or Honda CRFRs had no battery with their fuel injection. I'm impressed.

 

Hahaha IDRIDR!

So I sceptically trudge down to the basement to rummage around for my shop vac, haul it out the garage which is currently at -1C (30F) & plug it into the tip of my TBR M7 pipe.

My first observation is that it fits so perfectly that it's almost as though the shop vac was designed exactly for this purpose.

I switch on the ignition and without ANY choke I begin to crank and I'll be damned if the the thing didn't fire right up, IMMEDIATELY! Unbelievable. I figured that the valve timing would prevent any vacuum from reaching the carb, but there you go!

Just need to figure out how to mount the shop vac on my rack now!

 

Oh yeh, I forgot about the MXers with FI. So, it can be done without a battery.

Ride on
Brewster

 

There you go! Every year or two I have a novel idea. Completely unworkable and useless, but an idea nonetheless. Got to start somewhere.

Thanks for trying and letting us know. Interesting results.