[Jbrowne]

Hi all,

I’ve searched high and low but can’t seem to nail down exactly a starting method that will help me here..

Back story: Rebuilt my 2004 CRF250r over the summer and she ran beautifully. I haven’t started this bike in 2-3 months now and she won’t start.. I’m in Canada where last weeks feels like temp was -18C..

-Valves were done during rebuild (re shimmed and in spec).
-Old gas was removed in September, just refilled up with fresh gas.
-Currently on stock jetting (Perhaps I need a rejet to compensate for the temp drop but you’d think I’d get something).
-Spark is good

Starting process:
-Fuel on
-3 Full turns of throttle
-Choke on
-Turn engine over to TDC
-Kick bike over (nothing)
-Kick bike over while blipping throttle (nothing)
-Checked filter

-Sprayed some quick start in the carb and kicked it over and it POPPED with a ton of smoke coming from the filter under the seat? Thought I was on fire.. what’s up with that? You’d think timing but it’s been verified and ran fine two months ago.. can’t imagine I skipped timing, the bikes not been ridden!!

Anyways, I’m looking for some ideas here. The bikes for sale but hard to sell a bike that won’t start

As we all know reaching to the carb is a pain and I’m trying to avoid rejetting a bike I’m selling but if I must...

I want to emphasize that timing and valves are in check, the bike ran beautifully in the summer second kick. Not even a single hour on the bike since maintenance done.

Thanks,

[Back2-2]

Your pilot jet is clogged with old evaporated fuel residue [ crap]. The carb can be rotated to the right to get at the fuel bowl. Much easier than removing the carb from the bike.

[Jbrowne]

Your pilot jet is clogged with old evaporated fuel residue [ crap]. The carb can be rotated to the right to get at the fuel bowl. Much easier than removing the carb from the bike.

I’ll give it a shot tomorrow if it’s not too cold out. Thanks for the reply.

My next best option I feel like is a space heater beside the damn engine..

[Back2-2]

If the bike is going to sit for more than a month you need to be using fuel stabilizer and drain the float bowl of fuel. Ethanol is the worst thing for carbed bikes. If you can find zero ethanol I fully recommend it. When I lived in AZ I ran LL100 in everything I had for off-road because the pump fuel was so bad. Here is SD zero 93 is readily available at all stations.

[Leardriver]

You can re-jet in 5 minutes. It's nothing to fear. Twist the bottom of the carb to the left, remove the 17 mm plug, and it's all right there. If you want to change the pilot, it is helpful to lay the bike on it's right side.

At certain temperatures, starting an engine isn't worth the possibility for wear. I started my 450 in October on a cold day, and it let me know that I was committing a hate crime. I will wait until the March pre-Moab service.

[Back2-2]

At certain temperatures, starting an engine isn't worth the possibility for wear. I started my 450 in October on a cold day, and it let me know that I was committing a hate crime. I will wait until the March pre-Moab service.

That is just about the ridiculous thing I have heard you say...

[Leardriver]

I say lots of ridiculous things, so perhaps this is an honor.

What causes more wear, starting an engine at 90 degrees, or 20?

My airplane manual for my Bonanza prohibits starting the engine under 30 degrees unless it has been on a pre-heater for 30 minutes. My Lear 60 has to run for two minutes before applying takeoff thrust if the temp is below 20. My Kubota skid steer can't be started below 30 degrees without 2 hours of the block heater being plugged in.

Cold temps cause vastly accelerated engine wear compared to warmer temps. I don't want to start an engine for sport just to convince myself that it can be done. I'm not going to ride at 30 degrees, so I will save the additional wear cycle for a warmer day.

[Back2-2]

Yes, I agree with what you have just stated on some equipment. Believe it or no, I instrumented the seal break-in procedure for the turbine engines I engineered. So I know a little something about cold starts. In fact my last 10 years was working on cold start turbine testing down to -60F. We go from a cold soak of -60F to a start attempt and full power targeting less than a 60 second start. SOAP samples taken before and after show next to zero wear. Now that is a turbine engine not a piston engine but you get the point.

But your comment about not starting the guys bike in Oct. makes zero sense. If the guy wants to start his bike in the Oct or even dead of winter that is his decision and any wear that occurs is so minimal that you would be better to worry about other things.
If your bike acted up starting it in Oct. regardless of temperature you have other issues.