Cold weather jets for 2008 450X FCR carburetor

[Ben 500RR-S]

Somehow, the kickstarter had come off and has now gotten lost.

I was trying to get the bike started with no choke but I think that because it was colder out yesterday, when I pulled the choke out the bike, thankfully, started.

We're still learning how to get the bike started reliably. Freaking kickstarter.

 

[Sheetmetalfab]

Somehow, the kickstarter had come off and has now gotten lost.

I was trying to get the bike started with no choke but I think that because it was colder out yesterday, when I pulled the choke out the bike, thankfully, started.

We're still learning how to get the bike started reliably. Freaking kickstarter.

That bolt comes loose on most snowbikes. (High rpm for extended periods)

I recommend “nordlock” washers.
Available through fastenal.

 

[Ben 500RR-S]

That bolt comes loose on most snowbikes. (High rpm for extended periods)

I recommend “nordlock” washers.
Available through fastenal.

Yup, I did check it some time ago but the bolt had to have just come off.

At least new ones are from $60-used to about $130 new, not too bad.

 

[Ben 500RR-S]

The 450 is back in business. Thank goodness.

It was cold(er) Thursday morning, somewhere in the 20's. I had tried the e-start with full choke three times. The battery was not enough to get any life out of the motor. I hooked up my Weego JS12 and on the third try-the first two had the motor firing but not staying lit, on the third try the engine fired, stayed fired and settled into its high idle on full-choke.

After about 30 seconds to maybe a minute, I shut the choke off and the bike idled perfectly. All day long it was just pull in the clutch and press the button and the bike would start and idle and run, cleanly and with no more backfiring or needing to choke the bike for every start.

The blue JD Jetting needle in the 4th-or middle position, coupled with the 165 main jet, along with the R&D Flex Fuel Screw at 1 1/8 turns out has all worked together to have the carburetor and the engine running like it is new from 2008. It also helps that I had replaced the plastic hot start nut that had all of its plastic threads worn-out with an anodized aluminum one so there will be no more worry about that piece going bad and wearing out again.

 

[Ben 500RR-S]

It was 2-3F this morning. The 2008 CRF450X did not want to start in the cold but, and here comes the butt, I was not turning the throttle fully a few times to prime the carb. I had spent at least 30 minutes with a Weego JS12 with no joy. I had also hooked the battery up to another running snowmobiles battery, again, with no-joy.

We had gone out for a 1 1/2 hour ride and when we came back, I had remembered to turn the throttle 3-4 times and as it was very quiet, I could hear the accelerator pump squirting inside the carburetor so that when I went to hit the e-start button, I was getting some fire.

After 3-4 tries, the bike fired up like it was 15 degrees out.

I will know, from now on, to keep on turning the throttle at least 3-4 times before trying to start the bike when it is in the single digits. The bike did run great once I got it running. It was just cold out this morning.

 

[mumur]

Anyone have links to good articles or videos about jetting? I'm new to dirt bikes in general with a 2012 Beta 450RR. Lots of good advice in this thread but it's all going over my head . I've ridden a few times and haven't noticed any issues, but I'm not sure I would know how to notice them outside of a complete loss of engine power. Not sure what I should be paying attention to when riding to tell if I need to make jetting changes.

 

[Ben 500RR-S]

If your bike is running good in the cold, it starts up, idles well, and you don't feel anything odd while riding around, you are probably good to go.