needle adjustment for temp change?

I am dialing in my wr426 carb for cold north winters, snow riding.Do you think a needle height adjustment can compensate for a 90 degree swing in temps?

I think you'll get better results, assuming that your carb is right for cold weather, to leave the needle alone and go a little leaner on the pilot and the main.

Do you want to go leaner or richer for cold weather? I stepped my pilot up to a 48 (03 450 orig. 42) since the cold and have great results.

Sorry, I was multitasking and I think I misread your post. You would go richer, not leaner, for colder weather.

Somehow or other I got it that you had it set up for cold weather already and then had a heat wave :worthy:

Cold air is more dense, hence the need for more fuel. The pilot circuit is open durning all stages so it will richen all stages also.

My bike is also very hard to start for the first time when its below 40, once it's been started it restarts fine. I've been told that this is attributable to the starter jet which only comes into play in choke condition. Good info?

I first stepped up the pilot for cold (huge improvement), and will now try the starter jet (already purchased) if that makes sense. I am beginning to understand that there are some rules of thumb when it comes to jetting but each bike engine, climate, elevation, etc., make jetting a unique experience for just about everyone. I think make one change at a time based on the condition record the jet change, date, and result until it is dialed in.

My bike is also very hard to start for the first time when its below 40, once it's been started it restarts fine. I've been told that this is attributable to the starter jet which only comes into play in choke condition. Good info?

I first stepped up the pilot for cold (huge improvement), and will now try the starter jet (already purchased) if that makes sense. I am beginning to understand that there are some rules of thumb when it comes to jetting but each bike engine, climate, elevation, etc., make jetting a unique experience for just about everyone. I think make one change at a time based on the condition record the jet change, date, and result until it is dialed in.

Your technique of only one change at a time is spot on. I have read that the starter jet does make some difference (must be an 03 or newer). The pilot sounds like it fixed you up though.

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