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CRF250 Starting/Running Issues

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Hey guys, this is my first post so be nice haha

 

I recently bought a 2009 CRF250R with 140hrs on the meter and a rebuild at 120.

 

The thing is near impossible to start cold (its fine once its warmed up). It shows a lot of signs of running too lean including popping on decel, surging revs and getting hot. I pulled the carb out and found that the slow jets been changed to #48 which at sea level and 18C i thought it would make it run rich. The main jet is #178 and the main needle is at the 3rd position.

 

I'm just wondering if anybody has any thoughts on what could be causing this? Next on the list is a compression test to see how the valves are!

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Check the valve clearences. Do a leak down test. Do noit bother with a compression test.

 

Decel popping can be a result of a leaking exhaust, bad packing, or simply coasting on a bike with an open pipe.

 

Surging sounds like a poorly setup carb, too hot is normal, these bikes are designed to never go under 20 mph. 200+ radiator and 240 degree oil is the norm.

 

Yes, a 48 pilot is too large, a 45 or 42 probaly is more correct. But, check the health BEFORE you try to twek the jetting.

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Assuming the valves are in spec. Hard to start when cold is too lean on the pilot circuit, as is decel popping. Try opening up your fuel screw 1/4 turn at a time and retest. This is an easy fix

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