Fuel Screw Question

Create New Tag

7/10/2017 9:46 PM

This is probably a stupid question, but I can't find any other logical explanation. For you FCR carb guys, have you ever had the fuel screw tighten up on its own?

My son's bike - which is a well-used 2005 KX250F - runs good when started and even after several laps and up to temperature. After a few hours of riding, stopping for water breaks, riding some more, etc. the bike refuses to start.

I installed a MSR branded anodized fuel screw, with new o-ring, washer and spring to make adjustments easier. So the bike starts and runs really well at exactly two turns out. The last two times we went riding and we had starting trouble, I was finally able to narrow it down to the fuel screw. When I loosen the clamps and turn the carb up slightly to adjust the screw, it's no more than 1/2 turn out. All the way in, back out 2 turns, and bingo - fires on the first kick and runs like a champ.

Loc-tite? Other opinions? I've not encountered this problem, but the last four stroke I had was a brand new 03 YZ450F . . . so it's been a minute. wink


7/11/2017 10:20 AM


7/12/2017 5:10 AM