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Crf250r hard to start and sputters

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Hi all. I have a 2005 crf250r that’s being hard to start and sputters at mid range when riding it. Jets are 162 main 45 pilot and the rest are stock. Fuel screw is at 2 3/4 turns out. Has fmf megabomb header and factory 4.1 exhaust. Just had top and bottom end rebuild and has about 1.5 hours on it now. Valves are in spec tho one of the intake valves is a little bit tight. Sometimes the bike will idle and sometimes it won’t. Other than these issues it has tons of compression and power. Any help would be greatly appreciated

 

Thanks

Luke

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If it ever ran well with the jetting you have now, it's NOT a jetting problem.....

Fuel screw should be set at 1.5 turns out going from a VERY LOW IDLE. 

Your carb is 11 years old, so you should replace the emulsion tube, re set the float height.

Inspect your spark patch for corrosion or gaps.... stator> harness plug > grounds > coil ground > HT lead > plug cap > plug

On this bike, a bad ground can cause havoc.  Inspect the entire wiring harness, especially the grounds.

Did you replace the intake valves when you did the top end?? They must be very worn out by now.

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If it ever ran well with the jetting you have now, it's NOT a jetting problem.....
Fuel screw should be set at 1.5 turns out going from a VERY LOW IDLE. 
Your carb is 11 years old, so you should replace the emulsion tube, re set the float height.
Inspect your spark patch for corrosion or gaps.... stator> harness plug > grounds > coil ground > HT lead > plug cap > plug
On this bike, a bad ground can cause havoc.  Inspect the entire wiring harness, especially the grounds.
Did you replace the intake valves when you did the top end?? They must be very worn out by now.

When I bought the bike it was apart and had been sitting for awhile. That’s why I did the top and bottom end rebuild. I’ll look at the electrical system tonight and the valves felt super light like they were titanium.

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I bet it was. I bought a used 250r and pulled the carb apart to clean it and I discovered that it was already clean, but the bike was hard to start, wouldn't idle, and popped like crazy. So I replaced all the jets and seals and the jd kit told me to use a 175 main 40 pilot, and there red needle with the clip at the 5th position from the top. Still the bike would run right. Then I noticed that I had an extra part leftover in my carb rebuild kit, one that didn't look like anything I took apart. It was the pilot screw, which was completely missing on my new used bike. So after installing and adjusting it to 2 1/4 turns out ,as the jd jetting kit instructed, the bike started and ran like a champ. night and day difference at/from idle.

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