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I have an 08 I got used. After I got it the guy told me he had it re-jetted b/c it didn't start very well. It runs fine, but the idle is a MESS! I took apart the carb, cleaned out the jets, and here are the specs: Leak 58, Main 140, Pilot 42. Not sure if needle is stock, but clip is in 3rd position. Fuel screw I have tried everything from 1/2 to 3 turns out.

Here's what it does. After running you cut the throttle and it hangs high on idle (no matter where the idle screw is set) and depending on where the idle stop and fuel screw are set it either hangs on high idle for 15 seconds or more, then quickly drops RPMs way down, sputters a bit then dies. Adjusting the idle stop and fuel screw have only resulted in prolonging this, or shortening it depending on what I do to it.

If ANYBODY can help me solve this, or give me a place to start I would LOVE it! It's driving me crazy. My first FCR carb, and I can't make out what to do to solve it!

Trevor

The pilot sounds lean

The pilot jet is a 42, which is the largest possible if I understand this correctly. I am wondering if I need to adjust the needle position, or if the float level would affect this? What about air jets? Do people mess with those, or are they not so much a factor?

Thanks for your input!!

Trevor

I only took off the float bowl, removed the jets, and checked the needle position. Should I do more? The problem existed before I cleaned it, then didn't change. The carb had been taken apart before. I took it off the bike last night again, and it's on the bench awaiting dissection.

Let me add this, as well. Shameful to admit, but I'm learning. When I took the carb off the first time, I got a Tusk fuel screw. I took the old one off, but only the screw came out. I knew there had to be more there, so I shook the carb and the spring came out. "there, that's it" I thought and put the new screw in. Last night read there is another washer and O-ring, so I took the carb off again and sure enough, there was an extra set of o-rings and washers. So my fuel screw was essentially wide open. I find it odd, though, that the symptoms were virtually identical to before.

I also read that the fuel screw affects essentially only the throttle response off idle, so I am not sure how much it could affect my issues. Another guy reported similar probs on a bigger bike, and he richened up his needle by 2 positions and it fixed the hanging high idle.

I'd love to TALK to someone about this. Any suggestions? much easier than emails. Thanks!

Check to make sure the floating plate on the slide has the hole at the bottom. If it's not, it'll cause the symptoms you describe.

Reinstall the fuel screw in this order: needle, spring, washer and o-ring. Snug it down and then back it off 2 1/4 turns.

Pull the pilot (slow) jet and stick a small gauge wire through the main orifice and through all the emulsification holes.

The needle clip postion should be 3rd clip down.

It won't affect idle at all as it's not working at idle.

novocaine wrote:The pilot jet is a 42, which is the largest possible if I understand this correctly. I am wondering if I need to adjust the needle position, or if the float level would affect this? What about air jets? Do people mess with those, or are they not so much a factor?

Thanks for your input!!

Trevor

Don't know where you got that info????
Had a hard time with hanging idle with mine until I put a 48 pilot in it. That cured the problem and made it run much better.

Ok, I pulled the carb and fixed the fuel screw, put it back the way it is supposed to go. I took the slide out, and the hole is where it's supposed to be. The reason I said the 42 was the largest possible is the manual gives a range of like 35-42, so I assumed for this bike the 42 was the largest. Would it be too much for a 150 to put the 48 in?

I ran it again with the fuel screw correct and it is exactly the same. Hangs on a high idle, then drops low and dies.

I am confused by all this. If the bike came stock with certain jet sizes and has no modifications, why does it run like crap at the idle? I got ahold of the guy I bought it from and he said the bike never ran great at idle, even from new. I truly hope I don't have a lemon carb, and that it can be fixed with jetting.

Outside of the Cab, is there anything I should be checking, and might be overlooking assuming it's all carb issues?

thanks!
Trevor

509-nine4eight-0six1five
please feel free to call me if you can lend me some idesas

48 pilot. Try it you'll like it. $5 fix. You sure won't harm your motor with a richer than stock pilot jet. This fix allows you to get your airscrew and idle in correct balance with each other, and gets rid of the hanging idle. Do a search on hanging idle, you'll find it is a symptom of lean pilot circuit. I won't bother you any more with my outside the manual advise.

Cool, I'll get it ordered. What about the other jets, and the needle? Should I take those back to stock values?

I'd toss the manual, but the forums don't have pictures! thanks guys! I have heard from 2 sources to try the size 48 pilot jet. Got it on the way, and going to cross my fingers!

Wow, what a difference it made. I had no idea that the valves being out of spec could make such a difference. I had to put a pretty small shim in one of the intake valves. Am I going to need a head and valve job next?

If you've still got bog, try a 45 leak jet (aka accelerator bypass jet) and do the o-ring mod using wire instead of o-rings. This will take the bog away and allow you to lower the idle enough to where it doesn't hang while in gear.

A little shimming doesn't signal need for new valves yet.

it's 100% fixed with the valve fix. thanks

My bike is doing exactly the same thing that was happening with yours. So you think it was the valve shims that solved the problem? Or did you try the 48 Pilot jet as well? Thanks for the help. It's frustrating. Makes me not want to ride the bike.