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Discussion Starter #1
I recently bought a 2009 YFZ 450R with a acrb conversion. Ever since I got it, I can't seem to get the idle right. I did buy a tach/hourmeter that wraps around the coil, so I could see numbers and not guess at it. I know the service manual says the Idle should be right around 2,000, but when I adjust the idle it's either too low or too high. It also seems as if the idle hangs a little bit. I sure hope someone can help. This is really starting to bug me.
Thanks
 

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It could be something sticking in the throttle cable or in the carb that's keeping it hanging.
 

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My advice: start sourcing parts to put it back to EFI or part it out and get either a factory carb or EFI, whichever you prefer.

I owned a GT Thunder carb converted '09 for a long time. Eventually parted an otherwise solid quad over a wiring harness. Sounds crazy but there's no support there anymore with Laz gone.

I kept it going for awhile, rebuilt the carb, fixing the wiring harness (over and over), etc. It was a great quad in it's day, but the technology is old and the support isn't there. When my harness was finally complete junk, I couldn't get anybody to make one. With GT Thunder out of business, I couldn't get a diagram to figure out how the harness was modified.

I do know that you need 2 harnesses to make one. An '08 carb and '09 EFI. I tell you this because this could be part of your problem (if not now, it's coming). That harness has been in that bike for 10 years, by contrast, when I raced one, I replaced a harness every year.

Probably not what you want to hear and maybe yours is different, just giving you my experience. PM me if you need anything. I fought that quad for years.

Sent from my LM-V450 using Tapatalk
 

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Discussion Starter #4
Thanks for the replies. I'm leaning toward a carb issue here, as I'm pretty sure the throttle cable is ok. But for 10 bucks I'll replace it for peace of mind. And I already have an 05 YFZ, so I'm pretty familiar with carbs. This thing is just really bugging me, since I cant get it figured out. I'm going to order a rebuild kit for the carb. I really think it's a slide issue, possibly the o-ring for the slide plate. It also has an FCI intake, and a Dasa full exhaust, and a 13:1 comp piston (stock bore), so I was wondering if I could get some jetting recommendations.
The carb was setup like this when I got it:
Main: 168
Pilot: 52
NDSR needle: 3rd clip position
Fuel Screw: 2 1/4 turns out
My elevation is 427', any more help would be appreciated, my 05 has never given me as big of a headache as this thing.
 

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I've got FCR carb parts left over from that thing. You're welcome to them. I think I have a complete carb and assorted parts from others. You can have them for the shipping, I'm all EFI.

Sent from my LM-V450 using Tapatalk
 
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