Motorcycle Repair/carb problem

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Expert: Jan Ringnalda - 6/28/2009


Question
Hey man, i see your requirements for questions, but, this is a simple question i believe. I have a 1986 suzuki sp125 dirt bike with a mikuni carb in it. I have been working on this thing for a month and finally gave it a shot at starting just a minute ago. It fired up on 3 kicks and no throttle, but, once it started, it went wide open throttle. My kill switch would not kill it and the pipe quickly turned fire red. I let it run out of gas. All this carb has is an idle adjustment and an air adjustment, but, i cannot find any info on whether counterclockwise will slow down the idle, or speed it up. The idle screw stands at 2 1/2 turns out from a sitting position and everything else on the carb is screwed all the way in. Please help me if you can so i do not destroy this motor. Thanks a ton man, Jeff

Answer
Hi Jeff,

Sounds like your carb slide is hung up on something, and the cable may be snagged.  Make sure when you look into the back of the carb the slide is all the way down, and resting on the idle control screw.  The idle screw should be all the way out, and then screwed in until you feel friction; and then a little more to get the idle speed right.

Hope this helps,  Jan

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Jan Ringnalda

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PLEASE NOTE: PLEASE READ THIS!!! I can help with questions ONLY on any Honda CBX-1000 motorcycle, only 1978 to 1982. OR 1981 to 1983 Honda CB1100R models ONLY Honda CBX/CB1100R motorcycles, Please NO other makes, no other models. IF YOUR QUESTION IS FOR ANY OTHER BIKE Your question MAY BE FORWARDED TO THE QUESTION POOL WHERE IT MAY NEVER BE ANSWERED. IF I ANSWERED YOUR QUESTION, and you feel the need to give me marks lower than 10, first post a follow up question. If you mark me lower, I will respond and you run the risk I will never, ever, answer one of your questions again. I'm doing this free of charge, as a service to fellow motorcyclists. If you do not value my time, I do...

Experience

Have owned over 50 of these fine classic Honda motorcycles

Organizations
International CBX Owners Association, SAE, Materials Research Society

Publications
CBXPress, VLMC magazine, Used Bike Guide

Education/Credentials
PhD in Materials Science, Post-Doc in prototyping automotive components

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