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Rev goes high gradually on idle and stays high
Posted: Mon May 25, 2020 6:33 am
by moto_ram
I have a 94 Suzuki DR125SE. On idle it revs higher and higher gradually on its own. Also, when I open and close throttle it stays at high rev and takes forever to come down. I have checked the throttle cable, boots for vacuum leaks, adjusted the air/fuel screw on the carb, even changed carb to a totally new one and the problem still exists. The spark plug is black so I assume it's running rich. However, playing with the carb didn't seem to fix anything. It starts just fine.
I have not looked at valve clearance yet but not sure if it's got anything to do with this.
Any advice is appreciated
Re: Rev goes high gradually on idle and stays high
Posted: Thu May 28, 2020 10:47 pm
by BikerGran
When you say you've checked the throttle cable, what exactly have you checked? I had this problem on my Kwak GT550 and I lubed the throttle cable which made no difference. It turned out to be the linkages and return spring gummed up with old oil and dirt. Cleaned it up with a degreaser and a brush, put fresh light oil on it, solved the problem.
Re: Rev goes high gradually on idle and stays high
Posted: Fri May 29, 2020 6:35 am
by Shebee
Does it have a choke? Running rich would be a symptom of choke on?
Re: Rev goes high gradually on idle and stays high
Posted: Fri May 29, 2020 2:06 pm
by fatboy
Check the air filter/housing for obstructions
Has the end can been messed with as a lack of baffles enriches the mixture
Re: Rev goes high gradually on idle and stays high
Posted: Fri May 29, 2020 4:28 pm
by Ben
BikerGran wrote: ↑Thu May 28, 2020 10:47 pm
When you say you've checked the throttle cable, what exactly have you checked? I had this problem on my Kwak GT550 and I lubed the throttle cable which made no difference. It turned out to be the linkages and return spring gummed up with old oil and dirt. Cleaned it up with a degreaser and a brush, put fresh light oil on it, solved the problem.
Similar happened to me on my Hypermotard.