Aimara

intemitten high rpm when idle

8 posts in this topic

sometime it has normal idle , sometimes high rpm idle , something wrong with carb ?

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Well, perhaps tell is what carb we are talking about.
Is it stock or modified? If modified, how?
Has it been removed lately, dissembled, cleaned, inspected and reinstalled? If so what did you find?> If not, thats a great place to start.
Have you checked vacuum lines for cracks or other leaks?

Have you checked the choke for air leaks?

Have you checked the carb manifold for air leaks, tight clamps? 

Have you checked the blanking plug on the head, left side for air leaks 
 

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10 minutes ago, Erik Marquez said:

Well, perhaps tell is what carb we are talking about.
Is it stock or modified? If modified, how?
Has it been removed lately, dissembled, cleaned, inspected and reinstalled? If so what did you find?> If not, thats a great place to start.
Have you checked vacuum lines for cracks or other leaks?

Have you checked the choke for air leaks?

Have you checked the carb manifold for air leaks, tight clamps? 

Have you checked the blanking plug on the head, left side for air leaks 
 

 been a problem since day 1 when i bought the bike , its stock mikuni carb with james jean jet , already been clean out and service by a shop

 

Have you checked vacuum lines for cracks or other leaks?

vacuum lines as in the pipe link from tank to carb ?

Have you checked the choke for air leaks?

how to check ?

Have you checked the carb manifold for air leaks, tight clamps? 

not yet , can i spray it with wd40 ? or carb cleaner .

Have you checked the blanking plug on the head, left side for air leaks

wheres the blanking plug ?

Edited by Aimara

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10 minutes ago, Aimara said:

 been a problem since day 1 when i bought the bike , its stock mikuni carb with james jean jet

Have you checked vacuum lines for cracks or other leaks?

vacuum lines as in the pipe link from tank to carb ?

Have you checked the choke for air leaks?

how to check ?

Have you checked the carb manifold for air leaks, tight clamps? 

not yet , can i spray it with wd40 ? or carb cleaner .

Have you checked the blanking plug on the head, left side for air leaks

wheres the blanking plug ?

Ok so a DRZ400 with the BSR36 Mikuni carb, that has a James Dean Jet kit....and the issue was from day one???? was that before the jet kit was installed or day one after?
What clip is the needle on, which needle was used, what jets are in it? 

Check for air leaks by inspecting the items mentioned, if no visual damage, you can spray break cleaner at those areas to check for leaks, a rising idle would indicate  you found a leak.
Now that you have told us what bike and carb... don't worry about the plugs, you don't have them .. Your head should look like this 
5a5918b5627cf_blanksforplugs.jpg.fcd434fe47d4395b0ed4fa49d61a6569.jpg

 

If those to non machined ares have threaded barb fittings or a plug in them, you do not have a DR S / SM head and should check those fittings for air leaks. 

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in fact now i remember the problem was from day 1 with stock jetting has this idle problem , after jd jetting ,it was fine for two-three weeks , it came back just today , i didnt change the jet myself , i presume it to be hot setting , its hot all year round here , i check the he probably use 160 main jet , pilot jet 25 , red mark needle ,by the way its a  08 sm

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I had a similar intermittent problem like that on my WR250F a long time ago. I thought it was the usual hot start or choke, etc. But it seemed to happen more after riding over rough stuff, and I also noticed my rear guard was making a bit of a knocking noise. In the end I discovered two little bolts had gone missing from under the guard. When the rear was able to move just that little I think it was interfering with the airbox, pushing or pulling on it creating a slight air leak at the carb. Once I replaced those two little bolts my guard stopped moving and the problem never resurfaced. Not saying your problem is the same, but the intermittent nature could be something like a loose clamp, or a small crack, or something moving that shouldn't be. 

Edited by DirtShow
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7 hours ago, DirtShow said:

I had a similar intermittent problem like that on my WR250F a long time ago. I thought it was the usual hot start or choke, etc. But it seemed to happen more after riding over rough stuff, and I also noticed my rear guard was making a bit of a knocking noise. In the end I discovered two little bolts had gone missing from under the guard. When the rear was able to move just that little I think it was interfering with the airbox, pushing or pulling on it creating a slight air leak at the carb. Once I replaced those two little bolts my guard stopped moving and the problem never resurfaced. Not saying your problem is the same, but the intermittent nature could be something like a loose clamp, or a small crack, or something moving that shouldn't be. 

i will take note of that

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