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Buell Forum » Knowledge Vault (tech, parts, apparel, & accessories topics) » Engine » Fuel System: EFI/DDFI, Carb., Filter, Pump, Tank, Filler-Cap, Fuel » Archive through September 11, 2006 » Tired of carb questions? (Blast) « Previous Next »

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Hukturn
Posted on Friday, March 24, 2006 - 09:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Seems like there are several issues with the Carbs on Buells. Of course, carbs have been difficult to master for decades.
At any rate, I have been fighting with my wife’s carb. She rides a 2005 Buell Blast. I feel really dumb despite my mechanical abilities. But, I can not find a mixture screw on the HD carb. Directions please.
Also, I am open to theories. The bike is not incredibly responsive to the throttle. It vibrates about like a Sportster. And, when at running temperature, it will occasionally sputter. It has even shut down at idle a few times. I idled up some but that is like patching the problem rather than fixing the problem. Thoughts?
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Hukturn
Posted on Saturday, March 25, 2006 - 04:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Actually, the "sputter" is more like a "hiccup" and occurs about every thirty seconds during idle.
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Blake
Posted on Sunday, March 26, 2006 - 09:06 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

There is one and only one issue with carburetors on Buell motorcycles; they are set too lean in the low speed circuit as delivered from the factory. Change pilot jet to 45 and verify that there is no air leak downstream of the carburetor, especially at the intake to cylinder head seal. When you remove the float bowl, you see the pilot jet, the idle mixture screw is located behind a tamper-resistant brass plug. Some folks drill that out and adjust for optimum idle. If that requires backing mixture screw out more than 2.5 turns from full-in, then go up to next pilot jet size and reajust mixture screw.

The online service manual for the Buell S1 can be found in our Knowledge Vault - Service Manual topic. The carburetor section will show you all you need to know concerning where the jets and mixture screw are located.

The Blast also has an automatic choke. I'm ignorant about it though. You might get more in-depth and comprehensive advice from the Blast riding hooligans in the Thumper Forum topic.

Good luck.
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Jlnance
Posted on Sunday, March 26, 2006 - 10:08 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Hukturn - There is a rubber manifold connector which connects the carb to the manifold. It frequently cracks, particularly if the bike has a modified air intake. This will cause symptoms like the ones you describe.

The OEM part is less than $10, and you can just replace it every year to avoid this problem. I have a friend who replaced hers with a section of hydrolic hose which is more durable than the original connector.

You can find hydrolic hose couplers here:

http://www.turbotime.us/ProductDetail.jsp?LISTID=1EB0000-1130519024

Take Care,

Jim
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