Reply To: Idle speed or something stuck

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Hi Andy

If your not sure how to attack this and what all the screws do hang fire. You need to systematically go through everything one step at a time.

If I remember correctly you are running a B1 with BS38 carbs. Have you got the airbox fitted?

From the symptoms you are describing I very much doubt it is the cables. I also doubt that adjusting the tickover screw will solve the problem either issue either. The screw you are referring to is one of the mixture screws and again is unlikely to be your problem so don’t touch it yet.

The first thing to do is make sure the carbs are fitted correctly. Check the cables are routed and adjusted properly. The throttle should turn pretty freely and snap shut when released without hesitation. When shut it should be on the stops and there should be no tension on either cable. There will be a very small amount of play in each cable, app 5 degrees of nothing when you turn the throttle just using your finger and thumb.

As you have the bike running the next thing to check is for air leaks on the carbs AND exhausts. Although not quite as critical if the exhausts are leaking you will hear and even feel it. The most important area for leaks is at the head. Sort this out if there is a problem.

Next check for air leaks on the carbs. This is quite simple to do. Start the engine and let her tick over. Put your hand on each carb and with mild force try to rock them up and down. If the revs alter then you have an air leak on the rubbers, most likely to be the carb to head rubbers. If this happens check the rubbers are screwed tight to the head and that the clamps are tight enough. Do NOT overtighten the clamps as this can make them go oval and subsequently make the problem worse.

Don’t worry about any change to the running while doing this as we can address that later. Let me know how you get on and we can then move on to the next stage.



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