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Hi Friends,

I've got some new throttle return springs installed but the right side carb don't close properly, if I press with a finger on the valve the revs drop with 200rpm's, but as soon as I use the throttle it will be stuck again on the higher revs.

It is very little that the valve need to close properly, that I cannot even see it move if I press it down with my finger. This is not related to the cables or with the idling screw.

With 2 springs on it closes properly, but I know that's not the solution. Sync of the carbs is impossible as is.

Somebody here who had the same problem?

Regards
Johan

Is the high idle speed the reason for the new springs, or has this problem developed after putting the new springs on?

Maybe the rh butterfly plate is loose, or needs adjusting.

Boertjie wrote:Hi Friends,

I've got some new throttle return springs installed but the right side carb don't close properly, if I press with a finger on the valve the revs drop with 200rpm's, but as soon as I use the throttle it will be stuck again on the higher revs.

It is very little that the valve need to close properly, that I cannot even see it move if I press it down with my finger. This is not related to the cables or with the idling screw.

With 2 springs on it closes properly, but I know that's not the solution. Sync of the carbs is impossible as is.

Somebody here who had the same problem?

Regards
Johan

Boertjie, I'm afraid I don't understand parts of your post. When you say "valve" what are you referring to? The spring is associated with closing the throttle butterfly. Is the butterfly what you mean by the valve.

Also, I'm afraid I don't quite see how the carb might be unable to be synchronized with double springs installed on one carb. If there is no binding in the throttle butterfly assembly, it should still open a given amount for a given amount of throttle twist. The twist grip will be harder to turn, but I don't see any reason why both throttle butterflies couldn't be aligned to open and close together.

Have you had the suspect carb off the bike and in hand? I would want to play around with the throttle mechanism looking for any unusual binding while I apply pressure to different places on the mechanism. I would also be eyeballing the spring as I did so. I would eyeball the butterfly in the bore to see how well it is closing when compared to the other carb.

You have nothing to loose by pulling both carbs I would think since something is going to have to be done to the carbs which will mess up the settings you have now.

Have you been working on the carbs or had them apart recently, of did the problem just show up out of nowhere?


Ken

Hi ME & Ken, yes it's the butterfly I'm referring to (sorry, translated directly from Afrikaans )
I did change the springs, but it still have the problem. Ill follow your advise and pulling the carb to see if there is binding somewhere. The thing is, you cant even see the butterfly moving that last bit, so little is the problem. If double the springs does the job, then so be it. Thanks!

I would take the carb off, hold it up to a light source and look through the throat of the carb. With the butterfly in the fully closed position (idle adjust screws backed off the stops) there should be no light visible through the throat past the butterfly plate.

PS. don't get a facefull of petrol when yer hold it up to the light

ME 109 wrote:
PS. don't get a facefull of petrol when yer hold it up to the light

Ha, maybe it'll cure this stomach bug I am having