Hello all - I have just refitted the carbs to my SP - however I have used a set of non SP carbs from a "standard" model. I cleaned them and made sure everything was intact. Now.....

No leaks which is good news
It will start and tick over at 7K and the twist grip only makes the engine bog and there is no effect no more or less revs
If I add some chock the revs come down to around 5K

Any help would be great - thanks Dan

The revs DROP when you put the choke on? Are you sure about that?

High idling can be caused by several things.

Air leak
Incorrect synch
Loose vacuum line
Stuck choke
Sticky throttle cables

The non SP carbs are smaller than the SP ones, you wont have a TPS on your new carbs and the SP model has a diffrent CDI unit, i would imagine one of these could be messing with the running. Have the orings been replaced? if they are perished you get some very strange issues with the carbs.

VFRkieran wrote:The non SP carbs are smaller than the SP ones, you wont have a TPS on your new carbs and the SP model has a diffrent CDI unit, i would imagine one of these could be messing with the running.

I don't see what the CDI has to do with carbs?

Controls the ignition though which could be a reason its not firing correctly? Especially considering the carbs are delivering a diffrent amount of air/fuel mixture. I read somewhere that if fitting a set of SP carbs to a normal GK76 will require an SP CDI to run at its best, so i assumed it would be the case here but obviosly the other way round ie. non sp carbs will need a non sp CDI to run correctly. Or am i mistaken? I know this is pretty unlikely to be the main issue but it cant be helping it.

Thanks - It looks like I will fit the SP 35mm carbs back on and try and find what the problem is.

Where can I get a set of O rings from? I suspect it is going to be a long struggle to get them right.

Does anyone know someone that can rebuild the carbs at a reasonable cost?

Dan

I have just finished fitting orings to my gk76 today, a member here that goes by the name of variablevalves suck sells a full set for £11 pound delivered PM him and he should be able to help you out. I wouldnt bother paying anybody to fit them though its a simple job really! Give the jets a really good clean while your in there too.
If your not too far away from me i can come and give you a hand if you arent confident with it. When you have done it once its really easy, except the slide holder