Black Plugs..

[Anonymous]

Hi All

1980 GS750E ...This winter I gave the carbs a thorough cleaning, replaced o-rings, did everything by the book, put it all back together and my plugs are black and fluffy, I have the air screws out 3 1/2 turns, I am afraid to go further. I checked the induction boots and all checks out, no cracks, etc. She idles good on intial start up but when you give it gas she stays up around 3,000 RPM for 20 seconds then settles down to 1000 RPM, I have not synched the carbs yet, I believe one is supposed to get the color of the plugs right then synch, is this correct? Also any insight on the high idle would be greatly appreciated. I have seen similiar posts recently but not exactly like my problem.. Oh yea...I ride at 6,200 feet above sea level, would this explain the need for turning the air screw out four turns or more??

Scott

[Anonymous]

Scott

I think I have an solution that brings close to a result that you can live with.
First of all, you should have synched the carb. Then I have a procedure that brings you close to correct mixture setting for air-screwes.

Set all air screwes to 1 1/2 turn out, then you set idle lowest possible.
Start with cylinder 1 and turn slowly the air screw out so the rpm increase and at the same time reduce the rpm with the idle screw to lowest rpm thats possible. Stop this procedure when the rpm not inceases anymore.
Then you can do the same prosedure to the rest of the cylinders.

Now you have an approx. correct setting for your carbs.
( on my bike I had to turn all air screws 1/2 turn in to a perfect setting, because it was running a little to rich at 2500 rpm )

Best reg.
KnutK

[Anonymous]

Thanks, I will try that method when I get a chance. So should I synch first or get the mixture right first, does it really matter?? :?

Scott

[earlfor]

Its probably best to synch the carbs, adjust the pilot and air screws and then resynch the carbs.

Earl

Thanks, I will try that method when I get a chance. So should I synch first or get the mixture right first, does it really matter?? :?

Scott

[Anonymous]

Thanks Earl

I will synch first, I am waiting to receive a Manometer I orderd from the UK,i t will be here next week. Pilot screws???, these are CV carbs, do I have to mess with those also?, I thought you just seated them all the way in...

Scott

[earlfor]

OOPS! Sorry Scott. As soon as I get out of my remedial retention training classes, perhaps I will be able to remember that the 80 model with its CV carbs only has the throttle valve adjustment screws. Cylinder #3 is not adjustable , so 1,2 and 4 must be set to match number 3.

Earl

Thanks Earl

I will synch first, I am waiting to receive a Manometer I orderd from the UK,i t will be here next week. Pilot screws???, these are CV carbs, do I have to mess with those also?, I thought you just seated them all the way in...

Scott