77 GS 750 Carb Work

[Guest]

Have a nice 77 GS750 Has the old mikuni non cv carbs cleaned them rejetted start's good but run's like it's running on 3 cylinders looking for a good rebuilder previous owner has monkey with them run's okay after 50 miles trip but still feel something amiss any body recommend a good rebuilder I am in Washington State

Thanks JB

[tkent02]

Have a nice 77 GS750 Has the old mikuni non cv carbs cleaned them rejetted

The best person for the job is going to be you, no one you pay will give a damn except to take your money. Bike shops are there to sell new bikes, not prolong the life of old ones. For them to go through everything that an old bike needs to have done would cost many times what the bike is worth, technicians are not trained in most of the old technology anyway.
I have heard there are old farts that still do this stuff for a living but I haven't ever met one.

The cleaning and rejetting you did would be the first thing I would suspect.

How did you clean them, and exactly why did you rejet? What jets did you use? Where did you set the floats? Have you checked the fuel level? Is the cylinder that's not running getting fuel? Does it even have a decent spark? Is it always the same cylinder? Are the points set properly? Ignition timing? Cam timing? Are the valve clearances set correctly? Does it have any compression? Is the dead cylinder #3 or one of the others? Does the petcock work properly? How about a little history? Did it ever run correctly since you had it? How much fuel does it use? What intake and exhaust systems are you using?

Etc, etc, etc.

It's hard to tell from here, but if you put it in the carburetion forum or the four cylinder engine forum you will get more responses.

[chuck hahn]

I rebuild them and CVs and he is the best rebuilder if he wishes to do so. Heres some links for him.

Save this for future use and for the 8 VALVE 750 service manual.

http://members.dslextreme.com/users/bikecliff/

Your carb rebuild guide...

http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

And the oring kit from our very own member robertbarr. 1 kit does the entire rack. Be sure to get the intake orings on page also. Measure the inside diameter of the groove and get that size orings.

http://cycleorings.com/