The 750 pops after carb clean up and new main jets Why

[Anonymous]

Hello out There.
I have just joined the site and found this to be a great resorce.
And I hope that I can Get some in sight On a small Problem.
I got my 1978 gs 750 about a year ago and Im slowly bringing it back from the dead. My buddy was going to use the bike for parts. for his 79'.
But I have got it for two bills and done a lot of work to it. Paint, Tires,brakes, yad da yad da. And I love the thing.
Any how I just got done Putting new main jets in the carbs and cleaned them up. Along with new stock vilossity tubes, And reconed the stock air box. The filter is clean and good to go. The piolet jets are good, and the flowts are set. The carbs are the vm muniki 29mm stile.
I did this to try to get a little mor snap back in the old girl. She did run farly well before. The timeing is on, and the points are set to specs.
The idle is too. and I got the air flow screws set to the best rpm.
any Idea What i can do? Im thinking Spark Probem. Please let me Know what you think. The valves dont clatter. presser test to be done yet. 8O

[earlfor]

Re: The 750 pops after carb clean up and new main jets Why

A 78 750 is stock with 26mm VM carbs and 102.5 mains. I dont think Mikuni made 29mm VM's (could be wrong). If you have 28mm VM carbs, they would be off a GS1000 and main jets in the 77-79 1000's would be 90.0 . What size main jets did you install?

Earl

Hello out There.
I have just joined the site and found this to be a great resorce.
And I hope that I can Get some in sight On a small Problem.
I got my 1978 gs 750 about a year ago and Im slowly bringing it back from the dead. My buddy was going to use the bike for parts. for his 79'.
But I have got it for two bills and done a lot of work to it. Paint, Tires,brakes, yad da yad da. And I love the thing.
Any how I just got done Putting new main jets in the carbs and cleaned them up. Along with new stock vilossity tubes, And reconed the stock air box. The filter is clean and good to go. The piolet jets are good, and the flowts are set. The carbs are the vm muniki 29mm stile.
I did this to try to get a little mor snap back in the old girl. She did run farly well before. The timeing is on, and the points are set to specs.
The idle is too. and I got the air flow screws set to the best rpm.
any Idea What i can do? Im thinking Spark Probem. Please let me Know what you think. The valves dont clatter. presser test to be done yet. 8O

[Anonymous]

yes you are right , I was not thinking late last night . :roll: I have been looking at a
lot for models and wrote down the wrong info. 78 gs 750 dose come with
26mm vm carbs. And I replaced them with 102.5 mains in all carbs.

And the bike is all stock to my Knowlage. Just some after market lighting
But it was mostly all there When I got it, I have the petcock hooked up to the right vac line on number two. Vac. Is present. Has been Cleand. and works. If this info helps out. to let youall know whar has been done.
I did not replace needel jets. appear, to be fine and clean at the time.
and There is no blocked vac lines on 1 and 3 . I did not move the preset
jets that are calibrated at the factory. I beleive thease are the fuel mixture
screws. Any way sorry about the confushtion. Maybe this will clear up things. Thanks

[Anonymous]

Basics first. Nobody really wants to hear that, but it's the only way to make real progress.

Get the valve clearances set, check the compression (to find any radical problems; it doesn't have to be ideal), and replace the intake boot O-rings. Install brand new B8ES plugs, no matter what the old ones look like.

Once that is taken care of, THEN tinker with the carbs. Otherwise, you're wasting valuable time, patience & money.