Carb Adjustment Question

[marcolli]

Hello everyone. I just got done cleaning and replacing the O rings in the carbs of my '81 650g. The air screws on carbs 1 and 4 were backed out one full turn while the air screws on carbs 2 and 3 were backed out one and a half turns. Is that normal? Shouldn't they all be the same? Thanks in advance.

[robertbarr]

What they were set to isn't terribly informative, since we don't know what the previous owners had in mind (or in their bloodstreams, for that matter). Some people just want to turn screws to adjust <whatever> to make their bike <faster, smoother, etc>. Probably some just turn screws to see what happens.

In other words, if the bike has been through several owners, the carb settings can be more random than the lotto.

[marcolli]

I'll buy that. However, the bike is stock. So I guess I'd like to know if those were the factory settings and a good place to start, or should I set them all to one turn out and go from there?

[hampshirehog]

The carb sticky lists the settings for the 650: try

http://www.thegsresources.com/_forum/showthread.php?t=73723&page=2

[Nessism]

Set the screws to 2.5 turns out and see how it runs. Standard procedure is to warm the engine and then set the screws to achieve the highest idle.

Good luck.

[marcolli]

Thanks guys. I have them set to 1 turn out right now and it runs much better than it did before. It pulls like an ox now. However, after running at highway speeds, the RPMs don't want to drop back down to idle. Would backing the screws out another turn or so help with that or is that a symptom of another problem?

[chef1366]

Intake or airbox leak. Probably intake.
Change out the o-rings behind the intake boots.

[salty_monk]

1 turn out is pretty lean on the screws too... I would try 1.5, 2 or even 2.5 turns (2.5 always works for me) before messing with anything else as it's a super easy adjustment to test!

Have you changed the intake boot o rings?

Dan

[Steve]

I will second the suggestion to turn them out to at least 2 full turns, then tweak from there.

Setting them all the same is only to get them in the ballpark to get it running well enough to warm up the bike. When the bike is warm, turn each screw slowly, listening for highest engine rpm. I tend to go back and check them all again before I call them 'good'. Now you need to count the turns and record them for future reference. It is not unusual for them to be different, as each carb will have slightly different tolerances coming down the production line, let alone what they look like 27 years later.

.

[marcolli]

Yes, I replaced the O rings on the intake boots. After reading about the kinds of gremlins that gets rid of it wasn't even an option not to.

Thanks for the procedural help, Steve. I'll back them out another turn or so and then go through them as you have suggested.

As always, YOU GUYS ROCK!!! Thank you.

[marcolli]

SUCCESS!!! I backed the screws out 2.5 and then followed the tutorial on BassCliff's site...

http://members.dslextreme.com/users/bikecliff/images/highest_rpm_plug_chop.html

Hot damn!! Runs like a top and pulls strong throughout the entire power curve. No flat spots and great throtle response and the RPMs drop back to idle without hesitation.

Thanks for your help and guidance once again. Now it's on to the clutch and bolt kit.

[basta]

Are the carbs CV type on this bike?
Roy

[Suzuki_Don]

Are the carbs CV type on this bike?
Roy

Hi Roy. All 650s had CV carbs. They were only produced from '81 to '83.

[basta]

Hi Roy. All 650s had CV carbs. They were only produced from '81 to '83.

So I can use this method on my gs550 with CVs or Bs carbs fitted right?
thanks Roy

[basta]

Ime running 3,5 turns out as per the carb specs on this forum so is this just a starting point?
thanks Roy