Carb/Start/Run Issue ??

[dw200]

I have a 82 GS650G with about 50K miles that has been awakened from the dead.Valves have been adjusted and the carbs rebuilt. However, the mechanic could not things quite right with the carbs.It is running so lean that it is extremely hard to start when cold. Once it warms up it runs good and seems to build power(haven't rode it yet because of a brake issue). He said that he could either set them to start good and run like crap when warm or be a bitch to start cold and run good when warm.


Any thoughts????

[Steve]

If the valves have been PROPERLY adjusted and the carbs PROPERLY rebuilt, you should not have to do much more than thnk about pushing the starter button to have the engine roar to life.

If the valves are tight (especially the intakes), it will be hard to start when cold. Even a warm engine runs better with looser valves.

If the carbs were properly rebuilt and adjusted you should still need a bit of "choke" to start it when cold, but not when warm.
After all, that's the whole purpose of the "choke" (actually enrichener) circuit, it's for starting a cold engine.

If the float level is correct (22.4 mm), make sure the idle mixture adjustment screws are set to three full turns out from lightly seated.
If that does not work, you have some blocked passages in your carbs.

If your "mechanic" can't figure out the carbs, you need a new mechanic. The best one for the job is the bike's owner.

.

[Big T]

You need a new mechanic

[dw200]

That's what I am beginning to think. The valves are much quieter than before and it idles great when warm but it will not rev above 3000 rpm now on the tank. It did fine on a test bottle at the shop. I have had enough of this.

[Steve]

The valves are much quieter than before and it idles great when warm but it will not rev above 3000 rpm now on the tank.

Two things going on here:
1. If the valves are noisy, they are WAY too loose. Stock clearance is only .03 to .08 mm, which is the thickness of a piece of paper.
You can not hear the cam closing up those small clearances.
2. Do you have the airbox on? Or, if you are running pods, are they installed?
The bike will not run properly without something on the intake side of the carbs.

.

[5azzmonkey]

Are you sure the carbs were rebuilt correctly ie complete tear down and soak?

-Dave

[BassCliff]

Hi,

You and your mechanic read this: Top 10 Newbie Mistakes.


Thank you for your indulgence,

BassCliff

[dw200]

I'll address a couple of posts at once. The bike has the original airbox with a new, OEM replacement filter on it. I cannot verify what carb kits that the mechanic used in the rebuild. I only know the parts that he asked me to order (new main jets). The valves are quiet. I bought the shim kit from Z1 and he used what he needed. I gave him the clearances from the Suzuki book. And yes, I have read the "Newbe Mistakes".

The bike has a Dyna ignition in it now. I figured that problem out before I took it to him. However, I think it may have confused him a bit and I don't think he ever checked the ignition timing. That might be a root cause here.

I think I may have picked the wrong mechanic.

[cowboyup3371]

I think I may have picked the wrong mechanic.

You will find that most all of us will recommend you do the work yourself as 1) it's really not that hard, and 2) most mechanics don't know what they are doing with these old bikes and will try to rip you off.

[tkent02]

He said that he could either set them to start good and run like crap when warm or be a bitch to start cold and run good when warm.


Any thoughts????

He's full of crap. If everything is working correctly, a flick of the fingernail on the starter button and it is running, hot or cold.

[tom203]

If everything is working correctly, a flick of the fingernail on the starter button and it is running, hot or cold.

dw200; This stuff can be very frustrating and hard to believe, but it's true! My same bike at 39k starts so easily it sometimes startles me and I don't lavish it with lots of maintenance. Most "professional" mechanics don't have much interest in these old bikes- you're better off hanging out here and taking advantage of mountains of advice. It's not fun removing these carbs and making sure they are really clean, but if you want a decent running bike, there is no alternative.
If you have access to timing light, check to make sure the timing advances to about 35 BTDC by 4k.

[dw200]

I am not even getting to 4000 RPM to check the timing. I guess I will have to make the time to do it myself. I have the Z1 shim kit so I will start over from there.

[tom203]

I am not even getting to 4000 RPM to check the timing. I guess I will have to make the time to do it myself. I have the Z1 shim kit so I will start over from there.

That's odd, since you said it idled "great when warm"- in neutral , a blip of throttle should drive it past 4k at least momentarily even with dirty carbs. In any event, carb cleaning is #1 priority. How does bike look - any pics?

[dw200]

I got the bike back for a different shop today. Found an independant shop that had no problem working on the old thing. It just seems a little funny that after the other mechanic tearing the carbs down twice (his words), there were still very dirty (new mechanics words). They also found something in all 4 carbs that had been installed wrong. No wonder things wouldn't adjust right.

End result after another teardown, a rebuilt rear master cylinder, and setting the timimg....a decent running machine to be 30 years old. I'll put some pics up tommorrow.

[cowboyup3371]

And another reason you should just do the work yourself.

Looking forward to the pictures.