1982 Suzuki GS1100G Carbs Overflowing into Airbox.

[GalDemSuga]

Folks

The bike's Carbs and exhaust are stock, I am using the factory Airbox as well. I just had the Cylinder Head redone and valve clearances were set at the machine shop to be within spec once they Cam Caps are torqued to spec. I may have to recheck this for myself. The Carbs have been cleaned and new o-rings installed and the float heights was set to 22 mm.

I'm having what I believe to be Carb issues. I am here right now https://www.thegsresources.com/_forum/showthread.php?194050-Help!-Your-Bike-Won-t-Run-Well/page3, reading the valuable info that this member has taken time to assist us with.

I got the bike to run with what I now know was pure luck but it hasn't run consistently since. It takes me a long time and requires me fiddling with the Idle Screw to even get a brief start. Today I took the Carbs back off and rechecked the bench sync. I adjusted it and set the air screws to 2.5 turns out from close on each Carb. I reinstalled Carbs and attempted to start for an hour. It did start and ran for about a minute or less during which I was able to spray brake clean around all the boots and Airbox to detect leaks. I found none.

After the engine shut off I placed my hand on each of the exhaust pipes and noticed that only Cyl 3 and Cyl 4 were hot while Cyl 1 and Cyl 2 were still cold. It seems that those 2 were not getting fuel. I know all cylinders are getting spark as I have checked them all. The plugs are all new NGK BR8ES (edit: I just noticed that the manual calls for NGK B8ES, so I will change these out in the morning. I simply purchased new versions of what was in the bike when I bought it.) and are gaped between 0.02-.0.03 inches. I pulled the Carbs back off and rechecked the bench sync and this time I used a 0.127 mm feeler gauge and synced them all again. I will try again in the morning to get it running.

I welcome any input from you guys.

 

[GalDemSuga]

It has been 10 hours since I tried starting the bike and ultimately pulled the carbs. I just pulled the plugs; 1 and 2 were black and wet while 3 and 4 were brownish and dry. Tomorrow I do a compression check to ensure all is well with each cylinder.

 

[Steve]

Have you cleaned the carbs? Not just "clean", but REBUILT? The pilot jets are very small and plug easily if the bike has not been run for a while.

How long has it been since the bike ran regularly? (How long have YOU had the bike?)

If you don't know much about the history, or maybe only have the word of the previous owner, assume that NOTHING has been done. I'm not sure I would trust the machine shop to measure the valve clearances correctly. It's way too easy to do it wrong, and the clearances are critically small, so you don't want to get them wrong.

One other thing to check: are the spark plugs connected to the correct wires? The coil on the left should be connected to cylinders 1 and 4, the coil on the right should be connected to cylinders 2 and 3.

Checking bench sync with anything mechanical ("0.127mm feeler gauge") is a futile endeavor. The easiest way is to have the carbs off the bike (on the bench, of course), then use the idle adjustment screw to close the slides until you just barely see a sliver of light under #3 slide. Compare that sliver of light to what you see under the other slides, make adjustments as necessary.

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[GalDemSuga]

Have you cleaned the carbs? Not just "clean", but REBUILT? The pilot jets are very small and plug easily if the bike has not been run for a while.

How long has it been since the bike ran regularly? (How long have YOU had the bike?)

If you don't know much about the history, or maybe only have the word of the previous owner, assume that NOTHING has been done. I'm not sure I would trust the machine shop to measure the valve clearances correctly. It's way too easy to do it wrong, and the clearances are critically small, so you don't want to get them wrong.

One other thing to check: are the spark plugs connected to the correct wires? The coil on the left should be connected to cylinders 1 and 4, the coil on the right should be connected to cylinders 2 and 3.

Checking bench sync with anything mechanical ("0.127mm feeler gauge") is a futile endeavor. The easiest way is to have the carbs off the bike (on the bench, of course), then use the idle adjustment screw to close the slides until you just barely see a sliver of light under #3 slide. Compare that sliver of light to what you see under the other slides, make adjustments as necessary.

.

Hey Steve

I bought the bike in non-running condition. I don't know if and when it last ran and before 2 days ago I had never heard it run. The Carbs were completely torn apart, soaked for days and all o-rings as well as the fuel inlet Tee were changed. It was a rusty mess and everything was plugged by rust. Today I will check compression, recheck valve clearances and change the plugs to the factory NGK B8ES instead of the NGK BR8ES that I put in there. The plug wires and coils were checked for accuracy before I got it to run but I will verify timing and spark again as well. I am using a APE manual Cam Chain tensioner as I don't trust the auto tensioner.

 

[cowboyup3371]

Why don’t you trust the stock tensioner? They work exactly the way they are supposed to when installed properly

 

[GalDemSuga]

Why don?t you trust the stock tensioner? They work exactly the way they are supposed to when installed properly

It is the reason for the damage to the cylinder head. At some point it failed the PO and as a result I am now $400 vested in the head. I don't want a repeat of this under my ownership which will be forever. I have the stock tensioner and another I bought off Ebay for $10.00. I read up on the operation and they work off the bike. When I put them on and attempt to have the shaft release and take up the chain slack, it doesn't. When I pull it back off it suddenly triggers and pops out. I have cleaned and lubricated them both in my trials but it doesn't work for me. I would prefer to use them but I just haven't had the luck.

 

[GalDemSuga]

Update!!

I checked the valve clearances and they are all off. Exhaust 1 is too tight and all of the others both Intake and Exhaust are too slack. This made me mad as hell so I stopped what I was doing and went over to the machine shop to give them the "business". I wasn't even offered so much as an apology. I rechecked my timing while I was at it and got the factory recommended NGK B8ES spark plugs.

I also confirmed that the Carbs are factory type Mikuni BS34SS Model # 49400. Now I will try and get the valve clearances within spec and proceed with reassembly.

Update - https://youtu.be/ZbQizZOlm74

 

[cowboyup3371]

Have you read through BWringer's site and this article specifically? http://www.bwringer.com/gs/camchaintens.html

Pay particular attention to this instruction -

To reset the tensioner to get it ready to install, press the pushrod in as far as it will go while turning the knob out (counterclockwise).

Hold the pushrod in place (you can let go of the knob) and tighten the setscrew.

Reinstall the tensioner on the bike, using your sparkly new stainless steel bolts and the new tensioner gasket.

With allen head bolts, it's much easier to reach the top right bolt. Remember, the top right bolt is 5mm shorter than the others.

Once the tensioner is installed, loosen the setscrew 1/4 to 1/2 turn -- until you hear the pushrod pop out to press against the tensioner blade.

Tighten the locknut while holding the setscrew in place. Remember, the whole idea is to keep the setscrew a little bit away from the pushrod so it can move. The setscrew is only all the way tight when you're removing or installing the tensioner.

 

[Steve]

If you don't want the stock tensioner(s), I'll be happy to buy them from you. :encouragement:

.

 

[allojohn]

You mention either the carbs or fuel T were a rusty mess. That rust came from the gas tank and if you haven't fixed that it's still coming down the fuel line.....

Also, as Cowboy hints.... likely the cam chain tensioner was set incorrectly by the PO, which isn't unusual.

 

[GalDemSuga]

Have you read through BWringer's site and this article specifically? http://www.bwringer.com/gs/camchaintens.html

Pay particular attention to this instruction -

To reset the tensioner to get it ready to install, press the pushrod in as far as it will go while turning the knob out (counterclockwise).

Hold the pushrod in place (you can let go of the knob) and tighten the setscrew.

Reinstall the tensioner on the bike, using your sparkly new stainless steel bolts and the new tensioner gasket.

With allen head bolts, it's much easier to reach the top right bolt. Remember, the top right bolt is 5mm shorter than the others.

Once the tensioner is installed, loosen the setscrew 1/4 to 1/2 turn -- until you hear the pushrod pop out to press against the tensioner blade.

Tighten the locknut while holding the setscrew in place. Remember, the whole idea is to keep the setscrew a little bit away from the pushrod so it can move. The setscrew is only all the way tight when you're removing or installing the tensioner.

This is what I have been trying but that pushrod does not trigger with a 1/4 or 1/2 turn out. It works flawless until I actually put it on the bike. I will try again.

 

[GalDemSuga]

If you don't want the stock tensioner(s), I'll be happy to buy them from you. :encouragement:

.

I will try using them again before I let them go.

 

[GalDemSuga]

You mention either the carbs or fuel T were a rusty mess. That rust came from the gas tank and if you haven't fixed that it's still coming down the fuel line.....

Also, as Cowboy hints.... likely the cam chain tensioner was set incorrectly by the PO, which isn't unusual.

I used metal restore on the tank. I soaked it for about 2 weeks. Its sitting now empty and I will examine it before I put it back on the bike. I am using an Aux Tank to try and get her running.

 

[GalDemSuga]

Tonight's update:

I was able to get five valves clearances within spec and I will need three shims. Cylinders 1 & 4 are out of spec (Cyl 1 EX and Cyl 4 EX and IN). I checked compression today and they were; #1 @ 130 psi, # 2 @ 135 psi, #3 @ 135 psi and #4 @ 140 psi. I did the test with the Carbs removed and the engine cold, however it was 85F in the garage.

I attempted to start the bike using tight valve clearances on Cylinders 1 & 4 but it never started. It would sputter and when I touched the exhaust pipes after it would sputter, I noted that Cylinders 2 & 3 which are within spec were the only ones to ignite.

 

[GalDemSuga]

Today's update:

I took the Carbs apart while I await new o-rings for the Vacuum Tees. The o-rings on there now are new but those Tees seemed loose to me and they may have been leaking air contributing to my hard start issues. Cylinders 1 and 4 won't ignite when I was trying to start the bike while 2 and 3 did. I adjusted all of of float heights and pulled one Needle Valve. I also installed the Auto Cam Chain tensioner. and I shot a short video in the hope that you Guys can enlighten me about it's operation. I am rebuilding the Airbox which I cleaned up and I plan to rejuvenate all of its rubber parts before reassembly.

Carbs - https://youtu.be/Ssci6kqN7dk

Auto Cam Chain Tensioner - https://youtu.be/UMFqqbd-Az8

 

[allojohn]

I've been waiting for Steve to reply regarding the tensioner, but it seems to me you need to loosen the lock-nut, turn the screw out to release the plunger completely. Turn the screw in until light resistance is met, then back the screw out 1/2 to 3/4 of a turn and tighten the lock-nut taking care to hold the screw in place. I have no issues with this method.

 

[GalDemSuga]

I've been waiting for Steve to reply regarding the tensioner, but it seems to me you need to loosen the lock-nut, turn the screw out to release the plunger completely. Turn the screw in until light resistance is met, then back the screw out 1/2 to 3/4 of a turn and tighten the lock-nut taking care to hold the screw in place. I have no issues with this method.

Doesn't this turn the tensioner into a manual tensioner if the plunger is all the way out and now prevented from going back in because of the pin?

 

[Big T]

Doesn't this turn the tensioner into a manual tensioner if the plunger is all the way out and now prevented from going back in because of the pin?

No, what he's saying is that sometimes the plunger won't release until you loosen up the lock screw farther than 1/2 turn.
The plunger only goes out as far as the cam chain allows, shouldn't be all the way
Resetting the lockscrew to the stated clearance won't lock it in place. The force of the cam chain tension is much greater than that of the tensioner screw

 

[rphillips]

The orig. auto. tensioner will work like a manual tensioner only when the screw is screwed in, "tight against the plunger", holding it from going either direction. loosen the screw & the plunger will be pushed out with the spring pressure, to take up the slack as needed, but can't go back in unless you turn the big knob on the side with the spring wrapped around it. I've always wondered why buy an after mkt. manual when tightening the screw in tight, will do the same thing.

 

[allojohn]

Doesn't this turn the tensioner into a manual tensioner if the plunger is all the way out and now prevented from going back in because of the pin?

No, what he's saying is that sometimes the plunger won't release until you loosen up the lock screw farther than 1/2 turn.
The plunger only goes out as far as the cam chain allows, shouldn't be all the way
Resetting the lockscrew to the stated clearance won't lock it in place. The force of the cam chain tension is much greater than that of the tensioner screw

What he said.