82 Suzuki GS650GL #2 Cyl Down

[Skyboy8950]

Hey all,

The number 2 (from the left) cylinder is not firing on my bike. I got spark and plenty of it. The spark plug doesn't seem fouled. Very light gloss on the spark plug after running for 5 minutes. I'm thinking it is the carb. I took some things apart to see if I saw anything obvious. Take a gander at these shots and let me know what you think.

I have a feeling I am going to rebuild my carbs...

http://farm1.static.flickr.com/170/451104220_c231ba53ca.jpg

http://farm1.static.flickr.com/190/451104324_5c99ccee92.jpg

The other side looks clean.

http://farm1.static.flickr.com/209/451104372_3cf47ee331.jpg

http://farm1.static.flickr.com/194/451117901_5c859a98fd.jpg

Thanks for your help

[Steve]

A couple of things come to mind, but please rule out one thing, first. Swap the plug leads on #2 and #3, then run it again. If #2 still does not fire, at least you know it's not ignition related.

The extra dirt around the intake tube indicates there is a leak somewhere. The vacuum line to the petcock comes off #2. Could be a bit of gas leaking from the vacuum line, if you have a bad diaphragm in the petcock. It is also possible that you have bad o-rings between the intake tubes and the head. Based on your description of a basically clean plug, that it what I would suspect. If the o-ring has a leak, it will lean out the mixture, maybe to the point where it will not fire.



.

[Skyboy8950]

Steve,

Thanks for your help. In exploring the other posts, I did play with the vacuum line. I believe this is the problem because the petcock does not work at all. The previous owner put his own shutoff within the fuel line not realizing it has more than one function.

In fixing the petcock, would you recommend rebuilding it (seems simple enough) or buying a new one?

[bradleymaynar]

Do you know much history with the bike? If it sat with gas in it for any length of time (more than a month) it could be that the float bowl in the carbed gummed up and any number of things could be stuck/clogged. You also need to be sure the tank is not rusted inside. It doesn't take a large piece of debris to clog a passage in a carb. Though, the filter inside the tank should prevent this, so the probability is pretty low of this happening.

I'd suggest to go ahead and rebuild the carbs and have them synced. It definitely can't hurt.

Brad bt

[Skyboy8950]

Well, when I said I was playing with the vacuum line, what I did was pull it off the carb, plug it with my finger, run the bike on the 3 cylinders, then when I pulled my finger off the vacuum, the 2nd one fired for a few seconds, then died. This was repeatable. I will replace/fix the petcock this week. Hopefully this will do the trick.

As for the carbs, a rebuild would be great. I would like to see if this fixes the problem so it fires on all 4 cyls first. I'll let you know.

Thanks again.

[bradleymaynar]

Great! Best to work your way up to a problem. It can be easier on the wallet!

Brad bt

[bradleymaynar]

Oh, if you do decide to go through the carbs. This is where to go for the carb rebuild. And this is where to go for the O-rings. Any other incidental parts can be had through various part sites. I like mrcycles.com, their prices a good, but I'm not too sure about their delivery. I'm still waiting on a tail light lens ordered a little over a week ago. But that could just be an availability issue. Most part sites go through the same Suzuki distributor.

Good Luck!:-D

Brad bt

[Skyboy8950]

So close

Ok guys. I really need your help on this one. This is what I have done thus far:

I replaced the petcock. This did not solve my problem, but needed to be replaced anyway. Cyl 2 will still not fire; unassisted. I pulled the new vacuum line going from the new petcock to Cyl 2 and put my finger over the port on the carb with the motor running. When I pull it off, it fires a few pops. If I flutter my finger over it, it the engine flutters with it. I know it is firing cause when I pull the spark plug wire, it does not flutter when I flutter the vacuum line. Also, the #2 pipe starts to warm up.

I know the cyl is good, it has to do with that stinkin carb. I have a feeling it is an adjustment, but I have no clue which one.

If you guys can help me, please be thorough. It is my first bike and my manual is in the mail. I have a feeling someone knows what to do and I really appreciate the help.

Thanks all!

[Norseman]

Suggestiion

Hi, Skyboy.

I definitely would suggest you pull the carbs and do a thorough cleaning per the Carb Cleaning series on this forum. Get the o-ring kit from Robert Barr (cycleorings.com). You need to buy the float bowl gaskets, the intake boot o-rings, and drain screw rubber seals (they are not the ones you can get from Robert Barr) from a dealership or online.

My bike ran very rough when I got it, but the carbs didn't "look" to bad. However, I went ahead and did the carb cleaning and o-ring replacement and it made a world of difference. If you do that, at least you are eliminating a lot of potential carb issues.

By the way, I also recommend doing the valve clearance check/adjustment. These things are necessary maintenance, and unless you can vouch for the PO, assume maintenance was not done. Now you're learning a lot about your machine, learning skills, and will have the pleasure of a job well done when you're done.

At least, that's my 2 cents . Hope it helps...

Norseman

[Skyboy8950]

Norseman,

Thanks for the advice. I would love to do this. I am a gearhead myself, I have rebuild car engines and done substantial work like that. But this bike is in great shape besides the #2 cylinder. On 3 cylinders, this thing purrs. What I would like to do is find out how to make the 2nd one fire as I know it can. After I try everything I can, then I will crack those babies open. I would love to do this... But if there is an adjustment, I would love to do that first. Thanks for the advice and I will definately get those o rings.

[Norseman]

Good point, Skyboy, get the #2 problem out of the way. I'll defer that to the GS experts on the forum - I'm a relative newbie. Nice bike, though, mine's a 1981 GS650GL.

Good luck on the trouble-shooting, I'll be checking the thread as you proceed.

Norseman

[earlfor]

You have a model year 1982. That bike should have the dome top CV carbs. On every GS CV carb'd bike I have worked on, the nipple on the #2 carb is a float bowl vent fitting. The vacuum port that should be connected to the petcock is on the top left side of the #3 carb.

If you have your petcock vacuum connected to a float bowl vent, I can see why you would have trouble getting the bike to run. LOL

Earl

Ok guys. I really need your help on this one. This is what I have done thus far:

I replaced the petcock. This did not solve my problem, but needed to be replaced anyway. Cyl 2 will still not fire; unassisted. I pulled the new vacuum line going from the new petcock to Cyl 2 and put my finger over the port on the carb with the motor running. When I pull it off, it fires a few pops. If I flutter my finger over it, it the engine flutters with it. I know it is firing cause when I pull the spark plug wire, it does not flutter when I flutter the vacuum line. Also, the #2 pipe starts to warm up.

I know the cyl is good, it has to do with that stinkin carb. I have a feeling it is an adjustment, but I have no clue which one.

If you guys can help me, please be thorough. It is my first bike and my manual is in the mail. I have a feeling someone knows what to do and I really appreciate the help.

Thanks all!

[Skyboy8950]

Maybe we are getting confused. I am talking about the vent on carb 2nd from the left side of bike. It is on the engine side of the carb. Hope this clears things up.

[earlfor]

Since you have a G model, do you have CV carbs or VM carbs?
I could be confused about what you are doing. It wouldnt be the first time. :-)

E.

Maybe we are getting confused. I am talking about the vent on carb 2nd from the left side of bike. It is on the engine side of the carb. Hope this clears things up.

[Skyboy8950]

I believe they are the CV type. They are the same carbs found in the carb rebuild tutorial found on this site. Even within that, the port is listed on the #2 carb.

Somewhat related, can anyone tell me what other purpose this vacuum port serves besides engaging the petcock to allow fuel to flow? Thanks.