Cold cylinder

[Anonymous]

After some more puttering I find myself back hoping for some more advice.

First off, my 1980 GS850 had some problems earlier this year when I got it out of storage, and hasn't work well since. On the way from storage, it started to run really hot, had a cracked oil filler cap gasket and lost power.

Had it towed home, drained the oil (which was over filled) put in new plugs (which still look good) but did not remove and clean the carbs (still a little intimidated about doing that). Also did a compression test and everything was equal +/- 5% .

Well now, it will start with the choke fully open, however cylinder 4 is cold. But if I let the bike warm up and drive it a little bit around the parling lot, it will eventually heat up. But the bike stalls when I come to a complete stop.

I have pulled the plug while it is running and I can see a spark, but not much of one. However I have to admit I have no idea of how visualy to tell the difference between good spark and bad spark. I am fairly mechanically inclined, and I have the service manual, but I don't have the knowledge of where to start adn what to test.

Obviously cylinder 4 is either not getting spark (or not enough) or not getting gas. I have the gas tank off right now so I am curious... What should I check first? I have a multmeter so I can test that sort of thing.. but like I said, just don't know where to start.


Thanks so much and this site and everyone is great. It is why I haven't given up.. well that and I am stubborn.

Also, if there are any more mechanically inclined GS owners in the Minneapolis/St Paul area, if I need some more advanced help, I would appreciate any good shop suggestions or would be willing to pay for some help .

[argonsagas]

cold cylinder

You don't have an electrical problem. The spark often appears weak, especially in daylight, but your coil obviously works, as each coil powers two plugs, and you only have a problem with one cylinder, so, unless the plug is missing an electrode, you have a carb problem.

Don't be too intimidated by the carbs. Remember to loosen ALL the screws on the retaining rings on both the air cleaner and the carbs before trying to remove anything. (They will come apart with a little exertion, but you will have great difficulty putting them back together)

There is an excellent section on this site that tells you about the carbs. There will be gas in the bowl, so the first thing to do (after taking the carb bank off the bike) is open the plug on the bottom of each bowl and drain it.

When you clear the pilot jet with the tool the site tells you how to make (and it's a very good idea), you will dislodge any debris, but it probably will not fall out and will come back and re-block the jet very soon. Blowing it clear with compressed air or carb cleaner (you blow through that tiny hole) works well.


It helps if you have a bright work surface, good light, and a small tray for parts. An egg carton is a great help because it allows you to sort the parts any way you wish.

Allow lots of time, and be slow and careful.

PS install an in-line gas filter. It's amazing how little it takes to clog a carb.

[Anonymous]

How long did it sit in storage? It sounds like your number 4 carb needs to be checked out. You probably need to clean all of the carbs, but i'd concentrate first on the one giving you trouble.

Tim

[Dink]

Here is a thought in a different direction for you.Have you considered replacing the No4 plug cap, it may be breaking down. I tend to think that a good carb clean out is still a very good idea if for no other reason than these are old bikes and storage will always allow deposits to form.
Dink

[Anonymous]

Check your compression, make sure there is enough vacuum to draw the fuel into that cylinder. You may have a stuck valve or bad rings. Compression guages are cheap. Try JC Whitney.

[Anonymous]

Re: Cold cylinder

Well I finally got the courage to take the airbox and the carbs off, of course it started raining 20 minutes later. So I am going to see about doing this whole thing. Although since I don't have a lot of time I might just seea bout having it done. Now lets just hope I can put it back on

I a, hoping to just try and spray clean it out and put it back on and see if there is any difference.. ot is that just a waste of time. It took 20 minutes to take it off... hopefully not to much longer to put it back on.


Thanks everyone, and hopefully I'll be up and running soon.

After some more puttering I find myself back hoping for some more advice.

Also, if there are any more mechanically inclined GS owners in the Minneapolis/St Paul area, if I need some more advanced help, I would appreciate any good shop suggestions or would be willing to pay for some help .