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1980 GS850GL Need some advice

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The idle speed knob probably had a spring on it to maintain it's position. It must have fallen off while I was disassembling the carbs ..as I found a lone spring that was obviously from a carb.... I just had no idea where it went as I was in the middle of dipping and cleaning. When I put the idle adjustment knob back on it felt loose and I was concerned .....but not concerned enough to do anything about it...until it dawned on me while riding last night and having to pull over every 10 miles and turn down the idle again.

I'm going to play the the mixture screws some more.. I'm not getting the results I want with the "fastest idle" method, so I'm going to do some more searching. To 81gs850 Yes all the springs are on the mixture screws but some of the screws seem looser than the others, so I 'm going to pull them all out and look at that again.
 
Steve the PO had been in the carbs...he's done some good things (replaced all the bowl and cap screws with stainless steel button head screws) and some dumb things (all of the bowl gaskets were touching and rubbing on the floats) and some things I would have questioned even if I knew what I was doing with these things :D
He replaced the needles with the dynojet needles and put the largest (165) jets in place of the stock #115's ... I rejetted with the 135's from the dynojet kit he gave me when I got the bike..but I don't think that's the problem I'm having now as most of the missing and erratic idle is with little or no throttle open. The worse performance is at about 1/8-1/4 of the throttle ... and that's in correlation with about 1800rpm to 3500 rpm. I'm going to pull plugs first today... and see what they look like after my ride last night...
I'll be back in a bit.
 
ok.... starting to look at things a bit closer now... the spark plug wires are all different. I've got 3 different wires and 3 different boots ... so..before I do any more adjustments I'm going to re wire the plugs...
 
New NKG boots, caps and wires.... ran the engine for a short while... even for a short burst # 3 & #4 plugs became coated with carbon.. #1 and #2 clean as a whistle. I'm pretty sure the carbon build up is happening while the engine is idling because it runs so well once the throttle is opened up even a little.

And this is now a bit disconcerting .... after I re-did the plug wires... I accidentally leaned on the right coil..which startled me because it was hot to the touch.. the left coil was cool to the touch... somehow I don't think that's good...
 
Check the resistance in the coils... I do wonder... Are you sure the wires are going to their respective holes? Maybe the PO sent both plug wires from one coil to the right and both plug wires from the other coil to the left? 1-4 and 2-3 should be the respective coils, not 1-2 and 3-4.
 
Well...that's going to have to wait.. I've got the carbs torn back down and looking for mistakes...here's what I found so far in the carbs. The needle valves were not in straight from the piston ...the snap rings were in crooked and the needles were hanging up on the valve. this was in #3 & #4. so those were hanging up and not moving smoothly. One of the rubber plugs had (I think) come off as well (or I didn't snug it up ). Also I had not tightened up the drain plugs ...they were only finger lose. I have a lot to learn.

81gs850... The plugs are wired 1&4 to the left coil and 2&3 to the right coil. but as I said...I'm going to wait on that until I get the carbs back together.
 
Uncamitzi, any time I need a gasket, I try to go through ebay member janquishmotorsports. They use a felt type gasket material and I have had no issues with their gaskets yet. Also, give what ever you are working on a few light taps to break the seal loose. You'll have better luck at saving the gaskets and not damaging the part or gasket mating surfaces
 
... because of Steve calling me on it with the idle mixture air screws...I'm afraid to call anything a needle valve anymore...
And yet, it continues ...
... here's what I found so far in the carbs. The needle valves were not in straight from the piston ...
At least we know what you are talking about this time (except for the "pistons").


...the snap rings were in crooked and the needles were hanging up on the valve.
If the snap rings were not in their proper groove, the plastic retainer that it holds could come out of place. However, even when it's in the proper place, there is usually a small nub on its lower surface that will push on one side of the clip, forcing it against the side of the JET (not "valve") to keep it from rattling. Yes, when properly installed, the needle will not hang perfectly perpendicular to the SLIDE (not "valve").


One of the rubber plugs had (I think) come off as well (or I didn't snug it up ).
New plugs will have a bit of tension in them to hold them in place nicely, but even used ones are not in danger of falling out, once the float bowls are installed. There is a nub on the inside of the bowl that holds the plug in place, that is what makes that little round dimple in the top of the plug.


... the PO had been in the carbs...he's done some good things ... and some dumb things ... and some things I would have questioned even if I knew what I was doing with these things :D
He replaced the needles with the dynojet needles and put the largest (165) jets in place of the stock #115's ... I rejetted with the 135's from the dynojet kit he gave me when I got the bike..but I don't think that's the problem.
This raises a few more questions. :-k

I don't remember seeing mentioned, so will have to ask. You running stock airbox and/or exhaust? Or do you have pods and/or a header?

And, ... if a Dynojet kit was installed earlier, the air correction jets might still be installed. If you are going back to stock, you will not need them and they will certainly affect jetting while they are installed.

Also, if you are going back to somewhat stock, the DJ needles might be a bit too rich.

Please let us know what your setup is regarding intake and exhaust, we can help you a little bit better.

.
 
And yet, it continues ...
At least we know what you are talking about this time (except for the "pistons").


If the snap rings were not in their proper groove, the plastic retainer that it holds could come out of place. However, even when it's in the proper place, there is usually a small nub on its lower surface that will push on one side of the clip, forcing it against the side of the JET (not "valve") to keep it from rattling. Yes, when properly installed, the needle will not hang perfectly perpendicular to the SLIDE (not "valve").


New plugs will have a bit of tension in them to hold them in place nicely, but even used ones are not in danger of falling out, once the float bowls are installed. There is a nub on the inside of the bowl that holds the plug in place, that is what makes that little round dimple in the top of the plug.



This raises a few more questions. :-k

I don't remember seeing mentioned, so will have to ask. You running stock airbox and/or exhaust? Or do you have pods and/or a header?

And, ... if a Dynojet kit was installed earlier, the air correction jets might still be installed. If you are going back to stock, you will not need them and they will certainly affect jetting while they are installed.

Also, if you are going back to somewhat stock, the DJ needles might be a bit too rich.

Please let us know what your setup is regarding intake and exhaust, we can help you a little bit better.

.

glad you can mostly figure out what I'm talking about even though I mix the terms and labels around... I'll try to be more careful...

When I re-opened the carbs after my first attempt I found what I described. In my first post I did mention that I had made sure that the airbox was sealed... I am running the stock air box with K&N filter, lightly oiled (as per instructions) with K&N oil. In other posts here I had mentioned that the exhausts seem to have been shortened at some point in the motorcycle's 34 year life by what seems to be about 3 inches... I have NO idea why someone would do that but I'm thinking 3 inches wouldn't effect the jetting too much... I could be wrong.
When I was checking to see where the PO had placed the clips on the needles inside the pistons(sliders) attached to the diaphragm, I must have not seated the #3 & #4 circlips right ..they were crooked and the needle was hanging up in the needle jet. This more than likely accounted for the poor performance and the black soot on the #3 & #4 spark plugs.

Once the float bowl gaskets get here I'll put it all back together again.... As to the jetting... I've got the stock jets and a couple of other sizes from the dynojet kit.. Judging from some of the stuff I've seen on this cycle...the PO was jetting to be jetting... why he did things.... who can guess...?
 
The spring there on the idle adjustment knob is the one I was talking about.... I wondered where it went until I did a test drive the other day and had to keep turning down the idle in parking lots along the road...IMAG0085[1].jpg :rolleyes:
 
Ok...all back together... and I had a momentary sense of elation ...after getting the carbs back on, and the airbox tightened back on.... I hung my temp gas container, and pulled the choke... set the spark to it and waited for about 4 seconds of crank..and it fired right up.... and purrred in idle.....

so I let it idle for a bit to warm it up... about 5 minutes of idle and then I revved it a bit. dark smoke out of #3 & #4.... ...

When I bip the throttle it seems to flood out. If I increase the throttle steadily...it revs up ... but a bip kills it...

Where am I ?
 
Never mind...pulled the plugs and I'm not getting spark to #1 & #4.... back to the drawing board...
 
back together, some coil problems threw me out of time today. But I did get things fired back up. Sad to say #3 #4 got all soot covered again after just a short run. I'm beginning to think my spark plug problems aren't carb related.
 
Coil windings qill weaken over time, add heat and they will definately breakdown. Can you switch the coil and see if the issue follows? I can on mine but it is a twin.

Heat and rpm take out weak ignition components and can cause random spark and early or late combustion. It is common to see flames in the exhaust from unburned fuel igniting when you get ignition back
 
The odd thing and the thing that makes me not really believe that it's coil related is that #3 AND #4 are the ones ...if it were 2&3...or 1&4... sure.. and I wish I knew why I'm not getting a reading in the secondary coil and the bike still runs...

I'm going to tinker with it a bit more today...
 
back together, some coil problems threw me out of time today. But I did get things fired back up. Sad to say #3 #4 got all soot covered again after just a short run. I'm beginning to think my spark plug problems aren't carb related.

How do you get black soot without spark firing? :confused:
 
I was about to suggest that you verify that 3 and 4 are on the proper plugs, but you said some time ago that the engine "purrs" at one time or another. If those two wires were switched, it would not "purr".

.
 
All the plugs are firing (after my little solder job)... but #3 and #4 plugs are building up carbon almost immediately after firing. A motor run of only a couple of minutes produces a thick layer of soot (carbon) on both plugs. I did measure the float heights during the first and second reassembly and all 4 were within spec. stuck float? dyno needle valves set wrong? two bad float valves?... that's the agenda today.
 
I was about to suggest that you verify that 3 and 4 are on the proper plugs, but you said some time ago that the engine "purrs" at one time or another. If those two wires were switched, it would not "purr".

.

Ok.... that's actually not a bad point to bring up... while I know that 2&3 are on the right coil and 1&4 are on the left coil... does it matter if you are on the right or left HT lead off the coil?
 
Progress!! the airscrews take a VERY light adjustment. I just ran for about ten minutes with little carbon build up... with one turn out on #4 ...it's really techy...ain't it?
 
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