What does it feel like when a spot is rich or lean??

[chef1366]

Those plugs to look rich to me also
Bring the mixture screws in a bit.
Can you hit redline with the mains you have now? Does it seem to gurgle or does it hit it nice and clean? This is riding and not sitting on the center stand.

[Darin Jordan]

Those plugs to look rich to me also
Bring the mixture screws in a bit.
Can you hit redline with the mains you have now? Does it seem to gurgle or does it hit it nice and clean? This is riding and not sitting on the center stand.

Riding the bike, (of course... ), the bike will near redline in first gear at WOT, but does start the stumbling... around 6500 or so. In any other gear, If I roll on WOT from say, 3000 RPM, it'll pull fine until it hits around 5200-5500, then it'll start stumbling very severely and will NOT pull through it... just slowly revving higher... unless I back off the throttle to around 1/2 throttle or so, where it'll pick up again fine and accelerate up to near redline, starting to stumble again around 8500, which is generally the point where the throttle has to be opened beyond 1/2-2/3rds to keep it going.

Makes it very difficult to determine what I need for mains...

I'll bring the mixture screws back down a bit to fix the richness at low throttle openings.

[chef1366]

Do you have 12 volts to the coils?

[Darin Jordan]

Do you have 12 volts to the coils?

I'm working my way through the electrical system and am going to check that next. Already bought all the parts to do the Bosch relay mod, which I'm hoping to complete this weekend.

So far, I've cleaned up the connections from the battery, through the Ignitor and the fuse-box, and all of the contacts leading up under the tank. Need to remove the tank next and get to work under there. I'll try to do that tonight and get back to you with the voltage.

If it's less than 12V, would that cause this kind of problem??? (REALLY hoping it's something like that!!)

[Loki]

If it's less than 12V, would that cause this kind of problem??? (REALLY hoping it's something like that!!)

Yes it can, may have poor quality spark. With a quality spark you may not be too rich.

[LarryC]

New guy sticking his nose in

I had weird problems like this once. U still running the points right? Try replacing the condensers.

[Darin Jordan]

New guy sticking his nose in

I had weird problems like this once. U still running the points right? Try replacing the condensers.

No points on this bike... it's a 1980 GS850G...

[Darin Jordan]

Yes it can, may have poor quality spark. With a quality spark you may not be too rich.

After changing jetting so drastically all over the board and having none of it really affect the actual problem, I'm leaning this direction at the moment, with the hope of getting a resolution soon.

If that turns out to be it, then I should be able to hone in on the correct jetting pretty quickly.

[LarryC]

No points on this bike... it's a 1980 GS850G...

Hmmmmm.....

After changing the jetting so drastically all over the board and having none of it really affect the actual problem....

I concur. The dusky look of those plugs suggests incomplete ignition.

[Steve]

I guess the most puzzling part is that this is simply a stock GS850G motor... Nothing has been done to it that should have it requiring anything special to make work correctly.

Well, ... nothing except pods and a pipe.

Hahahaha... you guys DID warn me that Pods were fun! ...

It's amazing how many guys think we're just blowing smoke when we say that, it's nice to hear you admit it.

So far, I've cleaned up the connections from the battery, through the Ignitor and the fuse-box, and all of the contacts leading up under the tank. Need to remove the tank next and get to work under there. I'll try to do that tonight and get back to you with the voltage.

If it's less than 12V, would that cause this kind of problem??? (REALLY hoping it's something like that!!)

Yes, it can cause similar problems, but before you go to all the trouble of doing the coil relay mod, just check your voltage at the coils and compare it with battery voltage. You can do this with the engine ON or OFF, but get both readings under the same circumstances. If the difference is less than a volt, you probably won't notice any improvement with the relay.

.

[Darin Jordan]

Well, ... nothing except pods and a pipe.

OK, when I say "motor", I'm referring to the core motor... not the support systems...

It's amazing how many guys think we're just blowing smoke when we say that, it's nice to hear you admit it.

I totally believed you, and expected this kind of tinkering/trouble-shooting to be involved. It was a $400.00 bike with 21,000 on it, and was to be expected.

Had the stock airbox been installed on the bike when I got it, I'd have likely left it, but it wasn't, and it's a filthy mess that would take a lot of work to cleanup and re-install, and I like the looks and sound of the PODs, so I'm willing to do the work to make it happen.

Also, for reference, in case it matters... I DO still have the factory "velocity stacks" from the stock airbox installed (well...brand new ones, as the originals got melted in the fire that took place in the factory airbox with the PO)... I have them installed inside the K&Ns. I believe it's important to help straighten out the airflow prior to entering the carb to help prevent unwanted turbulance, especially around the jets at the carb opening...

Yes, it can cause similar problems, but before you go to all the trouble of doing the coil relay mod, just check your voltage at the coils and compare it with battery voltage. You can do this with the engine ON or OFF, but get both readings under the same circumstances. If the difference is less than a volt, you probably won't notice any improvement with the relay.

.

That's my plan! I will be checking everything as it is before I make any more mods... The ignition worked from the factory in stock form. I'll make it work that way again before I change anything else... unless I need a new one, in which case a Dyna-S is in my future!

Thanks again for the tips!

[49er]

Also, for reference, in case it matters... I DO still have the factory "velocity stacks" from the stock airbox installed (well...brand new ones, as the originals got melted in the fire that took place in the factory airbox with the PO)... I have them installed inside the K&Ns. I believe it's important to help straighten out the airflow prior to entering the carb to help prevent unwanted turbulance, especially around the jets at the carb opening...

You may just have hit the nail on the head. I doubt that DJ's tuning parameters include people fitting the velocity stacks inside the K&N pods. I'm not saying it won't work, just that it's probably causing an over rich condition when using the DJ recommended jet sizes. If you intend to keep using them, I'd be leaning off both the needle and main jet. May the experiments progress!

[Darin Jordan]

You may just have hit the nail on the head. I doubt that DJ's tuning parameters include people fitting the velocity stacks inside the K&N pods. I'm not saying it won't work, just that it's probably causing an over rich condition when using the DJ recommended jet sizes. If you intend to keep using them, I'd be leaning off both the needle and main jet. May the experiments progress!

I can pull them and give it a try... Willing to try anything at this point...


Tested the voltage to the coils... 12.5V across the battery... 11.3 at both coils with the ignition on (bike not running). Connections looks pretty dirty, so I'll get it all cleaned up. Will research the rest of the wiring tomorrow.

[Darin Jordan]

OK, Electrical/Ignition findings...

I think I've located the issue...

First the numbers:

Voltage at Battery: 12.4V
Voltage to coil: 11.3V
Coil Primary R: 1-4=4.3 Ohm 2-3=4.5 Ohm
Coil Sec (with plug caps removed, through wires): 1-4=12.08 kOhm 2-3=11.7 kOhm

Now the juicy part... WITH the plug caps on... the resistance through the secondary, WHEN it would read, was well over 200-300 kOhm. I pulled off the plug caps and measured them individually, and they read like this:

1= 8.9 Ohm
2= >130kOhm
3= >200kOhm
4= 71 kOhm

I noticed that the connection inside the end of the cap was loose on all of these, but even after screwing it all the way in, the resistance was still tricky to even read, and when I could get it to read something, it was WAY up there.

I pulled two of the caps apart and found that there was a lot of corrosion on one end of the spring, and just in general.

Looks like new plug caps are on my order list for today.

I'm a little concerned about the coils, as the BassCliff notes suggest that they should be reading 30-50kOhms... but they are only reading around 12kOhms... However, it's unclear if the measurement noted is suppose to be WITH the plug caps attached, or without.

If you could let me know if you think I need new coils, I'd appreciate finding out here shortly, as I'm about to make an order, and while I don't really have the extra $$$ to spend on coils right now, I'm in there, and if necessary, would like to get this done.

Thoughts?

Thanks!

[Darin Jordan]

Found the new plug caps (XB05F and VB05F) at Renton Motorcycles, just up the road from here, so I'm going to go pick them up at lunch and get them installed tonight. We'll put everything back together with those and see if that helps.

They're $4.25 each there, but it's about the same in the end by the time I pay shipping to order them, and I'll have them tonight...

Hoping this is a positive step towards solving this issue! (fingers crossed)...