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

[49er]

The petcock is freshly rebuilt and is operating correctly. Float level was set to the stock settings, but I recently raised it about 1.5mm or to see if that would help. No difference could be felt.

I'll admit, it DOES feel like it's running out of fuel supply, but there seems to be plenty of supply there... I'll double check it again, just to be sure.

Dynojet also mentioned something about the float-bowl breathers needing to have the lines removed and the outlets turned down. I've done that. I've also tried adding lines and routing them to a place with non-turbulent airflow, etc... All to no avail.

I'm left to think that it may be ignition related, so I'll try to rule that out for now. One would think that SOMETHING I've done to the carbs would have made some move towards a difference, better or worse, but thus far, the problem remains. Verifying the ignition system seems prudent at this point.

After re-reading your earlier post, your plug colour is classic leanness. If it was an electrical issue, I would expect the plugs to have darkened due to partially burnt vapours in the chambers.

Are you running an additional inline fuel filter? These often cause fuel starvation problems.

You can eliminate fuel starvation from the list by shutting off the engine when it starts playing up. Put the bike on the centre stand and remove one of the outer carb drain plugs to see how much fuel runs out. If fuel gushes out, and you collect equivalent to 1/3 to 1/2 a bowl of fuel, you don't have a fuel delivery problem.

 

[BassCliff]

Hi,

The petcock is freshly rebuilt and is operating correctly. Float level was set to the stock settings, but I recently raised it about 1.5mm or to see if that would help. No difference could be felt.

I'm sure you already know this but I thought I'd mention it.

If you raised the float height while the carbs were upside down, then you have actually lowered the fuel level in the bowls. When you lower the float height (when checking upside down) then the fuel level in the bowls will be higher.

Thank you for your indulgence,

BassCliff

 

[Darin Jordan]

Are you running an additional inline fuel filter? These often cause fuel starvation problems.

Nope... just a standard 5/16" fuel line.

You can eliminate fuel starvation from the list by shutting off the engine when it starts playing up. Put the bike on the centre stand and remove one of the outer carb drain plugs to see how much fuel runs out. If fuel gushes out, and you collect equivalent to 1/3 to 1/2 a bowl of fuel, you don't have a fuel delivery problem.

So, if fuel is flowing freely through the petcock when I apply vacuum to it, or when I turn it to prime, wouldn't that tell me the same thing?

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. I've been trying to follow all the basics on BassCliff's site, and none of it seems to be working. I'll verify that the ignition isn't an issue next.

I wouldn't expect that this motor should require an extra rich set of jets to make work correctly, given the above information. It doesn't have anything special for a cam, or header, or anything else.

Now... I suppose that I could take the needle jet to the extreme and move the clip all the way to the bottom, and see what kind of effect that has. One would expect that to make SOME kind of difference, right?

I did notice that these Dynojet needles are a little bit longer than the stock ones. I've measured the diameter and according to DJ, these are the right size, diameter wise, anyhow. I'm just assuming they kitted the right parts. Maybe I'll try going extreme rich on the needles and see what that effect is. Good or Bad, at least it would be a difference that I could use as a data-point, one would assume.

Thus far, NONE of the jetting adjustments have had ANY appreciable affect on this situation, and, like I mentioned, I've been from 155 all the way up to 175, all to no effect, and moving the needle up or down 2 notches hasn't seemed to make a noticable difference either, or, if it did, it was too subtle for me to pick up on.

 

[Darin Jordan]

Hi,



I'm sure you already know this but I thought I'd mention it.

If you raised the float height while the carbs were upside down, then you have actually lowered the fuel level in the bowls. When you lower the float height (when checking upside down) then the fuel level in the bowls will be higher.

Cliff,

Thanks, but yes, I did it correctly. I actually made a gauge that I could use while the carbs were in the bike, and I very carefully adjusted each of them (which takes a bit of time when carbs are in the bike, I might add). I've also verified the levels with site-tubes with the carbs mounted. The float levels aren't likely the issue, but then, either should be 10 other things...

 

[Guest]

From personal experience, and this is on VM carbs with 4-1 pipes and pods, I was too rich on the needles. It would start sputtering at around 5500-6000 RPM's, and there was an unwillingness to run smoothly up to red line. low end, idle and normal riding was fine. As it got hotter out it finally told on itself, and started fowling out plugs if I tried to force it through to red line. I dropped the needles back down to DJ's recommendations and everything cleared up. It just goes to show that every motor is a little different and what works for most won't work for all.

 

[Darin Jordan]

Did some electrical cleanup tonight and got it all back together. Rode about 20-miles, and decided to do a plug chop as I as coming home. This one happens to have been a 1/4 throttle chop, but the plugs look pretty much like they did during the WOT chop.

Am I wrong in thinking that these stlll look too lean? I know they are a little dark around the outside, but I think that's just from the off throttle riding. The insulator and electrode look really dry, and have almost no color.

If it makes a difference, the headers seem to be running around 360-degrees F about 7" out of the head, and the motor head temp was around 240 or so, all of which feels a little warm to me.

Thoughts??

 

[Darin Jordan]

Here's another plug shot, this time without the supplemental lighting.

For reference...

DJ Stage III
170 mains (DJ recommends 165)
DJ Needles set at recommended 3rd slot from top
Pilot screws at 5-turns out
All new O-rings in carbs, new manifolds, new manifold o-rings

 

[49er]

Here's another plug shot, this time without the supplemental lighting.

For reference...

DJ Stage III
170 mains (DJ recommends 165)
DJ Needles set at recommended 3rd slot from top
Pilot screws at 5-turns out
All new O-rings in carbs, new manifolds, new manifold o-rings

If that's at 1/4 throttle, your pilot circuit is too rich. There's nothing wrong with your porcelain colour. Mine run lighter colour than that with no heating issues.

Do DJ not suggest changing pilots up one size for pods? It seems crazy to be running the mixture screws so far out (5 turns). That setting is way too rich according to your plug base ring colour. Are you still running B8ES plugs?

 

[Darin Jordan]

If that's at 1/4 throttle, your pilot circuit is too rich. There's nothing wrong with your porcelain colour. Mine run lighter colour than that with no heating issues.

Do DJ not suggest changing pilots up one size for pods? It seems crazy to be running the mixture screws so far out (5 turns). That setting is way too rich according to your plug base ring colour. Are you still running B8ES plugs?

I've installed the main air correctors that DJ sent with their kit, installed as they recommended. (tap lightly in place with their included tool and put a drop of the included glue). I didn't see anything in there about pilot jets, but I'll go look again.

The pilot screws started at the recommended 4 1/2 turns, and I was still getting the backfiring on decell and a some popping/crackling at very light throttle openings. Everything I've read here suggests that means lean on the Pilot circuit, so I've been opening them, 1/4 turn at a time. I'm open to going the other way if that's not correct. In fact, I'm pulling the tank again shortly and am setup to do the "Highest Idle" deal here this weekend. I don't disagree that it seems to be a bit rich at idle and part throttle... If I'm getting an air leak in the system somewhere, I sure don't know where it would be from... everything is brand new and correctly installed, and all of the cylinders are running in synch and responding the same to adjustments...

I'm suppose to take a long road-trip at the end of the month with this thing... I'd sure like to get this sorted out before then.

SO.... if the plugs look like this after a full-throttle chop, with it stumbling and bumbling so hard that it simply won't accellerate.... what does that mean to me? The million-dollar question!

 

[Darin Jordan]

7. Engine accelerates until the midrange then pauses, stumbles, or shuts down until you back off the throttle. This problem gets worse the higher the gear used.
? Verify the parameters on the Fact Sheet are being met. For example, the mains are stage 1 mains if you have the stock air box. The stage 3 mains are used with the individual filters.
? Verify the intake and exhaust flow matches those described by Dynojet.
? Verify the float bowl vent tubes are removed (not applicable to Pressurized Air Box Models).
? Verify proper installation of parts, spacers under the needle etc. as Dynojet recommends, and that your needles and mains are all matched and free of obvious defects.
? If these items check out, lower the needle down to fix a slight pause or stumble. Lower the needle and install a smaller main jet to fix a more severe problem.

Almost seems to fit the symptoms... I've had a smaller, 160 main in there... Maybe I need a 155?? I'm grasping now, obviously... I've tried to do the "choose the correct main first" route, but I can't GET into the mains with it stumbling like this at WOT... so how the heck do I do that!?

Hahahaha... you guys DID warn me that Pods were fun! Not ready to turn back just yet...

 

[Guest]

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.

 

[Guest]

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 :idea:

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 :idea:

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.

.