GS1100E carb tuning

[MWrider]

After sorting out some issues with this bike I got some riding in but it was running poorly. It stumbled into low throttle, and didn't idle well. Also the top speed was pitifully low. I decided to clean the carbs and install the stage 3 dynojet kit, since I'm using the APE air filters and the Jardine exhaust that came with the bike. I got them apart, and saw there was already a stage 3 kit using the larger jets and the needle clip in the 3rd slot from the top. Moving UP, there was the spring, a large washer, smaller washer, clip (3rd notch from the top), then the spacer. I put everything back together as it was after dipping, spraying, bench syncing the carbs. I also setup the float heights using a digital caliper (they were WAY off). Used all new o-rings from cycleorings.com. I set the idle screw 2.5 turns out, then 3 turns out, then 3.5 turns out. I'm still not sure if this is rich enough. I'm also at ~4280ft (1519m) elevation.

Now the confusion: The engine starts cold without the choke which would lead me to believe it is running rich, except that when I give it some throttle it sputters, then falls slowly back to idle (lean, right?). I have the idle at around 1100.

for your viewing pleasure, with the colortune, after ~3 minutes of runtime:

 

[Guest]

Maybe your getting too much fuel. Have you synced the carbs and done the high idle adjustment with your mixture screws?

Whoops, didn't see the bench sync part. Valves adjusted?

 

[Guest]

Somethings not right. It almost sounds like it's not running on all 4 cylinders. Could be your vacuum is way out like already mentioned. .

 

[posplayr]

The jetting for a stock 1100E with pods and pipes is no big mystery. It sounds like clogged pilot jets. Or maybe that carb tune which is worthless.

You said you used the larger jets; help us out do you mean DJ132 or DJ138? Chef usually recommends the DJ138 but the 82 has lower lift than the 83 so start on the 138 but figure you may have to drop to 132. I just saw you are at higher altitude so the 132's are probably better. You did use the DJ3133 kit right?

http://www.dynojet.com/pdf/3133.pdf

Get the main right first, but sound like to do that you need to clean those pilot jets. Pull them and spray blow them out.

 

[chuck hahn]

If you go to the CARB /FUEL/ EXHAUST forum youll see STICKYS. One is CV carb tuning

 

[JTGS850GL]

The Color Tune is notoriously inaccurate when used with CV carbs. Look up "fast idle method" to adjust the mixture screws. From the sound of it, it sounds like it's not running on all four cylinders. Check to see if any of the pipes are colder then the rest.

 

[Weapon]

whats with the arcing plug? isn't that the problem?

 

[JTGS850GL]

whats with the arcing plug? isn't that the problem?

That's the Color Tune system. Shows you what the combustion color is.

 

[MWrider]

Wow, I'm a little embarassed that I couldn't tell the bike was running on TWO cylinders. #1 and #2 headers get very hot just after running for ~30 seconds. Nothing on #3 or 4.

I did initially try to adjust the screws by the "highest idle method" but nothing happened until I'd turn the screws in almost all the way, then it died. I didn't notice a change in the running before that. Then I tried to gauge by behavior with the throttle response method.

I did put a piece of wire from a wire brush through the jets according to John Bloemer's guide, before dipping. I also sprayed through all of the circuits with carb cleaner after dipping.

I'll pull the carbs again to check that the circuits are clear, and maybe by then I can have a vacuum gauge set at the house to fine-adjust the synchronization.

Thanks for the tips-

Dan

 

[posplayr]

Wow, I'm a little embarassed that I couldn't tell the bike was running on TWO cylinders. #1 and #2 headers get very hot just after running for ~30 seconds. Nothing on #3 or 4.

I did initially try to adjust the screws by the "highest idle method" but nothing happened until I'd turn the screws in almost all the way, then it died. I didn't notice a change in the running before that. Then I tried to gauge by behavior with the throttle response method.

I did put a piece of wire from a wire brush through the jets according to John Bloemer's guide, before dipping. I also sprayed through all of the circuits with carb cleaner after dipping.

I'll pull the carbs again to check that the circuits are clear, and maybe by then I can have a vacuum gauge set at the house to fine-adjust the synchronization.

Thanks for the tips-

Dan

What jets?

 

[MWrider]

I pushed through all the little holes in the needle jet, pilot jet, choke pickup tube, that passage in the float bowl, any passage I could find throughout the assembly. I took my time also to get familiar with the carburetor in a general way, clearing/spraying any and all passages. All I've ever done is the single Amal carb on my Tiger, so this was interesting. I thought I could calibrate my ears and sense of the running status while verifying proper running with the colortune, but I guess not. I really don't have a healthy baseline status with this bike for comparison.

I'm going to look up that sticky on carb tuning, thanks for that.

 

[posplayr]

I pushed through all the little holes in the needle jet, pilot jet, choke pickup tube, that passage in the float bowl, any passage I could find throughout the assembly. I took my time also to get familiar with the carburetor in a general way, clearing/spraying any and all passages. All I've ever done is the single Amal carb on my Tiger, so this was interesting. I thought I could calibrate my ears and sense of the running status while verifying proper running with the colortune, but I guess not. I really don't have a healthy baseline status with this bike for comparison.

I'm going to look up that sticky on carb tuning, thanks for that.

You still have not mentioned one jet size, but it sounds like the pilot jets are plugged.

BTW, you should have change the pilot jets as well to 47.5.

 

[MWrider]

Sorry postplayr, I put the 160 pilot air jet back in after cleaning, and replaced the main jet with the DJ138's. It looks like the stock spec pilot air jet is 170. Is pilot jet the same as starter jet? I know, bear with me.

 

[posplayr]

Sorry postplayr, I put the 160 pilot air jet back in after cleaning, and replaced the main jet with the DJ138's. It looks like the stock spec pilot air jet is 170. Is pilot jet the same as starter jet? I know, bear with me.

I don't think so, pilots come in between the idle and main circuit. There are no pilot jet replacements in the DJ kit but they typically need to be upped from MK45 to MK47.5 (for your specific bike stock 1100E 16V). Use standard Mikuni sizing If you never pulled them out they are probably plugged. It will never run right in the mid range till you change them.

You should always note what jets you have as you never know what someone else might have done.

 

[MWrider]

OK, I just found this and everything is making more sense: http://www.thegsresources.com/_forum/archive/index.php/t-221466.html . Catching up. I'll get the MK47.5, set the needle position in the middle, and start with the DJ138 main jet and see how the top end is first, Then set the needle, then idle.

Oh yeah, and get those "slow system" passages super clean.

 

[posplayr]

OK, I just found this and everything is making more sense: http://www.thegsresources.com/_forum/archive/index.php/t-221466.html . Catching up. I'll get the MK47.5, set the needle position in the middle, and start with the DJ138 main jet and see how the top end is first, Then set the needle, then idle.

Oh yeah, and get those "slow system" passages super clean.

After you get it idling, warm it up and run to redline. If it is rich swap back to the DJ132's run to redline and if all is good then tune the needle.

 

[posplayr]

I just re read that thread and most of the issue was a jet kit. FP v.s DJ; you have DJ correct?

Just so you know, Bill chef1366 can normally just dial these in with a DJ kit just knowing your configuration.

I'm not that good but have a O2 sensor and logger that allowed me to dial mine in.

 

[Weapon]

That's the Color Tune system. Shows you what the combustion color is.

I'm embarrassed to say I have never heard of that. It just looked like a plug with a carbon trail on it sparking all to hell. and the bike sure sounded like it wasn't running on four. well live and learn.

 

[evh]

sometimes the coils will arc to the frame where the plug wire boot comes off the coils... it will start running on 2 cyls because of this.. raise the rear of the tank with a piece of 2x4 then start it up in the garage with the lights off... have a look.. you might see arcing to the frame.. if you do clean the coils, frame around the coil area with alcohol and make sure all deposits are gone.. then make sure all your wires and boots are making proper contact..

 

[MWrider]

Yes I have the DJ kit. I did find some good info in jetting for my configuration with that thread - the 47.5 pilot jet, etc.

I'll shoot chef a PM.