1/8th throttle spudder stutter

[kurt112345]

Hi all, I have a 81 gs1100e and just finished about a month ago doing a carb rebuild, chem diped with new orings and floats. new carb boots on the head side, it has a dynojet jet kit installed and new dyna s ignition, coils and wires and a motoworks gp exhaust, did all of this at once. First start up I did carb sync with carbtune pro, then did highest idle a/f screw adjustment. Ok know my problem about 1/8th throttle just enough throttle to build rpm it stutters and sputters doesn't want to do anything if I give it more throttle clears right up and pulls like a train. I know rpm doesn't really matter mainly throttle position but its the worse between 2500-3000rpm any amount throttle below those rpms it runs fine and any above 4000rpm doesn't seem to have the symptoms. Another time it sputters and stutters if I go wide open throttle in 5 th gear at about 45mph lugging it to slowly build speed it wont go at all just refuses if I down shift to 4th at that speed and wide open its fine. I did lots of reading before I post this to make sure I covered everything, not sure what to do, I ordered new rubber intake boots for the airbox, and going to double check my carb sync job, its almost like its having a problem with diaphrams raising? I did check them to before installing they raise with air and are free. any thoughts? or stuff I missed pleast let me know, thanks

 

[mark's78]

I have the same issue with my '78 gs 1000. I'm running 29mm smoothbores. The problem is a lean spot at the transition from pilot circuit to needle. What I have found is that ethanol in the fuel causes this. I rode several days in a nonethanol gas area the problem cleared up. So I haven't found a jetting solution to this problem but I'm convinced that our needles were engineered for straight gas and ethanol just is to lean. Hope that helps.

 

[kurt112345]

Huh haven't thought of that, is there any additives that can help with ethanol? think octane boosters would help any?

 

[mark's78]

I don?t believe additives/octane booster will help. I occasionally run Seafoam thru mine and nothing changes. I am currently searching for some hard to find carb parts for my 29mms but they are fully adjustable racing carbs, I don't believe your cv carbs have as much flexibility. I'm at a point of living with it because the bike is perfect otherwise.

 

[posplayr]

Sounds like you probably got it all back together except for the jetting. I was going to say that was pretty brave to do all at once but, for a fresh rebuild I would have done the same.

What jetting settings? I assume you have the DJ 3133. I just summarized jetting settings for someone else 2 days ago. Run the dj138's with 47.5 pilots start with needles in the middle and adjust. Might be a bit rich. If so move to dj132's

Edit!!!!! What did you do to the intake???? Pods or k&n insert? Or anything . This is the biggest factor in jetting other than more cc's. The recommendations above are for K&n pods.

 

[GSX1000E]

Go back to a 45 pilot jet and change out the mains to a MIKUNI 127.5 and readjust the fuel screws. Report back.

 

[posplayr]

Go back to a 45 pilot jet and change out the mains to a MIKUNI 127.5 and readjust the fuel screws. Report back.

Does he have pods?

 

[kurt112345]

sry thought I had all the details, running stock airbox with k and n insert, iam running dj114 main jet and stock pilot jet which I think is 47.5, I had my needle in groove #3 but know its in #4 was trying to see of it helped the issue and not really.

 

[posplayr]

sry thought I had all the details, running stock airbox with k and n insert, iam running dj114 main jet and stock pilot jet which I think is 47.5, I had my needle in groove #3 but know its in #4 was trying to see of it helped the issue and not really.

You should throw those little DJ jets out. I have no idea what they are for.

You bike came with MK 107.5's main jet originally. The 83 bumps up to 110 as there is more cam lift.

A MK107.5 is like a DJ 117.5 so those DJ needles are actually leaning out your mixture. If you go up to a MK 110-115 you will be much better.

If you take the air box top off it will be even leaner.

The 47.5 pilot is not stock. Stock is 45. That 47.5 is a good call if you have the 4:1 (as opposed to stock 4:2 or 4:2:1).


Go back and sort out the main first, then the needle (after the main is correct and pulls to red line)

 

[Rob S.]

I recently had a professional racer/tuner/builder re-jet my '82 1100e (V&H, APE pods). He used the DJ stage 3 kit, but said it also needed more (different) parts (jets?) which he had in the shop.

I could call him and ask him if you'd like, but it's my understanding that the DJ stage 3 kit is just the starting point, that additional parts are needed.

 

[kurt112345]

So is the dyna jet kit useless? Good place to order jets?

 

[posplayr]

So is the dyna jet kit useless? Good place to order jets?

No if you did the pods, the 132./138's would be just right and with a 4:1 you need a different needle.

By using the stock air box you are not really making life any easier. The DynoJet 3133 stage 3 for 4:1 and K&N Pods is very well trodden ground. No big mysteries.

 

[Guest]

Huh haven't thought of that, is there any additives that can help with ethanol? think octane boosters would help any?

Use Lucas Ethanol treatment or some other brand. Octane booster won't help. Running some Sea Foam through the system every now and then won't hurt. Helps keeps the varnish off the carb throats and slides.

 

[kurt112345]

I have some pods laying here for a few years maybe I give them a shot with the 138"s, I will check my pilot jet and if it's not a 47.5 I will order some and probley some 110,112,115 main jets. Are all mikuni jets universal? Best place to.buy this stuff?

What you guys think of me trying the dj132 with say with.the airbox lid off? Really like to stay with stock airbox but if it's easier to.get here going with pods I will summer is coming going to put miles on here this year

 

[posplayr]

I recently had a professional racer/tuner/builder re-jet my '82 1100e (V&H, APE pods). He used the DJ stage 3 kit, but said it also needed more (different) parts (jets?) which he had in the shop.

I could call him and ask him if you'd like, but it's my understanding that the DJ stage 3 kit is just the starting point, that additional parts are needed.

Yes would be interested to know. Mains, pilots and needle clip position.

 

[kurt112345]

anyone have a source for jets?

 

[kurt112345]

Are the z1 enterprise jets anygood? The say there made by another company in Japan.

 

[Guest]

The small DJ main jets are too small.
The 132 DJ should be run with an aftermarket pipe and stock airbox.
Mikuni jets would be between 117.5-122.5 with the same set up.

 

[Guest]

mark's78, tweak the pilot fuel screws out a hair. That is typical on the VM26 carburetors, I'm not familiar with the 29's but they might work the same. That transition point is a PITA if it is lean because that is where you drive a lot in town. You will have to also adjust the air screw for highest idle any time you adjust the pilot fuel screws. I don't know the 29's but the 26's seem to run best with the pilot fuel screws adjusted where the air screws peak highest idle at around two turns out.

 

[tkent02]

Are the z1 enterprise jets anygood? The say there made by another company in Japan.

They seem good, the main jet sizes seem to jive with Mikuni jets.