Main jets

[Craig]

1983 GS1100 ESD. 0.348" lift, 257 degree duration @ 0.50" cams. 1168cc wiseco pistons. The cams are degreed to 107 for both. Running 4-2 MAC pipes. Stock air filter and box. The bike runs not bad. On roll on from 1K to 4k it is smooth. From 4k - 9K, it is rough. I pulled the needles out and raised the clip to the second ring from the top(originally in the third, or middle ring), and things ran a bit better. On the top ring, it was worse, so back to the second from the top. The plugs are white. Me thinks it needs more fuel?? Any ideas on how much I need to increase the main jets? I am at 2800 feet of elevation, if it matters...less O2 = less power? Also, I have the DYNA 2000 ignition. I can't seem to get the TACH to work correct. Anyone out there using this system on this bike? Thankis in advance for your help.

Craig

[RacingJake]

Check to see what size jets you have now and go from there. If they are stock most likely you'll need to go bigger. I'd start at 135's.

[Anonymous]

Craig ,

To ever get it to run best on top with the airbox you'll need to find the" can " looking KN filter to clamp on to the back of the airbox where the noise reducing box fits to it .

125 - 135 on the mains after that .

Question though , is the head ported ?

EDIT :

About that Dyna and tach troubles . I would not want it jacking with me while I try to tune the bike as in pulling current and holding back ignition fire . Disconnect the tach till you get the motor dialed in would be my suggestion .

Also , on the KN the one I speak of is not GS specific , measure and install the largest available . Sorry , no part numbers . It's been awhile... 1984

[Craig]

TwinCam: No the head is not ported. However the head has been redone with new guides, seals, grind, and the heavy duty valve springs from APE. There have been many talks about the stock air box and whether or not to replace it. Most guys say to leave it alone. Whaat is your reason to replace it with a KN "can" style.

Craig

[Detman101]

Check to see what size jets you have now and go from there. If they are stock most likely you'll need to go bigger. I'd start at 135's.

Are those dynojet mains or Mikuni mains?


Dm of mD

[Craig]

THey are stock Mikuni carbs

[RacingJake]

Check to see what size jets you have now and go from there. If they are stock most likely you'll need to go bigger. I'd start at 135's.

Are those dynojet mains or Mikuni mains?


Dm of mD

Last year I bought a K&N kit and had all sorts of problems with it. They don't tell you in the kit that their jet's size's are smaller than Mikuni's jet's. I was going back and fourth with jetting thinking they were the same. I finaly had eought and got rid of them. So now all I say is Mikuni's jets sizes.

Go Mikuni mains

[Detman101]

Kewl, I just wanted to clear that up.

The sizes are different between K&N, Dynojet and Mikuni.



Dm of mD

[Craig]

SO......do I go to 135 Mikuni?

[RacingJake]

SO......do I go to 135 Mikuni?

Yeap, that's what I would do. But first drop your bowls and see what size jets you have now.

[Craig]

112.5 mains. Mikuni I think...a box within a box in the left lower corner??

[KEITH KRAUSE]

112.5 mains. Mikuni I think...a box within a box in the left lower corner??

Yup, those are Mikuni's.