Increase in jet size on Mains ?

[rudeman]

GS1000T - 1980 Spoke wheeled basic model
GS1000ET - 1980 Alloy wheels (17" rear), triple disc brakes, stepped seat
GS1000ST - 1980 Sport Model fairing alloy wheels (18" rear) rearset pegs, diamond stitched seat cover
GS1000LT - 1980 "L" model (cruiser style)
GS1000GT - Shaft drive model

C = 1978
N = 1979
T = 1980

Download a copy of the factory manual and the 1980 model year supplement.

http://zeus.mtsac.edu/~cliff/storage/gs/GS1000_C-E-S-L_Manual.pdf

http://zeus.mtsac.edu/~cliff/storage/gs/GS1000_1980_Supplement.pdf

[mike10]

[mike10]

[mike10]

[mike10]

GS1000T - 1980 Spoke wheeled basic model
GS1000ET - 1980 Alloy wheels (17" rear), triple disc brakes, stepped seat
GS1000ST - 1980 Sport Model fairing alloy wheels (18" rear) rearset pegs, diamond stitched seat cover
GS1000LT - 1980 "L" model (cruiser style)
GS1000GT - Shaft drive model

C = 1978
N = 1979
T = 1980

Download a copy of the factory manual and the 1980 model year supplement.

http://zeus.mtsac.edu/~cliff/storage/gs/GS1000_C-E-S-L_Manual.pdf

http://zeus.mtsac.edu/~cliff/storage...Supplement.pdf

Thank you I will check it out

[mike10]

Carb sync

Thats as close as I can get so far. With a 4 into 1 levels should be all even. # 4 a tad lower but, Good enough?

[tkent02]

That should be absolutely close enough.

[duaneage]

For what it's worth my 1000 g ended up with 112.5 mains and 42.5 pilots which is a little lean . The mains were 115 out of the factory. I've got a Vance and Hines 12500 pipe with no other mods. Compression is 140 lb across the board.
I have a tiny stumble at 2800 rpm which some custom needles might fix but I'm ok with it. 97% of the time it's great and I get 36mpg all day long in mixed traffic and Highway driving.
Searching for perfect tune gets exhausting after a while. I was tired of dirty oil and plugs, 30 mpg, black smoke and pulling carbs.
A magazine in the 80s tested a 1100 with 8 different pipes and all except the super trap flowed less than stock. Keep in mind all the variables tend to cancel each other out eventually if you don't have any boot leaks, airboxe issues, proper timing, good fuel Flow through the petcock, clean plugs, good spark plug wires, etc.

[duaneage]

Check that the slides in the carbs are not binding and move freely.

[mike10]

Just took a ride. Stumbles from standing start. Taking off through about 3000 RPM first 1/4 of throttle then good after that.

[mike10]

Just took a ride. Stumbles from standing start. Taking off through about 3000 RPM first 1/4 of throttle then good after that.

I put the 110 main jets in. Spark Plugs look rich after the ride with the112.5's. Too late now I will fool with it again in the morning

[duaneage]

This sounds like a pilot problem not a main jet size issue.
The mains have no bearing on the lower speed. The pilot sits in a well that fills with fuel and is metered to small passages that go to the idle screw. There are 3 small orifices that are presented to the engine as the throttle plate moves off idle.
It seems you are not getting any love through this circuit then when the air intake picks up the slides come up and gas is let in through the mains.
Check one dumb thing: I had the wrong style of pilots for my carbs once. I installed 40 but they were open on the wrong g end. There are two styles and the correct ones have the tiny hole in the head not in the tip. Both styles are the same height and fit equally well.
Your description is what I experienced. It points to a dry pilot circuit. Of course you could have another reason but let's rule things out. And leave the mains alone for now.

[mike10]

I just took a test ride. This bike is running purfectly after putting in the 110 mains and that's all I did. Small adjustment to idle knob, idle was 2000 cranked it down a little below 1500 I like to Idle a little fast. My bike is stock except the Delkevik 4 into one exhaust and 110 mains. Why that fixed the 1500 to 3000 stumbling issue I do not have a clue. Doing one thing seems to effect everything on this bike. I think these bikes are engineered to run somewhat lean. early 1980's was a weird time 80MPH limit speedo bikes tuned down as if they were using all the Gas. I was flogging it hard, takes off like a bullet screems to redline. Thanks for the help everybody.

[duaneage]

Basically same setup I have now.
So much foe 120 mains and shimming needles.
I find mine runs better in hot weather than cold . It also idles better with premium gas and if I can find alcohol free it's better yet

[mike10]

Basically same setup I have now.
So much foe 120 mains and shimming needles.
I find mine runs better in hot weather than cold . It also idles better with premium gas and if I can find alcohol free it's better yet

My needles are shimed 3 washers. Plastic spacer removed I forgot that. Delveck exhaust stated,rejeting is not needed in most bikes. I guess if they have a 1000cc with slightly larger than 107.5 mains thats true.