'76 GL 1000 carbs on '83 GL1100

[SRob]

Hi Everyone, I had a spare set of GL1000 carbs that were done by Pete Boody (RIP, Pete!) and decided to try them on my '83 1100 Interstate bobber before paying to have the 1100 carbs rebuilt. So here's what I did and found out:

They won't go in (from the left side) with the caps and intakes installed on the right side. Leave the intakes off and remove the caps on the right side carbs. Also remove the little arm/clip for the choke cable, it sits a little high and catches on the frame.

The other thing is, there is an air cutoff valve between carb 1 and 2 on the plenum, and it is 1/4" too tall to fit under the frame, so you have to remove the cap. JUST the cap, not the entire body of the pump. Be careful removing the cap, there's a spring under it. Watch the orientation of the diaphram when you take it out and put it back in the same direction.

Once you slide the rack in you'll have plenty of room to re-install the caps and accelerator pump cap (assuming you have the tank shelter and air box out). You can move the rack back and forth (do this before anchoring it down). This is also a good time to install your cables/choke.

While I had the carbs off, I lubed my cables. The PUSH cable was kind of stiff (I think it was kinked) so I just eliminated it altogether. There is PLENTY of spring in the spring for just the pull cable (I know it's a "safety precaution", but hell, we're riding 85mph with a tank of explosives between our legs that's 3" from a hot engine...no risk there!).

There's no vacuum port on the 1000 carbs so I just cut off and capped the vacuum hose to the vacuum advance at the rear of the engine (other threads in the forum said the vacuum advance is kind of unnecessary or minimally effective).

Another hint: I got a restaurant squeeze ketchup bottle from the dollar store (with the tapered nozzle). I filled it about 3/4 full of gas. I put the inlet hose on the carbs (the one that goes to the outlet of the fuel pump), and squeezed the gas into the carbs to "pre-fill" the float bowls. Leave the nozzle in the hose, squeeze a little, and let off the squeeze and you'll suck the air out of the carbs. It took a little over half the bottle to fill the bowls. If you go easy, you'll feel a little resistance and when you let off, it will stop sucking air bubbles. Pull the bottle off the hose and attach it to your fuel pump.

Here's the verdict: HOLY COW!!! My bike has never run better or smoother (even with the fresh Boody rebuilt original carb rack in it). SRob gives this two thumbs up!

[Whiskerfish]

Confusing me a bit here. 1000 carbs do not have a Accelerator pump. In the middle on the front of the plenum is the Air cut off valve that needs to be removed to install in the 1000 frame.

[Old Fogey]

The small unit in front of the #! carb is an air cut off valve, not an accelerator pump.
The carbs are numbered RH front #1 RH rear #3, LH front #2, LH rear #4
You can take a vacuum line from the #3 manifold sync screw. The vacuum advance was put there for a reason.
There is also a very small O ring under the cap of the air cut off valve. Be careful not to lose that, it's easy to have it drop into the valve. A drop of superglue will hold it when replacing the cap.

[SRob]

OOPS, yes! My brain and fingers didn't connect on naming the carb parts on this one HA! I edited the post. Thanks guys!

[SRob]

You can take a vacuum line from the #3 manifold sync screw. The vacuum advance was put there for a reason.

Hi Fogey, it seems to be running great, however, if I decide to go back to the vacuum advance, do you just pull the synch screw and is there a threaded insert that goes back in to that hole? Thanks!

[Sidecar Bob]

You missed one when you edited.

I have '79 carbs on my 1100. Mine had a 1000 engine for over 20 years, with the points at first but Dyna S ignition for the last few years before I changed to an 1100 engine. Because the 1000 carbs didn't have the vacuum port for the 1100 timing advance I plated over the place where the timing parts were and changed to '77 cams so I could keep the Dyna S
Full details here https://www.ngwclub.com/forum/viewtopic ... 30&t=63232

[Old Fogey]

You can take a vacuum line from the #3 manifold sync screw. The vacuum advance was put there for a reason.

Hi Fogey, it seems to be running great, however, if I decide to go back to the vacuum advance, do you just pull the synch screw and is there a threaded insert that goes back in to that hole? Thanks!

You can use the screw-in adapter from your vacuum gauges (yes, you should have a set of these for synchronising the carbs).
Alteratively, the adapters are available here: https://www.motionpro.com/product/08-0013

[ericheath]

Pretty sure you will have better performance and economy with a vacuum advance.