1982 Choke assembly

[chrissiemens4]

i purchased a 1982 650 just the other week. The PO had the bike somewhat apart as it wasnt running 100%. It sputtered on him a bit, and didnt feel like it had all the power it should, so he started to work on it and then lost interest and sold it to me. After cleaning the carbs, i am putting everything back together and dont know if i have the choke assembly all put together properly. As you can see from the video, the choke butterflies dont move when the choke cable is pulled. Is this supposed to happen or is there some interlocking that i am missing? Thanks for the help!

LINK TO VIDEO: http://s88.photobucket.com/albums/k176/admiral4/?action=view&current=DSCN3206.mp4

[Handyman1018]

Mmmmm... on my 83 CB650SC the choke operates a plunger located to the front of the carbs.  The throttle controls the butterflies.  What happens when you twist the throttle?

[chrissiemens4]

the throttle seems to work fine, those butterflies move appropriately and dont seem to have an impact on the choke butterflies. Unless when the engine is all put back together, somehow the butterflies close themselves with the compression if the choke is up...

[Munkey]

You don't have the springs and linkages correct.  I'm sorry I'm not much more help than that. I sold my '82 650 back earlier this year and no longer have it for reference. When I had the carbs apart on it a couple of years ago, I do remember the choke linkage and springs being a little tricky to get back together correctly. I had the same problem as you have and it took me a couple of tries to get it back right.

[chrissiemens4]

hmm, i figured as much, just hoping someone had an easy answer for me. lol I just could not for the life of me figure out any other way that they went together.

[Bumblebee]

I can see that one from my galley.
The small gage spring is not tensioned properly.

This will solve your problem:
http://nighthawk-forums.com/index.php/topic,2962.0.html


Also here's the bench sync you need to do since you pulled the carburetors off the rack:
http://nighthawk-forums.com/index.php/topic,2961.0.html

Use a torque wrench and torque the carburetor rack bolts properly. If you don't, you'll wish you had. Too tight and the threads will strip. Too lose and the carburetor assembly will twist when reattaching it to the intake boots which totally trashes the bench sync.

[chrissiemens4]

so i followed the preload of the spring to a T about 6 times, and it still doesnt seem to be moving the butterflies. It moves it only about 1/6 closed. am i still doing something wrong? or is that all it will move?

[Bumblebee]

The spring looked a little loose in the pictures though it might have been the camera angle. It looks a bit different that mine when sprung properly. Either way the problem is not fixed.

The control will turn the plates almost 90 degrees.

A few notes:
1. What is the spring doing between #1/#2 on the choke shaft? There is supposed to be a rubber seal there, not a spring. The seal is missing off the #3/#4 shaft area also. That spring looks like the spring that is supposed to go between the throttle linkages on the other side. If that is the throttle linkage spring, it serves a purpose where it's supposed to be mounted - Without that spring between the throttle linkages there will be a problem doing the bench sync and keeping it in sync afterward.
2. Look at the #2 carburetor top bracket mounting screws in your pictures, they are not tightened down. They are out about 1-2 threads out which means they are extremely loose. Loose mounts cause misalignment of the carburetor bodies which causes friction on the choke shaft which causes it to not turn freely. Check all 16 mounting screws for proper torque.
Fix those problems before proceeding. (and yes, I know getting that spring off and putting the seals in place will involve pulling all 4 carburetor bodies off the racks again which is annoying however it needs to be done)

The control sequence: The control linkage that the choke cable attaches to is mounted on carburetor #3. The big spring between the linkage and #3 holding pin returns the lever to the full down (choke open) position as you can tell. The control linkage is spring loaded by the small gage spring directly to the #1/#2 carburetors choke shaft. The #3/#4 choke shaft linkage is then moved by the prongs on the #1/#2 linkage shaft.

The choke plates have a lot of play in them when they're being installed. They should be installed last after everything works and moves properly.

Remove the choke plates from the choke shafts. Is there any friction at all in the control linkage shafts #1/#2 and #3/#4 individually? (I think you'll find there is a fair amount of resistence on at least the #1/#2 shaft because of the loose mounting screws - and possibly friction on #3/#4 as well) Once the friction problem is fixed, move the linkage control lever again. The choke shafts should both turn freely and not bind. Once they move properly, reinstall the choke plates and center them in the intakes while insuring they do not bind against the sides of the intakes at any point. IIRC they barely even tough the sides of the intake if they touch at all.

[chrissiemens4]

so after trying the spring preload thing several times, i stopped half way and noticed that it was working to turn carb 1 and 2. just something about carb 3-4 were not working. so i took all that apart and noticed that the choke shaft at the end was bent so it was not rotating freely. so still working on it...thanks for all the advice!

[chrissiemens4]

i forgot to post last night, but its all back together and working! it was that bent shaft and once i torqued the bolts appropriately everything all lined up. thanks, this forum has helped me a ton!