Choke cable issue - 1980 CB750F

[Biggus Diccus]

Hey everyone - New to the forum - looks like an amazing amount of knowledge and support here.  

I just got my bike started after a long winter sit - and the choke cable keeps sliding down, stalling the engine.  I twisted it a bit and tightened the nut at the top of the cable to try and get it to stay in place, which works, as long as I'm not riding it.  Went for a spin and the vibration causes it to slide in, killing the engine whenever I'm not on the throttle.

Is this as simple as finding a way to make that thing stay in place or do I have bigger issues (gunk in the fuel line, etc.)?

Any help/advice/support is appreciated.

Thanks.

[TOOLS1]

I think you have bigger issues. If the bikes needs the choke on that long to stay running, you either have plugged pilot jets, or a vacuum leak.
TOOLS

[Biggus Diccus]

I agree there are likely other issues - it just sat through a really long winter so God knows what kind of varnish and gunk are in there.  I got the cable to stay put, but it still idles a little high and if I drop the choke at all it wants to stall.  In any case I was able to ride today.  I feel like some time on the road and fresh gas might do it some good.  Are there any fuel additives that make sense at this point, in an effort to avoid cracking everything open, cleaning, adjusting carbs, jets, etc?

[Truck]

Try running some Seafoam in the gas, stuff works wonders.

[LukeM]

+1 on Seafoam. However, expecting SeaFoam to cure all your dirty carb issues is optimistic at best.  It's great at maintaining a clean system.  I use one ounce per gallon on every other fill up. Some use SeaFoam on every tankful, but in my humble opinion, that's a bit much.

I recall the choke cable on my '79 CB750L not staying in the full out position very long: it usually slid back in on its own accord. Tightening by turning the knob may have helped, but I didn't want to over tighten it and break something.  

I agree with TOOLS: my guess is you need to work on your carbs. Choke should be used for the first few minutes to get the engine warmed up and get gas flowing.  You shouldn't need any choke when running normally and up to temp.

Luke M

[Biggus Diccus]

Thanks very much for your help, guys.  I appreciate the input as everyone here has more experience than I do.  I'm somewhat mechanically inclined, but I definitely know my limitations when comes to maintaining these things.  I think I may just hire a mechanic to do the carbs/jets to be safe, and then use SeaFoam going forward to keep it clean.

[Truck]

If the bike only say 1 winter try the seafoam. Due to electrical issues my bike sat over the winter with 1/2 tank of gas and stupidly I never drained the carbs. In the spring I pulled the carbs, pulled out the jets, sprayed/soaked all the bits and pieces with carb cleaner then ran a few tanks of clean gas with seafoam. Ran perfect without a major rebuild. If it still gives you issues then look into the mechanic, I always like trying the cheap fix first.

[Rockwork]

Here's my amateur input. My choke used to not stay up, but I accepted it as long as it idled enough to warm up, which took a few minutes (up to 5 minutes in cool weather), then it seemed to run fine. Put in iridium spark plugs and it ran better than I imagined, but still took awhile to warm up, which I accepted as normal. This spring my choke cable was getting more obstinate, so I replaced it. It gave my bike a whole new lease on life. Now I choke it to start, then push it in 1/3 and let it idle a few seconds and its ready to take off. My bike now idles perfectly at around 1,500. The old choke cable affected the whole system. It's a cheap try.