Topic: Throttle sticking? Idle 'resetting' after running

[Kev Nemo]

Hmmm-think the cable might be dirty?

I cleaned the throttle assembly with some Chemtool and blew a bunch of grime out. Returns much better but the new issue is much weirder. So I get up to speed (street/highway) and when I come to a stop, the motor is revving up to 3k, even though it was set to 1500 when I took off
I usually back the idle screw out to get it back to 1500, but it usually does this a few times until the screw is backed almost all the way out.

so what's the verdict?

[stevenmgrr]

I too would be interested in some of the answers to this post.  I am experiencing the same issue.

[bender01]

warming up?

[Gordon]

warming up?

+1

[Kev Nemo]

how long of a warm time are we talking about? This will happen after I've let it sit 5 min or so, ridden it, parked somewhere, restarted and ridden off. Should I be having to mess with the idle screw at all? If this is the warm up process, how high will the motor rev til it's ready?

[keener]

The choke cable may be climbing the vibrations. Check to see that the cable is not broken anywhere or that the choke cable springs are OK.

[bender01]

How clean are the carbs?

[number13]

Have you synched the carbs recently?

[hapsh]

Timing advance getting stuck at advanced will do exactly that.  The return springs expand and have less pull when hot making it possible for the advance mech to stay a bit advanced.

[stevenmgrr]

I too would be interested in some of the answers to this post.  I am experiencing the same issue.

Just provide an update for my version of this problem.  I was also having a problem of a sticking idle.  I rebuilt my carbs, properly sync'ed them and changed my throttle cables.  Problem solved.  My throttle response is perfect now.  I have read that if the carbs aren't properly sync'ed up, the other carbs will try to compensate for the weaker one(s) and this will contribute to a runaway idle.

If you or anyone else is still having a problem with this issue, you might want to check this.

Steve

[TwoTired]

Ever done  a tuneup on the bike?

[Kev Nemo]

Oh yeah-this is an old thread by now. Tune-up was the first thing I did-plugs, oil/ofilter change, then took off the carbs and cleaned EVERYTHING-reconditioned boots in the micro and treated with a little olive oil, cleaned filters and re-oiled. Afterward, ran Seafoam in steps. The response has vastly increased. Still need to clean and lube throttle cable, but almost there. So I guess 3 months to get running isn't so bad for a bike that I bought under the impression that it was 'weekly runner'

[TwoTired]

When we buy a bike, we actually buy three different ones at the same time.
There's the bike the seller thinks it is,
The bike the buyer thinks' it is.
and the there's the bike that it really is.

If you buy a 30 year old bike, you must have a lot of trust to believe in a seller that tells you it won't need any work.

Oh yeah-this is an old thread by now.

The thread is dated July 23.  My god I must officially be ancient.  I wonder if my toe nails have fossilized yet.  (checking)
Phew, not yet.!

I don't see a bike year or model statement.  Or, a statement that the carbs were synched. (Maybe my eyes have fossilized and I just can't see it?  )

I also don't see a statement about setting the idle at full operating temperature and then leaving that setting alone when the engine is cold.

Cheers,

[Kev Nemo]

Anything posted on the internets is ancient history the minute you hit post

"I don't see a bike year or model statement.  Or, a statement that the carbs were synched. (Maybe my eyes have fossilized and I just can't see it?"
-1978 cb750k model-adding it to my sig. Planning on hooking it up to vacuum guage soon, but honestly not running terrible now.
"I also don't see a statement about setting the idle at full operating temperature and then leaving that setting alone when the engine is cold."
-There was some discussion on determining when exactly that was reached in regards to start up. Your method?

[750fromhell]

I'm working exactly on the same issue, I'll let you know what happens. So far I changed the throttle cables, new coils, new spark plugs, new oil, put appart & cleaned entire carb assembly.
I too bought a bike supposed to be a daily driver for the last 3 years. Althrought she did run when I bought her, the next day after transportation, the engine kept dying and anthing electrical stoped working. I open the electrical only to find that the guy rewired everything ghetto style with all black wires

I wish I could put a bike/car appart when I'm buying something to really check the condition rather than trusting the owner on what he supposely did and a 2 minute test run. The poor condition of the bike, and the fact that the engine was already hot when I showed up was my only warning of a not so good deal.

But who cares, I got a project bike to tease my neurones for $800, I'm learning a lot of new stuff, and I'll enjoy riding her better in the end than buying a brand new bike from a dealer 

[Kev Nemo]

Yeah, I thought about the whole "If I knew then what I know now" thing and I get stuck on the fact that I paid him IN FULL before he delivered the bike via Paypal. Would I have held him hostage til he paid me? Of course I paid $500 more than you did for my 'project'...

[TwoTired]

"I don't see a bike year or model statement.  Or, a statement that the carbs were synched. (Maybe my eyes have fossilized and I just can't see it?"
-1978 cb750k model-adding it to my sig. Planning on hooking it up to vacuum guage soon, but honestly not running terrible now.

I have Sig display turned off, cause people keep putting huge pictures in their sigs, making it too hard to find the text among the advertising.

Carb sync has the most effect onidle performance.  Think about it, if one or more slides are open more than the others, how's the engine going to determine what idle speed to select?

"I also don't see a statement about setting the idle at full operating temperature and then leaving that setting alone when the engine is cold."
-There was some discussion on determining when exactly that was reached in regards to start up. Your method?

Looking back, I don't see any discussion in this thread about warm up determination.   Am I getting censored copy?
Warm up kinda depends on the time of year, 15-20 minutes on the freeway should do it, though.

You bike has a choke knob that bumps up the idle speed when applied, proportional to its application.  It is NOT an on-off device.  And, there is a separate adjustment for choke idle speed.

Cheers,

[TwoTired]

But who cares, I got a project bike to tease my neurones for $800, I'm learning a lot of new stuff, and I'll enjoy riding her better in the end than buying a brand new bike from a dealer 

Neurones... I like that.   Kind of a cross between cajones and something cerebral.

Seems like something a woman would think up, though.

Cheers,