Can stuck clutch cause high idle?

81 xj550 maxim that I've been working on:
First time I fired up the bike it idled smoothly. I did that a few times and for several minutes each.
Last weekend I started her up again on stand to shift through gears.
After that, it idled very high.
Since it was fine the first time, I am thinking that maybe it has something to do with the clutch/gears? I did remove the clutch cable but maybe something got stuck or did not shift back correctly? I have not replaced the clutch plates yet but will do so soon.
Is that a possibility? Bike hasn't been started for a long time before that.
I even removed throttle cable to make sure it doesn't keep the butterflies open.

 

Sticky butterfly shafts and or piston slides in the carbs from sitting I would guess. The clutch has nothing to do with A/F mixture and run away idle/ RPM issues

 

Ok thanks. I think I can exclude sticky carb parts as Dave/hog fiddles rebuilt them and they are pretty much like new but I will double check to be safe.

Just weird that it started when clutch came into play. Before, I did rev the engine and all was good, Idle dropped to normal every time.

 

is the ldle high when on the center stand and in gears or all the time now.?
the clutch does drag due to the oil between the plates if in gear and clutch is pulled in while on center stand tire will still spin.
More than likely your idle is not set correctly, bike is not really warmed up in a few minutes, readjust your idle.
my idle would be higher after a 10 minute ride 45mph, propane tested many times no leaks. just ended up turning down the idle after the ride and no problems no more high idle

whats your rpm?

 

Thanks for that.
Yes, center stand for now as I don't have a seat at the moment and my front brake still needs fluid.
And yes, rear wheel spins, that's known but thanks for mentioning it again.
It does spin faster than it should. So that's why I am thinking it is clutch related.
I don't have a tach anymore but can attach the old one for now. On startup, or at least before I went through gears, bike idles fine. Very consistent and at low rate. After the gear changes, it idles much higher. Not sure what the rev limiter is on the bikes but I'd say at least 3k.

If I turn down the idle, I am afraid it might stall in neutral.

So my question was more of a general question for now. I will try to replace the clutch plates and try again. It was on my list anyway but wanted to check it out without replacing first.

 

why do you think you need a new clutch?
with clutch pulled in
its going to spin and rpm will rise with no resistance from the ground this is normal.
as long as when sitting on the ground the bike does not roll forward your good
if it did not spin I would be worried.
clutches wear thinner so they tend to slip not get tighter.

 

go to your in box

 

Got it thanks.
Yes, the spinning is known.
It is just curious that before, it idled fine, and only after I started shifting through gears rpm went up.
Putting bike in neutral still didn't help lower the rpm.

So basically:

Turn on bike in neutral: idle is good and low
Shift through gears, put it back in neutral: idle is still very high and will not go down. Bike sounds as if half the throttle was open

But basically what I am hearing is: higher rpm are expected after if is warned up.
I will play with the idle and see how it goes. I guess that's carb-life, huh?

 

is there slack in your throttle cable there should be some free play adjustment is at grip.
is your throttle cable binding
cable end seated properly in the holder at carb
also make sure that throttle shaft is making contact with idle screw adjuster

have you done a propane test? turn on the propane gas do not light it and check your carb to head boots for leaks also check your throttle shaft seals for leaks . rpms will rise if you find a leak.
you can see the affect by pumping in a little propane to the air filter slot.

check to see that the enrichment plungers are fully seated when choke is off by pushing down on them.
fingers should be at bottom of groove not top

half throttle ? as in 4500 rpm?

 

if above is all good .
have you synced the carbs yet?

 

Dumb question...the clutch cable and the ec (choke) cable are correctly installed yes?

Gary H.

 

No dumb question.
Nope, I no longer have a choke cable attached. But I checked and it is "off/closed"
Clutch cable was removed completely as a first trouble shooting step and it was still revving high.
Anyway, I am moving this weekend and won't have time to check.

But definitely all good suggestions which will give me a nice trouble shooting list.

 

just because hf rebuilt the carbs, doesn't mean they are properly tuned. did you sync the carbs after installation?

FU

 

Not yet.
And yes, he told me I still have to do it and i am aware of it. They are only bench synced. But I would exclude stuck throttle mechanism or anything like that on the carbs. Dave's done an excellent job.

Again, I am not yet looking into it as I have to move my entire house plus garage. I noticed a difference in idle before and after using the clutch. Hence my general question if it could be related or if it was just a coincidence.

I read some very useful tips and will go through everything once I settled into the new house.

 

If you haven't synced them, that's gonna be where the issue is....

Bench sync is simply basic setting close enough to allow the bike to run. Once it's running, you gotta dial it in.

Dave F

 

In your first post you stated it had been sitting and not run for along time.
Even if Hogfiddles rebuilt them and did a quality job which I'm sure he did, humidity, crappy fuel , and time can take a toll on these carbs. My 750 carbs didn't sit for several months and the slides were stuck and the throttle shafts were gummed up. The fuel we buy today has a very short shelf life because its loaded with ethanol which is basically alcohol which attracts moisture. Moisture wreaks our gas tanks and certainly does not do well in the float bowls. The jets turn green and it rusts the pivot pin for the floats. So depending on how long it sat as per your first post you may have to pull the carbs of and give them a good look over before trying to sync and make other adjustments.
On that note if you leave the bike sit for any amount of time. Drain the carbs and put Stabil in the tank or better yet drain the tank and treat it with fogging oil to keep it from rusting up on you. Hope all goes well with your move.

 

If storage lasts only a six months, could it be ok to fill the tank and carbs with gasoline with no ethanol in it ? Does super has ethanol or not?

 

Most gasolines of all grades have 10% or so ethanol most of the time, and especially in winter. You can search online to try to find non-ethanol stations. There aren't many of them.

 

+1.

Gary H.

 

That depends a lot on where you are buying. Almost every station around here has the choice of E-10 or E-0 depending on grade; some stations even have the choice in every grade.