high rpms when i pull in the clutch

[climber_dhl]

As always thanks in advance again to everyone who answers this.

My main concern right now is all of a sudden when I was giving my friend a ride my bike completely wigged out. When I am in gear and driving when I apply no throttle at all I can cruise at say 15mph in 1st gear, and 20mph in 2nd gear, etc... all without even turning my throttle. The scary part is all of a sudden my idle is near red line at 8000RPMs!!! So when I pull the clutch in my rpms spike to 8000 so I put it in gear to not destroy my engine and I surge ahead as mentioned earlier. I need to ride home tomorrow and go to work on Thursday with it so any help ASAP would be appreciated. I am pretty sure I can ride it home on the highway I just need to know what I need to do to fix it once I am home especially because stopping the bike on normal streets is dang near impossible now.


History/State of the Bike:
Well I have a 1980 GS850G (T) that runs and is in usable shape. I bought it for $300 a year ago trashed and fixed it up to drive to school and back.
I've done a bunch of upgrades but recently haven't had to touch it for a while (ran fairly consistently for a year or so). I left it sit for a month or so for the summer and then a few weeks after that and now I am pretty sure my carbs are all clogged up since sometimes when I get the bike to finally turn over it has a super sluggish throttle.

When it is not being sluggish it has reduced power especially at higher RPMs. I am pretty sure that my carbs are either out of sync or really dirty, but any help would be appreciate. I haven't done a valve adjustment on it, but if you think i need to: Is it hard to do/expensive with the shims (i have only done the type with the adjustable springs)?

[bwringer]

Sooooo many issues...

1) First, check for a problem with the throttle cable. This is the most likely and simplest explanation for the immediate problem. One end may have jumped out of its ferrule.

2) You may have vacuum and intake leaks. Search the forum for lotsa advice.

3) Adjust the valves already. It ain't hard, it ain't expensive, and it definitely ain't optional.

4) Clean the carbs and reassemble with new o-rings.

All the above is very clearly explained with lots of pictures on Basscliff's site. And none of it is very expensive.

Oh, and please DON'T RIDE THE BIKE until it is safe to do so. Renting a car or pickup is a lot cheaper than skin grafts and emergency surgery.

It's a vintage bike, and it doesn't care how badly you "need" to get home, or to work or school. Part of the deal with vintage bikes is that Stuff Breaks. You have to keep a clear head and don't let "get-there-itis" force you into a bad riding decision. Something potentially very dangerous is wrong with the bike. It stays parked until you get it fixed, period, end of story.

[sparki]

what happens when you just start the bike... eg: ignition on and press the button? do the revs climb then or is it a std idle? .... then, on the stand, can you rev it and the revs rise/drop as expected or do they climb?

sounds to me like cable routing / attachment but.......

no idea what "completely wigged out" means but i guess that's a local thing huh?

[DanTheMan]

what happens when you just start the bike... eg: ignition on and press the button? do the revs climb then or is it a std idle? .... then, on the stand, can you rev it and the revs rise/drop as expected or do they climb?

sounds to me like cable routing / attachment but.......

no idea what "completely wigged out" means but i guess that's a local thing huh?

A term applied to mean totally nuts, crazy, "Hey she just wigged out on me, dude!!!!"

From the problem description, sounds like the o-rings in the boots just gave up and quit and it's sucking a lot of excess air.

[Dogma]

That's why I've trained my thumb to know where the kill switch is. I never kill the bike with the key.

Another possibility is that the idle screw somehow vibrated loose and adjusted way up. OK, maybe that's a long shot, but I'd check it anyhow.

[tkent02]

That's why I've trained my thumb to know where the kill switch is. I never kill the bike with the key.

That sounds like a good idea.

[Allenson]

Another possibility is that the idle screw somehow vibrated loose and adjusted way up. OK, maybe that's a long shot, but I'd check it anyhow.

I was thinking the same thing. Years ago when I bought my GS and didn't know much about them, the idle was quite high (somwhere in the 2000nds, I seem to remember) and all it turned out to be was my idle air adjustment at the bottom of the carbs.

Start with the easy/simple stuff first.

[argonsagas]

When you have this problem there are three rules to follow, in orderof importance:


1- PARK THE BIKE


2-You have already gone too far down the list.....Obey Rule ONE, then come back


3- Fix the bike.

[mighty13d]

Check to make sure you didn't open the choke all the way also. didn't see that mentioned yet.

[climber_dhl]

Lol. Thanks guys for your enthusiastic response. Just to clarify the issue, no I am not riding it home. I did state that I meant to 'ride' it home, but it was really late last night and I have a truck to take it home if I need (which I quite obviously need), I just needed to be home by Thursday and if it was a quick fix I wanted to knock it out so I could ride it home (not in the truck). The dang there is almost completely suicidal now and no way I am getting on it before it is back to normal. Thanks for all your concern, it is appreciated, but no worries I like all my limbs just where they are.

As per the problem. I thought of the throttle linkage but could that still be the problem if I can still turn the throttle and have it return back to just about it's normal state. When it was in gear just after it happened I could still give it gas. I was riding normal with my friend on back when all of a sudden I pulled the clutch in and my rpms shot up. To get home when it broke mid ride(since I was only a few miles on back country roads from home) I was in 5th gear cruising at about 45mph with no throttle applied just idling. To check (with my thumb hovering over my kill switch) the throttle I did give it gas and it responded almost normally and I was able to apply a little throttle and get to about 65mph. Then as a test I released the throttle and my bike slowed back down to 45mph cruise with no throttle at all. To me this means that the throttle linakge (which if I am not mistaken is just the cable coming from my throttle to my carbs) is old but fine. I thought about the idle screw, but it is still there. I guess supposedly it could have broke or something because I don't see it completely unraveling all the turns needed to jump from 800rpms to 8000rpms in a few seconds because of say a bump. Is there anyway to check or inspect the idle screw (which once again I believe is the nickel sized knob in the center of my carbs right between the filter pods. )

As for the choke it is not stuck all the way open since I can open it further using my finger and it snaps back to position. When the bike turns on the rpms kind of hover for a few seconds and than completely spike to 8000 or so and then it just stays there until I smack the kill switch. As mentioned earlier when it was in gear I could give it gas and speed up it was just a little sluggish.

So the above is all that I have tested, please let me know of what I should check next. Thanks again for all your help.

[49er]

Lol. Thanks guys for your enthusiastic response. Just to clarify the issue, no I am not riding it home. I did state that I meant to 'ride' it home, but it was really late last night and I have a truck to take it home if I need (which I quite obviously need), I just needed to be home by Thursday and if it was a quick fix I wanted to knock it out so I could ride it home (not in the truck). The dang there is almost completely suicidal now and no way I am getting on it before it is back to normal. Thanks for all your concern, it is appreciated, but no worries I like all my limbs just where they are.

As per the problem. I thought of the throttle linkage but could that still be the problem if I can still turn the throttle and have it return back to just about it's normal state. When it was in gear just after it happened I could still give it gas. I was riding normal with my friend on back when all of a sudden I pulled the clutch in and my rpms shot up. To get home when it broke mid ride(since I was only a few miles on back country roads from home) I was in 5th gear cruising at about 45mph with no throttle applied just idling. To check (with my thumb hovering over my kill switch) the throttle I did give it gas and it responded almost normally and I was able to apply a little throttle and get to about 65mph. Then as a test I released the throttle and my bike slowed back down to 45mph cruise with no throttle at all. To me this means that the throttle linakge (which if I am not mistaken is just the cable coming from my throttle to my carbs) is old but fine. I thought about the idle screw, but it is still there. I guess supposedly it could have broke or something because I don't see it completely unraveling all the turns needed to jump from 800rpms to 8000rpms in a few seconds because of say a bump. Is there anyway to check or inspect the idle screw (which once again I believe is the nickel sized knob in the center of my carbs right between the filter pods. )

As for the choke it is not stuck all the way open since I can open it further using my finger and it snaps back to position. When the bike turns on the rpms kind of hover for a few seconds and than completely spike to 8000 or so and then it just stays there until I smack the kill switch. As mentioned earlier when it was in gear I could give it gas and speed up it was just a little sluggish.

So the above is all that I have tested, please let me know of what I should check next. Thanks again for all your help.

\

Don't ride it until it's fixed.

Sounds like the butterflies are staying partially open when you shut the throttle. Try loosening off the idle adjuster to see if someone has tinkered with it. If the rpms drop, you have found the problem. As said elsewhere, your cable may be catching/binding somewhere too. You may have to take off the tank to see whats happening with the cable.

You mentioned filter pods above. Has the bike been tuned correctly to the pods? If not, that's your second priority.

[BassCliff]

Hi,

If your throttle cable is not sticking, it sounds almost as if the slides in the carbs are sticking open. You need to do some serious wrenching on your bike to make it safe.

CLICK HERE and follow the carb cleaning guide, the valve adjust guide, then click on this link to bwringer's site for the intake boot and O-ring replacement guide. Don't forget to properly seal the airbox. The link to my website is in my sig. Stop by and soak it all up. Getting to know your GS really, really well is the first step to keeping on top of the maintenance. Keep us informed.


Thank you for your indulgence,

BassCliff

[torque87]

I am having the EXACT same problem on my 82 gs650. It's an odd experience cruising down the road with your hand totally off the throttle :P I have already replaced the O-rings between the cylinder head and the intake tubes and that fixed my problem just slightly, it is still doing it pretty bad. I will be watching this thread pretty closely to see if you come up with a solution, likewise I'll post if I manage to figure mine out.

p.s. My next step is gonna be lubing the throttle cable (as per a friend of a friend motorcycle mechanic)