Throttle won't close

[New Guy]

I have a 1991 GS500E. It sat for a while and and began to run rough. So, I pulled the carbs, cleaned and rebuilt them. Now, the throttle return spring - the one that is supposed to snap the butterflies closed - doesn't.

Today, I couldn't even open the throttle. I thought the cable was hanging up or pinched so I pulled the tank and saw that the cable wasn't moving at all. I pulled the carbs and worked the throttle valve shaft / assembly by hand. It's very tight but did loosen up with a little effort.

So now the throttle is tight to open and slow to close. Any ideas?

[ben2go]

I would remove them, pull the plastic and rubber parts out and soak the carbs overnight in carb cleaner or kerosene.Then blow them out with parts cleaner and compressed air,if it's avalibile.Then use white lithium spray grease on the spings and shafts.Reassemble and tune.

[GSnoober]

Though I usually agree with the advice ben2go provides, I've had bad experiences with carb cleaner and rubber parts. You can soak the rubber parts in kerosene (or diesel fuel), which should help to get any old crud off the rubber, but keep the carb cleaner away from the rubber. Hell, carb cleaner even attacks and dissolves some types of plastic, so use it sparingly.

[scottpA_GS]

I think thats what he was trying to say 

[ben2go]

I think thats what he was trying to say 

Thanks Scott.That was what I was tryin to say.I'll correct that statement.


Corrected! 

[New Guy]

OK. In order to do that I have to remove the butterflies, right?
The heads of those screws have been rounded out so I can't get a decent grip with any size screwdriver.
Can they be drilled out? What size bit should I use so as not to goof up the threads of the throttle shaft? Or maybe someone has another technique to suggest?

[cd]

cut a slot in them before you drill them out, with a dremel or something, if you can, so that you can use a flat head screw driver....

[ben2go]

I've never removed the butterfly valves to soak them.If they're soaked over night and will not free up,I'd remove them.Id polish the shafts lightly.To much and you'll create an air leak.

[New Guy]

I'm a bit confused. Aren't there plastic and rubber bits that make up the throttle shaft bushings? I'm talking about part numbers 17 (seal) and 43 (ring), specifically, on the exploded carb diagram at bike bandit.
Is it safe to soak them overnight in carb cleaner?

[ben2go]

I'm a bit confused. Aren't there plastic and rubber bits that make up the throttle shaft bushings? I'm talking about part numbers 17 (seal) and 43 (ring), specifically, on the exploded carb diagram at bike bandit.
Is it safe to soak them overnight in carb cleaner?

I have mine apart and can't see any plastic or rubber parts.I don't have my shafts out tho.I looked at he diagram and they maybe plastic or maybe teflon?Mine have been soaking for a few days.Well,I guess I'll find out when I get my bike back running.

[New Guy]

Thanks, ben2go.
I'll pull mine apart again and let 'em soak for a good, long time. I also appreciate the suggestion about using a "lithium spray grease," though I've never heard of it before. Can I find that at my FLAPS? Or would Tri-flow be just as good?

[ben2go]

Thanks, ben2go.
I'll pull mine apart again and let 'em soak for a good, long time. I also appreciate the suggestion about using a "lithium spray grease," though I've never heard of it before. Can I find that at my FLAPS? Or would Tri-flow be just as good?

Most any chain type parts store will have it.I don't even remember the brand name of mine.I rarely use it.Not familiar with tri flow.

[GSnoober]

Thanks, ben2go.
I'll pull mine apart again and let 'em soak for a good, long time. I also appreciate the suggestion about using a "lithium spray grease," though I've never heard of it before. Can I find that at my FLAPS? Or would Tri-flow be just as good?

This is an example of white lithium grease in spray can:

http://www.valvoline.com/pages/products/product_detail.asp?product=37

Here's another one:

http://www.lowes.com/lowes/lkn?action=productDetail&productId=124739-39963-D10100101

Another:

http://www.valco-cp.com/gellube.htm

Some detailed information about the multitude of uses you'll find for WLG:

http://www.extremehowto.com/xh/article.asp?article_id=60343

Just FYI, Tri-Flow is NOT the same; it is a teflon-based lubricant, while WLG is (obviously) lithium based. WLG is a much denser product, though it can attract a lot of crap in a dirty environment. Use the Tri-Flow, and if you're not satisfied with the results, get some WLG. I prefer to use WLG in situations that are NOT likely to attract a lot of dirt or dust...

Just google "white lithium grease", and you'll see