sticking throttle only when running?

[Jaymann]

My completely stock (for now) '05 FZ6 has a weird sticky throttle problem that I can't figure out.
The throttle will only stick when running, and only if you gently rev the bike up and let go. If I'm just cruising at a steady speed and let off the throttle doesn't close and it's like having cruise control.
I have to manual roll back the throttle.

If you snap the throttle it returns briskly.
If you shut the bike off the throttle never hangs up.
I adjusted and lubed the cables and the throttle body return springs. I even replaced one of the cables because it was a cheap "made in China" cable.

I bumped into a dealer mechanic friend of mine and he immediately assumed it was cable adjustment. He quickly looked at my bike and said they were adjusted right and that I'd have to bring it in. $$$!

What could be causing this?
My mechanic friend thins possibly something in the Throttle bodies that's causing the butterflies to stay open.

Any thoughts?

 

[FIZZER6]

It could be the butteryflies but that's unlikely as there's nothing that can really hang in there that will allow them to close again.

An often overlooked component of a smooth throttle is the grip tube itself! I finally took mine off this spring after dealing with a less than smooth return on my throttle. Come to to find the bar end that the throttle tube slides on was actually showing a bit of rust from riding in the rain a few times and was very rough! I sanded it with steel wool and then took the high speed polisher to it and made it shiny again and then used silicone grease on it and it has been smooth as butter ever since. :thumbup:

 

[Jaymann]

I forgot to mention that I cleaned and greased the grip too.
What doesn't make sense is that if the bike isn't running the throttle doesn't stick.

 

[FinalImpact]

Although it says to use lithium soap based grease in the tube, be careful as it can cause it to stick.

I would loosen and remove the TOP cable from the throttle body (TB) and test each cable independently for smooth operation. The upper cable shown here is the return. With it removed, its relying on the return spring on the TB to shut the throttle. It should close from ANY position even w/out the Return cable! Verify this is TRUE!

I know you said someone looked at it, but the lack of free play between the two cables will cause it to bind. A quick SNAP offers momentum where small change does not. Perhaps that is the difference between running and off?

Its a double pull system as cables do not push willingly and if no freeplay exist between them, it locks the throttle. Follow the top cable here to the grip and "IF" there is an adjustment for it, add slack. If that helps, it was too tight! I may be in error here about "WHERE freeplay can be added", but its a balancing act. Get some freeplay between the cable sets. That is if both cables move freely on their own.

NOTICE FREE PLAY on lower cable! Thats the Throttle cable. The top is the return.

AT WOT

EDIT: With both cables removed you can verify the TB closes from any position with no cables attached. Also, is the clutch cable routed properly? Sometimes people tie stuff to the Stanchion tubes and it crosses over and binds the throttle (while sitting on it!!)

OEM CABLE ROUTING:

 

[Jaymann]

First thing my dealer mechanic friend did was check free play. He actually said when I asked him about the situation "I can fix that in 3 seconds" and then looked at it and said "oh, you have the free play adjusted right, usually the cables are too tight"

Throttle sticks even when it's sitting on the stand with no one on it. Regardless of the position of the handle bars. Wiggling the cables or turning the bars has no effect on it.

 

[Motogiro]

Since it only happens when running.... You might also pop the tank and open the airbox to see if something has occurred where the butterflies may be interfered with.

 

[Motogiro]

It could be the butteryflies but that's unlikely as there's nothing that can really hang in there that will allow them to close again.

A rodent?

 

[TownsendsFJR1300]

As Final posted, if your mechanically inclined at all and have a 10mm open end wrench, simply loosen the lock nuts on the cables at the throttle bodies(left side cam as shown) and remove the cable(just from the mount is fine at this time, you can leave the barrel end in).

Turn the throttle body plate and see if it snaps back.

In his pic, you can see the return spring with the hook on it.

If it does, your cables are likely the culprit. You could have a frayed cable end at either end.

Again, if your mechainically inclined, theres three phillips head screws to dis-assemble the throttle assembly(on the bar itself).

Below is a pic of the kill switch hotwire but you can see the insides how the barrel ends connect.

The cable play(that there is some) is critical as previously posted.

 

[Jaymann]

I've actually disconnected the push cable and rode it for a week while waiting for a new one and it still did the same thing. No difference at all. Cables aren't frayed.

 

[TownsendsFJR1300]

I've actually disconnected the push cable and rode it for a week while waiting for a new one and it still did the same thing. No difference at all. Cables aren't frayed.

Just sent you a PM...

What happened with the old push cable? Bent/ kinked at all?

Does the INNER cable move easily in the OUTTER CABLE? (could be screwed up in the middle) (both cables)

 

[Jaymann]

The old push cable nut broke off on the throttle body side. I was loosening it off to disconnect it and where the nut threads on to the cable just broke off. Cable was some cheap looking made in china replacement part, so I ordered a new factory replacement.
No binding in the old cable.
I disconnected both sides of the pull cable to check for binding and it feels smooth.

 

[TownsendsFJR1300]

And the TB plate (that the cables attach to) snap closed easily?

 

[TownsendsFJR1300]

I disconnected both sides of the pull cable to check for binding and it feels smooth.

How about the PULL CABLE, that cable is what would hold the throttle open..

Did you open up the throttle assembly at the handle bar?

 

[TownsendsFJR1300]

Any updates????

 

[FinalImpact]

If you install a new *push* cable, theres your trouble! Cables an chains don't push, they pull!

So, that tidbit of info about the cable being messed with is important as it tells us someone has been here before trying to correct an issue! There is more to the story so please tell us eveything you know and all that has been done. It will speed this along!

Thata important! My first deep dive into these bikes was to replace the throttle body on one becase somehow someone had broken the sides from them and glued them back into position and sold this poor sole a fubar bike... Point sh$%t happens.
You need to remove the cable and verify smooth operation the of the throttle shaft with no cables involved.

Get back to us after that. It could be the TB bases are not seated fully and are binding the pair.

 

[FinalImpact]

If you install a new *push* cable, theres your trouble! Cables an chains don't push, they pull!

So, that tidbit of info about the cable being messed with is important as it tells us someone has been here before trying to correct an issue! There is more to the story so please tell us eveything you know and all that has been done. It will speed this along!

Thata important! My first deep dive into these bikes was to replace the throttle body on one becase somehow someone had broken the sides from them and glued them back into position and sold this poor sole a fubar bike... Point sh$%t happens.
You need to remove the cable and verify smooth operation the of the throttle shaft with no cables involved.

Get back to us after that. It could be the TB bases are not seated fully and are binding the pair.

Pictures are gone but around post 34 it cuts to the chase with going to his house an removing broken TBs and replacing them with fleebay bodies.
http://www.600riders.com/forum/fz6-technical/37198-going-problem.html?highlight=hammer << Blah

 

[TownsendsFJR1300]

He PM'ed me back the following;

"I'm pretty sure it's something to do with the throttle bodies. I've unhooked the throttle cables and manually open and close the linkage and it seems the linkage sticks at about the last 16th inch of movement before it closes."

 

[FinalImpact]

He PM'ed me back the following;

"I'm pretty sure it's something to do with the throttle bodies. I've unhooked the throttle cables and manually open and close the linkage and it seems the linkage sticks at about the last 16th inch of movement before it closes."

Need to get the airbox off an look. Its now a wild card as to what may have happened to it!

 

[Motogiro]

He PM'ed me back the following;

"I'm pretty sure it's something to do with the throttle bodies. I've unhooked the throttle cables and manually open and close the linkage and it seems the linkage sticks at about the last 16th inch of movement before it closes."

Any progress on this?

I'm wondering if the throttle plate shaft of throttle plate may have shifted laterally and is catching? The TPS could also have a mechanical problem causing interference.

 

[TownsendsFJR1300]

I erased my PM's, but as I re-call, he was working 12 hour days, 7 days a week so his time was very limited (pretty sure the same bike/op), but no, I haven't anything back.

I suspect he just hasn't had the time... Something under that air box me tinks ain't right..