Throttle issues V65

[svanbremen]

Maybe some one has a briljant idea… ‘cause I’m lost and stuck.

First of: I’m from Holland, so sorry for any typos or mistakes!

The issue: after starting the bike, it goes to 5000rpm immediately. Not ideal so to speak…

The reason: I’ve replaced the handlebars. Or at least, it started after that.

Would be easy, right? Cables too short… well no not really! I went from the high handlebars to low handlebars and the cables are long enough and it does this with the original cables.

So what have I done and tried?
Taking the cables out of the throttle body fixes it, so definitely cable related.
Took the carbs a part and checked the slides, seem fine.
Ordered new cables, slightly shorter, no difference.
Rerouted the cables, no difference

I think it’s only the left carb, judging by the sound of something clicking (slide?) when I take the cables out of the handle. But this to me is even weirder…

So I’m stuck… some help??

[Tkelly]

I had a similar problem caused by throttle cable hanging up internally.

[SED]

Can you pull on the cable casing at the top of the carb?  There should be a few millimeters of slack on both carbs.  Usually the problem is the casing hanging up on the edge of ferule, but would have been solved by your work.  So does your bike have the original plastic twist grip from the '80s?  That thing is impossible.  Also, do the carbs have accelerator pumps?  Maybe one sticking inside? 

Let us know what works.

[pehayes]

What year V65?  Does it still have original ignition?  Points?
The mechanical timing advancer rides on the front of the camshaft.  When dirty it gets sticky.  It is entirely possible you are stuck at maximum spark advance which would make the engine race.  Would likely also make it very hard to start and you haven't mentioned that.  Make sure it is clean and free.  Usually it sticks at full retard so the bike starts fine and idles fine but won't accelerate.

How many cables do you have at the hand throttle?  If two, one goes to each carb.  If one, then you have a 'splitter' somewhere under the tank.  When fully removed for the kind of work you have done, it is easy for the little ends of each cable to dislodge from their seats and wedge up elsewhere.  This makes the cable appear shorter than it was originally and takes away all of your adjustment.  I would start by looking at the ends and seats for ALL of the cables involved. 

Patrick  Hayes
Fremont CA

[frozengoose]

Can you pull on the cable casing at the top of the carb?  There should be a few millimeters of slack on both carbs.  Usually the problem is the casing hanging up on the edge of ferule, but would have been solved by your work.  So does your bike have the original plastic twist grip from the '80s?  That thing is impossible. Also, do the carbs have accelerator pumps?  Maybe one sticking inside? 

Let us know what works.

I also replaced the handlebars on my v65 and had the same problem. Tried all the same fixes, except replacing the cables, cause they seemed long enough and worked fine before. Then I noticed that the tension adjustor knob, on the bottom of the throttle didn't seem to do much when turned either way, so took it apart. The block that is pushed in or out by the adjustment screw had separated, I think it's supposed to be snapped into the screw a ways, was loose, so took it out and ground off a bit on the grinder and then reset it into the throttle. Haven't had any problems with carbs sticking since. Something to check, it's easy enough to get apart, and anyways, never used that adjustor, so not something I'd miss.

[svanbremen]

Thanks for the replies.
1986 (85?) so, yes, the plastic non-adjustable piece of …..
Part of the problem, I guess.
And also one cable per carb, straight out of the throttle grip.

Pulling the outer cable at the carbs on both sides gives friction/pressure, they snap back straight away. But it does this on both sides and I’m fairly certain this only exists at the left side… although right side is running fast as well, but no clicking sound after releasing the cables.

I also have lubricated the slides with oil, no difference.

Given the fact that taking the cable out of the throttle fixes the issue, one would assume it is the cable, right? And not the points… also the fact that it started doing this after the handle bar change. (Not arguing, just thinking out loud… or as we say in IT ‘rubber duck-ing’)

[SED]

Pulling the outer cable at the carbs on both sides gives friction/pressure, they snap back straight away. But it does this on both sides and I’m fairly certain this only exists at the left side… although right side is running fast as well, but no clicking sound after releasing the cables.

There should be a few mm slack - no spring pressure - then spring pressure as the throttle slide is pulled up.  If there is no slack, it is usually the edge of the cable outer hung up on the edge of an adjuster ferule. 

Releasing the throttle you should hear a click as the slide closes against the stop screw.  If you don't hear the click on the right, it is probably the right cable that is sticking. 

Can you see into the mouth of the carb to see if 1 slide is higher than another?

[guzzisteve]

Sounds to me like it's in the throttle housing, maybe not all together in the correct place. That would eat up the play in cables. There are no adjusters on the V65C only on top of carbs. If you loosen the lock nut on adjuster screw them in all the way for maximum play.

[not-fishing]

I had the same problem with my V65 project bike of last year.  Yes it came in boxes

The problem ended up the outer casing was tensioning the inner cables.  I found it out by turning the handlebars left then right with a resulting large change in rpm.

I ended up fixing it with careful routing so that the cables come essentially down out of the throttle assembly.  For some reason only that orientation didn't cause jumps in rpm based on turning the handlebars left, center or right.

The nice thing about the fix is that you can easily test it to see if you got it right.

[moto-uno]

 Remove the cables from the throttle assembly
 Start bike , does it rev up ?
 If not , pull on each inner cable one at a time
 Does it stick and stay revved up on either one ?
 If not , it's possibly the routing and or the throttle assembly .
 Shouldn't take too long . Good luck , Peter
 

[svanbremen]

There should be a few mm slack - no spring pressure - then spring pressure as the throttle slide is pulled up.  If there is no slack, it is usually the edge of the cable outer hung up on the edge of an adjuster ferule. 

Releasing the throttle you should hear a click as the slide closes against the stop screw.  If you don't hear the click on the right, it is probably the right cable that is sticking. 

Can you see into the mouth of the carb to see if 1 slide is higher than another?

Checked the ferules, seem fine.

Sorry, should have been clearer, I hear the click when I take the cables out of the throttle housing, not when closing the throttle (as one would assume)

Don't know how to do that, the filter box is in the way, but it would give an answer as to which one (or both) it is.

[svanbremen]

I had the same problem with my V65 project bike of last year.  Yes it came in boxes

The problem ended up the outer casing was tensioning the inner cables.  I found it out by turning the handlebars left then right with a resulting large change in rpm.

I ended up fixing it with careful routing so that the cables come essentially down out of the throttle assembly.  For some reason only that orientation didn't cause jumps in rpm based on turning the handlebars left, center or right.

The nice thing about the fix is that you can easily test it to see if you got it right.

Right now moving the handle bars does not make a difference (at all), but changing the throttle body might work... is on my list to try!

[svanbremen]

Remove the cables from the throttle assembly
 Start bike , does it rev up ?
 If not , pull on each inner cable one at a time
 Does it stick and stay revved up on either one ?
 If not , it's possibly the routing and or the throttle assembly .
 Shouldn't take too long . Good luck , Peter

When the cables are out of the throttle housing, it does not rev up.
Pulling on either side RPM's go up, but down when released. So nothing appears to be sticking or hung up.
When I changed the handle bars I did not change the original cables or rerouted them. But rerouting them does not seem to make a difference. Even 'routing' them completely loose does not make a difference.

[svanbremen]

Thanx for all the input!

Did take the throttle housing apart, nothing seems out of place or broken.
The adjusters on the carbs are completely down, giving the most free play, right?

I must have pulled something when changing the handle bars, but there are only two cables... so it shouldn't be this hard....

[svanbremen]

Right.... after some more tinkering: it is cable related. It is binding somewhere or the routing is wrong, also the position (angle) of the throttle body itself is very important.

After repositioning the throttle on the handlebars, it came down in RPM, but moving the handlebars to the left caused significant dropping in RMP and to the right caused a serious rise in RPM.

Issue is, I don't know where to go from here. The cables can't be routed a different way and they are alway gonna move when you move the handlebars and there is no way to adjust anything.
Right now the cables come from the carbs and straight over te backbone of the frame (under the tank) and come out at the rightside from under the tank.

[guzzisteve]

We just had a thread not long ago about shortening the outer sheath to give more slack. It's not too hard to do.
Got to take loose the chrome end, it twists off like a jar top. Slice around the bottom of it to be free of the outer plastic/rubber skin then it twists off. Outer sheath is like a coil spring. The idea is to uncoil a bit of the end, snip it and readjust the edge so chrome cap screws back on.

[svanbremen]

I think I’ve fixed it! Or made it better atleast ;)

Took everything apart (again) and rerouted everything (again), but this time router the left carb over the back bone to the right, also exiting beneath the gastank at the right and the right carb over the backbone to the left, exiting left and around the stearingcolumn...

It actually idles now at 1400 rpm and twisting the handlebars from left to right only raises the idle by a 100rpm or so… so not a 100% just yet, but maybe the advise of shortening the outer sleeve a bit to have a bit more slack (and the ability to adjust at the carb) would not be a bad thing!

[moto-uno]

  Love to hear the feedback that you've pretty much isolated the problem and now get to tinker :) . Peter