Throttle doesn't return after a carb rebuild

[jmint]

I've rebuilt all the carburetors using the Redeye kit to include float bowls.  Before the rebuild, the throttle returned to zero with the quickness, but now it's pretty slow - something like 2 seconds before it starts to slowly creep back to the zero position.  Total cycle time is probably 5 - 7 seconds from WOT to fully closed.

I took apart the clamshell at the handlebar, fully removed the cables and shot cable lube down the sleeves.  I did this when the cable were off the carburetor, so I shot the lube and pulled/pushed them back and forth to help work down the lube.  There didn't appear to be any binding or sluggish movement here.

I rotated the throttle grip also, just to make sure that there wasn't a weird bind there - grip slides free and clear.

So that leaves me with the carburetors themselves.  All the springs are back in place; the only ones that were not removed were the ones that operate the butterfly.  The correct springs in between butterfly spring assemblies were replaced or put back in their correct spot.

I'm kind of at a loss here because I don't really have a ton of carb experience, so I'm kind of stuck at what the next step is.  I feel like I've narrowed it down to the butterfly and spring assembly, but I don't know how to fix it.  Pretty sure it's not the cables.

Any help on this one?

[JimC]

Do they snap back when the cables are not hooked up?
If the cables are good, and the throttle grip is good when not connected, it's probably in the adjustment between the two.

Jim

[Savage]

Did you re-route the throttle cables in a way that causes binding?

[jmint]

@ Savage - no, I did not re-route the cables, only disconnect.  I'm not entirely sure how they're supposed to route, however, and that may be adding to the issue.  Currently (and when I bought it from the PO), they are routed to the front of the triple tree and are behind the fairing.  A lot of the original plastic handlebar clips had been replaced with zip ties.

@ JimC - the throttle drum at the carburetor does not snap back when the cables are disconnected - it's pretty slow.  I'm sure that it's on the carb side, I just don't know what kind of adjustment there is here.  I would assume the post that the butterfly is connected to simply runs through the carb body.  Is there an o-ring on the post at the carb body to seal the interior off from the exterior?  That may be where the dragging is occuring?

[The emperor has no clothes]

I know a lot of guys have put the springs and washers on incorrectly on the rebuild. Take a good look at your pics and see if something is different. Good luck, and don’t be tempted to ride it and think it will even out.

[jmint]

@ meathead - by washers, are you talking about the bar that links the right to left bank?  If so, I did put that together correctly - followed the directions supplied by Redeye.

I only have the pictures from the valk shop manual and those are pretty well garbage.  do you have a better side shot pick that might show me the problem with the springs?

Edit: If I have a bad air cut valve, is that causing a pressure where a vacuum should be?  I didn't test them, I just replaced the o-rings.  Probably should have checked them when they were off the bike.

Edit 2: After thinking about my process, I disassembled everything except the throttle plate rod and put the whole carb in Berryman's, not realizing there is probably an o-ring on the throttle plate shaft, and the Berryman's probably killed it. Does anyone have a part number or know what size that o-ring is?

[indybobm]

Disconnect the crossover linkage and see if it is just one side. Should narrow it down.

[Led]

Yea.....all it takes, is just ONE cable routed above the other, somewhere along the way........where they were not before.

One needs to be meticulous when tearing these bikes apart. Remember where EVERYTHING was before!!

The fun always begins, on reassembly!!!!  And take it all apart again.   Put it back together again......take it all apart again.......

We have ALL been there!!!  Lol!!    

[3W-lonerider]

if you installed the airbox after hooking up the cables on the carbs. it is possible to have the one cable on the wrong side of the air tube. which will cause it to bind. you can't see it from the side of the bike but if you take the tank off and look down in there it is easily seen. i done it myself the first time i installed my airbox.

[Mooskee]

@ JimC - the throttle drum at the carburetor does not snap back when the cables are disconnected - it's pretty slow.  I'm sure that it's on the carb side,

If it is not snapping back with the cables disconnected, you are correct. It is on the carb side.
*I wouldn't think Berriman's would cause that problem.
*Check to see if the crossover bar is bent or binding on something. I'm not sure it is possible to route it incorrectly.
*Disconnect one end of the crossover bar and see if the binding is on one side or the other.
*Did you replace the bearings in the crossover bar? Could be a bad bearing, damaged during replacement or old bearing is bad, or new bearing was bad.
 

[jmint]

@ JimC - the throttle drum at the carburetor does not snap back when the cables are disconnected - it's pretty slow.  I'm sure that it's on the carb side,

If it is not snapping back with the cables disconnected, you are correct. It is on the carb side.
*I wouldn't think Berriman's would cause that problem.
*Check to see if the crossover bar is bent or binding on something. I'm not sure it is possible to route it incorrectly.
*Disconnect one end of the crossover bar and see if the binding is on one side or the other.
*Did you replace the bearings in the crossover bar? Could be a bad bearing, damaged during replacement or old bearing is bad, or new bearing was bad.
 

I wouldn't think so either, but Berriman's is known to eat gaskets/o-rings.  If there's an o-ring on the throttle plate rod, that might be it.  Going to check this out tonite.  Doesn't appear there's a part number, all the fisches only show a full carb body assembly with throttle plate/rod installed.  It may not be a service part, and that's why.

Good idea on the crossover bar, will check.  I did confirm bar was straight upon rebuild.

Good call on the bearings, those were replaced with the Redeye kit and spun well with a pencil tip installed.  It's possible the bearing hole axis is not true to the stud, I didn't check that, but I will tonite.

There's really only so many things it could be I guess.

[luftkoph]

I had a similar experience when I did my carburetors, but I noticed it on the bench before reinstalling them, I had to loosen the nuts on the 4 long bolts that tie the front and rear stay to the carburetor assembly, then used nylock nuts instead of the OEM’s

[jmint]

I had a similar experience when I did my carburetors, but I noticed it on the bench before reinstalling them, I had to loosen the nuts on the 4 long bolts that tie the front and rear stay to the carburetor assembly, then used nylock nuts instead of the OEM’s

Did you figure out what the problem with that was?  I used the new plastic dowels that came with the Redeye kit, but I also torqued those through bolts to spec.  Wondering if the torque is too much for those plastic dowels.  There's full bearing between the carbs on the aluminum surface at the connection point, but I don't know how much slop there is in the dowel hole bore - might have crushed it and tweaked the alignment?

[luftkoph]

Never actually figured out what it was, maybe just loosening and getting things lined up better, and with the nylocks  I could set the tension where everything worked smoothly

[rug_burn]

I think you're on the right track- it sounds like that liknage is binding somewhere,  or maybe the cable leading into it;  I didn't read back all the way in the thread.   Good luck, and keep us filled in.

[jmint]

Feels like I'm chasing demons.

Throttle butterflies started snapping after a day sitting in the truck.  Checked for any binding in the linkage, couldn't find anything.  Bearings appear to be as straight as they can get.  Oiled the throttle plate shaft and snapping improved.  Flicked it many times over the course of 30 minutes to work the oil into the carb body.

Got everything reassembled.  Rechecked the cables prior to drum reassembly - all free and clear.  Finished reassembly, checked throttle flick after every step of an added component - free and clear, quick return.  Start the motorcycle - free and clear, quick return.

And then, as I'm sitting in the garage blipping it, back to sluggish return.  Broke apart the housing at the grip, oiled it, worked it through.  Reassembled.  And exactly the same thing.  Sluggish.

I'm hot, need a break.

[luftkoph]

Try disconnecting the push cable, and see how it responds with only the pull cable, if the push cable is too tight it tends to bind things up

[jmint]

It's gotta be cable related.  I think it's dragging inside the sleeve, but I can't be sure.  Cables feel good when free, but it might be frayed inside, i dunno.

I went ahead and ordered a full set of cables, so we'll see.  I'll get to the bottom of it, just needed to step away for a minute.  It's also cold and rainy this week, so the need for wind therapy isn't too terrible.

[Buza]

It's just too tight adjustements, loosen them up.

[jmint]

@Buza - that's not it, they're as loose as they can be without being disconnected.

[rug_burn]

I know how it is-   sometimes you just gotta walk away.
  But- how do the  cables seem when they're connected?   If you flick your finger on them
or pull on them a little, do they seem real tight?  

If not-  could possibly be a vacuum situation going on in the carbs?   maybe if there was a blockage in the vent side of the vacuum circuit?    Speculation, admittedly.

[jmint]

I know how it is-   sometimes you just gotta walk away.
  But- how do the  cables seem when they're connected?   If you flick your finger on them
or pull on them a little, do they seem real tight? 

If not-  could possibly be a vacuum situation going on in the carbs?   maybe if there was a blockage in the vent side of the vacuum circuit?    Speculation, admittedly.

I suppose the cables seem fine?  It's real hard to tell - I get good snap on the throttle plate without cables, then sluggish with cables.  I'm just going to replace these MF'ers and see what happens.  Been through the whole bike at this point repairing and replacing, what's another $100?

Vacuum circuit - are you talking about the slide?  If so, that's free and clear.  When I push it up with a finger, I can hear the suck/vacuum from the slide diaphragm.  If that's not what you're talking about, that's something new for me to check if you can explain how?

[jmint]

Solution found: after replacing the cables and putting everything back together, there was a considerable amount of drag still.  I found the issue to be inside the housing on the handle bar.  It looked like the plastic piece that the cables connect to was dragging slightly on the housing.  After some silicone lube (already cleaned up from the install) and some careful tightening of the housing screws, we're back in business.

It is worse when it's cold outside, but once it warms up a little bit, back to snapping full off.

[The emperor has no clothes]

Excellent