Sticky throttle

Sticky throttle

There's a first time for everything.

While riding the track yesterday, my throttle stuck. I nearly had a very
bad crash, but somehow saved it at the last second.

This is one more strike against the auto clutch. Even with a manual
override, at high RPM you cannot disengage the clutch.

I will be replacing the throttle cable, inspecting the bar assembly, and
tearing down the carb to locate the fault.

I discovered why I was fouling so many plugs in Utah. My coil was bad. The
primary side measured about half the resistance it should. The bike worked
much better with a fully functioning ignition. With a stuck throttle, it
worked too well. :-/

I've never been sold on the auto clutches. I don't think I would have
bought one myself, but this bike came with one installed. After the Utah
trip, I was leaning more toward the auto clutch. This has set back my
expectations.

-Jeff-

Re: Sticky throttle

On May 12, 9:26 am, "HellSickle" <jldnospamee...@comcast.spammer . net >
wrote:
> There's a first time for everything.
>
> While riding the track yesterday, my throttle stuck. I nearly had a very
> bad crash, but somehow saved it at the last second.
>
> This is one more strike against the auto clutch. Even with a manual
> override, at high RPM you cannot disengage the clutch.
>
> I will be replacing the throttle cable, inspecting the bar assembly, and
> tearing down the carb to locate the fault.
>
> I discovered why I was fouling so many plugs in Utah. My coil was bad. The
> primary side measured about half the resistance it should. The bike worked
> much better with a fully functioning ignition. With a stuck throttle, it
> worked too well. :-/
>
> I've never been sold on the auto clutches. I don't think I would have
> bought one myself, but this bike came with one installed. After the Utah
> trip, I was leaning more toward the auto clutch. This has set back my
> expectations.
>
> -Jeff-

So no auto-clutches can be overridden with the lever when revved up?
Makes a great case for a pull-pull throttle.

I had *almost* the same thing happen yesterday.

I was going fairly slow, something snagged my leg, almost pulled me
off the bike, and of course it dialed up the throttle a whole bunch as
I was almost pulled all the way off the bike. Made for a nice wheelie
towards the trees, but I got it slowed down before then. Fortunately,
whatever snagged me pulled me right, if it pulled me left I would
still be lining up volunteers to pull my bike out of the mini-ravine
that was off that way, assuming I was able to get myself out of it.

Dave

Re: Sticky throttle


"XR650L_Dave" <spamTHISbrp@yahoo . com > wrote in message
news:171941db-fbf5-44d4-a8ea-4742511528b6@d77g2000hsb.googlegroups . com ...
> On May 12, 9:26 am, "HellSickle" <jldnospamee...@comcast.spammer . net >

> So no auto-clutches can be overridden with the lever when revved up?
> Makes a great case for a pull-pull throttle.

Revlok's new version may someday allow that capability. With current
designs, the centripetal force of the actuation balls generates a very high
load at high RPM. Far higher than the standard clutch springs, thus nearly
impossible to overcome. This is one of the reasons that the MX'rs have been
slow to adopt auto clutches.

Re: Sticky throttle

"HellSickle" sez:

> cuz "XR650L_Dave" sez:
> > So no auto-clutches can be overridden with the lever when revved up?
> > Makes a great case for a pull-pull throttle.
>
> Revlok's new version may someday allow that capability. With current
> designs, the centripetal force of the actuation balls generates a very
high
> load at high RPM. Far higher than the standard clutch springs, thus
nearly
> impossible to overcome. This is one of the reasons that the MX'rs have
been
> slow to adopt auto clutches.

I remember early talk about MX RDR types fraggin' tranny and hub components
when they'd land under power with the auto-clutches since they wouldn't slip
under heavy loadings like conventional spring baskets. The Rekluse design
contained something of a Bellville spring arrangement where it would allow
some ultimate slip where the Revloc wouldn't and Rekluse hyped it as a
competitive advantage. There was also the lawsuit at the time but I never
followed up on the outcome.

I had clutch envy when I watched you scratch your way through the rubble on
the notch climb out of Moqui Canyon but was able to accomplish the same with
judicious clutch work ... on balance, its hard to say which is better.

Good friction regulated moment tranferin' to ya,
VLJ
--

Re: Sticky throttle

On May 12, 9:26 am, "HellSickle" <jldnospamee...@comcast.spammer . net >
wrote:

> While riding the track yesterday, my throttle stuck.  I nearly had a ver=
y
> bad crash, but somehow saved it at the last second.
>
> This is one more strike against the auto clutch.  Even with a manual
> override, at high RPM you cannot disengage the clutch.

Yikes!

I didn't realize the manual override didn't work at high RPM. Having
had a stuck throttle in the past, I figured that whenever I got around
to trying the auto clutch it would have to have the override feature.
Going to have to re-think that.

Craig

Re: Sticky throttle

> I didn't realize the manual override didn't work at high RPM. Having
> had a stuck throttle in the past, I figured that whenever I got around
> to trying the auto clutch it would have to have the override feature.
> Going to have to re-think that.

How do you shift gears with these things, especially upshift? The ATV
systems (like on my Foreman) has a manual clutch that operates in
series with the auto. The manual clutch is actuated when you pull up
or down on the shift lever, so it disengages the drivetrain as you
shift. Does every shift slam your tranny?

JayC

Re: Sticky throttle

On May 13, 8:29 am, JayC <j...@sysmatrix . net > wrote:
> > I didn't realize the manual override didn't work at high RPM. Having
> > had a stuck throttle in the past, I figured that whenever I got around
> > to trying the auto clutch it would have to have the override feature.
> > Going to have to re-think that.
>
> How do you shift gears with these things, especially upshift? The ATV
> systems (like on my Foreman) has a manual clutch that operates in
> series with the auto. The manual clutch is actuated when you pull up
> or down on the shift lever, so it disengages the drivetrain as you
> shift. Does every shift slam your tranny?

Oh yea, it's amazing you don't hear of more blown trannies due to
them.

I'm sure it'll someday strand me way out in the wilderness, ooops, I
mean "semi-primitive non-roadless forest area open to off-road
motorcycle use."

Nobody should use an auto clutch.













Well, nobody except me of course.

Whelan Dowd

Re: Sticky throttle


"Whelan - '02 200exc (x2) & '04 MTD 38" <yosef@sisna . com > wrote in message
news:d1578bd2-fa6a-4675-bb01-e1a70a8734b8@x19g2000prg.googlegroups . com ...
> On May 13, 8:29 am, JayC <j...@sysmatrix . net > wrote:
>> > I didn't realize the manual override didn't work at high RPM. Having
>> > had a stuck throttle in the past, I figured that whenever I got around
>> > to trying the auto clutch it would have to have the override feature.
>> > Going to have to re-think that.
>>
>> How do you shift gears with these things, especially upshift? The ATV
>> systems (like on my Foreman) has a manual clutch that operates in
>> series with the auto. The manual clutch is actuated when you pull up
>> or down on the shift lever, so it disengages the drivetrain as you
>> shift. Does every shift slam your tranny?
>
> Oh yea, it's amazing you don't hear of more blown trannies due to
> them.
>
> I'm sure it'll someday strand me way out in the wilderness, ooops, I
> mean "semi-primitive non-roadless forest area open to off-road
> motorcycle use."

Motorcycle trannies are fully synchronized. As you know, any bike can be
shifted without the clutch. I use my manual override on casual upshifts,
and on all downshifts (both, low-rpm situations).

> Nobody should use an auto clutch.
>
> Well, nobody except me of course.

So, everybody who's nobody? :-)

I haven't torn my bike down yet. I have ordered a new throttle cable, just
in case. Also, I don't like how the cable can interfere with the damper, so
I'll be fabridating a new cable guide.

Admitedly, there were many places in Utah where I really liked the auto
clutch on the ascent, but not on the descent. Here's a couple of examples:

* stevensix.smugmug . com /photos/289033649_yfr9Z-L.jpg
* stevensix.smugmug . com /photos/289033734_aSEHM-L.jpg
* home . com cast . net /~jldeeney/utah2008/HITR7.jpg

-Jeff-





>
> Whelan Dowd

Re: Sticky throttle

> Motorcycle trannies are fully synchronized.  As you know, any bike can b=
e
> shifted without the clutch.  I use my manual override on casual upshifts=
,
> and on all downshifts (both, low-rpm situations).

Yes, I DO know any bike can be shifted without the clutch. I ask not
regarding dirtbike use, but simply because I was thinking about the
Harley Davidson clutches. Harleys barely shift as it is, much less
after 100,000 clutchless shifts.

JayC

Re: Sticky throttle

> Admitedly, there were many places in Utah where I really liked the auto
> clutch on the ascent, but not on the descent. Here's a couple of examples:

I really like my left hand rear brake (LHRB) in steep, loose downhill
situations. I'm not sure why, but I seem to have significantly more
control with the LHRB, i.e., being able to apply the brake right up to
the point where it starts to skid, then back off just a skosh. I used
to think downshifting the XR & yanking the compression release was
cheating in situations like that. Now I think a LHRB is cheating.

I also don't miss having my right foot below the peg so much...

-Whelan Dowd

Re: Sticky throttle


"HellSickle"

> Admitedly, there were many places in Utah where I really liked the auto
> clutch on the ascent, but not on the descent.

That's what I experienced. They are a little spooky on the downhills.

>Here's a couple of examples:
>
> * stevensix.smugmug . com /photos/289033649_yfr9Z-L.jpg
> * stevensix.smugmug . com /photos/289033734_aSEHM-L.jpg
> * home . com cast . net /~jldeeney/utah2008/HITR7.jpg

chunky stuff, dewd

Re: Sticky throttle

On Tue, 13 May 2008 08:29:27 -0700 (PDT), JayC <jwc@sysmatrix . net >
wrote:

>> I didn't realize the manual override didn't work at high RPM. Having
>> had a stuck throttle in the past, I figured that whenever I got around
>> to trying the auto clutch it would have to have the override feature.
>> Going to have to re-think that.
>
>How do you shift gears with these things, especially upshift? The ATV
>systems (like on my Foreman) has a manual clutch that operates in
>series with the auto. The manual clutch is actuated when you pull up
>or down on the shift lever, so it disengages the drivetrain as you
>shift. Does every shift slam your tranny?
>
>JayC

I guess in can hammer your tranny, but they are desined for shifting
without the pulling the clutch. My Concous shifts super smooth if you
back-off the throttle for an instant.

Mike Baxter

Re: Sticky throttle

Tore it down last night. Could not get it to stick. No debris in the slide
or carb. The control end looks fine. The only thing suspicious is that the
outer cable is degrading where it goes into the throttle end ferrule. I can
see where the spiral steel outer core has been stressed & partially come
apart. I think it may have gotten buggered by the PO twisting the carb
sideways for a jetting change without removing the top of the carb (cable
hits on the pipe). $15 for a new cable from MotionPro ($32 from KTM).

Checking the service manual, KTM says to replace the slide and needle after
100 hours. The carb should be replaced after 200 hours.

I think the lawyers were heavily involved with determination of the service
schedule. I agree that carbs eventually wear out. My XRL carb is probably
kaput, but Honda can't deliver a needle and needle seat (BO'd for almost a
year now). My ATK worked amazingly well when I replaced the carb after 6
years.

Re: Sticky throttle

On May 14, 1:47 pm, "HellSickle" <jldnospamee...@comcast.spammer . net >
wrote:
> Tore it down last night. Could not get it to stick. No debris in the slide
> or carb. The control end looks fine. The only thing suspicious is that the
> outer cable is degrading where it goes into the throttle end ferrule. I can
> see where the spiral steel outer core has been stressed & partially come
> apart. I think it may have gotten buggered by the PO twisting the carb
> sideways for a jetting change without removing the top of the carb (cable
> hits on the pipe). $15 for a new cable from MotionPro ($32 from KTM).
>
> Checking the service manual, KTM says to replace the slide and needle after
> 100 hours. The carb should be replaced after 200 hours.
>
> I think the lawyers were heavily involved with determination of the service
> schedule. I agree that carbs eventually wear out. My XRL carb is probably
> kaput, but Honda can't deliver a needle and needle seat (BO'd for almost a
> year now). My ATK worked amazingly well when I replaced the carb after 6
> years.



I thought either Craig or I were going to line you up with a carb?

Craig, dig through yer pile o' crud!


The only reason you don't see the pulled ones for sale is there's no
market for 'em.

Dave

Re: Sticky throttle

On May 14, 2:00 pm, XR650L Dave <spamTHIS...@yahoo . com > wrote:

> I thought either Craig or I were going to line you up with a carb?
>
> Craig, dig through yer pile o' crud!

The carb has been excavated and is sitting on my workbench waiting for
me to get a minute to box it up.

It probably has only a few hundred miles on it as it was pulled for an
aftermarket carb when the bike was still new. It's missing the pin for
the float and the screws for the top. Otherwise I think it's all
there.

Craig