FOAK: Throttle Spring Tension Question

 

Subject bike is a Kwak 550, the throttle does require a lot of effort
to over come
the return spring. It soon makes my hand tired because of all the grip
I need to generate.

Is this normal?

I am tempted to reduce the tension by weakening the spring.  (I'll
remove it from the bike and heat a few coils until they turn red with
a propane torch.)

Can I simply remove the spring entirely and just roll the throttle
back and forth?  Is there some safety reason why I shouldn't do that.

TIA

Biker Dude.

 



What sort of Kawasaki 550? IIRC, the early z550 had slide carbs,
replaced on later bikes (z550F, GT550, GPz550, Zephyr 550) had CV carbs,
which require less effort to open.

If your model has CV carbs, then I'd suggest changing the throttle
cable(s)[1] because it's probably gunged up. Same goes for slide carb
bikes, actually.

Whatever, removing the return spring is not a good idea. Yes, springs
and twin throttle cables[2] are a belt-and-braces idea, but from
experience, having done this myself, sometimes you go too far and you
make precise throttle control more difficult. And should a closing cable
ever break, you'll be in real trouble.

[1] Can't recall which/whether bikes had a twin throttle cable push-pull
set-up but it's not hard to tell: just look at how many cables come out
of the twistgrip.

[2] See above.



--
BMW K1100LT Ducati 750SS  Triumph Street Triple  Honda XBR500 CB400F
SH50  MZ TS250 GHPOTHUF1  chateaudotmurrayatidnetdotcom
Nothing damages a machine more than an ignoramus with a manual, a
can-do attitude and a set of cheap tools

 

The Older Gentleman wrote:

I had a 77 KZ650 with slide carbs and an 81 KZ750 and a 82 GPz550, both
of the later bikes had CV carbs.  None of them were particularly difficult
to operate but I would say the 650 did require a little extra effort.

I agree with TOG, the problem is most likely grungy cables.  It can also
be misrouted or bent cables, as well as a sticky throttle grip tube.
Don't be tempted to "re-engineer" the system as you will invariably make
it worse.

If everything is up to snuff and you still need a little help to keep
the throttle open, I highly recommend the Crampbuster.  I have an earlier
version known as the Throttle Rocker, not to be confused with the current
offering sold under that name.  My TR is a one piece plastic doohickey
that slides over the right hand grip and lets you operate the throttle
with the heel of your hand.  It's easily adjustable and does not get
in the way of normal throttle operation.  Don't get the new Throttle
Rocker that uses Velcro to attach to the grip, it's totally bogus,
the shape is right but the Velcro attachment method is far inferior to
the one-piece design.  My old TR combines the best attributes of the
two products, the one piece design coupled with the contoured shape of
the heel rest.  The Crampbuster has a less elegant flat heel rest which
looks less comfortable to me, although I admit I haven't tried one.

http://www.crampbuster.com/
http://www.throttlerocker.com/

 



Using the heel of your hand to operate the throttle just invites
carpal tunnel syndrome pain.

 


Somebody once said that lubricating the throttle cables might cause
deterioration of the teflon inner sheathing. You might want to do some
research into cable lubricants.


I went to my local hardware store and bought a weaker spring to
replace the garage door spring on a set of Mikuni round slide
smoothbore carbs. Good hardware stores have drawers filled with
specialty hardware.


If the throttle pull cable broke at a critical moment, you could kill
yourself.