Throttle
screws; friction & anti-friction devices; Snowbum gets OFF
and RUNNING!
©
A DIFFERENT viewpoint?
throttlescrews,etc.htm-8
Are throttle screws (throttle locks) a good or
bad idea? What about ThrottleRests?
Many use a throttle lock or friction device, or the stock BMW
friction screw (on some models) to ease hand forces whilst on the
road for long distances, some use them for tuneup purposes,
etc. I have used all sorts of these devices, and even
have a pet conversion method that is 'different', an
anti-friction, reverse spring method, described later
herein.
There have been two of these reverse spring devices sold commercially in years past....one was called the Twist Assist....did the same thing as mine, just different method of attaching and adjusting.
I have found that the simple, inexpensive,
ThrottleRest is a good item, and I like the product. ONE of
the secrets of using these.....or, just using the stock bars
without any such devices, is to have leave a V between
thumb and forefinger, and not have too strong a thumb grip on the
bar twist. In fact, in some situations, as on dirt, trying
to manipulate a throttle ever so gently, one might put the thumb
over onto the metal of the assembly, as a 'steadying
rest'.
While I have nothing against friction screws and friction clamps,
and reverse springs...be aware that they are potentially
dangerous in a get-off.
Be aware of all the ramifications....read on!
So....here.... I will relate my own involvement with the little
knurled BMW friction lock screw, ETC. and add some information
about some, not all, types of devices.
This little adventure happened in 1985.
I will NEVER forget it. Even today I smile when I think of it.
Luckily for me it turned out OK. I not only had the stock
BMW friction screw lightly tightened to
where it was adding some noticeable friction (although not enough
'on its own' to hold the throttle at any fixed point); but,
I had another device I made up and installed. NOTE that
just a throttle lock or use of just the friction screw is LIKELY,
if a bit too much is used, to have the SAME effect...the
throttle will NOT return to the idle position on its own, when
your hand is removed from the throttle! If one uses
it at all, the use of only a wee bit of the friction screw is
preferable, to allow the throttle to return to idle.
Preferring a light action on the throttle control, I had near new cables, silicone greased carburetor throttle shaft O-rings, smooth operating T adapters, proper cables routings, and had made up and installed a special spring device. This spring was several inches in length, inserted into the end of the right end of the handlebar. The bar tubing, not the throttle tube, was drilled and a roll pin installed into the BAR (only), thence through the inner eye of that spring, and back to the bar wall oppositely. The outer, right end of the spring, was fastened to an adjustable screw/nut/large washers, that clamped onto the END of the original closed-end throttle rubber grip. Thus I could have a considerable amount of the turning friction forces eliminated...that is.... the spring could be 'anti-wound adjusted' for almost any amount of 'help'. It was possible to adjust it so much that the throttle went wide open if you took your hand off it. I never used it like that, of course.
Some of the throttle forces come from friction in
the cables and the throttle assembly, but far more are from the
springs at the carburetors. By the way, BMW used
nylon to line the inside of the cables, all, from about 1977 or
so, and they are not to be oiled. The same
throttle friction and other devices, can be used on other BMW
models, such as the K bikes....which have different sort of
return spring setups.
The friction or spring action is severe in some of the old
/5...(models having springs OVER the cable ends at the carbs are
the worst). The /5 can be modified for smoother
throttles, by eliminating the springs over the cables, making up
something that operates like the later carburetor levers and
springs. ...(without changing the carb tops, with some
work).
The effect, as far as this story goes, is the same, whether the
knurled nut is used for friction, or a locking device lever, or
my device, or both, in operation.
In the early days of my riding with this setup, I never ever gave
any thought to safety. It never occurred to me that the friction
screw, or my anti-spring, could cause ANY problem. That
sort of thing comes about from NOT THINKING about changes versus
consequences.
So, in 1985, on the first of September, amidst a
serious bout of Early Winter CabinFever, I made a 10 minute
decision and a 10 minute packing-up, and jumped on the bike,
leather race suit and all, and headed for Oak and Tiger's home in
the Chicago area, to annoy him, and to probably annoy Tiger. I
have, over the years, annoyed Oak a very considerable amount, and
probably also annoyed Tiger.
Not exactly a short ride from Lake Tahoe, California. Warp 9,
Highway 80 superslab. Got an $5 'energy' violation in Nevada for
using too much fuel....think I was at Warp 9.5 at that
moment. I hit warp 11 or 12 for LONG stretches. A G/S
at WOT did not keep up with me....he got a energy violation along
with me....and I cooled it a bit so he could stay up with
me. Yes, I was 'cruising' for HOURS at over ...well
over...100 mph.
Once in Chicago, and pestering my put-upon hosts, we all left,
Oak and wife (Tiger) on his bike, pulling his camping trailer
(!!!), and me on my R100RT, to attend the Land Of Lincoln
Rally. On the way to that Rally, it was raining cats,
dogs, and elephants. There was a LOT of standing water on
the roads. We were, as Oak remembers some of these details
better than I do, on Sauk Trail, mostly doing warp
speed. Oak and Tiger made it through 'my' traffic
signal, this was pretty much in the boonies....and they
were quite far in front of me. I was slightly more
cautious (us California riders seldom even know what rain is, and
I am sure I was thinking of my tire tread depths, and I NEVER
ride in deep heavy rain, NORMALLY, at over 40 mph, to avoid
aquaplaning).
As I slowed for the traffic light in the middle
of nowhere, I probably used a tad too much rear brake for
the 1-1/2 or 2 inches of standing water on the road. Maybe.
NO excuses, really, I was traveling at a high rate of speed,
trying to catch up to Oak and Tiger...who were barreling along
pulling their TimeOut Camper trailer at their usual...ah...
speed. At that traffic signal that THEY made it
through, I did NOT.
I became an aquaplaning missile, or a rear tire friction deprived
rider...some such...so to speak. The bike and I came to a
reasonable square and upright ...and almost a stop.... at the
proper place for the red light. FOR AN INSTANT.
The bike then continued into the intersection
withOUT me!, but the bike was now on its left side valve cover
and lower left edge of the left side BMW Tour case. The throttle
was not about to reduce to idle by itself. The bike decided it
was time to prepare a special, just for me, edition of fun and
games, and proceeded into the intersection, where it began
turning left doughnuts in a fairly tight diameter
circle.
As the bike left me, or, I left the bike...I was on my feet....
running. I was NOT, at that moment, trying to run. I was
running FAR FASTER than a 4 minute mile...for about 30 feet. My
boots were skiing AND moving to and fro, and I was UPRIGHT! This
was, and still is, hilarious, but the bike was spinning like a
top. The side of the rear wheel still had just enough purchase on
the wet road to keep the bike moving. The bike was moving a bit
too fast, I thought, for me to jump in and use the kill switch or
reduce the throttle. At least it looked that way. I
had no intention, at first, in having many hundreds of pounds of
something run into me.
A car stopped. Driver got out. We are both laughing, and also
trying to figure a way to stop the damn bike. We began by running
in a circle in the same direction as the bike, with decreasing
radii. With the water on the road this was, again,
hilarious. I only wish I had movies of
this. Finally I caught up just enough (I jumped onto the
pile of moving bike, to tell the truth) to shut off the engine.
I learned my lesson. Well, maybe not. In any event, at least as
far as throttle springs and friction screws go?? WELLLL....
I still use them, now and then. BUT...I don't set them up for
zero return force. Never in traffic, never on wet roads. I guess
I have not truly learned all my lessons here, but I rationalize
it by having SOME return spring action.
The damage to the bike was hardly noticeable...due to all that
water acting like a lubricant I suppose. I refuse to get into the
crash bars controversy, it had none of those, and I am not sure
what would have happened if it had them.
On this trip, Oak and I refueled with what must
have been Winter blend of gasoline. My R100RT was not
carbureting too well. Oak's K100 had boiling fuel in the
fuel tank, and was acting up a lot.
OH....the 'Land of Lincoln BMW Rally' was nice, small, a great
group. On the way back from that Rally (Starved Rock
State Park), we went by a different route, which Oak remembers as
Beecher Peotone Road. We raced a storm back to Oak and
Tigers house. It was bright, sunny, and QUITE hot.
Oak remembers the sky being painted in two colors, and towards
the East, clear blue, towards the West, pitch black....SOLID
BLACK. So, Easterly we went, at a VERY high rate of
speed, indeed, racing that storm....to I-57, then North to Monee,
then off and back roads to Oak's....and quickly into the
garage...and then, the storm hit. We never had time to get
into the house....we were, as Oak says, 'trapped' in the garage
until the storm passed. Never got rained on, missed that
deluge by seconds.
BMW offered its own friction devices. The primary
usage was originally for setting the throttle, for such as
adjusting the carburetors; but a secondary purpose was to relieve
some right hand stress. It has been, over the years,
on various models at various times. Sometimes the throttle
assembly was not drilled and tapped for them. There are
some variances, and the part number for the knurled screw with
its spring (the knurled screw has a nylon or similar hard plastic
tip, which works nicely against the throttle tube), is:
K bikes: 32-72-1-454-414
Airheads: 32-72-1-230-874
The above parts are obsolete, but some may well be found.
http://www.schneidersinc.com/flip_a_lever.htm
These folks make the fairly popular adjustable lever
type....and they can drill your housing if yours is not drilled,
ETC. Schneider's Inc. 43B Mullan Rd. West;
Superior, MT 59872
http://www.schneidersinc.com
There are other sources for various types of these, including CC products in California.
Your BMW dealership may well have a number of types in stock.
***Note: I LIKE the Throttle Rest (the name
I give to BOTH of the products, which are similar but not exactly
the same), a simple piece of plastic, it makes for lots less
effort on my hand. They work pretty well, although some may slip
some on some types of grips, without a layer of tape underneath.
Two companies make these sorts of things, and you often find them
at BMW dealerships. I use
them on all my BMW bikes.
There was some sort of lawsuit over this product, Throttle Rest
versus Crampbuster folks...I don't remember the details.
The Throttle Rest (two words) is still available...do a Google
search.
The other version, they say there's is the patented original one (??)... is the Crampbuster www.crampbuster.com 1-800-735-5240
Another such palm rest type unit is the Wrist Rest, from WolfTrax, etc.
There is also the Throttlemeister's, which have substantial weight, look fancy, cost more, and can work well on reducing vibration, and are easily adjustable for friction amounts. I have a set on my K1100LT. (414) 464-6060, FAX (414) 464-9423; www.throttlemeister.com; Marker Machine, Inc. 5240 N. 124th St. Milwaukee, WI 53225. These also can replace the stock BMW weighted bar ends on those models using them.
rev.:
09/21/2005: updated to exact information on
the Land Of Lincoln Rally, roads traveled, weather, etc., in the
sections on me in Illinois, and spinning in the road, and
returning to Oak's house. Minor typos and clarifications in
other areas.
01/26/2008: add information at end of article