Handlebar Throttle Tube

[tagordon]

Having tried a used part. That was received with the same damage as my original part. I ordered a new OEM replacement part.
The contruction of which is different that the original. Just sharing this info with all FWIW.
My throttle is notchy. Once past the initial 5-10mm movement from idle it is fine.
Inspection showed damage to the teeth on the tube. The disfigured teeth still function, but not smoothly. Bought one on eBay fairly cheap. Seller said it was fine not excellent. I did not specifically ask for details of the condition of the teeth.
It arrived exactly as the one I have.
So I chalked it up to buyer's remorse.
Live & learn.

Moving forward:

The new throttle tube has two mateials in its construction. Appears to be an insert of sorts. Appears to be the same machined end that mates to the cam & chain to pull the cable. But the reainder of the tube appears to be synthetic/ABS/Black unknown material(read plastic). The tube came with a BMW hand grip already glued to it.
I have tour master sticky grips installed presently.
So now I can either cut it of or order the BMW one for the other side.
Probably will order another BMW grip.

Anyone else have this condition with the throttle? I did not wish to ask untill now as the second tube is the same as the first tube. I figured a hard drop caused this on my bike. May the other bike had a hard down also. Or is it a characteristic wear condition?

[Ed Miller]

By "notchy" do you mean that you can feel the gears moving against one another?  I can feel that, but it doesn't bug me.  I have to say that is one weird throttle set up, though.  But it works.

[Justin B.]

Maybe you can dress the "teeth" with a jewelers file?

[airhead]

The teeth on the cam and tube are very similar material and do eventually wear, particulary in a pattern that makes them look disfigured, especially in one general area, where it usually lives at mid throttle.
They should be a part of general maintenance greasing to help prolong life and smooth the action.
When buying parts, as with most gear/cog mating arrangements, it is false economy to just buy one mating part as the other worn part will rapidly wear the new part as well. Buy both parts for best feel, life, performance.
Did you correctly line up the two parts? There is a mark on both to line up at the start of travel.

Bill...................;-)

[tagordon]

Thanks for the replies.
Bill especially, for reminding me that I should replace the cam & chain as well.
By notchy I mean, it hits a particular spot & will not smoothly pass that point.
Considerably more torque is required to continue opening the throttle.
Thanks again all; for the replies.
Troy

[tagordon]

Ed,
This setup is better as far as the pull is concerned.
I remember some awfully long pulls on the direct linked cable setups from the past. You know the ones that look like you have a doughnut stuck on the handlebars.  Note to self: Order cam/chain & grip for other side.

[Ed Miller]

I spoke too soon anyway.  Friday on my way home from work, the bike's revs wouldn't drop down quickly when I let off the gas.  I've cleaned up some other stuff in the linkage, but it looks like my gears are in bad shape too, so I will also be ordering a gear set.  I don't want to wait until several of them break off on a long ride.  

After cleaning the gears the throttle goes back off more easily, but I'm wondering if I didn't also have too MUCH grease in there, so that it was interfering with the movement of the chain.  I used moly grease.  The cables, which are only a year old, all moved freely as did the carb throttle mechanism.  I was wondering at first if both my throttle return springs had broken.  

I still have the original throttle on my Bonneville and it works fine.

[tagordon]

Ed
Be advised that BMW redesigned the cam.
You may need a new top cover also.
Visit Bob's BMW parts catalog for the info to tell if you need a new cover.
There's description of what to eyeball on the one you have; to tell if you can reuse it.
I have an 81 also & I think mine is still usable with the new part. But check yours.
Restocking fees sure add to the final price of the correct part.
Troy

[Justin B.]

If you greased the inside of the tube, and end of bar, that WILL definitely hinder free return of the throttle.  I use synthetic motor oil and it seems to work great and confine the grease to the gear mechanism.

[not-so-fast-ed]

My book says Lithium Grease.  But just on the gear assy.  Don't grease the twist grip handlebar cover.  I did and it slowed it down.    

[Bob_Roller]

If you can hold off until tomorrow evening to order the throttle tube, I might just have the reciept from when I purchased mine about 8 years ago, may be some old stock still available without the grip 'glued ' to it, if you can find the correct number.

I'm at work as usual, until 11 pm tonight, so it will be 6 pm Monday ( which is my 'Friday'), until I can search for the number.

If you have the original throttle cam and cover, it won't work with the new cam, the 'hole' in the middle of the cam is about 1/4 inch larger in diameter, than the old one, and it won't work, I tried.

I've always 'gobbed' the grease into the throttle cam and chain area, and it never seemed to cause any dragging on the throttle movement.

I used Molykote 33 extreme temperature grease, no viscosity change from -44 F. to 400 F.

[suecanada]

So I gotta remove that grease (moly) from the handlebar and inside of tube....hmmm, thank you!!! I just figured greasing evrything that moved was a good thing!!  NOT!

My original top lid for the throttle mechanism couldn't be reused as it didn't match the "new" innards. Costly in the end but worth it. Worth it once I remove all that grease from the wrong place, that is! Always wondered why nothing felt better and I had ordered some lighter throttle springs but they were useless....now I know why.

[Justin B.]

Greasing doesn't bother me as I always have my throttle screw cranked down.  BUT, the first time I serviced Barbara's bike I "greased the tube" and caught all kinds of heck for it because the throttle was very slow to return to idle position without "help"!  That was when I found that synthetic motor oil allowed the throttle to return crisply on it's own...

[milkman]

I fuond a problem though with heavily gerased throttle tube gears, that the gerase was forcing itself through the tube and inot my new grip, so when its warmer my bloody grip keeps sliding half way off.

Very annoying on a long trip.

Before my tube gear teeth wore off on teh first two teeth, it started to stick at 1/4 throttle, and I had to really pull it to get past it. Then it "gave way" and now deons't grab until teh third or so tooth - so I have free play before te throttle activastes -  a bit annoyig in cold weather idling, but I alomst forget abut it now. (repair kit on teh way)

[Bob_Roller]

I found my invoice from 8 years ago, and the 8 year old part number is the same as the current number listed on the on-line parts sources.

So it looks like I can't help out on this one !!

There's not much you can do to repair the teeth, as it's a soft cast material.

Can you post a picture of the currently available part, as I'm curious as to what it looks like ?