How do I lighten up my throttle at the twistgrip?

[steve hawkins]

That is what I am saying, you do not have to Rob.

Steve H

[Rob Valdez 79 R65]

Oh, but Steve, see how shabby this is!


click for more photos

[mikethebike]

I took my throttle apart to grease it and when I put it back it was as you described in your post. The thing was very difficult to twist and sticking with open throttle.  I realised that I must have disturbed something so I pulled it apart again.  The first time that I put it back (as per manual) I looked for the marks to line up on the gear which "pulls the throttle chain". I had mistaken the casting mark for the line.(DOH!) I cleaned the grease off to find the mark and then realised that the lining up mark on the twistgrip is actually on one of the teeth. I lined up the marks, refitted the top and "Hey Presto" it all works beautifully again.  Maybe you should check the alignment marks are in the correct place.
Mike

[Sunbeem]

Hi Sue,
I got my first BM recently, a '78 R100 RS, which had been converted to the handlebar brake reservoir, with two throttle cables . The action felt like I was grinding walnut shells in a peppermill.
I replaced the moving parts, and made new cables, and now things are smooth, but still very
heavy on the wrist.
I confess to using bicycle gear cable materials, and I suspect friction may not be as important
in that application. The proper cable outers are lined with something like plastic, which I suppose
eventually wears through wherever a bend occurs.
Ironically, this is the mechanical equivalent of "Tennis Elbow" a painful condition which makes a
heavy throttle particularly unwelcome.........
On the Airheads website a spring device inside the handlebar is described, it's a simple job, though
the spring should be chosen with care, my attempts didn't come to much, and the idea makes me slightly apprehensive!
So maybe we both need to look at those cables?

Best Wishes,
Sunbeem.

[steve hawkins]

Oh dear my new R100 has this single pull throttle arangement and it is as stiff as....well you know.

Next job will be to solve this issue.

But I can see already that I need a new twist grip as there is some play in it.

Having a throttle that will return to the off position unaided is an MOT requirement.  My bike will currently fail.

R65 Cafe Racer is very smooth and light in comparison as it is the 1979 twin pull as mentioned above - so I now know what you are all talking about....

Cheers

[suecanada]

I see that I never got back to the Forum on this issue!! Wonder why??  Anyway, I decided to take all the cables and distributor right off one day before I left on my trips south and west. Noting of course the routing!!! I poked and prodded what I could to test the thing off the bike so:
What I found was that the NEW single cable that goes to the handlebar twist was very hard to push and pull it in and out when attached to the piston/distributor. I then isolated it (took it out of the distributor) as well as the bottom two cables. (The bottom two cables could move the piston within the distributor and they could be pulled in and out easily when not attached to anything.) So I concluded the piston WAS NOT the problem and neither were the bottom two cables.

This leaves the top single cable.... even when isolated one had quite a time moving it in and out within its sheath!! I even tried to dribble some oil down it against all the rules to no avail.  SO I put the original cable on!!! (The original cable wasn't looking bad at all and served as a good comparison. ITS cable moved very freely within its sheath!!!  I dusted some dry graphite into the distributor and put everything back together. I even took the throttle tube off and cleaned off the handlebar and greased with a lighter oil/grease mix.  Checked lube/alignment of gear at the throttle cam and screwed everything back down.

Conclusion...new parts aren't always perfect and don't always work!  The throttle isn't as snappy as nhmaf's Tillies but it certainly is a huge improvement!! Returns pretty well. I am happy for now but need to remember to order a "new" spare upper throttle cable!!

[Justin B.]

Hmmm, can you send the "new" cable back for exchange?

[steve hawkins]

Looks like I have every chance of getting away with a 'clean and lube'.

Something to bear in mind when I have finally managed to release the carb balancing screws.....to enable me to use my 4$ balancer - which I am a fan of.

Cheers for the update.

Steve H

[bjamesw]

This is a another opportunity for me to flog one of my favorite tips.    I keep on hand a decent selection of electronic type black shring tubing with internal adhesive/sealant.   The one into two junction of the throttle is one spot that benefits.   Keeps the elements out once you've got things working perfectly.   Service is no prob cause you just scissor it off and put new on afterward.  Actually the best way to remove this stuff is with one of those hook blades that goes in your Stanley utility knife.

I've put this stuff on a dozen or so places on my bike and it's amazing.   I always seal electrical connections,  spark plug to coil connection,  vacuum line connections, etc.  It's also great for building up strain relief, esp where the choke and throttle cables connect at the carb.   I swear this stuff was made for motorcycles!

Don't look in Radio Shack.   You have to go to a real electronics supply for the heavier walled internal adhesive grade.

Oh, and steve...   i'm now a convert to the four dollar balancer as well!    My variant uses aquarium tube (i just knew that thirty foot bag of random tubing that I picked up at goodwill was gonna come in handy).     I took a 2 X 36 X 1/4 oak stick and painted it white with black lines across every half inch.  Drilled holes along both sides every six inches and secured the tube with the tiniest zip ties I had on hand.    I tried 2cycle oil first but it was just too heavy.    I cleaned that out completely and tried 7W fork oil (tinted a deep blue).    Must say I had my doubts that anything this easy could do as advertised but I balanced the vacuum from idle all the way up to about 4500 and WOW.   I've had this bike for almost twenty years.  This is the first time it's been so sewing machine smooth out on the road.  

I've heard reasonable objections to the method.  Especially that vacuum alone is not going to accurately take into account mixture, spark, etc.  I'm nowhere near a 'mechanic' or engineer but I realize that vacuum/combustion/spart/mixture/etc are going to be a new ballgame depending upon whether the motor is spinning freely in the shop, or pulling a motorcycle and rider down the road.

Say one EXACT throttle position gives you exactly 2500 rpm on both cylinders while the bike's on its stand.  When the motor is pulling the bike and rider into the wind,  that EXACT throttle position may not balance nearly as accurately between cylinders because operation under load makes different demands on spark strength (for instance) and mixture and other conditions that may not be mirror perfect between the carbs.  

I'm not convinced that 'static' methods of tuning via single cylinder rpm spotting is therefore superior to doing it with the diy manometer.   While the jury's out,  I'll do it this way from now on since it's so damn easy, and I'm so impressed with the results on the road.  

[Justin B.]

I've read that some folks strap something similar to the bike and tweak the cables while under load.  Sounds like a lot of work...

[Mr_Smart]

Dont forget Tony Heyman`s rather splendid modified Bing Springs...well worth fitting and at very modest cost too  

Tony can be found at :

channelcat57@yahoo.com

www.canbeseen.com/10

Have a read her for more info:

http://www.airheads.org/content/view/277/98/


Its all in the wrist action I reckon !!!