Topic: modified throttle, shorter travel way ?

[Viktor.J]

Have anyone modified the throttle ?

My throttles "travel way" is estimated (by me) 110+ degrees and its not comfortable to ride with the wrist twisted 90 deg.
Any one tried to modify the "throttle grip" so the travel way gets shorter ?

I will try to explain 

Alternative Original:
original throttle gripp (i dont really know the numbers) but lets say the throttle has a radius "R", thickness "t" and the throttle cable moves 1 mm / degree (twisted throttle) .



Alternative modified:
thicker "t" => bigger R , throttle radius so the throttle cable moves 2 mm/ degree hence total travel length is 80 degrees ?

The numbers fictional but the principle is the same.

Well, for every added 1mm to the throttle grips radius, the "mm throttle pull/degree twist" ratio increases with 0,017, the question then is, how much can you modify (increase the radius) before the throttle cable interfere with the "switch house"  ??

Any thoughts ? recommendations ?

[liPPy]

http://www.venhill.co.uk/Controls_and_Levers/MOTORCYCLE_CONTROLS/TWISTGRIPS/888_VENHILL_FAST_ACTION__PUSH-PULL_TWISTGRIP.html

[Viktor.J]

http://www.venhill.co.uk/Controls_and_Levers/MOTORCYCLE_CONTROLS/TWISTGRIPS/888_VENHILL_FAST_ACTION__PUSH-PULL_TWISTGRIP.html

Thanks, but the question wasnt really if i could find another throttle with shorter "pull"
I want to modify the one that i have, cheaper and stock look

[LesterPiglet]

If you could find something suitable to modify the diameter of the throttle tube where the cable wraps around that would work. I have a spare tube, I must look into this.

[RickB]

I have a similar problem with my CB400F. I changed from bulky cafe style grips to slim GP style grips. Now I have to 're-grip' if I'm at full throttle. I like the stock switch/throttle assembly and would love an ingenious way to make the twist quicker other than using a bulkier grip.

[Viktor.J]

I dont have my stuffs here.. anyone know how much space in the "switch house " => how much you can build up the throttle hence get a bigger lever arm, or any internal measurements  ?

worst case i guess you'll have to some turning in the switch house if there's enough material.

[lucky]

They have made 1/4 turn throttles since 1950's.
Just go to the dirt bike catalogues.

Street bikes have 1/2 turn throttles and racing motorcycles generally use 1/4 turn throttles.
And it all started with 7/8 diameter handlebars too so you are in luck.

One more thing. Almost all of those plastic throttle sleeves fit most switch housings.

End of problem.

[lucky]

I have a similar problem with my CB400F. I changed from bulky cafe style grips to slim GP style grips. Now I have to 're-grip' if I'm at full throttle. I like the stock switch/throttle assembly and would love an ingenious way to make the twist quicker other than using a bulkier grip.

Just buy a 1/4 turn throttle sleeve and put it in your switch housing.
Not a big deal.

[RickB]

I think Viktor wants to keep the stock switch/throttle assembly, so that would mean a modified tube, not the whole throttle assembly. I wasn't aware there were 1/4 tubes, so thanks for bringing that to my attention.

Something like this perhaps?

http://canyonchasers.net/shop/sv/R6-throttle.php

Rick.

[RickB]

There's some great pictures and walkthroughs here too Viktor, I think this will answer your question:

http://cbrforum.com/forum/f4i-main-forum-11/want-more-oomph-1-6-quick-throw-throttle-mod-must-see-****-132894/

If you try it, be sure to report back!

[Viktor.J]

I have a similar problem with my CB400F. I changed from bulky cafe style grips to slim GP style grips. Now I have to 're-grip' if I'm at full throttle. I like the stock switch/throttle assembly and would love an ingenious way to make the twist quicker other than using a bulkier grip.

Just buy a 1/4 turn throttle sleeve and put it in your switch housing.
Not a big deal.

The switch housing have this extra space ? i mean for a 1/4 throttle you would need a bigger "throttle radius"..
But if there place in the switch house, then everythings cool..

There's some great pictures and walkthroughs here too Viktor, I think this will answer your question:

http://cbrforum.com/forum/f4i-main-forum-11/want-more-oomph-1-6-quick-throw-throttle-mod-must-see-****-132894/



If you try it, be sure to report back!

Great thanks !

That was exactly what I thought of doing, the question now is then what the measurements are inside the switch house. As earlier mentioned i don't have the housing here, so if someone have easy access you are welcome to measure it for me

[bjbuchanan]

Increase the radius where the cables attach. Take thin wire and wrap it to increase the radius where the throttle cables ride. If you want you can hog the innards of the switch a little to make some clearance. It will reduce to an extent the needed "twist" due to a larger radius where you want it, not where you sometimes get stuck having to apply it(i.e. grips)

[RickB]

Did you have a chance to see how much room you had to play with inside the housing Viktor?

[bjbuchanan]

I'm a fan of epoxies so I would say jb weld and would build up the circumference of the throttle tube plenty oversized and the file and sand to take it down to how I would like. I don't mind hogging out a stock switch because mine were a little beat up anyway. It seems to me like a little 3 beer project to try it out

[HondaMan]

Also try a lighter return spring: this helps.

[MRieck]

I have used R1 sleeves in othe bikes.

[Viktor.J]

Did you have a chance to see how much room you had to play with inside the housing Viktor?

No, the bike is 200 km away, and i have a lot in school now so I can't find the time
But maybe next week.

Also try a lighter return spring: this helps.

In what way ?
At first thought i can't se how a lighter return spring (<Fs) would change the travel lenght of the throttle cable, in another way then that the weaker spring dont have the power to return the throttle gripp to start. pos.

[DJ_AX]

It's on my list to modify the tube. I'm going to try the wire (plus some JB weld maybe) method.

Also try a lighter return spring: this helps.

This makes sense... as the twist distance (twistance?) is reduced it'll require a little more wrist.

[lucky]

Its plastic it can be modified.

[lucky]

If you work on bikes long enough you will see good throttles with different "ramp" configurations for the throttle.

[DJ_AX]

If you work on bikes long enough you will see good throttles with different "ramp" configurations for the throttle.

I like it!
As a kid, I've built lots of ramps!

[BuffaloBill]

How about leaving the throttle tube stock, and using a smaller radius pulley on the carb shaft?
Bill

[Dimitri13]

When I had my Ninjette, a common mod would be to put a zip tie on the area where the cable lies on the throttle tube, making the diameter larger.

[bjbuchanan]

How about leaving the throttle tube stock, and using a smaller radius pulley on the carb shaft?
Bill

I think that would probably be the hardest way to go about it. Not knocking you but its prob true

[BuffaloBill]

How about leaving the throttle tube stock, and using a smaller radius pulley on the carb shaft?
Bill

I think that would probably be the hardest way to go about it. Not knocking you but its prob true

You're right, it would be more involved.  It'd be handy to have a lathe and milling machine for that project.  I'd think there'd be a market for an after market kit including a new pulley and cable mounting bracket.  What would be the optimum amount of ratio change be? 30% less rotation at the grip or so?