Push Pull Thumb Throttle

24 replies to this topic
  • ButtonFly

Posted December 01, 2000 - 04:43 PM


I cannot bear to ride with my twist grip. I broke my arm about a year and a half ago (broke both bones, snapped chunks out of my wrist socket in compression fracture, cast to upper arm, 8 weeks in it) and I can't take this twisting. I can't open my throttle all the way on my 1999 WR400 (I didn't even know it had top end... I couldn't twist it far enough), and can't ride very long without it hurting. I will come home from a ride, and move my wrist as far as it goes, and listen to it pop. Loudly. I can ride a quad all day with a thumb throttle going at it in the dunes. Are there any real reasons to stick with the twist? It is very hard for me to use... and does anybody make a thumb throttle that has push/pull cables, or can I convert my WR to just pull? This is getting frustrating... I feel like I have infinitely better throttle control with my thumb (maybe 15 years of quads will do that)... How about some feedback either way. I don't want to go to a 1/4 turn throttle. So... does anybody know of any Push Pull thumb throttles, or how to use just a pull throttle by converting the carb somehow to pull? Is it safe or feasible. I LOVE my WR, it is just hard for me to ride with the twist grip. Thanks for any help.

  • Howard_Huge

Posted December 01, 2000 - 08:27 PM


Quarter turn throttles aren't all that bad. As far as the push pull thumb throttle goes? I broke a throttle cable two weeks ago the throttle still worked so I don't see why you couldn't run a single cable at least give it a try make sure your kill switch is working just in case that sucker gets stuck wide open.

good luck, huge

p.s. sorry to hear about the arm

  • MS

Posted December 02, 2000 - 04:59 AM


Sorry to hear about the arm... sounds painful and sore.. I just recovered from ACL reconstruction surgery this past January.

I also installed a new throttle cable this week as my old one was frayed at the carb.
The only reason Yamaha installed two cables is to give the operator a chance to physically close the throttle if it becomes stuck... I looked at the carb and before removing cable only hooked up the top one... the pull cable, it worked fine as the carb has a return spring on the slide...

A friend of mine broke his wrist about 8 months ago and rides Vet class on a YZ400, and was requesting the same device you are seeking, I will check with him and see if he actually installed a 4 wheeler throttle device... will let you know either way..

  • GPS Dual Sport

Posted December 02, 2000 - 08:28 AM


BIG WARNING. Do not remove the push cable from your throttle.
4 stroke have much higher intake velocities than 2 smokes. At high RPM the slide will not return with the spring force alone. To make the spring strong enough to close the slide on worst case conditions the throttle effort would be unacceptable.
This is not BS. I worked for Honda in the Mid `80s and throttle effort was a real big deal on the prototypes. All the 4 Stroke ATVs with thumb throttles (single cable systems) have compound Carbs. with a butterfly downstream of the slide (Honda) or Street bike type CV carbs (Kawasaki Mohave).
Using a CV street bike carb on the WR would be difficult to find because of the throttle position sensor hook up to the CDI box. On top of that CV carb slides tend to slam shut when pounding through the whoops.

  • ButtonFly

Posted December 02, 2000 - 10:46 PM


Can you offer any alternative solutions? I had heard about the slide problem before, and I understand you are saying a spring on the return will have to be so big that it will make the throttle impossible to open? How does the push pull cable alleviate this, other than by allowing you to manually close the throttle? It seems like it would be VERY hard to twist the throttle shut under the same conditions you describe...

  • MS

Posted December 02, 2000 - 05:57 PM



Talked to my contact with the broken wrist, and it was a no go.... besides the safety factor mentioned, it just could not be done.

Frankly, I agree with the earlier comments, both cables must be attached for safety reasons.

Give your arm and wrist time to heal, I guess by now you have probably been told to quit riding, heck, give yourself time to heal, as your arm muscles atrophied while in a cast, do some reverse wrist curls, anything to start strengthening those muscles again.. good luck.

  • ButtonFly

Posted December 02, 2000 - 09:30 PM


This is a permanent condition... I broke it about a year and a half ago... so I am back up to strength, I just can't move it far enough regularly to be much fun... I chipped part of the socket, so if I bend it all the way over, like I would need to to open the throttle all the way it pops, and moves around in the socket. I have no pain riding a quad, it is just the twisting motion. I had heard a dirty rumor that Banshee quad throttles had an auto cutoff circuit, since they do not have push pull. In the event that the carbs get stuck open and the throttle closes, but there is slack in the cables, the throttle body has a switch that shorts the kill switch, killing the bike... can anyone confirm this? Thanks.

  • Dave_VanBrocklin

Posted December 03, 2000 - 06:28 AM


Yes, I know the Banshee and Blaster have a safety system that wont allow the machine to come off idle if both switches in the system don't make contact. It will just die at anything over an idle. The problem is that they fit on the carburetor and are very big. I can't believe they would fit in the space we have on the WR. What about a snowmobile throttle. I know that they have a safety system in the throttle lever itself that will kill the engine if you let off the throttle and the carbs stay open.I know the handlebars are the same size and I have to believe the wiring for the kill switch in the lever wouldn't be that hard to figure out. They all run similar carbs to what we run.I would check into that. Good Luck!!

  • GPS Dual Sport

Posted December 03, 2000 - 10:59 PM


About your question on the return cable. The deal is high RPM and wide open throttle the slide is surfing on the intake flow. The slide spring force is not big enough to overcome the intake flow. A slack single throttle cable can't push hard enough to help the spring close the slide. The return cable is a manual close on the slide. The surfing forces are not huge and the return cable can easily close the slide.
If you run a single throttle cable you run the risk of a stuck slide at high RPM and wide open throttle. When this happens punching the kill button will drop RPM and the spring will close the slide when intake velocity drops.
If you get creative with the thumb throttle and somehow build in a kill button you will be covered.

  • ButtonFly

Posted December 03, 2000 - 11:12 AM


Which spring are you referring to when you talk about unacceptable throttle effort? The spring on top of the slide pushing it down? I was thinking about attaching a small spring from the boss where the return cable attaches to someplace on the frame or carb, just to be safe, but am I to understand that will make it too hard to pull (or push the thumb part)in terms of throttle force? I am not sure which spring you are talking about... I want this to be as safe as possible, but also possible... Keeping a finger on the kill switch would be marginal at best. I am willing to put up with Banshee-esque throttle pull, but I don't think I can deal with much more...

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  • GPS Dual Sport

Posted December 04, 2000 - 04:17 PM


You are seeking a solution to a very difficult problem. The push pull cable system is the cheapest mass prodution solution the factory can come up with. Adding any extra spring any where on the throttle or slide will make the throttle effort higher. Your only choice maybe to build yourself a push/pull thumb throttle.
The Honda ATC 350X had a single cable throttle system that might be adaptable for a push pull cable set up with some creative thinking.
Good Luck.

  • ButtonFly

Posted December 04, 2000 - 04:40 PM


Cool, thanks a bunch. I picked up a thumb throttle today in the junkyard to play with, so we shall see. Anybody know what kind of carb the DRZ has?

  • James_Dean

Posted December 04, 2000 - 04:43 PM


Try the EKP needle or EKN for dunes. This needle has a steeper taper and delivers more fuel earlier. It takes less wrist movement for acceleration. It will be much like a quick throttle, but will still be the stock spring tension.

I know its not going be as good for you as a thumb throttle, but it might be worth considering.


  • ButtonFly

Posted December 04, 2000 - 04:49 PM


Thanks, I will try that if I can't figure something out. The DRZ has an FCR 39mm also... how does the linkage on one of those work? One or two cables?

  • kaseyc

Posted December 16, 2007 - 08:48 PM


maybe there's a four wheeler or something that uses the same carb as your wr.. just switch um, if you can find one

  • brt 426

Posted December 16, 2007 - 09:51 PM


This sounds nuts , but how about putting the throttle on the left side. If your desperate enough. I'd try it for sure. If your not racing , just trailing.
Note: I'll not be responsible for my stupid comment if you decide to try this on your own.

  • drtrcr400

Posted December 16, 2007 - 10:22 PM


The yfz450 is running the same carb and a single cable. I could be wrong but i think the only safety difference is the ignition kill device(whatever its called).

  • SID013

Posted December 16, 2007 - 11:36 PM


Have you considered a quick twist throttle arrangement which has different cams? It may be possible you can fit one which means you don't have to twist the throttle as far as you do now. The link below might help.


Cheers from Oz

  • tweav

Posted December 17, 2007 - 03:54 AM


Why not just put the twisty on the left side ?????

  • tweav

Posted December 17, 2007 - 03:55 AM


Why not just put the twisty on the left side ????? then maybe a slipper clutch


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