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mike_dean

Left hand throttle

16 posts in this topic

Damaged my right wrist and might be getting it fused. Looking for options on left hand throttles for the FCR carb. Was going to mount stock throttle and switch sides with the cables so it doesn't turn backwards. Has anyone heard of this? Thanks, Mike

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You could switch the cables, but you're going to have trouble with the throttle tube stop.  It is designed to stop the throttle tube from going past closed throttle in the counter clockwise direction.  (When looking into the throttle tube.) You may be able to modify it to make it work, but modifying a throttle tube is a risky move and not endorsed by me.  You don't want to find out that your modification failed you on the face of a jump, or on entry to a corner in the woods.  

 

Also, if I remember right the end of the cable that inserts into the throttle tube on the pull cable I think may be a different diameter than the push cable end.  Don't quote me on this, I may be dreaming this up, but it's something to check.  

 

Have you ever thought of a thumb throttle of some sort?  It may get you where you need to go.  Problem is I think that most of them are only single cables.   I don't know if an FCR can run on just one "pull" cable.  I know on my old KTM that had a FCR there was quite a hefty spring on the carb that would return the throttle to closed even without the push cable hooked up.  

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And the 2 cables are different, they have pegs on the throttle end so they only go on one side of the housing.

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I'd go to the "Health and Fitness" section and consult Dr. Mark about a wrist fuse before I figured out a left hand throttle.

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I use a thumb throttle on my 06 yz 450. Not for wrist issues but because that's what I'm comfortable with. Custom made by motion pro it's a single line cable and works fine. Never had an issue with it closing properly.

Anyway, I say this because I helped a few other guys do thumb throttles on their bikes because they had wrist issues...

It can be done...

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I use a thumb throttle on my 06 yz 450. Not for wrist issues but because that's what I'm comfortable with. Custom made by motion pro it's a single line cable and works fine. Never had an issue with it closing properly.

Anyway, I say this because I helped a few other guys do thumb throttles on their bikes because they had wrist issues...

It can be done...

Looks like you found the man to work with.  This is the type of topics that need to be on a forum.  Tech issues and REAL problems.  Not beauty shop gossip.

 

Hope you find a solution that works, and if you do, make sure to post an update with some pictures if possible.  With wrist injuries pretty common in this sport you know there will be someone else out there looking for an answer.   

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Actually, there is no rotation stop in the YZF throttle tube.  The throttle tube is stopped at the closed position by the closing cable.  Never tried it, but you might really be able to simply reverse the position of the two and have it rotate in a normal direction on the left side.  Take it apart and fiddle with it.  See what you come up with. 

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Actually, there is no rotation stop in the YZF throttle tube.  The throttle tube is stopped at the closed position by the closing cable.  Never tried it, but you might really be able to simply reverse the position of the two and have it rotate in a normal direction on the left side.  Take it apart and fiddle with it.  See what you come up with. 

 

What's the reasoning behind the "push" cable?  Is that just there as an added safety measure.  Why do 4T's have push/pull and 2T only have a pull.  

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Neither cable pushes.  One pulls open, the other would pull shut if the spring were to fail to close the throttle.  It's a safety measure based on the fact that four-strokes, particularly bigger ones, can generate so much higher levels of intake vacuum than two strokes that they can be capable of trapping the slide against the throttle body on deceleration, preventing it from closing immediately when released.  The dual cable isn't the only precaution designed into things with an eye toward preventing this.  The floating vacuum release plate on the engine side of the FCR slide, and the rollers on the slide itself are two other major measures taken.

 

In point of fact, the YFZ quads have only the single cable, and with the sophistication of the FCR, they don't really have a problem with it.  The practical realities of thumb throttles more or less preclude a dual cable setup on those in any case, anyway.  I know that some folks have eliminated the dual cables so they could use a large drum two-stroke throttle to quicken the opening, but I rather like the security of the dual setup, personally.

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I'd go to the "Health and Fitness" section and consult Dr. Mark about a wrist fuse before I figured out a left hand throttle.

2/3 of my lunate and scafoid bones are eroded from a staph infection that I got in the urgent care, I've seen 2 Drs. It's been 4 months now, I can move my wrist 20 degrees but the pain is unbearable, and I can take a lot of pain. Basically I need some stem cells.

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Neither cable pushes.  One pulls open, the other would pull shut if the spring were to fail to close the throttle.  It's a safety measure based on the fact that four-strokes, particularly bigger ones, can generate so much higher levels of intake vacuum than two strokes that they can be capable of trapping the slide against the throttle body on deceleration, preventing it from closing immediately when released.  The dual cable isn't the only precaution designed into things with an eye toward preventing this.  The floating vacuum release plate on the engine side of the FCR slide, and the rollers on the slide itself are two other major measures taken.

 

In point of fact, the YFZ quads have only the single cable, and with the sophistication of the FCR, they don't really have a problem with it.  The practical realities of thumb throttles more or less preclude a dual cable setup on those in any case, anyway.  I know that some folks have eliminated the dual cables so they could use a large drum two-stroke throttle to quicken the opening, but I rather like the security of the dual setup, personally.

I've seen too many people hurt on 2-strokes with the slide sticking to run 1 cable. My cables look to be specific to the side of the throttle they are mounted on, could maybe cut off the pegs and remachine housing. The carb ends seem to be specific also. Maybe some one could make custom reversed cables. Thanks to everyone for the replies.throttle yz450 007.JPGthrottle yz450 006.JPG

Edited by mike_dean

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Yeah, I forgot exactly what the throttle end of them looks like.  It would take some tinkering.  Back in the day, we used to build custom cables all the time, but you don't find too many sources for the raw parts any more.  All it would take is to remove the barrels from the top end, cut the housings back a quarter inch, and switch the two elbows at the throttle end, then re-solder another pair of barrels in place.  If the cables are stainless, though, then you have fluxing issues.

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We had a pull cable fail before. Removed the push one and moved it over to the pull one. Rode the bike the rest of the day. Rider fell and broke it. KTM 525.

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Ktm must have a different throttle and cable assy. I have an'09 ktm I'll look at that. Maybe get ktm throttle and cables

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