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This is an easy little mod that will help reduce thumb fatigue. I’ve done this mod on all of my FCR’s and have helped a few guys do theirs also. So I thought I’d do a little write-up for others that are interested. On a scale of 1-10, this mod is a 3 on the difficulty scale.

First off, don’t attempt to do this while the carb is still on the bike. There are too many small parts, and a loose part flying around inside a carb can be very dangerous.


To get started, you must first remove the top cover.





Next, you’ll remove the screw that secures the link arm to the throttle pivot shaft.





With the bolt removed, the throttle pivot shaft should simply pull out. Note the return spring attachment and the placement of the two washers. Clean up the shaft and assorted parts. Set these parts safely aside









Now for the mod, Use a 1/16 drill bit and drill a hole thru the idle screw bump stop, this will be the new throttle return spring mounting location.



By doing this, the spring will now have 90-120 degree less preload. Standard location preload is around 270 degree’s.

 

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That’s it! Now it’s time for re-assembly. But before you do so, take a second and add a little grease on the throttle shaft needle bearings. I just put a little on a toothpick and dab it on.







Now reinsert the throttle pivot shaft back into the carb, make sure the spring tab is in the correct place on the carb body. Getting all the throttle-valve parts lined up takes a bit of fiddling, but once they are arranged, the throttle shaft should easily slip through the freshly greased bearings





Also, make sure both washers are in place on each side of the link arm.





Be sure and use Loctite on the set screw!





Install the top cover and that’s it, here is the finished product. You won’t feel a huge difference in the throttle tension, but you’ll know the difference at the end of the day when your thumbs not aching.

 

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After all that why is your beer still full?[/b]
i was just going to ask the same question
 

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After all that why is your beer still full?[/b]

Ha-ha, We have beer on tap at my house. The mug never goes dry!
 

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if u want a little more "softness" to the throttle you can also bend the end of the spring back a little to take a little more preload off of it when its assembled, ive done the mod that posted and bent the spring a little and its perfect for me
 

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i modded mine a little different i cut the throttle spring exactly 180° of rotation and removed the spring from the throttle housing itself

but either way is definatly worth doing
 

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Awesome write up Mark.... I figured that was the case with the brew........ and were you workin on that thing in your kitchen? Looks like marble counter top, unless you have marble in your shop... lol
 

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Awesome write up Mark.... I figured that was the case with the brew........ and were you workin on that thing in your kitchen? Looks like marble counter top, unless you have marble in your shop... lol[/b]

Yep, it was the kitchen table. The carb was empty, and clean and it was cold out in the garage! LOL
 
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Awesome write up Mark.... I figured that was the case with the brew........ and were you workin on that thing in your kitchen? Looks like marble counter top, unless you have marble in your shop... lol[/b]

Yep, it was the kitchen table. The carb was empty, and clean and it was cold out in the garage! LOL
[/b]
thats what the counter is for. but that is a good idea. im going to have to give it a try.
 

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That is an awesome way to do it!!! Have you ever had the FCR stick though??? When I first decided I didn't ned 2 cables on my CRF250 I was at a loretta's qualifier at the Shoug and I had that bizniggle stick wide fn open over the chucker. Not fun, I realized that the vaccum on the four strokes was enough to stick a carb at times. Not fun when you come over the backside of chuck son and your still 30ft in the air with your bike about to blow up. Oh ya it can be bad not having anything to return the throttle to closed...
 

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That is an awesome way to do it!!! Have you ever had the FCR stick though??? When I first decided I didn't ned 2 cables on my CRF250 I was at a loretta's qualifier at the Shoug and I had that bizniggle stick wide fn open over the chucker. Not fun, I realized that the vaccum on the four strokes was enough to stick a carb at times. Not fun when you come over the backside of chuck son and your still 30ft in the air with your bike about to blow up. Oh ya it can be bad not having anything to return the throttle to closed...[/b]

No chance of it sticking doing it this way. This is by far the safest way. You won't feel a huge difference in throttle stiffness. But you will feel the difference at the end of the day.
 

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Discussion Starter #19
Thanks Jake!
 

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Haha when I had my bike torn down i decided to do this mod. If you have the stock FCR that came on a quad you cannot do this... Only way is to cut a section out of the spring itself and re-bend it.
 
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