throttle discovery

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Old 10-25-2012, 05:02 AM
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Default throttle discovery

Well made the trip across Texas without much issue on my 09sf (besides my *** feeling like it got hit with a 2x4). Ran into a problem with my throttle about 50 miles before I got home, snapped the throttle cable randomly. Jerry rigged the other throttle cable into place which gave me up to 6k rpm's, roughly 60mph which is too slow for the highways out here so I decided to just reach down to the carb and operate it by hand.

Before the cable broke I could not get the bike over 82mph on flat road. Working the carb by hand I was able to go above that without issue, hell could take the bike up to redline in 6th gear with ease. Does the stock throttle cable on the 09 and up bikes not allow for full movement of the carb?
 
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Old 10-25-2012, 11:24 AM
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hmmm..... interesting.
 
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Old 10-25-2012, 01:40 PM
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Yes that is interesting.
Yamaha puts in a Longer set screw on the Off Road versions of the WR models to limit full throttle for emission purposes. You have to either cut the screw or buy an YZ screw. I wonder if there is a block or set screw in the hand throttle itself?
 
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Old 10-25-2012, 03:18 PM
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So that is where the Mikuni carb gets the extra boost, it goes to 11!
 
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Old 10-25-2012, 03:52 PM
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You were crouched on your bike, wasn't you? Maybe you was just offering less air resistance than you do when sitting strait up???
 
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Old 10-25-2012, 04:40 PM
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i actually carry a complete cable replacement for throttle and clutch for long rides...certain parts like clutch and throttle cable assembly, spark plug, all bulbs, few bolts and nuts, zip ties, etc. i keep spares at all times...usually pick up complete clutch and throttle cable assembly on ebay from total loss klx250s/sf for super cheap...like $10 each...
 
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Old 10-25-2012, 04:44 PM
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Originally Posted by DustyCowboy
You were crouched on your bike, wasn't you? Maybe you was just offering less air resistance than you do when sitting strait up???

That is what I thought about also. But it would be nice to know if there is a restriction in the throttle movement.
 

Last edited by cmott426; 10-25-2012 at 05:08 PM.
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Old 10-25-2012, 04:51 PM
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Okay, who's taking their carb off next to check this out?
 
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Old 10-25-2012, 06:49 PM
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Originally Posted by IDRIDR
Okay, who's taking their carb off next to check this out?
Mine's off right now setting on the workbench after installing the TM36. What exactly do you want to know? Not sure what inspecting the carb will do in light of what the OP is describing. I'm kind of thinking the OP may have had too much slack in the pull cable.
 
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Old 10-25-2012, 07:29 PM
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Originally Posted by TNC
Mine's off right now setting on the workbench after installing the TM36. What exactly do you want to know? Not sure what inspecting the carb will do in light of what the OP is describing. I'm kind of thinking the OP may have had too much slack in the pull cable.
From what I recall, turning the throttle assembly from the outside of the carb opens the butterfly valve fully. It stops at full open. Can you check that? Is there any set screw or other mechanism on the carb that stops the full-open condition? So, it would be fairly easy, I'd think, to twist the throttle full open, then check to see if there was any more turn available on the carb pull assembly to check for slack in the pull cable or some other issue.
 


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