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Post Info TOPIC: Countershaft sprocket


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Countershaft sprocket
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Thought I would throw a new 14T sprocket on the front of the TTR, I went back from a 120-90 to 120-80 rear tyre with a 13T sprocket and as I want to use the TTR to reduce the KMS on the WRR

Anyhow as soon as I removed the sprocket cover I thought the nut may be loose & yes as suspected it was loose, only just loose, the tab on the lock washer broke, replaced the sprocket and cleaned it up ready.

Ordered two new lock plates from the local dealer, it's never come loose before but never broke the tab before either.  Looking forward to getting the TTR back out

Cheers Terry



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Not unusual.  The lock washers are cunningly built to only get one good use out of each tab.  The nut does come loose at times but using a torque wrench helps keep it on 

One thing that catches people out the nut tightens against the shaft not the sprocket so you will find the sprocket can still move a bit on the splines which Is correct 



-- Edited by ttboof on Saturday 22nd of June 2019 10:31:02 PM

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It was only just moving & no damage done, never liked the retaining method that Yamaha use on both the TTR & WRR, Had 4 Honda's & the offset plate on the splines with 2 x 6mm bolts is much easier & as scary as it seems with the sprocket loose on the shaft it never damages anything.

BTW the WRR sprocket does not use a lock tab washer, you punch the outer surface of the nut into the slot on the shaft, even more of a pain if swapping sprockets on the run...The Honda system was easy to change the gearing out on the trail if needed.

Terry

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Honda out put shafts are a common replacement on the larger motors
because of the movement chewing up the splines on the shaft..
small motors don't seem to have the issue of the larger motors...
a tight nut is far better...



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Can't beat a tight nut LOL

How do you hold the sprocket to tighten the nut ?

Terry



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put the chain on then hold it with the rear brake....




.

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petenz wrote:

put the chain on then hold it with the rear brake....




.


 I tried that before, had the wife sit on the bike with her foot on the brake, tried to drive through it. I used my 1/2" air rattle gun, but when I changed the WRR front sprocket after the VHC could not climb up to get my rattle gun with my broken ankle so I borrowed a battery rattle gun from a lad at work, boy O boy did that thing have some grunt or what.

Terry



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our 3/4 Makita guns at work put out 900nm...
I have snapped a 16mm bolts with them...



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Thats a lot of ugga duggas  I'd be breaking bolts all the time 



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Got a battery 1/2" rattle gun off ebay last week, works a treat. Got my new lock tabs today so new tab & do the nut up with the rattle gun, peace of cake. Even checked the nut with a 12" strongarm, held the sprocket with a tyre lever jamming the rear wheel, good result

Cheers Terry

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TT-R250 & WR250R for dirty fun

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