Front sprocket gk73a

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Carpediem
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Front sprocket gk73a

Post by Carpediem » Tue Jul 11, 2017 9:00 pm

Im in the middle of changing my chain and sprockets on my bike. The front sprockets got play in it as its only held on by a circaclip. Does anyone know if this is right? Seems to me there should be a washer or something just to keep it tight. The new sprocket is exactly the same. Thanks for the help

moforockband
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Bike owned: GK73a SP CRM250 mk3
Re: Front sprocket gk73a

Post by moforockband » Wed Jul 12, 2017 6:50 pm

It's not meant to be tight, but have a small amount of axial play. Replace the circlip every time, and make sure you put the sharp edge of the circlip facing OUT. Also make sure you are using 525 sprockets and not 520. If you are using 520 you must use a sprocket with an offset boss.
In ex race/high mileage machines the output shaft can wear on the splines directly where the sprocket sits, and you can guess the repair for that. :!:

Carpediem
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Re: Front sprocket gk73a

Post by Carpediem » Thu Jul 13, 2017 12:38 pm

Ive checked the sprockets and they are 525's. Ive spoken to crescent suzuki and they confirmed its just the circlip holding the sprocket. So ive ordered a new one which should arrive soon. Also double checked how i put the old one back on. So all is ok now. No play at all with chain on so im hoping that means my output shaft isnt too bad. Fingers crossed.
Thanks for the reply

moforockband
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Bike owned: GK73a SP CRM250 mk3
Re: Front sprocket gk73a

Post by moforockband » Thu Jul 13, 2017 6:38 pm

Your output shaft should be fine as long it has always run 525 front sprockets. You can simply run your finger along each spline to check.
RGV's are a PITA, as they wear their output shafts, but they are often tuned to 70hp, and use a smaller 520 setup.

bluex5
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Re: Front sprocket gk73a

Post by bluex5 » Wed Jul 19, 2017 9:11 pm

They all do it. If it gets terminal it's possible to effect a fix with a GK76A gearbox cluster (the output shaft is the same as the 73 but longer and the sprocket sits in front of a spacer so the chain will clear a 160 rear tyre, swop the the sprocket and spacer around and the sprocket is all of a sudden sat on virgin splines).

martinsamuel
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Re: Front sprocket gk73a

Post by martinsamuel » Tue Aug 15, 2017 3:23 pm

On my 76 i didn't like the look of the 520 so put a 520 DRZ400? sprocket on, it has a ~10mm inside shoulder on the sprocket, so loads of extra engagement. Obviously i had to turn that ~10mm off the inside spacer. But it feels much better than a stock 525 now.

Martin


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