GS550 front sprocket fitment

[Toadstool Food]

My clutch cable locked up. While investigating I pulled the cover off and the front sprocket fell out on the floor. It’s always that one thing you don’t check that gets you when you buy a bike. The nut and washer are missing and the sprocket is FUBAR. I was thinking of using the JT 18 tooth replacement, since my bobber has no extra weight and no room for 2 up. My problem is I haven’t been able to find the hardware to go with the sprocket for my specific year model, 78 GS550. Any advice on cross fitment from other models would be helpful.

Toad

[BassCliff]

Hi,

You can get the parts OEM. It seems you need #37, #38, #39.



#37 = p/n 27511-47000 (Wasn't the stock front sprocket a 15 tooth?)
#38 = p/n 09140-20009
#39 = p/n 09167-25011

These can be had from just about any of the OEM vendors in your "mega-welcome". You can probably get them from Z1 too.


Thank you for your indulgence,

BassCliff

[Toadstool Food]

Wasn't the stock front sprocket a 15 tooth?

Thanks for the info Bass. Yes, the original sprocket is 15 tooth. I was hoping to bring the gearing more in line with all the highway driving I do. Being stripped down, it has more than enough low end power. I was searching on line for the parts. I am sure the part numbers will help a great deal.

[BassCliff]

Hi,

Give Z1 a call and they can help you with your sprocket and gearing. It's usually recommended to replace both sprockets and the chain as a set so that they wear together.


Thank you for your indulgence,

BassCliff

[Toadstool Food]

I was just coming to the same conclusion Bass. ATM I am pondering weather to use the stock size chain or convert to a smaller chain. I have read quite a few posts opting for a smaller (lighter) chain. The general idea being that modern chain is much stronger, and therefore need not be as hefty.

[BassCliff]

Hi,

Doesn't your bike use a 530 chain?



Thank you for your indulgence,

BassCliff

[Suzuki_Don]

My clutch cable locked up. While investigating I pulled the cover off and the front sprocket fell out on the floor. It’s always that one thing you don’t check that gets you when you buy a bike. The nut and washer are missing and the sprocket is FUBAR. I was thinking of using the JT 18 tooth replacement, since my bobber has no extra weight and no room for 2 up. My problem is I haven’t been able to find the hardware to go with the sprocket for my specific year model, 78 GS550. Any advice on cross fitment from other models would be helpful.

Toad

Toad, don't go for an 18 tooth sprocket or you are in for a shock. Have a look at your sprocket, chain & clutch rod setup before purchasing another front sprocket. If you want to alter your gearing best to come down from the 50 tooth rear sprocket size to a 45 tooth. It will give you what you are looking for.

[Toadstool Food]

Doesn't your bike use a 530 chain?

Yes, I’m sure it is still a 530. I have been reading threads about the conversion to a 520. The availability of larger front sprockets its better in that size. ATM I am tempted to replace the 530 front sprocket and chain only because it will get me back on the road quicker if I don’t have to take the back wheel off to replace the back sprocket. I haven’t made a purchase just yet.

Toad.

[Toadstool Food]

best to come down from the 50 tooth rear sprocket size to a 45 tooth.

Thanks for the input Don. I have read many posts that are Pro and Con both ways. I did not find any consensus. I have no choice to but to change the ate up front sprocket, so it seems easer and more economical to get a bigger front. Maybe not as big as an 18, but bigger. If I do opt for the 520 conversion, I will probably opt for the smaller rear. I have another week to ponder all the angles before I have time to work on it.

Thanks,
Toad

[makenzie71]

JT Sprockets rocks... you want part number JTF513.18T (if you're running stock chain sizing).

[makenzie71]

If you don't want 18...then JTF513.17T...or JTF513.16T...

[Toadstool Food]

you want part number JTF513.18T

That is the exact gadget I had in mind. Thanks Makenzie. At ~$20 I can afford to change my mind later and get a smaller one. I have been given a lot of good input however, so I am taking a moment to sort it all out.

Toad