Thumper Club Forum

Technical => Bike Problems/Questions => Topic started by: des barrett on December 03, 2006, 09:08:13 AM

Title: gb500 rear srockets
Post by: des barrett on December 03, 2006, 09:08:13 AM
trying to locate a smaller size- 33 or 34t.  Anybody know where to get one please?
Title: Re: gb500 rear srockets
Post by: SteveC#222 on December 03, 2006, 12:35:12 PM
I don't know if anyone stocks them in those sizes, but if you have no luck try www.bandcexpress.com as they used to make one off rear sprockets from blanks for a reasonable price.
Title: Re: gb500 rear srockets
Post by: Richard 003 on December 03, 2006, 08:05:44 PM
trying to locate a smaller size- 33 or 34t.  Anybody know where to get one please?

Why? (He asked, curiously)
Title: Re: gb500 rear srockets
Post by: des barrett on December 04, 2006, 07:34:06 PM
trying to locate a smaller size- 33 or 34t.  Anybody know where to get one please?

Why? (He asked, curiously)

just an idea, enjoy playing - could make a more relaxed ride
Title: anywhere
Post by: GB500nz on December 05, 2006, 09:33:09 AM
except maybe motorbike dealers. Wreckers and aftermarket suppliers have bins full. It's a standard type of sprocket. A few teeth smaller will make the bike better for highway work, but will make low-speed operation less pleasant.
Title: Re: anywhere
Post by: Richard 003 on December 05, 2006, 06:41:04 PM
except maybe motorbike dealers. Wreckers and aftermarket suppliers have bins full. It's a standard type of sprocket. A few teeth smaller will make the bike better for highway work, but will make low-speed operation less pleasant.

The danger if you up the gearing too much, is that you don't get near enough to the power in top to overcome the wind resistance. Depends partly on what speed you want to cruise at ....
Title: Re: gb500 rear srockets
Post by: steveD on December 05, 2006, 08:23:06 PM
I would personally try for either one tooth bigger at the front or 3 teeth smaller on the rear. I do this for the summer on my DR 750 and the fuel increase is significant as cruising at @ 70mph is more rerlaxed and less revvy, but then that's a 750.
BUT I usually do carry a lot of touring gear.
I use 3 teeth smaller on the rear as the front sprocket has a guide which runs closely to the chain and would not facilitate a bigger front sprocket.
I just may try a 1 tooth smaller front sprocket on my SRX to see if it will rev out better in top!

SteveD
Title: Re: gb500 rear srockets
Post by: themoudie on December 05, 2006, 11:26:39 PM
Aye Steve,

Have tried the Yam350 ypvs 39 tooth on the rear of Sally and definitely makes her more revvy. I don't like it and consequently have a 39 tooth sprocket if you wish to give it a try! I've reverted to 37 teeth.

Regards, Bill
Title: Re: gb500 rear srockets
Post by: Richard 003 on December 06, 2006, 08:22:05 AM
I would personally try for either one tooth bigger at the front or 3 teeth smaller on the rear. I do this for the summer on my DR 750 and the fuel increase is significant as cruising at @ 70mph is more rerlaxed and less revvy, but then that's a 750.
BUT I usually do carry a lot of touring gear.
I use 3 teeth smaller on the rear as the front sprocket has a guide which runs closely to the chain and would not facilitate a bigger front sprocket.
I just may try a 1 tooth smaller front sprocket on my SRX to see if it will rev out better in top!

SteveD

The thing to bear in mind with the GB is that it has a different power delivery from the DR - peak "power" is made at over 7000 revs. Whether raising the gearing  is a good thing to do will, in my experience, depend on what "relaxed" cruising speed is being aimed at. If you want to do 70, then wind resistance isn't going to be much of an issue and it's probably worth doing. If, on the other hand, you want to get to the upper reaches of the GB's speed range (ie 90-100), raising the gearing could have the effect that you can't overcome the wind resistance to be going fast enough to get into the power in top, in order to maintain your speed and avoid needing to drop down into fourth again. That's been my experience with the 500 engine in some wind conditions, even on standard gearing. If your engine is tuned in any way, then disregard the preceding ;-)