Hard to find rear sprockets??

[I Russ]

Hi all,
Just thought I would share abit of info with you,
I have just converted my KT250 to a 520 chain from a 428.
I used a Kawasaki KX500 sprocket set (Talon)both front and rear with a 1:4 ratio as per the original set I had on, the only difference being the original was 13/52 and the new is 11/44.
Reason for this change in teeth is the sprockets vary in diameter due to the pitch so the 520 set now ends up being about 15mm bigger in diameter of original rear.

The main reason for this topic is I CNC machined up an adaptor plate/spacer to over come the dish, plus adapt the original KT250 PCD to an off the shelf KX500 PCD.
Rather than using a spacer and a special blank sprocket machined every time I need a new rear sprocket.
Now then is this special sprocket/spacer a big problem for the older bikes?
Is there a market for certain bikes?if so how many do you want???
All feedback welcome + or -
Thanks
Russ
p.s The front sprocket is also the same as the TY250 (Talon TG110)

[David Lahey]

Nice job Russ. The KT is a bit of a problem child for sprockets. Getting a small enough front KT sprocket for 428 chain is hard too. The fronts are easy in 520 chain like you found. I do know that there are both 428 chain and 520 chain dished rear sprockets made for the TY250 so that one is covered already. The KT and the TY250 are the only popular twinshock trials bikes I have come across with dished rears.
I made a spacer for my KT250 rear sprocket to use with a flat blank from Titmans and was resigned to drilling another 428 blank next time I need one. The 428 front (I think it is smaller than 13T) came from KT specialist Fred Carter in NZ.
Is a KH500 sprocket cheap compared with a blank? If so you are probably on a winner. Can you do a photo of what it looks like assembled on the bike?

[I Russ]

The sprocket set cost 6(TG110) + 20(TR107) pounds + postage(6.50 pounds)$72 all up from trialbits.co.uk
When a flat spacer is used does the sprocket still locate on a center diameter or rely on the bolts for location??
Excuse the rear shocks,previous owner must of liked no movement?,new ones on order.
Russ

[David Lahey]

The spaced-out flat sprocket centre hole still locates on the hub spigot, but only overlaps the spigot by about 1.5mm. I'll post a photo after tea.

[I Russ]

Thanks for that David,
I dont see why the adaptor idea has to be a dish type sprocket,It could work on a flat type.The adaptor would just have to be recessed at the rear to suit.
The reason I used the KX sprocket was not just because it had the same spline front,but also the bolt holes for those rear sprockets were set well out from the center giving room to adapt.

Russ

[Jansk]

Hi Russ,
I know this is an old post but I just got my hands on a KT and was wondering if you could still produce one of your spacers for the 520 KX 500 conversion?
Cheers, Jared.