Rear sprocket - Can't find one

**Devil** · 26th March 2007, 07:53

Long story short. Want to go up a few teeth on the rear (3 to be exact) for a little more zip when I want it. Cant go down one on the front due to chain/swingarm clearance issues.

It's an absolute mission trying to find a 48 tooth rear sprocket for a Triumph Speed Four, can anyone help? (Currently 15t front and 45t rear) JT dont make them, renthal do but NZ or Oz distributors dont have any and there'd be a 6-8 week wait (wtf?). Vortex Racing do them, but I haven't been able to track any down yet (the Oz distributor has given me the name of a couple of shops in NZ to try).
I THINK I found a 47 tooth rear somewhere (on the net) but would going up two teeth really make much difference to be worthwhile?

The guy at Holeshot recommended getting someone to make up one from a blank. I have all the measurements, can anyone do this for me?

**CM2005** · 26th March 2007, 09:03

i can't make one for you, but i think the holeshot guys have the right idea. have you rung triumph, they have alot of genuine parts from memory.

**HDTboy** · 26th March 2007, 09:12

Most engineers should be able to recommend someone to make one up for you. The engineer I used to use in Takapuna is Dave at Precision Engine Reconditioners. I believe the busines name has changed now, but the phone number is still the same if you can find a 2 year old white pages.
If he can't do it he'll be able to point you in the right direction

**geoffm** · 26th March 2007, 20:54

You can buy the blanks with the teeth and no centre drillings. Whites used to import them, so any bike shop should be able to get them. You will then need to drill the bolt holes and possibly bore the centre.
Anyone with a lathe can do it. A rotary table helps with the bolt holes, but you can lay the old one on as a pattern at a pinch.
Geoff

**White trash** · 26th March 2007, 20:59

Get a blank, there's an engineering firm in East Tamaki I got mine done by. Cost $80 for them to do a steel blank, alloy's probably a little cheaper but the blank will cost you more.

**Nonbeliever** · 26th March 2007, 20:59

make sure your chain will accomodate an additional 3 teeth before you go to the trouble of getting a blank machined up.(or you may need additional chain length)

**Mental Trousers** · 26th March 2007, 21:07

EDIT Sorry, missed bits of your original post. JT do make sprockets for the Speed Four. Did you mess up the search or something?

Try this set of results - JT Sprockets. Find your bike in there and it'll tell you a part number for a front, rear and alloy rear (if there is one) + chain. Once you have the part number you can ask your friendly local bike shop to get one for you.

EDIT2 has your bike had a chain conversion done on it cos the OEM chain is 525 (wtf??) with 14/42 sprockets

**Devil** · 27th March 2007, 08:54

Heh, bad wording. JT do them (i have JT's a the moment) but weren't available in the size I want.
The first Speed Fours (and TT600's) had 14/42t but there were swingarm clearance issues which lead to accellerated chain guide wear so the last models (mine) went to 15/45 (still 525). 45 is the biggest we could get hold of at the time, but I see that there's a 47t there...I wonder if I can get hold of it...
hrm.

Investegated blank sprockets, the cheapest one I found was $85!!!

Cheers people.

**Macktheknife** · 27th March 2007, 11:48

To answer your other question mate, 2 teeth should make a noticeable difference.

**xwhatsit** · 27th March 2007, 12:26

Originally Posted by Mental-Trousers

EDIT Sorry, missed bits of your original post. JT do make sprockets for the Speed Four. Did you mess up the search or something?

Try this set of results - JT Sprockets. Find your bike in there and it'll tell you a part number for a front, rear and alloy rear (if there is one) + chain. Once you have the part number you can ask your friendly local bike shop to get one for you.

EDIT2 has your bike had a chain conversion done on it cos the OEM chain is 525 (wtf??) with 14/42 sprockets

Wah, cheers for that site, I've been wondering where I can get sprockets for my bike in the size I want. They even have my model listed! Brilliant.

**more_fasterer** · 27th March 2007, 15:37

Glad you got it sorted. I went up 6(!) teeth on the rear of the NC30 and it took it from way overgeared to slightly undergeared.

Originally Posted by HDTboy

Most engineers should be able to recommend someone to make one up for you. The engineer I used to use in Takapuna is Dave at Precision Engine Reconditioners. I believe the busines name has changed now, but the phone number is still the same if you can find a 2 year old white pages.
If he can't do it he'll be able to point you in the right direction

These guys are now called Engine Specialties ltd, ph 489-4806. Got them to weld up my footpeg hangers & use them for the machining work on the engines I build in my spare time. Always impressed by their work.