Pinned C/Shaft Sprocket for FZR 3LN3-5-6-7 & Zeal

This is with regard to the late fizzers (Yamaha FZR250) having different sprocket thickness to the earlier 3LN1. The part number for this sprocket is 1YL-17460-00
Only the genuine sprocket has the correct thickness. To date, all known aftermarket sprockets have been made to suit the 3LN1 which has a shorter output shaft. These aftermarket 3LN1 sprockets are flat and look like the diagram shown.


EDIT: Also, thanks to Mr @HiveFleetAbyss, the correct information for the Zeal sprocket, which is available as an original part (3YX-17460-00) but very expensive.

This is the part that JT sprockets show for the 3LN. From the information that Mr Grey and other have provided this will be 3LN1 only, the others being thicker.



JT sprocket for 3LN series but actually only fits 3LN1



EDIT:
Since this thread could get quite long I will post latest known information here.
Okay thanks to Stu and HiveFleetAbyss we have these known facts:

Common:
1/ The spline dimensions of the sprocket in question are known and very common across multiple brands and models.
2/ The tightening torque for the sprocket nut is 6.0 kg m or 43 ft lb.

FZR250
1/ The later model FZR250's have a thicker sprocket.
2/ A standard 3LN3 sprocket has been measured at 9.70mm thick including the shoulder.
3/ Fitting a 520 conversion may be a solution - chain will weigh a bit more but greater longevity of sprockets and chain
4/ It appears that the shoulder should face out. This has not been proven yet and we are waiting for an owner to check alignment with stringline or laser.
ZEAL:
1/ Zeal rear sprockets are also offset to in order to align with the drive sprocket.
2/ The offset shoulder faces inwards on the Zeal
3/ A 520 conversion sprocket that was supplied for a Zeal is 9.14mm thick including shoulder.
4/ It is not known if the 520 conversions, supplied by various aftermarket vendors for the Zeal, aligns correctly.

PRODUCTION:
These sprockets are now available.
http://litetek.co/Sprocket_Drive_Yamaha_FZR250_3LN3.html
Same dimensions as the OEM part but no rubber sound dampening nor holes.



So here is an image of what seems to be needed for the 3LN3 and later (note that the sprocket in the pic incorrectly only has 16 teeth).



Dimensions for 3LN3 & later



This is a genuine 2nd hand 3LN3 sprocket. The rubber (sound dampening?) ring has perished. The shoulder can be clearly seen.




ZEAL:
Here are the dimensions for a Zeal Sprocket as supplied by measurement of an original part by @HiveFleetAbyss

Zeal Dimensions

Note the 5.3mm offset of the sprocket. The offset shoulder faces inwards on the Zeal.

 

Sprockets with same spline dimensions (16-20-4) are used by all of the big four Japanese manufacturers. Here is one that is close to what everyone was looking for.

It is 10mm thick rather than the 9mm that I recall was mentioned. But a step in the right direction.
This is from a Suzuki GN125
http://www.jtsprockets.com/catalogue/model/1585

15 Tooth being the largest available size for this one
http://www.jtsprockets.com/catalogue/sprocket/JTF410

 

Good stuff Mr Green ... I knew something equal or close would have to appear on other bikes /machinery
I was going to research this also

The one u linked for the 400 is interesting ...... says its available as 19 and 20T ..... but mentions a 16
Stock for 250 is 17T ..... 16 would be good .... not sure about clearance with 19T

 

Well someone needs to confirm which shaft they use first. The listed version for the 250, second pic, is completely different to the 400.

 

250 shaft




More discussion

http://2fiftycc.com/index.php?threads/grasshoppers-fzr-3ln3.2004/page-4#post-34263

 

Amongst all the suppliers are ChainGang in Aus and they have a listing for the Zeal. Worth an email
http://www.chaingangchainsandsprockets.com.au/front-sprocket-specs/6-countershaft-sprockets.html

 

So is this what is needed in 16 or 17 teeth?

 

Looks most likely .....

 

17, 16, 15 in my opinion would be fine ..... anything smaller the chain rubs the chain guide on the swingarm excessively ..... anything over 17 might create problems also ..... would have to look at the setup and clearance with the sprocket cover and the like.

 

Maybe someone should send an email off to the ChainGang with that pic and see what they come back with.

 

http://www.chaingangchainsandsprockets.com.au/front-sprocket-specs/6-countershaft-sprockets.html
Oh Grasshopper ... you have not been paying attention, have you?

 

To do wat exactly?

 

Did u ask them if they knew anyone that could have them, sell them, make them?