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

Your enquiry is very clear, Grasshopper.
I think just scratch them off the list and move on.

 

Response from Renthal:

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Hello Blair,

Thank you for your enquiry.

I nor Renthal can confirm these fitments without new chain wheels for comparison with our broaches and test shafts.
Theories below are offered for brainstorming purposes only.
I nor Renthal can confirm these options without access to a suitable machine for test purposes.
Any up-take on the below potential would be at your own risk and should be carried out by trained personnel ;

On the face of it appears you have a Renthal 366 fitment with a 428 chain pitch, thereby being a 366- -428-17P
Unfortunately Renthal never produced this pattern / pitch size combination.
However, Renthal still produce a 366- -520-13GP and 366- -520-14GP, thereby requiring you to run 520 chain.

Our distributor B&C express will be able to sell you one of these for around £15 for your technician to confirm the fitment.
Assuming the FCW fits, I would suggest the 366- -520-14GP is the better option for a road bike (assuming you have space in the FCW housing).
The larger tooth count means each link has angular movement to achieve, resulting in less wear amongst other things.

Assuming you are able to confirm the fitment, you'll then need a matching 520 rear CW.
The standard fitting for a Yamaha FZR250 EXUP (3LN) is a "Renthal 175" and with the 520 pitch you'll need less teeth.
Renthal no longer produce the 175 range as the turnover does not justify them, but B&C can make them under licence.
Based on this, the RCW 175- -525-46P-HA with the teeth back face skimmed to 520 pitch will give you a close match to stock ratios.
If you have to go for the 13 tooth, a 43 tooth rear might be a more appropriate match.
B&C express can be contacted on 01522 791 369.

Kind regards

Kevin

Kevin Gladstone
Product and Pricing Specialist

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I wasn't clear enough about the number of teeth. At least they can be bothered to give a comprehensive answer. Doesn't sound like any option except the 520. But maybe if they know the correct number of teeth it might make a difference. I think it will be also necessary to confirm that the thickness of the sprocket is exactly 9mm. Now that I have an email I can send Mr Grey's images of the different shafts. Can someone take a pic of the two different sprockets being measured (thickness) and I will send them too.
cheers
Blair

 

The 520 option is probably the simplest. Look on the bright side, the chain and sprockets will last a lot longer.

 

@TechHeadFred if you get stuck with parts for your 3TJ let me know because I will be throwing a lot of mine away.

 

@TechHeadFred you will find a parts book for the 3TJ on my carb kit page for that model. http://litetek.co/Carb_Kit_Yamaha_3TJ1.html
and a heap of other docs.
Sorry for hijacking thread.

 

Correct Murdo, it seems to be a common size.
I actually found lots of them for Honda, Suzuki, Yamaha and Kawaski but no thick ones except the 10mm example that I posted.

 

Re the 520 chain conversion.
Since the pitch on the 520 chain is 5/8" pin to pin and the 428 is 1/2", a 17 tooth 428 has the same diameter as a 13.6 tooth 520. It would be impossible to fit a 17 tooth 520 on a fizzer. So a 14 tooth or 13 tooth countershaft sprocket will be the choice and then you will have to go down on the number of teeth at the back to get the correct gearing. Maths courtesy of Kevin at Renthal not me.