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Discussion Starter #1
Hi,

I should replace the final transmission on my F4 750 SR.

I would like to use a Z14 pinion with a Z38 chainwheel.

Is this solution problematical? In particular: are there any problems of contact with other parts of the bike and rapid wear of the chain slider on the swingarm?

Thank you!!
 

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?

originally MVs were geared;
15x39...2.600x1 which on a 750 is stupid tall

then they went;
15x40...2.667x1

Brutales are
15x43...2.867x1

SPRs are ~10% taller in 1st and ~10% shorter in 6th (close ratio box)

you want to go
14x38...2.714x1

try 15x41...2.733x1

its 0.7% different (shorter) and your chain will last longer......
never use an even number of teeth on the driving sprocket or gear, check any engineering manual or power transmission book
 

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Discussion Starter #4 (Edited)
Thank you guys for your answers.

I take into consideration this gear ratio cause of i have the original z38 chainwheel pretty new, i changed it for a z40 after a few kilometers.

The original z15-z38 is too tall for running on the curves of Appennino ToscoEmiliano..

I know that a lower number of theet on the pinion isn't correct and it could cause a rapid wear of the pinion itself. But this effect also depend from the angle of the chain. So using a z38 the chain angle is closer than using a z40(using the same pinion).

Please correct me if i'm the wrong.
 

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The F4 Oro and S have a 14/41 secondary drive.
The EVO3 have 15/40 and the rest of the F4 750 15/38.
The primary drive is different on the earlier F4 Oro and S although.
So I can't imagine why a 15/41 or 14/38 would cause any issues concerning wear.
 

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Ralph, the SR and SPR have different gearbox ratios.
But I hear what you're saying, I also read what Noel referred to about the even number 14 front, I have had the same recommendation from various other sources.
My choice is to go with the odd number 15 front, and adjust the rear to suit my needs.

The 14 put's far too much strain on the swing-arm pivot point and induces unwanted suspension reactions.
 

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Discussion Starter #8
The F4 Oro and S have a 14/41 secondary drive.
The EVO3 have 15/40 and the rest of the F4 750 15/38.
The primary drive is different on the earlier F4 Oro and S although.
So I can't imagine why a 15/41 or 14/38 would cause any issues concerning wear.
I don't understand what you're saying...Could you explain it better?
 

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Guys all of the 750's (even 1000, 1078, 1080) have the same swing arm, same chain guide, same sprocket covers etc.
If the early 750's, as mine, are operating with a 14 tooth front sprocket without a problem, why the hell would this make a difference on a SR, SPR or EVO03 ?
Same is for the rear sprocket.
The early 750's have a 41 tooth rear sprocket and there is no problem, why would a 41 sprocket do not work on a SR, SPR,...
Except the different acceleration / top speed experience from different gearing I see no problems for the Lizzardking to try out different gearings.
 

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I don't agree about that..


SR and SPR have the same gearbox ratios...and the same engine...

I meant, the SR and SPR have different gearbox to the other 750 F4's mate. You have to read what I said, in relation to what Ralph said.

Guys all of the 750's (even 1000, 1078, 1080) have the same swing arm, same chain guide, same sprocket covers etc.
If the early 750's, as mine, are operating with a 14 tooth front sprocket without a problem, why the hell would this make a difference on a SR, SPR or EVO03 ?
Same is for the rear sprocket.
The early 750's have a 41 tooth rear sprocket and there is no problem, why would a 41 sprocket do not work on a SR, SPR,...
Except the different acceleration / top speed experience from different gearing I see no problems for the Lizzardking to try out different gearings.
I never said the 41 would not work on the SR or any other F4, or that the 14 front would not work.
What I said is that because of all the info I have gather about the front sprocket sizing, I would recommend using a 15 instead of a 14.
Try what you like, I merely said what I would do, not what Lizzardking has to do.
 
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