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CB650F Front sprocket

Lihp88

2018
CB650F ABS
Jun 16, 2018
Hi all, I read through the gearing thread and found it very helpful. He changed out two teeth on the rear sprocket. I would like to drop one tooth on the front sprocket (equal to 4 teeth on the rear) and go with a full superlite set up. Has anybody on here done this? I am curious about how much it affected gear change frequency and top speed. My goal is to have the bike top out at 125-130mph but get there faster. My bike is a 2018 CB650FA
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
My only advice is not to use aluminium sprockets. If you want to save weight go for the sprocketworx... Aluminium in the middle with steel teeth for life.

So far, recommended!

Out part is 1304 (rear), available in 41,42 and 43 teeth and a variety of colours.
IMG-20180617-WA0000.jpeg
HTH
J
 

Lihp88

2018
CB650F ABS
Jun 16, 2018
Thank you for the reply! After some consideration I may just go larger in the rear. I’m somewhat concerned with the tighter radius of a smaller front sprocket! Doing some math yields about a 3.00 final drive ration by going up 3 teeth in the rear. Does anybody know how much this will affect the wheelbase?
 

ADIOS600

2015
CB650F ABS
May 16, 2017
LINCOLNSHIRE
Thank you for the reply! After some consideration I may just go larger in the rear. I’m somewhat concerned with the tighter radius of a smaller front sprocket! Doing some math yields about a 3.00 final drive ration by going up 3 teeth in the rear. Does anybody know how much this will affect the wheelbase?
I went up two on the rear for many reasons. In the past i have gone one less on the front on various bikes and never had a problem.
 

Lihp88

2018
CB650F ABS
Jun 16, 2018
Two is maximum because the rear wheel will not go forward enough. Have a look at my post on the gearing change. I think it would be fine one down on the front. But you will really need a speedo healer also.


Thank you very much for all the insightful knowledge!! Correct me if I’m wrong here. If I went down one in the front and up one in the rear that would be about an 8.8% Increase of gearing.(3.07)
Stock gearing (2.8)@5500=70mph. The gearing mentioned above would yield about an increase of 484rpms. So the new rpms @ 70mph would be about 5984?
 

ADIOS600

2015
CB650F ABS
May 16, 2017
LINCOLNSHIRE
Thank you very much for all the insightful knowledge!! Correct me if I’m wrong here. If I went down one in the front and up one in the rear that would be about an 8.8% Increase of gearing.(3.07)
Stock gearing (2.8)@5500=70mph. The gearing mentioned above would yield about an increase of 484rpms. So the new rpms @ 70mph would be about 5984?
That sounds about right. You have to decide what you want to do with the bike, and after all the calculations you will still have to go by seat of the pants, in the end. You may end up doing something different than your calculations.
 

ADIOS600

2015
CB650F ABS
May 16, 2017
LINCOLNSHIRE
One down on the front will be a nice jump from standard gearing, and one up on the rear with a fancy sprocket would look good.😎 PS I bought a cheap sprocket for a start because I did not know for sure how it would feel. Now I am happy I will paint the sprocket and fit some polished titanium nuts.
 

Lihp88

2018
CB650F ABS
Jun 16, 2018
One down on the front will be a nice jump from standard gearing, and one up on the rear with a fancy sprocket would look good.😎 PS I bought a cheap sprocket for a start because I did not know for sure how it would feel. Now I am happy I will paint the sprocket and fit some polished titanium nuts.


Thank you again! Enjoy the ride and be safe brother!!
 

Stephen Seo

2014
CBR650F
Jul 26, 2017
Los Angeles
I did the same and went 1 down and 1 up. Gave a nice little torquey boost, but speedo is off by 10%ish I bought a speedo healer but didnt install yet cause I cant find the same speed sensor coupler. Anyone have an idea where it is? I've already looked under the tank and still nothing.
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
It's on the right hand side, above the gearbox. It's a pig to get to.

Look in the gap behind the clutch cable. Page 4-38 of the service manual.

You'll need small hands.

J
 
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Lihp88

2018
CB650F ABS
Jun 16, 2018
I did the same and went 1 down and 1 up. Gave a nice little torquey boost, but speedo is off by 10%ish I bought a speedo healer but didnt install yet cause I cant find the same speed sensor coupler. Anyone have an idea where it is? I've already looked under the tank and still nothing.


That’s great to hear 😊 how did it affect shift frequencies and top end?
 

Lihp88

2018
CB650F ABS
Jun 16, 2018
Tend to shift more often, I'm pretty sure lost some off the top end, last time I maxed out at 129mph. Once I get the speedo healer in I will max it out again


That’s pretty much exactly what I was expecting. Thank you for replying! I figured on a loss of around 10mph off the top end. But at the same time I had my bike @139mph and it wouldn’t go any faster. I still had gear left just no power to get me faster.....
 

victorkkq

2018
CBR650F
Oct 30, 2018
My only advice is not to use aluminium sprockets. If you want to save weight go for the sprocketworx... Aluminium in the middle with steel teeth for life.

So far, recommended!

Out part is 1304 (rear), available in 41,42 and 43 teeth and a variety of colours.
HTH
J

Brammers Brammers What a beauty the gold SPROCKET ! Match with golden chain. This is what I am looking for Aluminium in the middle to save weight with steel teeth for life. Initially I wanna order Red to after seeing yours I prefer gold. Just Wow!

Does it really makes a difference when acceleration? I mean the feel is it lighter? Marginal? :)
 

victorkkq

2018
CBR650F
Oct 30, 2018
Marginal at best. Probably better to get Jt steel one and pocket the money to be honest.

Does look good though 👍
Aww man.. marginal is not what i expect.. thought its would be noticeable improvement due to "reduction in direct rotational mass". Anyways thanks for the info, it is still valuable!!! I will archive it for my future crazy weight reduction project including changing the "controversial" titanium bolt, carbon fiber parts etc cheers :)

Oh btw you maintained the no. of teeth right? How long do you think the Supersprox sprocket will last (km)?
 
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