Author Topic: 1250 front sprocket 1 tooth up?  (Read 1370 times)

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Biker1250

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1250 front sprocket 1 tooth up?
« on: October 01, 2016, 12:00:30 PM »
I find the 1250 a little low geared. 1st is not quite tall enough and I often search for 7th. I am thinking of going one tooth up on the front sprocket to get taller gearing. I understand this will true up the speedo as well. Anyone done this on the 1250 - will it make much difference? I believe one tooth on the front is equivalent to 3 on the rear. I'm not too worried about losing some of the ferocious torque but would like things a just a bit more relaxed whilst retaining most of the 1250's exceptional power. Also, without a torque wrench, would reinstalling the sprocket nut 'nice and tight' be ok bearing in mind the chain pulls the other direction so it's not going anywhere, so to speak. Buying one might make it not cost effective and I may as well go to the dealer to get the job done.
Thanks in advance - I'm fairly ok with a spanner but like to check with others as well as following the Workshop Manual.

sambo

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Re: 1250 front sprocket 1 tooth up?
« Reply #1 on: October 03, 2016, 10:29:05 PM »
 I think you will find that putting on a larger front sprocket will lower the gearing even more. Putting a smaller front sprocket or larger rear sprocket will make the gearing taller.

Biker1250

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Re: 1250 front sprocket 1 tooth up?
« Reply #2 on: October 03, 2016, 11:01:43 PM »
I think you will find that putting on a larger front sprocket will lower the gearing even more. Putting a smaller front sprocket or larger rear sprocket will make the gearing taller.
Everything I've been told or read says the opposite. This quote is from Sport Rider Magazine:

Substituting a larger front or smaller rear sprocket lowers the ratio (sometimes called "taller" gearing), resulting in more speed for a given engine rpm. Likewise, a smaller front or larger rear sprocket gives less speed for a given rpm ("shorter" gearing).

Basically I want to lower the torque and increase the speed I can go before I need to change gear.

gosman767

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Re: 1250 front sprocket 1 tooth up?
« Reply #3 on: October 04, 2016, 09:19:56 PM »
Have a look here www.gearingcommander.com , I haven't looked for the 1250 but the 650F is in the database, you can input any combination of front and rear sprockets and it will give you speed in gears etc HTH

Biker1250

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Re: 1250 front sprocket 1 tooth up?
« Reply #4 on: October 04, 2016, 09:56:48 PM »
Very useful, thanks. On the face of it, just going one tooth up doesn't seem to make much difference. I suppose it might feel a bit different. Short of talking to someone who has done it - trial and error seems the only way. Food for thought.