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Buell Forum » Old School Buell » Archive through July 09, 2013 » The shop put on a -1 front sprocket...educate me on the implications « Previous Next »

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Jramsey
Posted on Wednesday, June 12, 2013 - 11:13 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

You should have went +1 on the front for more speed at less RPM's.
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B1rdman
Posted on Wednesday, June 12, 2013 - 11:14 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Actually, I think that's what I meant to say. They went with more speed and less rpms, I just got my +1/-1 confused lol.
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B1rdman
Posted on Wednesday, June 12, 2013 - 11:19 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Crap, I meant to delete this thread (or edit my title) but this board format sucks lol.

Here's my original post since I can't do the above:



They told me they could only get a -1 or +1 and instead of looking for one myself, I told them a +1 to increase my top speed and maybe improve my mpg.

I definitely notice that the rpms seem much lower than before, and not sure I like it to be honest..

How does it affect my speedometer? How can I fix that? There's no way I'm doing 80mph with traffic when I'm sure they are doing 55-60.

What about my mileage? I think I read that it will make my bike rack up more miles than it is really doing?? Will recalibrating my speedo fix that issue as well?

Will changing the rear pulley to a bigger one help equalize my issues? }
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Akbuell
Posted on Wednesday, June 12, 2013 - 12:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Changing the rear pulley to a larger one will get you get you back to (or towards) stock. Basically negating any advantage the larger front pulley gives.

Short version, divide the number of teeth on the rear sprocket by the number of teeth on the stock front sprocket. Put that number aside. Do the same with the teeth on the new front sprocket. Find the percentage difference between the two. That is how much 'off' the speedo will be.

Using the sprocket numbers from the parts book, I get a difference of 2.5%, in round numbers. Or about 2MPH at 80.

Hope this helps (if my math is correct) Dave
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B1rdman
Posted on Wednesday, June 12, 2013 - 01:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I guess the easiest and cheaper option is to then change the rear pulley to a larger one. I don't think I like the difference in the larger front one.

Will I have to change belts or will I be fine with the one on there?
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Fasted
Posted on Wednesday, June 12, 2013 - 02:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

SMALL sprocket up front equates to LARGER rear

small sprocket(or larger pulley)lowers gearing, so lower top speed with quicker acceleration.
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B1rdman
Posted on Wednesday, June 12, 2013 - 02:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Fasted: Don't you mean "higher top speed with slower accel"?
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Alfau
Posted on Wednesday, June 12, 2013 - 03:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

dakota Digital Speed Recalibration Unit.
\newurl

http://www.dakotadigital.com/index.cfm/page/ptype=results/Category_ID=519/home_id=-1/mode=cat/cat519.htm

(Message edited by alfau on June 12, 2013)
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Gmaan03
Posted on Wednesday, June 12, 2013 - 03:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I had the same problem, but with a tranny swap. I purchased a used tranny but it was out of a sportster. The final drive gear had a different pitch ratio, and messed my speedo up by around 8 MPH. I wish they just kept with a speedo cable off of the front tire............
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Akbuell
Posted on Wednesday, June 12, 2013 - 04:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ummm, is there a reason you can't go back to the original front sprocket, rather than changing both of them?
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B1rdman
Posted on Wednesday, June 12, 2013 - 04:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The original front sprocket was worn out on the inside teeth. I wouldn't mind going back to a stock size/count though..
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Fasted
Posted on Wednesday, June 12, 2013 - 05:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

no. i don't......decreasing the size of the countershaft lowers gearing which results in lower top speed but quicker acceleration. think about the bonnie bikes with very tall gearing that have problems moving away from a dead stop, take a long time to top revs, and have high top speed.
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B1rdman
Posted on Thursday, June 13, 2013 - 03:07 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

If I change out the rear pulley to larger, will that start to fix my speedo problem? Or no because the sensor measures the front sprocket?
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Hootowl
Posted on Thursday, June 13, 2013 - 10:05 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Why don't you put a stock pulley back on, rather than horse around with trying to get back to a stock ratio by other means?
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B1rdman
Posted on Thursday, June 13, 2013 - 11:32 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

How hard is it to replace? I figured the rear was easier.
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Hybridmomentspass
Posted on Thursday, June 13, 2013 - 12:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

its not hard at all man, just replace the front
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