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Discussion Starter #1 (Edited)
Another question from the Sportynube:

I'm preparing to get the 1200 conversion done on my 2000 883 and have decided to install the 29-tooth sprocket on the front. I understand the 29-tooth should help with vibration on the highway via the RPM reduction.

How does that sprocket affect the speedo? Does the speed sensor "sense speed", and adjust automatically/ electronically, or do I need to recalibrate something?

Thanks for the help.
 

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Changing from a 27 to a 29 tooth belt sprocket will make your speedometer 7.4% off (29/27=1.074). You'll be going 7.4% faster than your speedometer indicates. The speed sensor senses before the sprocket, so it doesn't know any better.
Might be as easy as changing the speedometer to one from a 1200, not sure about that.
 

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Discussion Starter #3
murphdog,
Thanks, the 1200 has the 29-tooth sprocket and same trans. :duh?: The answer was hiding in plain sight; it shouldn't be hard to pick up a speedo locally.
 

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I doubt if the speedo calculates the MPH. I believe it is just sent a signal. Check the speedo part number for an 883 vs. a 1200, I bet it is the same number and it is instead a module that calculates the speed. Just do what I did, get rid of the speedo altogether. But seriously, the speedo was probably about 2-4% optimistic stock, now it will be 2-4% pessimistic. Another way to fix this is to play around with tire size. A shorter tire will read faster than actual speed. There are several websites that can calculate indicate speed differences based on gearing or tire changes. Just do a search, I think even "Nightrider.com" has one. I believe the other post said about 7% difference, cut that to about 4-5% or so as a correction to the factory error then figure out if you can get a slightly different tire size the next time you need one.

Check out this site: http://www.csgnetwork.com/tireinfo4calc.html
It says the difference between a 130/90/16 and a 130/80/16 is 4.06%
 

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Discussion Starter #5
cfromc,
Thanks for the tire idea; the shorter tire (190/80-16) should be just the compensation I need.

Thanks for the inputs and ride safe!
 

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If you put a bigger front sprocket on to reduce rpm then put on a shorter tire to correct the speedometer, you just negated most of the what you originally set out to accomplish. You reduce rpms by 7% with the sprocket then increase rpms by 4% with the shorter tire. If you just want to correct the speedometer after changing the sprocket, find out what the difference is between the 1200 and 883 speedometers and change whatever that is. Maybe it's not the speedometer, but it's something. They both have the same primary ratio and the same transmission ratios. The only difference in gearing is the front sprocket.
 

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Discussion Starter #7
Sounds like I need to go to the local dealership and ask the parts counter to look-up part numbers for speedo and sensor of both bikes.

murphdog,
You are right: my point of installing the sprocket IS to reduce the engine rpm. Thank you for keeping me on-task.
 

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Discussion Starter #8
cfromc, murphdog.
I appreciate your feedback on the sprocket change. Just happened to find a recalibration module by Dakota Digital that is a plug-and-play unit that plugs in between the sensor and the speedo. Fully adjustable to correct for speedometer error.

After I got the bike put together yesterday, I took it out onto the interstate. I averaged the loss of about 1/10 mile per mile; 10 percent error.

Again, thanks for the help. The 1200 conversion is next.

Curt
 

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nube, if you ever find out where the difference is between 883 and 1200 speedometers, let us know. I'm curious now.
Good luck on the 1200 conversion, let us know how it goes as well.
 

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I'm glad you got it sorted out. I am actually going to a slightly taller tire to reduce highway rpm. Eventually I will be buying a Supermax pulley/belt system to even further reduce RPM's on the highway. I no longer have a speedo so the difference doesn't matter to me. I've run some scenario's on nightrider.com and, depending on the ratio, I may even lower 1/4 times due to the changes in shift points. I think the change would be negligible in that respect though but if I can lose a couple hundred rpm on the highway without much affect on performance, I'm all for it. Plus the Supermax system weighs a couple lbs less than the stock stuff (at least according to supermax).

By the way, consider going the 1250 route as it should be the same cost as a 1200 kit yet give you a few more hp.
 

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Was the sprocet change noticeable?

I do alot of highway driving to work on my 08 883r.
Will the 29 tooth make a noticeable improvement?

Thx
 

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Discussion Starter #12
I don't have a tach but the RPM is lower at 60. I also have to stay in 4th during my ride to work at 40mph or the engine lugs where before I could almost get away with riding in 5th. I don't seem to have lost any torque in the low end but then, I don't usually accelerate fast.

I call it a "5 and a half" speed.

Hope this helps.
 

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Discussion Starter #13
Update of Dakota Digital Speedometer Module, etc.

I received the module and installed it; really, plug and play at the connector underneath the seat. I left it hanging out and took a ride down I-35 south of Waco; using the mileage markers, I was able to calibrate the speedo easily and then attach it underneath the seat.

My opinion stills supports the 29-tooth sprocket change. Sprocket: $85 at local indy; module: $85 from ebay. RPM is noticeably lower (don't have a tach)

I also bought a used set of 883 cylinders and the Wiseco reverse dome pistons for the 1200 conversion. The plan is to get 3 runs on the dyno: before conversion: with HD air filter; with K&N air filter. After conversion: 1200 with K&N air filter, 45K coil/Accel 8.8 plug wires.

Anything I haven't thought of? I'm still wanting to get a set of used 883 heads with a mild massage to install with the conversion.

Thanks for your opinions!
Sportynube
 

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In 2004, HD changed the primary gearing of the 883's to be quite a bit lower than the 1200's. To get an 883 to a 1200 gearing for 1991-2003, all you had to do was change the transmission pulley from the 27 to a 29. With the 2004-2012, 883 you need to change the 28 transmission pulley to a 32 tooth pulley. Luckily the belt is long enough to accept the 32 tooth. However, while the earlier change out to a 29 tooth was just wrench work, to get a 32 onto the 883 requires some grinding on the cover standoffs.
 

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Thanks Sirrom1 for updating this thread with info for the newer 883's gearing.
 
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