Raising the gears on a 1200 Sporty

Discussion in 'Sportster Models' started by King Herald, Aug 24, 2008.

  1. King Herald

    King Herald Member

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    I just bought a 1990 4 speed model and it seems too low geared, hits 3000 rpm at 60mph. This seems pretty revvy to me, feels like it could easily pull an extra gear to get a better cruising speed before my fillings vibrate out.

    I'm thinking of getting a smaller rear chain wheel made ('sprocket' as we Brits call them) Any suggestions how many teeth I should lose off it to get a better speed to rpm ratio?

    I'm sure I've seen an article on this already, rpm versus speed versus gears chart, on one of the HD forums, but I sure can't find it now I need it. :(

    [​IMG]
     
  2. King Herald

    King Herald Member

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    I'm seeing 57mph in 4th at 3000rpm, which seems about right, assuming the speedo is somewhere near accurate. I'm going on a 1.6:1 primary ratio, and 1:1 top gear

    Assuming I have the 51/21 tooth rear sprockets I saw in another thread, I could lose 5 teeth off the rear sprocket and still have decent pulling torque in 1st gear, but get a smoother cruising speed of about 65 at a smooth 3000rpm.
    :small3d026:
     
  3. King Herald

    King Herald Member

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    I think that adding one to the front is the equivalent to taking two off the back, as the sprocket is nearly double the size. Probably easier to get a rear one made, as I assume the front has some sort of special spline in it? There used to be companies that advertised sprockets made from samples, drawing etc. I'll have to do a Google.

    Unless Harley/Aftermarket offer a higher ratio front sprocket for just this purpose? :33:
     
  4. King Herald

    King Herald Member

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    Thanks, that'll make life easier. :D

    Strange how none of our American brethren have joined in with this thread.

    Maybe they don't ride their Sportys faster than 50mph? :naughty
     
  5. glider

    glider Veteran Member

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    That Hobbit guy scares me, 130 MPH on the streets and in 4th gear too:lolrolling
     
  6. tsp45acp

    tsp45acp Active Member

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    Picked up my 08 1200C yesterday. First bike in about 15 yrs and first Harley ever. I was a little surprised how "high" 1st gear was. At an idle in 1st, I'm doing 10 mph, my old bike (77Kaw 750 2cyl), I could "creep" at less than walking speed. It really lugs at 50mph in 5 gear, so I figure this should do OK at higher speed. Being a "harley newb", maybe I'm just not in tune with my bike yet (but I do love it)

    Please excuse the newb hijack. Tracy
     
  7. tsp45acp

    tsp45acp Active Member

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    Hobbit, Thanks, I'm in the "experimental mode" right now---finding out what works at what speed. As soon as it lugs I downshift. Didn't say earlier, but I did have my wife with me so it's prob worse with a passenger , than with just me. But I'm learning.

    Man, the wind and rush of getting on the gas" feels good again.


    Thanks for your knowledge, I'm really learning. Tracy
     
  8. King Herald

    King Herald Member

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    I found I rode smoother if I didn't look at the tacho, just shifted when it felt right.
     
  9. tsp45acp

    tsp45acp Active Member

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    This one doesn't have a tach, and since I've never had a Harley before, finding the right rpm's and when to shift up and down is a learning experience. I like the low rumble at low speeds, but once you get over 40 mph, the wind noise drowns out the engine (stock exhaust) and makes it difficult to know. I upshift and down shift periodically to "feel" the differences in the rpms in different gears. I'm starting to get the feel for it, and have 250 miles on it after the ride this morn. Wife has ridden approx. 170 of those miles, so it takes a little bit time to get re-adjusted in the shift mode with the difference in weight and slower country road driving. Tracy
     
  10. King Herald

    King Herald Member

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    What do you reckon the lowest rpm you should use is? I reckon that for burbling through town and traffic it is perfectly okay to run at 1500rpm or thereabouts as long as you are in 1st or 2nd and not accelerating.

    Some guy on another forum tells me you should NEVER run the motor below 2000 minimum, in any gear, unless you are decelerating, on the overrun etc. He reckons it is bad for the motor.

    My Sporty feels happy at low rpm, in low gears, at low speed, but definitely likes to be over 2000 if I'm getting it on a bit.