L rear sprocket and rpm ?'s ... Mathematicians welcomed!


6 replies to this topic
  • Huffa 2

Posted June 26, 2007 - 06:14 PM

#1

OK, the L is geared at 15/45. I want to gear mine a bit higher by using a 42 or 43 rear sprocket.

:thumbsup: You may need the 5th gear overall ratio to answer my questions, I think?

1) What RPM is the L cruzing at going 65 mph with stock gearing?

2) Same ? with 42 & 43 on.

3) If you can't answer either 1 or 2, can you tell me approx how much RPM drop I would have? With 42 around 500 RPM or so :thumbsup:

16 tooth front, no one makes, just so you all know. It was hard enough to find a smaller rear one! :busted:

OH.......What the heck is the redline on these, 6-7000 or so ?

http://www.motostran...m/husuresp.html

  • drtlvr

Posted June 26, 2007 - 06:35 PM

#2

http://supermotoworl..._Sprockets.html

if a xr600 sprocket is the same then this place has sizes to make your bike do 200mph check it out

  • bosshog

Posted June 26, 2007 - 06:43 PM

#3

I don't have an L so I can't answer your question directly but I did find these links very helpful for sprocket choices vs RPM at different speeds.

try here
http://www.4strokes....earing_calc.xls
and also...
http://www.4strokes....ratio_chart.pdf

Bosshog

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  • Huffa 2

Posted June 27, 2007 - 01:40 AM

#4

Thnaks all.

Bosshog, think I know someone that can help me out with that sheet, I'd like to learn how it's done.

10-4 on that link drtlvr, I emailed them asking just that and if they say a 16 will fit, that would be great., otherwise a 42 rear is in order, maybe just a 43 :thumbsup:

  • ItZaLLgOOd

Posted June 27, 2007 - 05:10 AM

#5

Let us know if the 16 tooth XR600 sprocket will fit. It would help me out as well.

  • XR650L_Dave

Posted June 27, 2007 - 07:51 AM

#6

45:15 = 3:1

42:15 = 42/15 : 1 = 2.8:1

(3-2.8) / 3 *100 = 6.67% increase in top speed at redline.
(6.67% increase in speed for a "same gear-same RPM" comparison).

So if the stock geared XRL would do 100mph at redline, the new speed at redline would be:
100 * 0.0667 + 100 or 106.67

Dave

  • scooter1100

Posted July 05, 2007 - 07:18 PM

#7

Xr650l gearing vs rpm

formulated using the following data:
tire 686 mm dia = 2.155 circumfrence approx.86 inches
309 tr=40kmh
464 tire rotations per minute @60kmh = 1 to 1
619 tr=80kmh
773 rotations in 1.666km= 1 minute@100kmh
928 tr=120kmh
1082 tr=140kmh
1237 tr=160kmh

primary crank/clutch ratio=2.0294

X engine rpm = 1 tire rotation
@13/45 sprockets (3.46) 530 tire

gear ratio km 40 60 80 100 120 140 160

5th 5.97 1850 2775 3700 4625 5550 6450 7300 rpm@kmh
4th 7.021 2175 3250 4350 5425 6525 7600
3rd 8.78 2725 4075 5425 6775 8150
2nd 11.73 3625 5450 7250
1st 18.75 5800 8700

ratio is # engine rpm = 1 tire rotation
@14/45 sprockets (3.214) 530 tire

gear ratio km 40 60 80 100 120 140 160

5th 5.47=1TR = 1690 2550 3400 4225 5075 5900 6775 rpm@kmh
4th 6.52=1tr = 2025 3025 4025 5050 6050 7050
3rd 8.15=1tr = 2525 3775 5050 6300 7550
2nd 10.69=1tr = 3300 4960 6625
1st 17.34=1tr = 5350 8050

X engine rpm = 1 tire rotation
@15/45 sprockets (3.0) 530 tire

gear ratio km 40 60 80 100 120 140 160

5th 5.11=1TR = 1575 2400 3150 3950 4750 5550 6325 rpm@kmh
4th 6.088=1tr = 1900 2825 3775 4700 5650 6600
3rd 7.61=1tr = 2350 3525 4700 5900 7050
2nd 9.98=1tr = 3100 4625 6175 7700
1st 16.192=1tr = 5000 7500


X engine rpm = 1 tire rotation
@16/45 sprockets (2.81) 530 tire

gear ratio km 40 60 80 100 120 140 160 rpm@kmh

5th 4.847 1500 2250 3000 3750 4500 5250 6000
4th 5.70 1750 2650 3525 4400 5300 6150
3rd 7.12 2200 3300 4400 5500 6600
2nd 9.40 2900 4350 5825
1st 15.20 4700 7050

X engine rpm = 1 tire rotation
@13/48 sprockets (3.69) 530 tire

gear ratio km 40 60 80 100 120 140 160 rpm@kmh

5th 6.378 1975 2950 3950 4925 5925 6900 7885
4th 7.48 2300 3475 4625 5775 6950
3rd 9.35 2900 4350 5775 7225
2nd 12.34 3800 5725 7600
1st 19.97 6175

X engine rpm = 1 tire rotation
@14/48 sprockets (3.42) 530 tire

gear ratio km 40 60 80 100 120 140 160 rpm@kmh

5th 5.90 1850 2775 3700 4625 5550 6450 7300 rpm@kmh
4th 6.94 2175 3250 4350 5425 6525 7600
3rd 8.67 2675 4025 5375 6700 8150
2nd 11.45 3550 5300 7100
1st 18.53 5725

X engine rpm = 1 tire rotation
@15/48 sprockets (3.20) 530 tire

gear ratio km 40 60 80 100 120 140 160 rpm@kmh

5th 5.52 1700 2550 3400 4275 5125 5975 6825
4th 6.49 2000 3000 4000 5025 6025 7025
3rd 8.11 2500 3750 5000 6275 7525
2nd 10.71 3300 4975 6600 8275
1st 17.33 5350 8050


X engine rpm = 1 tire rotation
@16/48 sprockets (3.0) 530 tire

5th 5.11=1TR = 1575 2400 3150 3950 4750 5550 6325 rpm@kmh
4th 6.088=1tr = 1900 2825 3775 4700 5650 6600
3rd 7.61=1tr = 2350 3525 4700 5900 7050
2nd 9.98=1tr = 3100 4625 6175 7700
1st 16.192=1tr = 5000 7500





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