Theoretical Motor Perf Estimator
by: Kurlon

Motor - 55 mm x 41 mm x 2 cylinders - 194.82 cc / 11.93 ci
Target CR - 9.0:1

Bore : Stroke Ratio - 1.34 : 1
Max RPM - 14868 RPM with a cast piston (4000' per min max)
Max RPM - 22302 RPM with a forged piston (6000' per min max)

Cam Data - Intake Valve Count - 1 - Valve Size - 28 mm - Intake Lift -  6.24 mm
Suggested minimum intake valve lift - 7.00 mm [1]
Suggested maximum intake valve lift - 11.20 mm [2]
Your cam specs are undersized for your valves.

Simulating a 18 mm carb

Motor Perf Estimation - Rear Wheel HP
 RPM  |  Mean  | Mach  |  Mach | Intake |  Carb  |  HP  |  CR
      | Piston | Index |  With |  Flow  |  Flow  |      | Adju.
      | Speed  |  [3]  |  Lift | dm/sec | dm/sec |  [5] |  HP
      | m/sec  |       |  [4]  |  [6]   |  [6]   |      |  [7]
------+--------+-------+-------+--------+--------+------+-------
3000  |    4.1 |  0.12 |  0.13 |  44.37 |  59.81 |  5.8 |  5.4
3500  |    4.8 |  0.14 |  0.16 |  51.76 |  69.78 |  6.7 |  6.3
4000  |    5.5 |  0.16 |  0.18 |  59.15 |  79.75 |  7.7 |  7.2
4500  |    6.2 |  0.18 |  0.20 |  66.55 |  89.72 |  8.6 |  8.1
5000  |    6.8 |  0.20 |  0.22 |  73.94 |  99.69 |  9.6 |  9.0
5500  |    7.5 |  0.22 |  0.25 |  81.34 | 109.65 | 10.5 |  9.9
6000  |    8.2 |  0.24 |  0.27 |  88.73 | 119.62 | 11.5 | 10.8
6500  |    8.9 |  0.26 |  0.29 |  96.13 | 129.59 | 12.5 | 11.7
7000  |    9.6 |  0.28 |  0.31 | 103.52 | 139.56 | 13.4 | 12.6
7500  |   10.2 |  0.30 |  0.33 | 110.91 | 149.53 | 14.4 | 13.4
8000  |   10.9 |  0.31 |  0.36 | 118.31 | 159.50 | 15.3 | 14.3
8500  |   11.6 |  0.33 |  0.38 | 125.70 | 169.47 | 16.3 | 15.2
9000  |   12.3 |  0.35 |  0.40 | 133.10 | 179.43 | 17.3 | 16.1
9500  |   13.0 |  0.37 |  0.42 | 140.49 | 189.40 | 18.2 | 17.0
10000 |   13.7 |  0.39 |  0.45 | 147.89 | 199.37 | 19.2 | 17.9
10500 |   14.3 |  0.41 |  0.47 | 155.28 | 209.34 | 20.1 | 18.8
11000 |   15.0 |  0.43 |  0.49 | 162.67 | 219.31 | 21.1 | 19.7
11500 |   15.7 |  0.45 |  0.51 | 170.07 | 229.28 | 22.1 | 20.6
12000 |   16.4 |  0.47 |  0.54 | 177.46 | 239.25 | 23.0 | 21.5
12500 |   17.1 |  0.49 |  0.56 | 184.86 | 249.21 | 24.0 | 22.4
13000 |   17.8 |  0.51 |  0.58 | 192.25 | 259.18 | 24.9 | 23.3
13500 |   18.4 |  0.53 |  0.60 | 199.65 | 269.15 | 25.9 | 24.2
14000 |   19.1 |  0.55 |  0.62 | 207.04 | 279.12 | 26.8 | 25.1
14500 |   19.8 |  0.57 |  0.65 | 214.43 | 289.09 | 27.8 | 26.0
15000 |   20.5 |  0.59 |  0.67 | 221.83 | 299.06 | 28.8 | 26.9
15500 |   21.2 |  0.61 |  0.69 | 229.22 | 309.03 | 29.7 | 27.8
16000 |   21.9 |  0.63 |  0.71 | 236.62 | 318.99 | 30.7 | 28.7
16500 |   22.6 |  0.65 |  0.74 | 244.01 | 328.96 | 31.6 | 29.6
17000 |   23.2 |  0.67 |  0.76 | 251.41 | 338.93 | 32.6 | 30.5
17500 |   23.9 |  0.69 |  0.78 | 258.80 | 348.90 | 33.6 | 31.4
18000 |   24.6 |  0.71 |  0.80 | 266.19 | 358.87 | 34.5 | 32.3



Bore:             mm
Stroke:           mm
Cylinder Count:   cylinders
Compression Ratio::1

Intake Valve diameter:mm
Intake Valve count   :
Intake Valve max lift:mm

Carb size:mm

Drivetrain Efficiency:%



[1] http://www.v-eight.com/tech_forum/viewtopic.php?t=148
[2] http://forums.dragbike.com/forum_posts.asp?TID=665
[3] http://www.forgecycle.com/FF/2v4.htm and http://www.rbracing-rsr.com/machcalc.html
[4] http://www.x386.net/TTR/tech/cgi-bin/motorsim.cgi This was based on multiple sources which I failed to write down at the time...
it uses some baked numbers that I haven't reversed out yet.
[5] HP is computed by taking the ideal CFM of the engine based on displacement, reducing it by the user set VE and dividing by 1.62
based on SAE HP correction table standard atmospheric conditions and stochiomatic mixture.
[6] http://web.archive.org/web/20080618032018/http://www.armyofdarkness.com/homepage/1995-6.htm
[7] http://www.bgsoflex.com/crchange.html Adjusted HP is based on 11.5:1 compression being the norm.

This sim underestimates modern engines horribly.  Punch up the numbers for a current supersport bike to see.