Roller Bearing Failure Survey Thread

Hi MikeJ

Thankyou so very much in providing this information - really, thankyou so very much.

Ok

Can you please tell me the number of sprocket teeth on each of the cogs on your cassette.

On my bike i currently run a 9 speed Shimano Deore 11-32T (11 , 12 , 14 , 16 , 18 , 21 ,24 , 28 , 32).

With the 11 tooth optional sprocket fitted to the Jackshaft and when i'm in first gear (32 tooth sprocket), my bike is down to 8 kilometers per hour (5 miles an hour) before i have to help the motor with pedal power.
In top gear (11 tooth cassette sprocket), i don't exceed 50 kilometers per hour (31 miles an hour) and change gears at 35 kilometers per hour (21 miles per hour).

I would love to know what rpm's the engine is spinning at whilst travelling at the above listed speeds.

Kind regards

Fabian
 
Hi Foximus

I want to gain an intimate association with this motor, that's why i am relying on your intellectual fortitude and mechanical knowledge of gaining blueprint specs.

I am again in agreement with your comment: in a 2 stroke motor you already have ignition (depending on a setup) at 20-30* before TDC. And not only that, it is fighting against 125-185 static PSI.
Having said that, the cushioning effect can be overcome depending on how hard the engine is over revved.


Calling MikeJ on this one.

Can you please do the math to give me an rpm figure (and this is only a hypothetical situation for any law enforcement authority watching this thread) if a 2-stroke motorised bicycle engine was able to rev high enough to give a speed figure of 79.6 kilometers per hour (49.75 miles per hour) with an 11 tooth jackshaft output sprocket and an 11 tooth cassette sprocket.

Fabian
 
Hi Foximus

I want to gain an intimate association with this motor, that's why i am relying on your intellectual fortitude and mechanical knowledge of gaining blueprint specs.


Fabian


well currently I have no knowledge of this motor as mine hasn't arrived yet. lol :rolleyes:


And unfortunately I'm going to force myself to install and run it for a week before I tear it back down and start with the blueprinting, so I can get accurate before and afters.
 
Last edited:
Just figure your average piston speed to be at 3500 ft per minute and you will be safe from most needle bearing failures.

Cm = 0.166 x L x N

Where Cm is mean piston speed in feet/min
L is stroke in inces
N is cranshaft speed - rpms
 
BGF 66CC slant head.
about 300 miles on engine using Lucas semi-synthetic 20:1
Flat road going about 20 MPH.

Bikeberry 66CC
1300 miles on engine
flat road going 15 MPH
 
Back
Top