Jack Shaft

JonnyR said:
ratio and offset the engine is to wide to go strait back
Click to expand...

If you ran a 9 tooth & 54 tooth at 3500 rpm it would be around 45mph, but you still have the offset issue. So with the Jack Shaft it make it easier all around even if it doesn't seem to be easier.
 
dracothered said:
If you ran a 9 tooth & 54 tooth at 3500 rpm it would be around 45mph, but you still have the offset issue. So with the Jack Shaft it make it easier all around even if it doesn't seem to be easier.
Click to expand...
That's a 6 to 1 ratio

9 tooth
54 tooth

5000 rpm = 64 mph`

No motor we use redlines at 3500 rpm and the 99 cc HF
motors won't pull much over 45 mph

So you would need an 80 tooth sprocket to go 45 mph
with a 9 tooth sprocket and I don't know of any centrifugal
clutches that use as small a sprocket as a 9.

`
 
MotorBicycleRacing said:
That's a 6 to 1 ratio

9 tooth
54 tooth

5000 rpm = 64 mph`

No motor we use redlines at 3500 rpm and the 99 cc HF
motors won't pull much over 45 mph

So you would need an 80 tooth sprocket to go 45 mph
with a 9 tooth sprocket and I don't know of any centrifugal
clutches that use as small a sprocket as a 9.

`
Click to expand...

oops, forgot about the centrifugal clutch.... HAHAHA
 
gokart25 said:
Why do all the 4 stroke bikes have a jack shaft?
Why can't they run right off the clutch, to the rear wheel?
Click to expand...

i dont have a jack shaft i have a 60 tooth rear sprocket with 9 tooth output on the trans from a 4 g tranny.. i do 20 mph tops but then again im 300 lbs.. lol ive wanted one of those kits but who has 200 to shell out anymore
 
locutus_1 said:
i dont have a jack shaft i have a 60 tooth rear sprocket with 9 tooth output on the trans from a 4 g tranny.. i do 20 mph tops but then again im 300 lbs.. lol ive wanted one of those kits but who has 200 to shell out anymore
Click to expand...
The 4G tranny is the jack shaft.
That makes your bike have 2 final drive ratios not one.

20 teeth
80 or 100 teeth

9 teeth
60 teeth
 
The cheapest and easiest way to use a HF 99cc would be to use
11t #35 clutch and 20" wheel on a rear rack, IF you could mount a
72t rear sprocket. This would give 45 mph at 5000 rpm. Rider would
probably need to be under 180 lbs. and need to pedal up to 10 mph.
 
then there is the problem of the bike never wanting to stay upright thats a heavy engine to even consider rack mounting
 
JonnyR said:
then there is the problem of the bike never wanting to stay upright thats a heavy engine to even consider rack mounting
Click to expand...

Indeed.

My 2 stroke over rear is about 25~lbs in total with rear rack mounts included. I couldn't imagine a 30lb motor plus the mounts
 
Many of the ebike racers mount their batterys higher than i would expect.
For racing there may be an advantage.

With a 20" wheel at least your mount would be would be 6" lower than
on an 26" wheel.

One of Scotto's early race bikes was a 196cc on a rear rack:
 

Attachments

  • img1428q.jpg
    img1428q.jpg
    69.2 KB · Views: 209
You must log in or register to reply here.
Back
Top