automatic 2 gear jackshaft

[CrazyDan]

What are the gear ratios of first and second gear, and what rpm does the second clutch begin to engage. With you engine now ungoverned you might be able to go with a higher engagement speed. I myself would try to get engagement speed at somewhere around 4700-5000 rpm, right around max torque.

 

[Spare_Parts]

So happy it works!

 

[dmopedMA]

Here is a video (I know short and with no much content... I'll do more next time) that shows how it looks:


CrazyDan If you go back few pages, you will see the details of the gear ratio and so, but I'm gonna recap it here:
- First common reduction is the 4G transmission which is a 4:1 reduction
- Second common "reduction" is from the 4G to the second shaft where I put a 10T on the first shaft and a 9T on the second so it's a 10:9 Increase, I know it doesn't make sense, but it is here from when I tried the previos set of springs that were too strong, considering changing it to 10T to 10T.

- 1st gear reduction is from 10T to 48T (4.8:1) - I may put here the 9T that I want to remove from the previous link
- 2nd gear reduction is from 10T to 36T (3.6:1)

TESTING:
So when I was testing, it was not really reliable, improvements are needed here, but I managed to do few laps around the block, what I noticed was that around 10mph, you can hear the pads of the second clutch hitting the bell (kinda bell ticking noise), there rpms (sorry I don't remember how many rpms...) get stuck and speed keeps going up, being like that up to around 20-25 mph (this is not really accurate, my street is short and full with potholes, so better testing needs to be done) there I had to brake to stop but RPMs where not even 6K yet.
Right away I was able to feel like it starts from stop faster than when I had only one gear (40T sprocket), I guess not as fast as if I had only the 48T with no gears since there are now more chains and bearings to be moved.

After few test I noticed that the whole jackshaft was rotated few degrees compared to the frame of the bike (first gear sprocket was closer to the back wheel than the second gear one), and then the first gear chain started to jump out of the 10T sprocket, so improvements on the attaching of the gearbox? (I guess it's a gearbox now ) need to be done, ideas are welcome.

Other issue I noticed is that even that I screw the bolts of the small sprockets quite tight, I lost 2 of them! luckily I had some spares, but I'll be glad to hear your tips about this issue... blue loctite maybe?

I'm not sure when I'm gonna have other day to spend doing more tests, but be sure I'll keep you guys posted!

 

[dmopedMA]

I updated the first post with links to all the most important updates I made so far, I find it useful for such a long thread...

BTW, I forgot to thank again all you guys for your help, support and tips and specially to Tony01 who helped a lot with his experience and his posts in the other forum.

 

[dmopedMA]

I'm going to do an update on this old thread...

After I was able to do few miles on the bike, the gear box moved a bit living the chains out of alignment, I noticed that was a problem, but I never got around fixing it, so I lost interest/didn't have time to work on it... that was back in 2019.

Last summer in 2020, I wanted to give it a try, but I was not able to start the engine... didn't have the time to go over the problem...

This summer I decided I wanted to fix it for real, so I got the engine and the gearbox out of the bike, after few tries of cleaning the carburetor, I got a new one, so the engine is back. I modified a bit the gearbox and added two crews to the bottom of the aluminium case, after installing the gearbox I tighten them, this prevents the whole assembly from moving (I'll add a picture here, I don't have any handy).

Glad to inform that today I was able to run my first 3 miles with no troubles, you can't notice when your are in 1st or 2nd gear, but I'm able to go uphill from stopped way easily, and still able to do +25mph (haven't tested max speed yet, but I expect it to be ~30mph).

I'll keep you posted!

Few pics of how it looks as today: