How do 2 speed Jackshafts work?

[cojaro]

I found some one bmikarts.com

http://www.bmikarts.com/shop/?shop=1&cart=354452&cat=1&itemid=355&&thumbval=thumb

http://www.bmikarts.com/shop/?shop=1&cart=354452&cat=1&itemid=344&&thumbval=thumb

How do these work?
I haven't been able to find anything that explains how it works.

[jrjulien1]

ya i saw those to i think that ther use a gear system that creates two different gear ratios or they use a belt system to change the gear ratio like a torque converter i was going to buy one for my next project theyre pretty cheap btw i was only guessing as to how they work

hope this helps

[cojaro]

ya i saw those to i think that ther use a gear system that creates two different gear ratios or they use a belt system to change the gear ratio like a torque converter i was going to buy one for my next project theyre pretty cheap btw i was only guessing as to how they work

hope this helps
After thinking about it overnight, I think I have an idea how it works.

The larger sprocket (let's say it's 20 teeth) on the jackshaft is 1st gear (gear ratio drive 12: driven 20; or 1: 1 2/3). This sprocket is the one being driven until the clutch on the jackshaft engages at so-and-so rpm, and the now small clutch sprocket (let's say it's 12 teeth as well) is the driven sprocket. Now the gear ratio between the jackshaft and engine is 1:1 instead of 1: 1 2/3.

I'll definitely use this on my go kart, even though I won't be starting on it till spring/summer.

[jrjulien1]

ya theyre a good idea im going to use one the only problem with them is that you cant shift them manually