what is a Jackshaft?

[JerboaJohn]

lolz,,
I take it at face value, someone asked an innocent Q and might been confused what they find on a search.
there's jokers here for real!

 

[The_Aleman]

Easiest answer:

In general, a jackshaft is any shaft that is used as an intermediary transmitting power from a driving shaft to a driven shaft.

Jackshaft - Wikipedia

en.wikipedia.org

Weird Al answer, sung to the tune of "Spam":

If you're geared low, go to the store
Carry some money to help you buy more
The shaft is there to hold onto gears
The gears are there to spin with the shaft

Oh, spam on my screen at home
(Do a search)
Think about selection, are there different threads now?
(Let's read)

 

[HumanPerson]

Does anyone make a belt jackshaft kit?

 

[PsychDoc]

Found this thread searching "jackshaft vs offset" Glad i didn't ask

 

[gary55]

This is a jack shaft and this is what you stick it in.
View media item 61603
View media item 61556
View media item 61555

 

[DistantWolrld101]

let say you have a 2-stroke engine, with a single speed bike, is there really any point in getting it if so what are the gains in getting it other then no more ragjoint sprocket lol

i was always told more speed but is this true?

 

[PsychDoc]

Gary- first, that's a cool bike! second- in the first picture the 'powered' chain seems to connect to the pedal side, yes? at first blush one would think your pedals are spinning like a Tasmanian devil- but I know that is not happening. What is happening there? and no coaster break option?

oh- not to get to personal here, but what is that extra wire on your air filter?

 

[gary55]

let say you have a 2-stroke engine, with a single speed bike, is there really any point in getting it if so what are the gains in getting it other then no more ragjoint sprocket lol

i was always told more speed but is this true?

If you have the power you get more speed and great hill climbing ability. Very quick acceleration. Cruise at 1/2 throttle going 30mph so longer engine life. I have had this setup for 2 years now and with minor adjustments have never had a chain issue.

Thinking back the only issues I can recall is 1 bad CDI, chain adjustments, fuel filter. brake adjustments/pads, 1 time I let the air filter get dirty enough to run rich, and air filter grommet got loose enough to make me put some modified cable shield springs on it for a fail safe. It didn't fall off, but I knew once I noticed it it would If I didn't do something. They have been there at least a year now.

 

[gary55]

Gary- first, that's a cool bike! second- in the first picture the 'powered' chain seems to connect to the pedal side, yes? at first blush one would think your pedals are spinning like a Tasmanian devil- but I know that is not happening. What is happening there? and no coaster break option?

oh- not to get to personal here, but what is that extra wire on your air filter?

Thank you Sir.The ring gears are connected to a freewheel so pedals spin freely when not under load. On another bike I have with a similar setup I did have a freewheel go bad. Luckily I was going slow so no injury just had to ride looking like a idiot with my legs sticking out in the air till I got home.
No problems with this one and when I contacted the supplier they said they had a batch that came with no shield on one side. I had already replaced it by then so have to take their word on that.
The springs are a 2hp bolt on made from cable guards that also serve as a fail safe holding the filter on. It didn't fall off, but the loose grommet got me scary.
No coaster option with a freewheel shifter setup.

 

[gary55]

let say you have a 2-stroke engine, with a single speed bike, is there really any point in getting it if so what are the gains in getting it other then no more ragjoint sprocket lol

i was always told more speed but is this true?

I didn't answer the main question. No real advantage with a single speed unless you have serious chaining issues like on a fat tire bike.