jackshaft kit
- Thread starter oldsurfer
- Start date
BarelyAWake
New Member
Um... yes - it'd work, but I really don't see any advantage without gears as you'd be trading two chains for three: primary chain frm engine to jackshaft, secondary chain frm jackshaft to freewheel chainring, tertiary chain frm chainring to hub.
While it's w/o a doubt worth it for gears, it is in fact added complexity and marginally higher maintenance *shrug* I'd suggest getting a (new) internally geared hub for that clean look or simply using a 5-7sp rear wheel & derailleur to utilize that jackshaft's potential...
Or skipping a jackshaft altogether
While it's w/o a doubt worth it for gears, it is in fact added complexity and marginally higher maintenance *shrug* I'd suggest getting a (new) internally geared hub for that clean look or simply using a 5-7sp rear wheel & derailleur to utilize that jackshaft's potential...
Or skipping a jackshaft altogether
caprirs302
New Member
Um... yes - it'd work, but I really don't see any advantage without gears as you'd be trading two chains for three: primary chain frm engine to jackshaft, secondary chain frm jackshaft to freewheel chainring, tertiary chain frm chainring to hub.
While it's w/o a doubt worth it for gears, it is in fact added complexity and marginally higher maintenance *shrug* I'd suggest getting a (new) internally geared hub for that clean look or simply using a 5-7sp rear wheel & derailleur to utilize that jackshaft's potential...
Or skipping a jackshaft altogether
Ya, it would work just fine, but for the money you wouldn't be getting much. I had a similar situation though. On my bike the motorcycle chain would rub the frame when it was mounted as intended, and a jackshaft solved that problem entirely, but it also still has 7 speeds so it was a bit of a no brainer...
camlifter
Active Member
i've ran a standard coaster brake wheel with a j-shaft before. (shifter hub was broke at the time) with a 20 tooth sprocket on the wheel it comes out to about the same as running the 44 tooth on the other side, a 24 tooth gave more take off power but lowered top speed, a 16 tooth was about like a 32 tooth w/o the j-shaft.
georgebrew
New Member
sounds a little expensive to do if i was going to do it i would definetly use a multi speed set up. with no benifit its just to having it on a single speed bike its just to complex. and if you break a chain you are stranded but if you break a chain with standard set up at least you can still pedal it would be nice if someone would design a two speed gear box
BarelyAWake
New Member
In theory, yes - in practice however I've found that if you break a chain it's either the primary or secondary chains that fail, not the tertiary - which is the only one needed to pedal home (...and I've gone through a couple few chains at this point with the mileage I've accumulated) Actually come to think on it, even if the third chain were to fail ya could always rob a link or two outa the secondary ta getcha home (provided ofc you've a chain breaker w/ya) 
TBH I've a bit of a shameful habit of runnin' kinda cheap chain... I know it's foolish of me but I've not gotten around to replacing it with quality as honestly it's become a bit of a "quantity vs quality" thing... while they're not the "bargain basement" chains, they're not nearly as expensive as a truly good bicycle chain... which TBH kinda offends my sensibilities a bit as I've noticed it's pricing is not dissimilar to decent motorcycle chain... which is just downright odd
...so I carry a chain breaker and a handful of spare links lolz
But I'll agree there's really no benefit at all in having a jackshaft w/o the ability to shift, that in fact it's added complexity would only be a liability in that particular case *shrug*
Actually come to think on it, even if the third chain were to fail ya could always rob a link or two outa the secondary ta getcha home (provided ofc you've a chain breaker w/ya) TBH I've a bit of a shameful habit of runnin' kinda cheap chain... I know it's foolish of me but I've not gotten around to replacing it with quality as honestly it's become a bit of a "quantity vs quality" thing... while they're not the "bargain basement" chains, they're not nearly as expensive as a truly good bicycle chain... which TBH kinda offends my sensibilities a bit as I've noticed it's pricing is not dissimilar to decent motorcycle chain... which is just downright odd
...so I carry a chain breaker and a handful of spare links lolz
But I'll agree there's really no benefit at all in having a jackshaft w/o the ability to shift, that in fact it's added complexity would only be a liability in that particular case *shrug*
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I have a Jack shaft kit but the front two chain rings are the same tooth width, ie both fit motorised bike chain. My question is, isn't one of the chain rings supposed to fit a normal push bike size chain? I'm hoping you guys can help me out, you seem to know your stuff.
I also think the seller did not know what they were selling.
Thanks in advance.
I also think the seller did not know what they were selling.
Thanks in advance.
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MotorBicycleRacing
Well-Known Member
Sounds like you got the shoddy Chinese knock off instead of buying the Made in USA shift kit from it's inventor Sick Bike Parts.
Yes the SBP kit front chain ring fits bicycle chain.
where did you buy it from?
KCvale
Well-Known Member
Wow, old topic (2010).
Motorized bike engine sprockets in come in 410 which is standard coaster brake single speed chain (older Skyhawks used this) and 415 which is fatter.
You can also use 41 which is fatter still for a direct drive or to a jackshaft first sprocket as fatter chain will usually work fine a thinner sprocket.
You can use 415 from the 2nd JS sprocket to the outside sprocket of the dual chain ring but the inner sprocket depends on the sprocket on you back wheel but you need to beware here...
These 2 chains on the front dual pair cross paths, one up, one to the back wheel.
You didn't mention what JS kit exactly you bought but it wasn't it wasn't from Sick Bike Parts, the inventor of the thing.
They come with 410 sprockets for everything but the small inner dual chain ring to the back wheel, that is 7-speed chain (710 I think) which is thinner to accommodate a 7-speed rear derailleur.
If you use an internal geared bike with a single sprocket both 410 and 415 will work but the rub (literally) will be how far apart the sprockets are on the dual chain ring so they don't hit during use.
If you have a 7-speed rear and your inner sprocket is too fat you are in luck, that sprocket easy to change and you get one from Sick Bike parts, if it is the outer one you are screwed as even with the proper Freewheel Removal tool the chances of breaking it free from the threaded pedal arm are less than 50/50 in my experience.
Thanks so much for the information it's really appreciated. i bought my kit off Oz bicycles, I also got screwed on parts and now have to replace the missing pieces, I spoke to the seller and he told me to get the missing pieces from SBP, great service also he knew nothing about motorised bikes. So to those in Australia, just buy from SBP and save the hassle.
I'm wanting to keep the original bike chain and derailleur and 7 speed, so a new sprocket might fix my problem.
I will try to stick with the freewheel I have but I'm not optimistic about getting a sprocket with four stud pattern instead of five. Thanks again .
I'm wanting to keep the original bike chain and derailleur and 7 speed, so a new sprocket might fix my problem.
I will try to stick with the freewheel I have but I'm not optimistic about getting a sprocket with four stud pattern instead of five. Thanks again .
St*ve, from Oz Bicycle 3ngines is a %$#@%&*.
I have a couple of similar crap shift kits that I have made work, See 'Twin Carb Softtail'
I bought a cheap set of front crank rings for like $20, drilled out the studs, and used the smallest ring 28t?, the one in the photo is the middle ring 36t?.
But I ran the secondary chain to the 36t wide section sprocket on the outside of the freewheel and the 28t final drive chain sprocket to the inside with a couple of washers to space them so the chains wouldn't rub.
I've got this kit working quite well, but the sprockets are crap! and may need filling to make work smoothly.
I'll try and get a few more photos up for you.
I have a couple of similar crap shift kits that I have made work, See 'Twin Carb Softtail'
I bought a cheap set of front crank rings for like $20, drilled out the studs, and used the smallest ring 28t?, the one in the photo is the middle ring 36t?.
But I ran the secondary chain to the 36t wide section sprocket on the outside of the freewheel and the 28t final drive chain sprocket to the inside with a couple of washers to space them so the chains wouldn't rub.
I've got this kit working quite well, but the sprockets are crap! and may need filling to make work smoothly.
I'll try and get a few more photos up for you.
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, and St8ve's still selling crap!
Do not buy his crap 'GT5' motors, weird piston/rod combo! unbalanced crap, not to mention all the metal filings and Chinese soil inside the motor.
Yes I had a falling out with him too.
I also had to use a different crank spindle to get everything to line up right.
Throw away the chain tensioners, which are mounted on the wrong side of the chain?
I made sprung tensioners, but didn't have room for it on the secondary chain on the Softtail.
I hope this helps.
Do not buy his crap 'GT5' motors, weird piston/rod combo! unbalanced crap, not to mention all the metal filings and Chinese soil inside the motor.
Yes I had a falling out with him too.
I also had to use a different crank spindle to get everything to line up right.
Throw away the chain tensioners, which are mounted on the wrong side of the chain?
I made sprung tensioners, but didn't have room for it on the secondary chain on the Softtail.
I hope this helps.
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You will like the gear ratios you end up with if you use the same sprockets I have, I worked it out once, in relation to a normal sprocket something like a 56t sprocket down to a 28t? I can't remember. The standard 14 to 28 has more gears than my motor would push happily, It will crawl up steep driveways and cruise at 60 k at minimal revs. I originally got a new 8 speed 11 to 34 ? I think it is, I didn't need the 1st or last gears! And put it on my favorite pedal only bike instead.
I used good Quality BMX chain for the secondary chain and used a half link in there to get the chain to a better length for the Soft tail, I have also shift kitted an alloy mountain bike which was a lot of fun and am still deciding whether to put it back together as the 'Mountain Goat' as I called her or build her in to a single speed Racer.
I have found that my shift kit doesn't seem to like the high revs, and I don't know that it'll get you any faster top speed than a 36 t sprocket might, but great for off roading/cruising.
A pull start is a very worthwhile addition to the shift kit if you can make it fit, as I kept bending the crappy steel crank arms with my moderately high compression motor, and also put a decomp valve in the head, which is not necessary but helpful.
I still havn't got the primary chain to run smooth, and have put it down to crap chain and sprockets and this will be my next upgrade.
I used good Quality BMX chain for the secondary chain and used a half link in there to get the chain to a better length for the Soft tail, I have also shift kitted an alloy mountain bike which was a lot of fun and am still deciding whether to put it back together as the 'Mountain Goat' as I called her or build her in to a single speed Racer.
I have found that my shift kit doesn't seem to like the high revs, and I don't know that it'll get you any faster top speed than a 36 t sprocket might, but great for off roading/cruising.
A pull start is a very worthwhile addition to the shift kit if you can make it fit, as I kept bending the crappy steel crank arms with my moderately high compression motor, and also put a decomp valve in the head, which is not necessary but helpful.
I still havn't got the primary chain to run smooth, and have put it down to crap chain and sprockets and this will be my next upgrade.