besides, if I did the math right, which I am pretty sure I did, the agk tranny will give me close to the same final gear ratio as the qmatic, so it doesnt make too much difference to me. I guess if you havent used the agk tranny, you dont reeally know how loud it is or what maintenance it requires. it doesnt matter to me anyway, i enjoy doing maintenance on my bike. its a good way to gauge how your parts are working.
Predator/Cranny 2 speed
- Thread starter wayne z
- Start date
I haven't used the AGK jackshaft, but I have used go karts and minibikes with the chain on the centrifugal clutch. The chain has to bend a very small radius at very high speed.
This causes the chain and sprockets to wear out rather quickly. The chain will last a little longer if lubed frequently. This slings everywhere and is messy.
A chain secondary isn't so problematic because it travels much slower around the sprockets than the primary.
The AGK jackshaft was originaly made for karts. They don't have to last for many many miles like a MB used for commuting. If you don't mind all the lubing, adjusting and e replacement of chain and clutch sprocket every couple hundred miles, then it's not a problem.
I would perfer the agk jackshaft used with a Maxtorque pully clutch and a belt sheave on the shaft. Then you would be in the quiet low maint realm of the Qmatic.
that sounds like its probably good advice, but does it cost extra? the agk jackshaft is 135, and the standard maxtorque clutch is 38. how do i turn that into a belt primary, what parts do i need, and what is the added cost of parts to convert it to belt primary?
Not sure what the Maxtorque belt clutch costs, maybe a little more than the chain version, maybe not. Talk to Maxtorque, they will sell their clutches direct.
I do know they sell a premium belt clutch with sealed roller bearings for $89. The cats meow of clutches LOL but they also sell the standard belt clutch for a lot less.
Maybe AGK will sell you a jackshaft minus the sprockets and chain for less money, and you can apply that to a belt(about 8 bux) and diecast jackshaft pulley(bout 12 bux). The belt and pulley can be found locally.
Good idea about 2nd opinion. Be sure and ask for reliability compared to a belt vs chain.
Wayne,
I'm glad to hear you may be selling kits. If you don't go all the way with kits, then consider selling a set of plans with templates. So I gather that that on this build your primary will be belt and from the variable pulley it will be chain drive, is that right? What is the advantage in chain drive to the rear wheel as opposed to belt to a sheave on the rear wheel... mostly expense?
I think there is a need out there for a 2 speed tranny for the Predator. I'll be following your thread and wish you all success. Options for people's different needs is a good thing. I'm glad there's a Qmatic kit, the AGK kit, the SBP shift kit and now this.
SB
I'm glad to hear you may be selling kits. If you don't go all the way with kits, then consider selling a set of plans with templates. So I gather that that on this build your primary will be belt and from the variable pulley it will be chain drive, is that right? What is the advantage in chain drive to the rear wheel as opposed to belt to a sheave on the rear wheel... mostly expense?
I think there is a need out there for a 2 speed tranny for the Predator. I'll be following your thread and wish you all success. Options for people's different needs is a good thing. I'm glad there's a Qmatic kit, the AGK kit, the SBP shift kit and now this.
SB
Hey SB. No chains. The primary is belt, and the varipully is on the secondary, so it has to be belt.
Don't think I wanna deal with selling kits. I am considering plans, instructions and templates though.
This is an older thread that was recently revived. My vari speed tranny thread is newer, and the one that I've posted the video clips recently.
Never thought to look at the date of the thread. So that clears things up. I wanted to do the belt drive anyway. I like the look and figure it has to be pretty quiet.
I wouldn't want the hassle of selling kits either. Plans,instructions and templates would be good. I'll be one of your first customers.
SB
i like the use of the varipully and changing gear by tightening the belt
with so much tourque from the HF pred, one could gear the engine higher then normally and use the belt tightener in shorter increments making it a 3 speed.
maybe use a 3spd bike sifter
i mean you have pedals for the takeoff, you should gear it high anyway,
let it cruise in 1st gear(slack) @ 25mph tighten it half way for 2nd, and all the way for 3rd
man that thing would boogie!
ive been running it through my mental MB skematics, its quite handy in a small package
well done
with so much tourque from the HF pred, one could gear the engine higher then normally and use the belt tightener in shorter increments making it a 3 speed.
maybe use a 3spd bike sifter
i mean you have pedals for the takeoff, you should gear it high anyway,
let it cruise in 1st gear(slack) @ 25mph tighten it half way for 2nd, and all the way for 3rd
man that thing would boogie!
ive been running it through my mental MB skematics, its quite handy in a small package
well done
the reason I said I am gonna get in touch with agk and ask them about it is because I saw on their website that they had put one of their transmissions on a motorized bike. In fact, when you add that transmission to your shopping cart, you have to select if you are using the 79cc greyhound or the 99cc predator. I personally dont believe they would sell a transmission to a customer knowing they might use it on a motorbike, if it were not designed to be reliable in that application. but i am still going to get in touch with them later today and ask them.
also figured out what to do for an exhaust. basically something i already did to my current exhaust. i have a pocketbike exhaust that i had to cut to fit on my bike. originally it was held together with fiberglass. i had my head pipe welded recently, but the tailpipe was still glassed. glass started getting too hot and flexing. didnt have the money for another weld job, so i went to home depot and got a copper pipe coupling. I joined the pipe, coated with hi temp silicone, and painted with barbecue paint to seal. I am gonna take the stock exhaust off the predator, cut whatever i have to off so im left with the flange and a couple inches of header, get a copper elbow, attach my tailpipe from my current exhaust, coat with hi temp silicone and paint with barbecue paint. then just figure out a pipe hanger and i am good to go.
I emailed the people at agk. They replied back and assured me that their chain driven jackshaft would be reliable for use on a motorbike, as long as i perform regular maintenance on it, which i have no problem doing. I mentioned in my email that a fellow motorbike enthusiast had advised on a belt driven primary for noise and lower maintenance. in the reply, they stated that a belt drive would be less reliable and wouldnt work as well. they said the belt clutch, which they sell, is great on takeoff, but slips at higher rpm's, especially when more torque is needed. in short, they advised me that those who want the performance and climbing that any motorbike should be capable of should indeed go with the chain driven jackshaft. so thats what i am gonna do. I am saving money wherever i can without sacrificing reliability, and installing the predator on my bike is going to cost me under $350 bucks. that is including the engine, motor mount, transmission, and pipe coupling for my exhaust. i am probably gonna need some help with the install, but i have a buddy that can help.
Well, I disagree with AGK about belt primary on a bike with a preddy. They probably have no experience with this. I say this because I have built 2 Preddys with belt primary, and have had no trouble at all with belt slippage. My first one has almost 1000 miles on the original belts with hardly any wear at all.
Now, on a kart which is much heavier and has more rolling resistance, and a 200cc motor, I could see belt slippage being a problem.This is prolly the experience AGK speaks of.
Here's the one with hi miles.
http://www.youtube.com/watch?v=LDxy...DvjVQa1PpcFOQGyOI5LMkndKLwoxW5uwdnIWGKEGQ7RU=
And here's the one I just finished. Gets to 40mph in about 25 seconds. Watch this one and see if you think the belt is slipping.
http://www.facebook.com/video/video.php?v=428397917176313
There's a reason why you don't see open chain primarys on any production motorbikes or mopeds. Short life and high noise.
I have seen quite a few moped brands that use a v-belt primary though.
Last edited:
Hi guys, it's time for us to speak up now. Our advice and our opinion is starting to get skewed here. I'm not going to jump on a belt drive vs. chain drive debate here. We've used both systems and we like both for different reasons.
The belts are smooth and quiet and we like that. The belt and jackshaft mounted clutch combination slips more on engagement versus a chain drive with a clutch mounted on the output shaft. Again, this is a good thing for a smooth take off from a standing start.
The jackshaft with chain drive has a very positive engagement (limited slippage). The clutch locks up quicker when it's on the output shaft of the engine because it's spinning faster than it would be if mounted on the jackshaft. As a result the shoes fly out with greater speed and provide a solid lock up. I'm not saying this is better...it's a difference we have noted in the two designs which relates to a difference in feel and performance.
We've built several bikes using both systems. Some of our customers would prefer the belt drive for its feel and smoothness. Others, like us, would prefer the chain drive. We are more focused on racing our bikes and chain is what works best for us on the track. Not saying chain is the best system...just our preference for our application.
As far as maintenance is concerned we've had to replace several belts for our customers as well as several chains. The belt change is a messy job as belt dust is everywhere and gets all over your hands. Changing a chain is no fun either as you get chain lube all over your hands. The chain will last a long time as long as you keep it lubed and maintained. And just like the EZM guys discovered with belts, if you use a quality chain it will last much longer than a cheap chain. Chain noise is not an issue for us. If the chain is aligned, lubed and the tension is set properly the chain will not be noisy. Most of us are using a chain secondary.
Those of you who have met us know we're a pretty easy going group. We're not going to put down anyone's product. We are an EZM dealer and currently have a Q-Matic with a custom shaft length for a new project. We own and ride bikes with belt and chain drive systems.
Sorry this went off topic Wayne. We've been watching your two speed as we've been playing with one too. We hope to meet you at a ride or race so we can talk bikes together. You are knowledgeable and give good advice on this forum.
The belts are smooth and quiet and we like that. The belt and jackshaft mounted clutch combination slips more on engagement versus a chain drive with a clutch mounted on the output shaft. Again, this is a good thing for a smooth take off from a standing start.
The jackshaft with chain drive has a very positive engagement (limited slippage). The clutch locks up quicker when it's on the output shaft of the engine because it's spinning faster than it would be if mounted on the jackshaft. As a result the shoes fly out with greater speed and provide a solid lock up. I'm not saying this is better...it's a difference we have noted in the two designs which relates to a difference in feel and performance.
We've built several bikes using both systems. Some of our customers would prefer the belt drive for its feel and smoothness. Others, like us, would prefer the chain drive. We are more focused on racing our bikes and chain is what works best for us on the track. Not saying chain is the best system...just our preference for our application.
As far as maintenance is concerned we've had to replace several belts for our customers as well as several chains. The belt change is a messy job as belt dust is everywhere and gets all over your hands. Changing a chain is no fun either as you get chain lube all over your hands. The chain will last a long time as long as you keep it lubed and maintained. And just like the EZM guys discovered with belts, if you use a quality chain it will last much longer than a cheap chain. Chain noise is not an issue for us. If the chain is aligned, lubed and the tension is set properly the chain will not be noisy. Most of us are using a chain secondary.
Those of you who have met us know we're a pretty easy going group. We're not going to put down anyone's product. We are an EZM dealer and currently have a Q-Matic with a custom shaft length for a new project. We own and ride bikes with belt and chain drive systems.
Sorry this went off topic Wayne. We've been watching your two speed as we've been playing with one too. We hope to meet you at a ride or race so we can talk bikes together. You are knowledgeable and give good advice on this forum.
so long story short, both systems are good for different reasons. the agk jackshaft tranny seems to be a reliable, affordable alternative to the qmatic. I think it will work just fine for me, and will keep the cost of my preddy install under $350. I am just trying to be economical.
Hey AGK, I didn't mean to get opininonated about your product or methods, which I actualy have no experience with, but I do know that all your products and reputation are excellent. Funny how easily a discussion can turn into s debate on the 'net LOL.
Yer right, different drive choices appeal to different people for different reasons.
My system does have the quick lockup that you explained though. My clutch is on the engine. I like this because it allows cruising at lower speed and rpm.
So basicly, my system is a combination of both trannys . Snappy early clutch engagement for low speed cruising and a belt drive for smoothness.
More choices in the 4 stroke MB world is good, :~)
Yer right, different drive choices appeal to different people for different reasons.
My system does have the quick lockup that you explained though. My clutch is on the engine. I like this because it allows cruising at lower speed and rpm.
So basicly, my system is a combination of both trannys . Snappy early clutch engagement for low speed cruising and a belt drive for smoothness.
More choices in the 4 stroke MB world is good, :~)
I'll hafta let AGK chime in on that, I have no experience with both types. I would think that the higher rpm engagement would help off the line, but lower geared drive ratio and early lockup is a better way to achieve your goals, especialy hill climbing.
my gear ratio is going to be 8.89:1. that should be okay for hill cimbing, considering my current gear ratio is about 4:1. currently i dont have much climbing capability. i dont get off the line without pedaling either. is 8.89:1 more torque than 4:1, or less?
