ColdCruiser
Member
Tight on space...
Predator 79 Transmission Options?
- Thread starter ColdCruiser
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ColdCruiser
Member
Going to need a different transmission option...
I'm always a little hesitant to try a new supplier because you never know if you will receive your parts quickly, if it will be missing anything, if it will work, and if you can return it if it doesn't work. On top of all that, it's hard to tell if you're dealing with a rickety operation run from a garage or just what. Generally I'm willing to give people the benefit of a doubt.
Anyway, I should have known there might be an issue when AffordableGoKarts com didn't stock the clutch they recommended to fit their custom jackshaft, especially since it seems to be the most popular clutch on the market. Not really a big deal, except now I have a max-torque clutch on the way from someone else, but no transmission!
Here's the part that kills me... AffordableGoKarts com WILL NOT SHIP to anywhere EXCEPT your billing address. This does me no good because I live in California but I'm building a bike in Arizona. My billing address does not accept deliveries anyway! Why does every invoice ever printed have both a "billing" address AND a "shipping" address?? BECAUSE I'm not the first person with this setup! I even paid with PayPal who has verified me, my phone, email, hundreds of successful transactions, etc. This doesn't even seem like a real business to me.
I admit that I'm a bit perturbed by this, maybe others will have a better experience trying to deal with them. Basically, I guess I feel a bit insulted because David Pothe wants me to trust him as a supplier and take the risk of dealing with his business for his profit but is not willing to trust me as a customer even when I pay in advance?? <sigh>
Anyway, it looks like I'll need a different option for the extra reduction gear. Other suggestions?
I'm always a little hesitant to try a new supplier because you never know if you will receive your parts quickly, if it will be missing anything, if it will work, and if you can return it if it doesn't work. On top of all that, it's hard to tell if you're dealing with a rickety operation run from a garage or just what. Generally I'm willing to give people the benefit of a doubt.
Anyway, I should have known there might be an issue when AffordableGoKarts com didn't stock the clutch they recommended to fit their custom jackshaft, especially since it seems to be the most popular clutch on the market. Not really a big deal, except now I have a max-torque clutch on the way from someone else, but no transmission!
Here's the part that kills me... AffordableGoKarts com WILL NOT SHIP to anywhere EXCEPT your billing address. This does me no good because I live in California but I'm building a bike in Arizona. My billing address does not accept deliveries anyway! Why does every invoice ever printed have both a "billing" address AND a "shipping" address?? BECAUSE I'm not the first person with this setup! I even paid with PayPal who has verified me, my phone, email, hundreds of successful transactions, etc. This doesn't even seem like a real business to me.
I admit that I'm a bit perturbed by this, maybe others will have a better experience trying to deal with them. Basically, I guess I feel a bit insulted because David Pothe wants me to trust him as a supplier and take the risk of dealing with his business for his profit but is not willing to trust me as a customer even when I pay in advance??
<sigh>Anyway, it looks like I'll need a different option for the extra reduction gear. Other suggestions?
ColdCruiser
Member
Perhaps one of these...
$130 (plus $22 shroud) - GTC JACKSHAFT KIT [1201]
http://gtcmanufacturing.com/GTC-Jackshaft-Gear-Reduction-Kit-Gokart.aspx
$65 - 1056 - GTC Bicycle Engine Jackshaft Plate, GX120(3.5hp)/160(5.5hp)/200 Lifan(2.5)
http://gtcmanufacturing.com/GTC-Bicycle-Engine-Jackshaft-Plate.aspx
$109 - PMR Jackshaft (13t - 15t)
http://www.nrracing.com/product-p/pmrjackshaft1315.htm
$120 - PMR Jackshaft Kit 79-97cc
http://www.shop.hotrodminibike.com/PMR-Jackshaft-Kit-79-97cc-PMRJSK.htm
$99 - Jack shaft kit only 35 chain
http://www.909minibikes.com/Jack-shaft-kit-only-35-chain-CM500.htm?productId=8
$130 (plus $22 shroud) - GTC JACKSHAFT KIT [1201]
http://gtcmanufacturing.com/GTC-Jackshaft-Gear-Reduction-Kit-Gokart.aspx
$65 - 1056 - GTC Bicycle Engine Jackshaft Plate, GX120(3.5hp)/160(5.5hp)/200 Lifan(2.5)
http://gtcmanufacturing.com/GTC-Bicycle-Engine-Jackshaft-Plate.aspx
$109 - PMR Jackshaft (13t - 15t)
http://www.nrracing.com/product-p/pmrjackshaft1315.htm
$120 - PMR Jackshaft Kit 79-97cc
http://www.shop.hotrodminibike.com/PMR-Jackshaft-Kit-79-97cc-PMRJSK.htm
$99 - Jack shaft kit only 35 chain
http://www.909minibikes.com/Jack-shaft-kit-only-35-chain-CM500.htm?productId=8
Last edited:
The_Aleman
Well-Known Member
#35 chain is 3/8" pitch, or 0.375". Your clutch will also be #35. You will want at least 3:1 reduction from your transmission (ie: 11T -> 33T). 4:1 is better, really.
Not sure what you're asking here. Keep in mind that SBP's sprockets are for bicycle chain, 1/2" pitch, 1/8" or 3/32" width chains.
The 17T will be a 1/2" pitch sprocket. The 22T will be #35. You can only make the 22T work in the 17's place if your transmission output is also #35.
If you decide you want even more engine-to-crank reduction, we will need to rethink your pedal-side gears again to lower hub torque and increase speed.
If you replace the 17T with the 22T, you will be increasing reduction, making taller pedal gears necessary. You may need a 44T inner crank to compensate.
Regardless, you'll want to drop your hub gear to a 15T. You're going to making quite a bit of torque with engine and legs combined, it's easy to overload the hub.
I have 69.09:1 EtoC reduction on my bike and run 44T -> 15T. Your engine with governor has effectively half the revs of mine, so around 40:1 reduction may be optimal.
40:1 EtoC = 25 pedal rpm per 1000 engine. The average person pedals between 40 and 80 rpm. With a 44-15 pedal gear and 3-speed IGH you would have:
1st: 18.18:1, (8.3 @ 2000, 15.4 @ 3600)
2nd: 13.64:1, (11.4 @ 2000, 20.5 @ 3600)
3rd: 10.25:1, (15.2 @ 2000, 27.4 @ 3600)
38MPH @ 5000 no governor
Slightly lower gearing, but now with a considerable torque advantage. Your bike would be a monster with engine + legs. Mine does 0-30MPH in 4 seconds, yours may too!
Which is why you'll have to test fit things so you know what size gear you're limited to. I switched my 17T to an 18T, I can't fit any larger, for example.
The GTC plate looks good. You're gonna need to customize the input/output gears on transmission anyway to achieve the reduction you want.
Don't let AGK get ya down. They can be problematic to deal with. If they are a problem, do business elsewhere
Last edited:
KCvale
In memory of KCvale 1959 - 2019
Then why the big engine and all the extra work and expense?
You could have just dropped in a 49cc HS with a 4G right on the SBP JS kit you have installed, they work perfect together.
No muss, no fuss, and work great with a 3-speed.
ColdCruiser
Member
That's a good looking ride. I actually had something real close to that in mind. I definitely considered everything I could think of. In retrospect, I probably should have started with a 49. It's still an option if it becomes too difficult this way.
Honda GXH50
http://www.smallenginewarehouse.com/
$225 Honda GXH50QHA 2.5hp Horizontal 5/8"x1-5/8" Keyed Shaft,
To answer your question...
I wanted a 4-stroke for less noise and maintenance. The HF 79 is half the cost of the Honda (I thought that mattered somehow). I thought it was an American engine and that seemed like a bragging point. OHV sounded like a good idea. Easy to find cheap replacements. Lots (well some) aftermarket and performance parts.
I actually DID decide that the Honda (or HS even) with the Grubee 4G setup WAS just what I was looking for. BUT they seem to be non-existent. There have been none for many months. I even came across posts about no availability from YEARS ago. Legal disputes, etc. "They're on the way" and stuff like that is not very reassuring. The other basic kits appear to be cheaper knock-offs of the cheap china kits which knock-off japan.
The bottom line was that I figured if I build it using the best parts I can, it will last for a decade and I won't have to scrap it and build another one. I usually don't have access to a garage and tools.
Another thing is I've been worried about the weight of me and the dog. I've put on a few pounds and she's put on a few pounds. Our combined weight is around 300 lbs. It's also a big heavy steel bike with a bunch of gear and pulling a little trailer for my dog. I didn't want to strain the parts too bad. I want to keep up with (or pass) regular bicycles. I don't want to push it up hills.
Since this is my first one, I really don't know what I'm talking about. The 49 might be able to handle it. As I'm finding out, a lot has to do with the gears.
It's starting to shape up as a real nice ride but progress has been slower than I'd like, everything is more expensive than expected, and I won't be able to really tell how it does until it's 90% finished. It's kinda fun to build it. I can choose specific parts for everything. It's not too expensive. I have a little budget because it might be my main transportation. This forum and others are very helpful. I enjoy reading and talking about people building these. I've wanted one for 30 years, lol.
Cheers!
Honda GXH50
http://www.smallenginewarehouse.com/
$225 Honda GXH50QHA 2.5hp Horizontal 5/8"x1-5/8" Keyed Shaft,
To answer your question...
I wanted a 4-stroke for less noise and maintenance. The HF 79 is half the cost of the Honda (I thought that mattered somehow). I thought it was an American engine and that seemed like a bragging point. OHV sounded like a good idea. Easy to find cheap replacements. Lots (well some) aftermarket and performance parts.
I actually DID decide that the Honda (or HS even) with the Grubee 4G setup WAS just what I was looking for. BUT they seem to be non-existent. There have been none for many months. I even came across posts about no availability from YEARS ago. Legal disputes, etc. "They're on the way" and stuff like that is not very reassuring. The other basic kits appear to be cheaper knock-offs of the cheap china kits which knock-off japan.
The bottom line was that I figured if I build it using the best parts I can, it will last for a decade and I won't have to scrap it and build another one. I usually don't have access to a garage and tools.
Another thing is I've been worried about the weight of me and the dog. I've put on a few pounds and she's put on a few pounds. Our combined weight is around 300 lbs. It's also a big heavy steel bike with a bunch of gear and pulling a little trailer for my dog. I didn't want to strain the parts too bad. I want to keep up with (or pass) regular bicycles. I don't want to push it up hills.
Since this is my first one, I really don't know what I'm talking about. The 49 might be able to handle it. As I'm finding out, a lot has to do with the gears.
It's starting to shape up as a real nice ride but progress has been slower than I'd like, everything is more expensive than expected, and I won't be able to really tell how it does until it's 90% finished. It's kinda fun to build it. I can choose specific parts for everything. It's not too expensive. I have a little budget because it might be my main transportation. This forum and others are very helpful. I enjoy reading and talking about people building these. I've wanted one for 30 years, lol.
Cheers!
Last edited:
The_Aleman
Well-Known Member
If you have to ask that, you're a decent but overrated bike assembler rather than the wise old bike builder you try to portray yourself as.
You've never fooled me since day 1, FYI. I recall countless threads where you didn't know what the heck you were talking about; fumbling the simplest details
1) The 79 is cheaper, makes at least twice the torque (and down low), very reliable, replacement/performance parts are readily available
2) The clutch system is far more robust, far less bushing fuss, no bearing mod necessary. Performance parts easy to obtain
3) The transmission gearing is far more customizeable; the jackshaft system doesn't have to use SBP mount
4) No waiting for Chinese slow boats for Huasheng or Grubee parts.
Right about now you might like to advertise your own 10G shifter system. But I'll point out some things about your 10G:
1) Your 10G has a terribad engine-to-crank reduction ratio, it just overspeeds the drivetrain, pedal is lost under engine
2) Your system is nearly as wide as a 79 with PMR jackshaft, probably wider if using the 53CC Huasheng
3) You're stuck with a Huasheng, while a nice little engine, it will lug under 3600 and doesn't have much torque
4) Your system is supplied by Chinese slow boats, therefore subject to parts unavailability
5) Your system is proprietary
Overall the 79 route might cost more, but that should be no surprise. It's not a mass-produced kit; it's much more capable.
Might as well do it the best you can the first time, right? I mean, get it as right as you can. Many of us keep tinkering even after we're "done"
lol
Last edited:
ColdCruiser
Member
#35 Engine Gears
$19.50 - Tritan #35 Sprocket [35BS40HX] 3/8" Pitch, 5/8" Bore, 40 Teeth, 5.0" dia,
http://www.globalindustrial.com/p/m...35bs40hx58-38-pitch-58-finished-bore-40-teeth
$16.25 - Tritan #35 Sprocket [35BS33HX] 3/8" Pitch, 5/8" Bore, 33 Teeth, 4.2" dia,
http://www.globalindustrial.com/p/m...35bs33hx58-38-pitch-58-finished-bore-33-teeth
$19.50 - Tritan #35 Sprocket [35BS40HX] 3/8" Pitch, 5/8" Bore, 40 Teeth, 5.0" dia,
http://www.globalindustrial.com/p/m...35bs40hx58-38-pitch-58-finished-bore-40-teeth
$16.25 - Tritan #35 Sprocket [35BS33HX] 3/8" Pitch, 5/8" Bore, 33 Teeth, 4.2" dia,
http://www.globalindustrial.com/p/m...35bs33hx58-38-pitch-58-finished-bore-33-teeth
ColdCruiser
Member
I ordered a few new items today...
- Switch inner crank from 30T to 36T
I'm not sure how this will play out but I'm willing to give it a shot. (NOTE: The existing pedal/gear ratios are pretty good for easily cruising around at slow to med speeds.) Jim at SBP took a couple of minutes to help me solve a couple issues so I decided to throw him my business. He has 36T-44T, they are each around $9. I ordered a 40T. If that doesn't work out, I can try larger or smaller.
http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=197
- Switch rear hub from 18T to 15T
Sturmey Archer Sprocket 15T x 1/8 - HSL715
This part number is sold out in America. It's 3 Euros from England but that might take a while or get lost. A couple of US vendors have one but it is priced very high. The 15t and smaller are flat instead of dished. Sturmey-Archer 1/8" 15t coaster brake cog looks like exactly the same thing by the images and description (FW2206/HSL850?). I ordered one. I'll see if it works when it gets here I suppose.
- Different option for extra reduction gear
The one AGK was selling is the PBR jackshaft kit with a 22t instead of a 17t. The product literature boasts about all the gears going on the front, so I chose to go with the GTC one instead. GTC has a couple different versions. One seems designed more for a torque converter and has extra flanges. The one I ordered looks more like a flat plate of aluminum with some holes in it. It comes as a kit with bearings, hardware, shaft, and gears. The large gear is only a 17t so it will need to be replaced. I realized that gear goes on the front so there is no shortage of space. I can probably go pretty large there. I suppose I will take some measurements and see if I can find a 44(?). I'll probably have to get a "mini-hub"(?). I'll look into that.
$120 - 1055 - GTC Bicycle Engine Jackshaft Kit
http://gtcmanufacturing.com/gtc-bicycle-engine-jackshaft-kit.aspx
I updated my drawing a little...
- Switch inner crank from 30T to 36T
I'm not sure how this will play out but I'm willing to give it a shot. (NOTE: The existing pedal/gear ratios are pretty good for easily cruising around at slow to med speeds.) Jim at SBP took a couple of minutes to help me solve a couple issues so I decided to throw him my business. He has 36T-44T, they are each around $9. I ordered a 40T. If that doesn't work out, I can try larger or smaller.
http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=197
- Switch rear hub from 18T to 15T
Sturmey Archer Sprocket 15T x 1/8 - HSL715
This part number is sold out in America. It's 3 Euros from England but that might take a while or get lost. A couple of US vendors have one but it is priced very high. The 15t and smaller are flat instead of dished. Sturmey-Archer 1/8" 15t coaster brake cog looks like exactly the same thing by the images and description (FW2206/HSL850?). I ordered one. I'll see if it works when it gets here I suppose.
- Different option for extra reduction gear
The one AGK was selling is the PBR jackshaft kit with a 22t instead of a 17t. The product literature boasts about all the gears going on the front, so I chose to go with the GTC one instead. GTC has a couple different versions. One seems designed more for a torque converter and has extra flanges. The one I ordered looks more like a flat plate of aluminum with some holes in it. It comes as a kit with bearings, hardware, shaft, and gears. The large gear is only a 17t so it will need to be replaced. I realized that gear goes on the front so there is no shortage of space. I can probably go pretty large there. I suppose I will take some measurements and see if I can find a 44(?). I'll probably have to get a "mini-hub"(?). I'll look into that.
$120 - 1055 - GTC Bicycle Engine Jackshaft Kit
http://gtcmanufacturing.com/gtc-bicycle-engine-jackshaft-kit.aspx
I updated my drawing a little...
ColdCruiser
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