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bullsmj23n

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Seems like i will need a adapter to attach the sprocket to, will the adapter ever slip since its being tightened on the hub? This seems like the best route to go atm. Manic Mechanic seems like they offer custom stuff is this the route to go?
 
MotorBicycleRacing

MotorBicycleRacing

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bullsmj23n said:
Seems like i will need a adapter to attach the sprocket to, will the adapter ever slip since its being tightened on the hub? This seems like the best route to go atm. Manic Mechanic seems like they offer custom stuff is this the route to go?
Click to expand...
What diameter is your hub?
There are also a few stock hub adapter sizes made.

MM hub adapters do not slip if you have an accurate
measurement which equals a tight fit around the hub.
They are available here.
CUSTOM ADAPTERS

I just got a wheel that had a 1.097" MM adapter on it and it
was on so tight that I had to use a 9" cheater bar to crack it
loose. The adapters do not have to be that tight.

The 3 bolts holding the sprocket to the adapter need to be
snugged down good though. Use a short cheater bar on the
allen wrench to tighten.
 
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bullsmj23n

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I need to get the tool from hf to measure my hub, thanks for the reply, I was worried that the adapter would slip, but it seems like it's greatly made.
I will go forward with MM it seems. What sprocket should i get?, don't need to go 40mph, i want to be able to climb some hills.
 
GearNut

GearNut

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He will make any tooth size you want. A 50 tooth will pull you up quite steep hills, but have a slooow top speed. 25 mph or so with the engine screaming it's little guts out.
 
MotorBicycleRacing

MotorBicycleRacing

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bullsmj23n said:
I need to get the tool from hf to measure my hub, thanks for the reply, I was worried that the adapter would slip, but it seems like it's greatly made.
I will go forward with MM it seems. What sprocket should i get?, don't need to go 40mph, i want to be able to climb some hills.
Click to expand...
I think you have a HF 6.5 hp and you want to do something
crazy like rack mounting it on a 26" bike??

Can not help you with a sprocket size unless I know all the details
like what gearbox you are using.
Not a real great idea is my opinion. Lot of bulk, weight and power in
the wrong place. going to be very unstable.
HF 6.5 hp motor is too big a motor for most builds and especially for a
first build.

scotto- made a 4.2 hp motor with a Q Matic rack mount but it was on a tandem which made it somewhat workable.
 
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bullsmj23n

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I am not going to use a gearbox, I've started up the engine yesterday it's not as bad as what people make it with the vibrations ect. I don't see the issue to be honest, it weighs 33 lbs with no fluids, i am sure if the weight is more on one side of the bike i will still be able to balance it out, i am not worried there lol... It's not like it's going to be 100 lbs on one side. I am going to pick up a rack from walmart that supports up to 100lbs which will be plenty in reality the rack can prob support 150lbs, I am looking for a basic setup not a gearbox/or cvt. Just a sprocket adapter, sprocket and a clutch with a built on sprocket to it?
 
MotorBicycleRacing

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Download the ratio calculator and start playing with it.
jpilot's Gear Ratio Calculator - - MotoredBikes.com: Motorized Bicycle Forum
I like to have 3 open side by side to try our different set ups.

No one said anything about vibrations being a problem. Those 6.5 hp
are smooth.

bullsmj23n said:
I am not going to use a gearbox, I've started up the engine yesterday it's not as bad as what people make it with the vibrations ect. I don't see the issue to be honest, it weighs 33 lbs with no fluids, i am sure if the weight is more on one side of the bike i will still be able to balance it out, i am not worried there lol... It's not like it's going to be 100 lbs on one side. I am going to pick up a rack from walmart that supports up to 100lbs which will be plenty in reality the rack can prob support 150lbs, I am looking for a basic setup not a gearbox/or cvt. Just a sprocket adapter, sprocket and a clutch with a built on sprocket to it?
Click to expand...
 
spad4me

spad4me

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(My six hp two stroke engine with the 5 to 1 tranny feeding a sick bike parts front freewheel crank setup which feeds a 7 speed mega range freewheel.) These parts weigh about 12 pounds total. over the stock bike
A monster 40 to 1 reduction in first to as fast as I dare to go on a bicycle.

You are going to be frustrated at every turn. Engine too heavy. Drive train reduction too small for decent performance.
Sure the calculator says it will do 60 or maybe more. But can you peddle up the the speed that the engine starts to make usable power.

A 44 tooth sprocket will never work , more like a 244 tooth sprocket.
 
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GearNut

GearNut

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Aww to heck with it! Just weld chain ring teeth to the rear rim. :D

With only a centrifugal clutch and a small sprocket on that, you will need a rather large rear wheel sprocket. You have to consider the diameter of the rear wheel assembly into the equation. Consider that the rear sprocket on my Briggs powered mini bike is darned near the same diameter as the rear tire, and slightly larger than the rear rim. 3.5hp gets me about 35 or slightly less MPH with the engine thumping it's little heart out.
 
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bullsmj23n

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my goal isnt to go 60mph, my goal is to do 25-30 and be able to go up some med. size hills. I would download that program, but im on a mac. So are you suggesting a higher toothed sprocket? It would make sense since the sprocket on the clutch is tiny..
 
MotorBicycleRacing

MotorBicycleRacing

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bullsmj23n said:
my goal isnt to go 60mph, my goal is to do 25-30 and be able to go up some med. size hills. I would download that program, but im on a mac. So are you suggesting a higher toothed sprocket? It would make sense since the sprocket on the clutch is tiny..
Click to expand...
Hey, I wanted you to figure it out for yourself so you understood gearing ratios.
Also you wouldn't have to rely on the "experts" offering their advice in this thread LOL
It took me a while to get ratios.

Don't most Macs run windows these days?

Max Torque clutch with a 41 chain 10 tooth sprocket like a Q Matic
Harbor Freight 6.5 Hp runs at 3600 rpm? maybe 4000 rpm???
How fast do they rev when you remove the governor?

What is the idle speed on a HF 6.5 hp?? I don't know but it may change the numbers.
You won't have much of a rpm range?
============================
26.5" diameter rear wheel at 3600 rpm

56 tooth sprocket = 50.7 mph

62 tooth sprocket = 45.8 mph

74 tooth sprocket = 38.4 mph

azbill had a custom 74? tooth sprocket made by ManicMechanic for
his 4 stroke 50 cc Huasheng Q-Matic bike. It is a BIG sprocket!

You could use 35 chain which would make the rear sprocket smaller
in diameter.

I suggest you talk to AGK in Santa Barbara as they have a lot
of experience with these motors and have built an inframe 6.5 hp
bike with their centrifugal clutch chain gearbox.

I am sticking with legal sized motors like the 2 hp Honda GXH 49.4 cc and it's
Chinese Huasheng clone.
A HF 6.5 hp may be cheap but putting it on a bicycle is ridiculous IMO
especially as a rack mount.

culvercityclassic is building a 6.5 hp HF bike but it's for the Willow Springs race
and should be more than a match for the 9.6 hp and 11 hp H2O Morini's with
it's CVT transmission.
 
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bullsmj23n

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it's a .exe application(windows only)in order for a mac to run a application like this would take to much time and hassle. Anyhow

Pirate Cycles Custom Sprockets (Now In Stock)

I am thinking Manic Mechanic can make me the adapter, and then get the sprocket from pirate since it works with manic's adapter, but pirate's sprocket uses a #415 chain. It seems like a stronger chain which is great, the problem is I haven't found clutches that have a sprocket that uses a #415 chain, it seems like they use #35.
 
MotorBicycleRacing

MotorBicycleRacing

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bullsmj23n said:
it's a .exe application(windows only)in order for a mac to run a application like this would take to much time and hassle. Anyhow

Pirate Cycles Custom Sprockets (Now In Stock)

I am thinking Manic Mechanic can make me the adapter, and then get the sprocket from pirate since it works with manic's adapter, but pirate's sprocket uses a #415 chain. It seems like a stronger chain which is great, the problem is I haven't found clutches that have a sprocket that uses a #415 chain, it seems like they use #35.
Click to expand...
Max Torque clutches or similar use either 35 or 41 chain which has the
same pitch and roller diameter as a 415 chain.

415 has 3/16" between the plates
41 has 1/4" between the plates

They both fit on the same 415 sprockets from Pirate, but the 41
has a little wiggle room side to side.
Pirate only stocks a 56 tooth, pretty sure that your set up will need larger.

MM can make you a larger custom sprocket as well as a hub adapter.

How about a little thanks for all the help eh?
They don't pay me by the word....lol

and how about an answer to these questions?
How fast do they rev when you remove the governor?

What is the idle speed on a HF 6.5 hp??

Strap the 6.5 hp HF on the back of your bike and pedal it
around as a bicycle to see how you like that high up weight
behind you?
You gonna need a wheelie bar on your build! LOL
 
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bullsmj23n

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May 18, 2011
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Ok ty for the clarification, i would have been lost for a while there. My manual says "Speed 3600 +- 150 rpm" I would assume this is idle, and I am not sure at all about the governor questions since i don't plan on removing the governor. And of course, Since you say a 56 tooth prob won't be enough are you suggesting a 74 tooth? I thank you for helping me out, without your guidance I would be lost once again, and your speedy replies is a huge plus. Also can you point me to a clutch $45 and under? I owe you after all of this!
 
MotorBicycleRacing

MotorBicycleRacing

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bullsmj23n said:
Ok ty for the clarification, i would have been lost for a while there. My manual says "Speed 3600 +- 150 rpm" I would assume this is idle, and I am not sure at all about the governor questions since i don't plan on removing the governor. And of course, Since you say a 56 tooth prob won't be enough are you suggesting a 74 tooth? I thank you for helping me out, without your guidance I would be lost once again, and your speedy replies is a huge plus. Also can you point me to a clutch $45 and under? I owe you after all of this!
Click to expand...
The 79 cc 2.5 hp HF would have been a better engine for your rack mount build.

Call AGK as they know these engines and will help you out.
Affordable Go Karts - Home page - AGK - http://www.affordablegokarts.com
3600 is the running speed not the idle speed.
AGK has a good article on removing the governor which you need to
do along with a few other mods.

Did I mention that AGK was sponsoring the Willow Springs Race? LOL
 
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bullsmj23n

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