hey guys im new here. im wanting to build a 4 stroke bike with prob the HF 99cc. i havent seen any one run a direct drive 4 stroke. why cant you do it without any reduction? thanks!
can you run a 4 stroke direct drive??
- Thread starter toni4289
- Start date
You can if you want, but it could not be a 1:1 drive ratio. Reduction is a must or you would not have enough torque to get moving unless you can pedal your bike up to 45 MPH or so before engaging the engine drive, you would however have an insane top speed though.
To get an idea of what I am talking about, imagine trying to drive a car or a truck from a dead stop or a slow roll and you could only use 5th gear. The engine would stall before you could get going. If you tried to feather the clutch it would overheat and burn up in a short time.
To do it right you would need a very small engine pulley and a very, very, very large rear wheel pulley. Look at the Whizzers to see what I mean. Considering that Whizzers do have a primary reduction system between the engine and output pulley, the rear wheel pulley that you would need to use would be even larger than what Whizzers use.
Also look at very old motorcycles (1900's to 1905-ish.). They had direct drive and no primary reduction.
Edit (smacks self in forehead):
Look at GEBE kits. They have exactly what I am describing and you can get one today.
Golden Eagle Bike Engines, Geared Belt Drive Bicycle Engines / Motors for Mountain Bikes & More
To get an idea of what I am talking about, imagine trying to drive a car or a truck from a dead stop or a slow roll and you could only use 5th gear. The engine would stall before you could get going. If you tried to feather the clutch it would overheat and burn up in a short time.
To do it right you would need a very small engine pulley and a very, very, very large rear wheel pulley. Look at the Whizzers to see what I mean. Considering that Whizzers do have a primary reduction system between the engine and output pulley, the rear wheel pulley that you would need to use would be even larger than what Whizzers use.
Also look at very old motorcycles (1900's to 1905-ish.). They had direct drive and no primary reduction.
Edit (smacks self in forehead):
Look at GEBE kits. They have exactly what I am describing and you can get one today.
Golden Eagle Bike Engines, Geared Belt Drive Bicycle Engines / Motors for Mountain Bikes & More
Last edited:
ok cool! thanks for the help. would something like this work? GTC Gokart and Minibike Gear Reduction Jackshaft Kit or maybe something cheaper. thanks
i havent done much welding or machine work. but i have a friend that welds. and i can prob figure stuff out
That certainly could do it along with using a small output sprocket off of that reduction unit and a large rear wheel sprocket.
As for something cheaper, the GTC unit is extremely cheaply priced. Anything priced cheaper than it I would question for reliability and quality of construction.
thanks for the info guys. im thinking about doing a direct drive with a belt, like the early 1900s motorcycles . and use a 24 inch rim for the rear wheel drive. it seems like the easiest way to go.
That sounds like a good plan. Please keep us updated on your build, and share pictures of it if you can.
Good luck!
Good luck!
so i think i want to build a early 1900s style bike. any suggestions on a 4 stroke engine that looks older? i want to build one as close to how they were then as possible. also how do the old pedal start bikes work? ive been studying pics of them. if you pedal to start them dosent that mean they are always in gear. how do you stop? also my budget id around 200...lol thanks for any info yall can give!
i can go alittle more money. but im not buying a kit. it going to be all homemade. i can get the HF engine for 100.
well...I have the hf 99cc pred and so far my build is at $750 and not even done yet
The motor its self is the cheap part. i would have been better off to buy a kit from Staton.
The motor its self is the cheap part. i would have been better off to buy a kit from Staton.
I'd bet a used briggs, set up like WayneZ's FD belt, or CB2's single belt could be done for $200 on an old thrasher mtb or cruiser...
rc
rc
4-865 - 5/8" Belt Drive Clutch Max-Torque | MFG Supply
theres $50 plus shipping just for the clutch whizzer belt mount is
32/34 Bracket & 2 Screws-Belt Sheave (9 sets necessary) N-3018 $5.15
33 Sheave - (Does not include brackets & screws) 2973 $27.85
Whizzer Motorbike
plus a belt that fits sooner or later your going to break spokes/bend rim and will need to replace the rear wheel
if you want a clutch like a snowmobile...thats $200 and still have connect it to the rear wheel
theres $50 plus shipping just for the clutch whizzer belt mount is
32/34 Bracket & 2 Screws-Belt Sheave (9 sets necessary) N-3018 $5.15
33 Sheave - (Does not include brackets & screws) 2973 $27.85
Whizzer Motorbike
plus a belt that fits sooner or later your going to break spokes/bend rim and will need to replace the rear wheel
if you want a clutch like a snowmobile...thats $200 and still have connect it to the rear wheel
To pedal start a bike you first disengage the clutch (or with a direct drive belt system relax the tensioner away from the drive belt).
Next you pedal up to a suitable speed and while still pedalling hard....
engage the clutch (or tighten the tensioner against the drive belt) to force the rear wheel to spin the engine.
When you want to come to a stop you must disengage the clutch (or tensioner) to disconnect the engine from the drive system allow the engine to idle.
To go again, pedal to get the bike rolling again and then slowly engage the clutch (or tensioner) to re-engage the engine to the drive system.
If you think that's complicated, try riding a suicide clutch chopper motorcycle.....in traffic....up hill.....with no front brake.
I have, and if I ever get the chance to do it again, I'll politely say no thank you.
Next you pedal up to a suitable speed and while still pedalling hard....
engage the clutch (or tighten the tensioner against the drive belt) to force the rear wheel to spin the engine.
When you want to come to a stop you must disengage the clutch (or tensioner) to disconnect the engine from the drive system allow the engine to idle.
To go again, pedal to get the bike rolling again and then slowly engage the clutch (or tensioner) to re-engage the engine to the drive system.
If you think that's complicated, try riding a suicide clutch chopper motorcycle.....in traffic....up hill.....with no front brake.
I have, and if I ever get the chance to do it again, I'll politely say no thank you.
found an engine today! it's a 3.5 briggs & straton edger motor. it was running at one time but need a new carb. I have no idea were to find the right kind of carb for it. i'm guessing a gravity fed one. please let me know if anyone knows of one. thanks! heres pics
If you still have the old carb, they rarely need replacing. A good cleanup inside and out should work well for you.
yeah thats what i was thinking. i'll prob get a rebuild kit. i was just wondering if there were aftermarket carbs that would fit.
