Heritage build

[Dan]

My next build. The Heritage from felt bicycles.

am shopping for a 4 stroke that I plan to mount by using 2 "L" beams that will also be the platform/mount.
The gearing accidently came out perfect. 12T centriugal clutch on the engine to a 30T sprocket married to a 4" belt wheel. That drives a 6" wheel that goes to another shaft that drives a 10T srocket that drives the rear wheel.
(12Tx30Tx4"x6"x10Tx 48T)

That gives me a gear ratio of 18.00:1. at 7000 RPM, 30.1 MPH.

The belt will be on the right side over the bike chain and be adjusted by moving top bracket on seat tube where both are mounted.

No gearbox and will have funky, old world look.

Gear ratio calculator; This thing is awesome once you get the hang of it. a few days ago I had no clue about gear ratios. This program excited me as much as when I discovered MBs! no kidding.
Index of /ratiocalc

 

[MrMike]

Hey Dan can ya tell me how to use that calc? I got it but have no clue as how to use it.For my main sprocket drive today I went from the 48T and picked me up a 60 T. That should gear me down should'nt it?NowI've got a 11 T to 13 T to 18 T to final drive 60 T.Tell me guy where do U put these #.It would be grately appreciated.BTW is this new 60 T ger gonna bring my ratio low enough?

 

[Dan]

Mike, I was right there with you bud. Just not getting the ratio thing. After you play with it a wile you will. If you want 4:1, 11 times 4 is 44, then do it again. 11 is your motor driven sprocket number of teeth. Now run that to a 44T, that turns a 10T that turns your wheel with a 44T sprocket . Now you have 19:20 and are doing 28 MPH. (type in first box "11". second box 44 then 10 in next box, in fourth 48) Sad thing is a jack shaft kit just ain't gonna get it done. You have to run small to big, to small to big. much larger then jack shift kit offers. With your build, have you considered a belt in the mix? I honestly am just learning this stuff and would hate to steer you wrong. Hey, we can be "Team Havntaclue" Wait, thats my Indian name. (my nic is "dances with beers")
11T X 13 X 18 x 60 = 3.94 to 1. wont work. when the drive shaft turns four times, the rear wheel will turns once. The engine is turning 7000 times a minute. Giving you a top speed of 135 MPH. (I based all these #s on a 26" rear wheel. have to figure that in))

Another option for you is a ready built gear box. Gear Box Assembly

Not as much fun as your own , but will work.

No matter what, build some thing cool even with the "pulling your hair out" times. Is like playing pool, there is always a shot. I look forward to seeing pics!

 

[ocscully]

Possible helpful hint? I found when frame mounting a Honda GXH50 that it was very helpful to have a clutch that could be mounted to the motor with the driver inboard. With the driver inboard it allows you to keep the motor centered better in the frame and also keeps the driver supported better as it is closer to the shaft bearing. See photos below.

ocscully

 

[MrMike]

I put tape on the wheel and tape on the clutch gear and for evey 6 times the cluth gear revolves 6 times the wheels turn 1 time thats a 6 to 1 gear ratio if I am correct .Figure it out using a 6 to 1 ratio please.

 

[Dan]

Oh snap Ocscully, That is gonna be pretty! The drive belt just makes it..dunno, just does. Might have to "borrow" the idea from ya. What ratio are you going with? With your set up and option of and option of placing the last sprocket pretty much any where, why is a "inboard" clutch necessary? Looks awesome. Will the peddles clear with your set up?
I really can't wait until you get that beauty finished. Is this to be your entry for the winter build? I am going to have trophys made. Thanks for Possible "helpful hint" (probable)

 

[ocscully]

Dan,

It's been quite a while since I ran the #'s but I think the total reduction comes in at 18.4:1 The clutch has a 23t driver to an 88t driven on the jackshaft to a 20t driver on the jackshaft to an 96t driven on the rear hub. Max speed as I remember should be around 30mph and it should cruise at 25 pretty easily.

Reasons for Inboard driver: First off the Honda Motor has a very short output shaft and just about any clutch you mount to it a portion of the clutch does not actually engage the shaft. Metric Timing Belts need a greater amount of tension on them for them to function properly and also due to the width of the belts I'll be using (20mm - 25mm wide) the driver portion of the clutch is what needs to be supported (closest to the output shaft bearing). Secondly the inboard driver allows the centerline of my motor to be within 3/4 in. of the center line of the bicycle.

What ever way you go with your project you need to be aware of the special needs of the Honda GXH50 or its Chinese clone when purchasing a clutch. First is the high idle speed (2000 rpm) you need to be sure that the clucth you buy engages around 2800 rpm - 3000 rpm. second you want to be sure that the clutch comes with the proper length output shaft extension bushing.
I bought my clutch from Max-Torque MaxTorque. They have a clutch specifically tuned/modified for the Honda motor, and also they were a great group of people to do business with.

ocscully

 

[MrMike]

I've got a max torque cluth also and was on their site and it said clutch engages at 2200 RPM's. I had no option of placing the last gear it is all relative to where the motor sits on the mounting plate.It's a 6 to 1 ratio the way I was gonna set it up but 6 to 1 ratio with 48 T gear is way to high so I was told.Have'nt ridden it yet them pics are just a mock up to know where everything sits.
I'm going to go with a 60 T gear so it is'nt running as high.Got the gear yesterday just have to instrall it on to my axle.
Hey buzz this is my 1st build so I'm just learning ,it's called trial and error.

 

[Dan]

Wow Mike, your all most ready for the "shake down cruise" eh? Looking forward to pics

 

[Dan]

Ocscully, Thanks for the link, Jim @MaxTorque has been awesome. Crunching the numbers I am still finding it necessary to go with 2 jack shafts. (or a 72T wheel sprocket) But an outboard centrifugal clutch is a very cool thought. I didn't know it could work like that and didn't catch on looking at your pics. What I am thinking of now is 10T on the engine then via chain to a 24T X 11T clutch to a 22Tx44 wheel sprocket. All mounted on the chain stay like a china girl chain tensioner. first set above, rear below so they pull away from the spokes. Is a work in progress, so dunno yet.

 

[Dan]

Hey Dan can ya tell me how to use that calc? I got it but have no clue as how to use it.For my main sprocket drive today I went from the 48T and picked me up a 60 T. That should gear me down should'nt it?NowI've got a 11 T to 13 T to 18 T to final drive 60 T.Tell me guy where do U put these #.It would be grately appreciated.BTW is this new 60 T ger gonna bring my ratio low enough?

Sorry Mike, I missed your question. type 11 into the first box then 13 in the second and so on. then wheel size and finally RPM in last. If you play with it a bit, it will become clear for you.