Heretic starts new bike

[heretic13]

Ok. So this will be my second gasbike. I learned a lot from the first and started setting aside parts for the next
even before the first one was done. The first one if you haven't seen it is in the intros you should check it out.
http://youtu.be/rnnLI-M00DE
I'm starting with the motor and drive train first.

Upright Briggs 5Hp

Then to jackshaft, with a manual clutch on one side and a skiptooth cog on the other.
I like to keep the pedal drive as well that will allso run to the jackshaft with a free wheel.
the skip tooth chain will run a 3speed hub by large chainring mounted to it.

I'll start the frame after I get the math worked out to the back wheel.
Its better to build a frame around it then have a frame you can't fit eveything on.
I am going to make a leaf spring front end, I made one once before for a friends minibike.

and I re-coverd a seat a while back. should do fine.

I'll post the math for the gearing soon. I just have a few more things to work out.

 

[curtisfox]

I think the two leafs will be a little stiff for a bike,maybe just use one. I used a snowmobile (older ones had three leafs) and just used two leafs.............Looking good ................Curt

 

[heretic13]

Yeah that was the only trouble with the last one, all most no travel. how much did the snowmoble one have?
I'm in vermont so it can't be to hard to track one down.

 

[curtisfox]

Sorry to say its not compleated yet,but they have three leafs and I took one out because it just looked to much and sort of pushed on it to judge. They are getting scares so if you find some hang on to them. I am finding that a few people are intrested,and I have a sorse but don't know how many I can get eather. $20 a pair I pay for mine the leafs are 1/8" thick and they are predrilled so easy to mount.............Curt

If you pm me your email can send you a couple of shots on how I mounted mine.

 

[heretic13]

Worked out most the math yesterday. Anyone who's ever tried to put a non-kit motor on a bike before has learned if you don't
work this crap out ahead of time you can end up being way off if you guess at it. and this may not be perfect but it should
get me in the ballpark.
First thing you need to know is your motors rpm at peak Hp. Mine's 3200rpm
So to go from a 2inch pulley on the motor to a 5inch pulley on the jackshaft I multiply 3200rpm by .4
So my jackshaft is now spinning at 1280rpm.
The other side of the jackshaft has a 8 tooth sprocket going to a 30 tooth chrainring on the wheel hub.
so i multiply 1280 by .2667 that means the hub is spinning at 341rpm.
I'm using a three speed hub so 1st gear is .75 , 2nd is 1 to1, 3 is 1.3
I'm finding top speed first so i multiply 341 by 1.3 that gives me 443rpm
now 443rpm x 60 min's is 26580 rph
and 26580 rph x 82.12(my wheel cir.) gives me 2182749.6 inchs per hour
that divided by the number of inchs in a mile (63360) put the bike at 34.4 mph top speed.
I can live with that.
I allso ran all the same math starting with my motors idle. 1750rpm
and came up with 10.8 mph in first gear.
I can live with that to so long as it doesn't stall the motor.
Like I said " not perfect, but in the ballpark"

 

[heretic13]

Worked on the spacing for the jackshaft today, I welded a bottom bracket bearing cup to the end for the free wheel to thread onto
I didn't realize they were the same size and thread pitch untill just a few weeks ago.so now I have the clutch on the motor side,
a skip tooth sprocket lined up with the back wheel, and the free wheel lined up with the chainring for peddleing.

 

[FatBoy]

This is gonna be good! Im keepin my eye on this! 8) :mrgreen:

 

[heretic13]

Machined an adapter plate out of a 20t coaster brake sprocket to mount the 30t skiptooth chainring to the back hub.
and allso made new pillow blocks for the jackshaft bearings to be welded to the motor mount so the main stress won't
be on the frame. pic's coming soon.

 

[curtisfox]

Manual clutch were did you get it from? And what chain are you going to run on the skip tooth?...............Curt

 

[heretic13]

The clutch came off an old DR mower, and the chain I have is a 1inch pitch
Skip tooth off an old hand drill made about the same time as the early bikes.
And I think the chain ring was made in 1910 for a tandem.

 

[curtisfox]

You can't buy skip tooth chain any more so when your weres out you will be changing sprockets. Maybe just ebay what you have and change them now............Thanks I will check out DR and see what they have......................Curt

 

[curtisfox]

You can't buy skip tooth chain any more so when your weres out you will be changing sprockets. Maybe just ebay what you have and change them now............Thanks I will check out DR and see what they have......................Curt

It seems they want a model # and what kind you wouldn't happen to know that would you thanks ......Curt

 

[volkswagner]

Hello, from a fellow Vermonter,

I like your previous build and I can't wait to see how this one turns out.

 

[heretic13]

Just a little up date . The frame is almost done. And most of the part mocked up.my computer is down so photos are still stuck in my phone . Does know if there's a way to send them straight to here?

 

[RollinLow]

Just a little up date . The frame is almost done. And most of the part mocked up.my computer is down so photos are still stuck in my phone . Does know if there's a way to send them straight to here?

If its a smart phone try downloading tapatalk it's a forum app. That is what I have been using to upload my build from my phone.

 

[heretic13]

thanks i'll try that. in the mean time here some pic's i load the old way.

frame i started with.

in progess.

made new drop outs.

motor mount, stainless steel.

worked on the seat.

mocked things up.still have plenty to do. i always have way more ideas then time.

 

[heretic13]

Here is a better shot of the frame with the jack shaft and rear hub.

 

[Sphinx]

I can't help but wonder if a motor is going to be too much for a Skiptooth Chain. Any concern with you as well?

 

[heretic13]

The chain ring on the rear hub is the only part I worry about , its about a 1/4 inch wide. But I would feel better if it was solid and not a clover. The chain is all there,Its a one inch pitch and stronger then the standard 1/2 inch pitch bike chain. I miked the rollers and side plates and its about the same as a no. 41 chain but more importantly it looks really really cool.

 

[murraymadman]

I can't help but wonder if a motor is going to be too much for a Skiptooth Chain. Any concern with you as well?

I can't help but wonder the same! that 5hp briggs is going to put out some serious power left stock, not to mention if you go doing any aftermarket mods to it.