Chainsaw powred bike!!! open discussion

[bbechtel16]

I'm planning on taking my 26", 21-speed, front suspended bike with oversized steel frame (heavy as crap so it should take the abuse) the i never ride and using a medium to large chainsaw to power it. So, having never done this before, I have some questions and concerns:

1. Does the final output sproket have any gear reduction applied to it? If it spins at full crank speed (about 9000 rpm right?) I'm pretty sure I would have to run from the saw, to the largest front sproket, then from the smallest front sproket, to the back sprokets with shifting abilities to get the propper gear reduction, right? Could anyone figure out about how fast that would be at 9000 rpm in the smallest rear sproket with the setup mentioned, and also in the largest rear sproket. I realize all bikes are slightly different and the same for the saw sproket, but it doesn't have to be perfect.

2. Can I put a "normal" sproket on the chainsaw? Since the chainsaw uses an "inverted chain/sproket setup, that would need to change. Would I have to end up welding on on?

3. Can I find a beefy exhuast system for a 2-stroke engine that small? With and expansion chamber and silencer deal Is what I'm looking for. More power and hopefully a little less noise. FMF? LOL Is there any other mods I can do to a chainsaw for more power?

4. Please any other tips, comments, or experiences from similar projects.

[ATCRYDER]

Just to save you a whole lot of trouble: They sell those dumb ass kits (electric AND gas) on eBay all the time for under $75.

Rob

[CHAINSAW]

I dunno.. but it sounds pretty damn cool.

I remember as a kid building go-carts. My neighbor, which was a man in his late 40's told me to put 2 Chainsaw's on the back. One for each tire. According to him, the thing would fly faster then any 5-10 HP briggs n Stratton I could find. I never tried it, but it sure sounds fun to try.

[bbechtel16]

I dunno.. but it sounds pretty damn cool.

I remember as a kid building go-carts. My neighbor, which was a man in his late 40's told me to put 2 Chainsaw's on the back. One for each tire. According to him, the thing would fly faster then any 5-10 HP briggs n Stratton I could find. I never tried it, but it sure sounds fun to try.

That would be a trick to sync the chainsaws. Can you say torque steer? LOL

[3WheelHouston]

actually the torque steer might be an added benefit, if you had two throttle pedals. It'd be neat to try. I bet it'd turn on a dime if you had two break pedals too. Skid steering plus a wheel? heh. What a ride.

[bbechtel16]

actually the torque steer might be an added benefit, if you had two throttle pedals. It'd be neat to try. I bet it'd turn on a dime if you had two break pedals too. Skid steering plus a wheel? heh. What a ride.

Heh, you try it and tell us how it runs. That would be great.

ATCRYDER: I don't know where to look for it on ebay. Although I don't really want to go with the kit route, I want to use a chainsaw engine, its funnier that way.

How can I beef up a chainsaw? I was reading on this one logging forum or w/e it was about modifing the exhuast for freer flow and such. How do you tune the carb on a saw? Is it the same setup as an ATV or bike?

[FullBore]

Yeah, a Chainsaw runs its sprocket and clutch at engine speed, It may also be an idea to use V belts instead of chains, quieter, less dangerous and easier to line up, i.e. they won't jump off as easy!
You can get tuned pipes for chainsaws somwhere, I've seen them, you could run it on alcohol, and put a bigger carb on it instead of the wimpy walbro that'll be there!
As for tuning small engines with pipes, if you could find a saw thats near 50cc you could use a pipe of a kiddies MXer, YZ50?? or Honda 50 pipe off somthing, even a moped one might be better than a stock saw box. I had a go-ped with a 22cc Komatsu Zenoah Engine on it, the amout of tuning parts you can get is staggering, stock they do 20mph, a few $$$$ later and you'll do 40mph! Have a look at www.goped.com and www.goped.co.uk
Any chainsaw engine over 30cc if geared right should give you 30mph on a pushbike, a good saw engine to use would be the Sthil TS400 Stone Saw as it is belt drive so you already have a clutch with belt pulley for your beltdrive.

My 2 or 22 Cents! or 110?

Nat

[CHAINSAW]

now way, dont use a belt.. Use the Chainsaw blades.. ahhaha Make it evil looking

[bbechtel16]

:D :D :D

[FullBore]

how about attach chainsaw chain to the front wheel..........

[J.D.]

Sounds interesting.......but weird. I knew a guy who attached a B&S 5 hp engine to a bike, so I guess anything is possible.

[hondaracer250R]

yeah man go for it all those other people oviously dont know i mean i am dave borden.

[TimSr]

Theres a guy here with a weedwhacker motor on a kids scooter that he uses for a pit bike. Ive never seen it closeup to see how its configured.

[punkbek3886]

me and my friends just got done putting a 3.5 horse edger motor on one of those three wheeled bikes that you see old people driving. he clocked it in my car going 45, it was going 40 but then i leaned down and got more aerodynamic :D . we had it set up w/ a kill switch, choke cable, and brake cable to the handlebars but my friend decided it wasnt good enough so its apart again, this time getting a 6 horse snapper mower engine and a riding mower 3 speed transmission w/ reverse. btw on the original we had a 1.5" pulley on the engine w/ a 6" on the axle for a gear reduction of 4:1. i think we might have gotten better acc. and top speed if our reduction was a little more, but those were the biggest and smallest pulleys we could find.

[bbechtel16]

Sweet deal!!! Thanks for metioning the gear reduction stuff you did. I think I'm gonna use the front spockets of the bike for a jackshaft so I have a better range of gears to experiment with and such.

Keep your similar projects comming!

[hondaATCman]

Hey, check this out - http://www.gokartracing.org/Calculate.htm Its a tool I use for checking racing go karts speed, but it should give you an idea of what kinda speed your looking at with that chainsaw. Just type in the gear sizes and the RPM and you've got you're estimated speed. Hope that helps!

[bbechtel16]

Hey, check this out - http://www.gokartracing.org/Calculate.htm Its a tool I use for checking racing go karts speed, but it should give you an idea of what kinda speed your looking at with that chainsaw. Just type in the gear sizes and the RPM and you've got you're estimated speed. Hope that helps!

That rocks, thanks man!!! Now if I was smart enough write my own to include jackshafts in the calculations!

[mart]

hey i have a pushbike with a 80cc chainsaw motor on it i didnt use the chain wat ya do is get a big socket an weld it to the nut on the clutch nut of the motor then mount the motor so it pivets bac an fourth have the pivet at the front of the motor then get a big rubber an mount it on the bac of the motor mines got a lever on it so than i pull the lever forward so the socket sits off the wheel so i can start it than when the motor is runnin i let the lever bac slowly kinda like usin a clutch then the socket is spinning then it pulls against the wheel an off i go ill post some pics when i take some of it it goes so good i had one trailprotrailpro this one an we clocked it next to my brothers car an it hit 50klm about 25miles i think an this one kills my last so yeh but i suggest u dont use a chain they r to much trouble an you will never get the right ratio i might take some photos tmoz