STIHL ms650- 84.5cc 6.4hp 13000rpm need help with gearing

[TREEWK]

Plinko

You Are Correct, I Hinted At The Same Thing. A Post After Mine Also Did.

Plus Saw`s Are The Worst To Look At Or Resale. I Wish Him Luck And Fun, But Hope He Sells The Saw For More Suitable Power.

When You Are A Newbe It Is Hard To Decide Which Path To Take.

The Old Saying Is Always Good Advice!!

"When In Rome, Do As The Roman`s Do". It Is Hard To Go Wrong When You Do That. Hope He Stays Enthused!! Ron

 

[unior]

Gear it for 60, a balance between speed and torque ripping apart you wheels, frame, etc.

He has been warned now it's his decision to make lol.

Although dude, you could resell that saw for a lot of money, profit and purchase a 4-5hp gp460 or 2 for that matter. The value of the saw will be greatly reduced once it's in pieces.

http://www.motoredbikes.com/showthread.php?t=7711

 

[G-Superior]

check out mine with a STILL ms260 engine( I just posted it in the picture gallery) http://www.motoredbikes.com/showthread.php?p=281324#post281324
just the right size and got it for free and it was in bits so i didnt even had to put it all back togeter
Good luck and be careful
G-Superior

 

[5-7HEAVEN]

Gear it for 60, a balance between speed and torque ripping apart you wheels, frame, etc.

He has been warned now it's his decision to make lol.

Although dude, you could resell that saw for a lot of money, profit and purchase a 4-5hp gp460 or 2 for that matter. The value of the saw will be greatly reduced once it's in pieces.

http://www.motoredbikes.com/showthread.php?t=7711

I agree. The GP460 engine will bolt onto any aftermarket drive systems available. If you're hard on it, this engine might rip thru tires, break belts, chains, etc.

The 460 engine's weak link is its narrow power band. Once you learn to harness it, you'll have a VERY powerful setup.

Not as reliable as the Stihl, though.

 

[aero07]

hey all name is Matt from memphis i am working on my first motorized bike
STIHL chainsaw engine---woooo
riding lawnmower gas tank
stater off of 3 wheeler on crank ??
Gary fisher marlin M.B. 26" rims
I have a final drive ratio calculated with my gear reduction(11tooth on engine to largest chainring gear on crank and smallest chainring on crank to largest on rear casette gear... 11t-44t-22t-30t final drive ratio = .34-1 i have no idea how to calculate my top speed at 13,000 rpms with this gearing...
any help would be greatly apppreciated

using gear rat this gear set up would put you doing 184.4.mph @ 13000rpm

 

[5-7HEAVEN]

hey all name is Matt from memphis i am working on my first motorized bike
STIHL chainsaw engine---woooo
riding lawnmower gas tank
stater off of 3 wheeler on crank ??
Gary fisher marlin M.B. 26" rims
I have a final drive ratio calculated with my gear reduction(11tooth on engine to largest chainring gear on crank and smallest chainring on crank to largest on rear casette gear... 11t-44t-22t-30t final drive ratio = .34-1 i have no idea how to calculate my top speed at 13,000 rpms with this gearing...
any help would be greatly apppreciated

Your final ratio is 5.45:1, which is unusable. Not going anywhere, and your clutch will burn out. You need an additional 5:1 gear ratio, which would place 1st gear at 27.27:1, which is okay for starters.

That's the disadvantage of using uncommon engine powerplants. You need at least two jackshafts to attain proper gearing, especially if you intend to wind up that engine to 13,000rpm+. Let's gear it to max out at 50mph at 13,000rpm:

1. Use 9-tooth engine sprocket to 36-tooth sprocket on jackshaft = 4:1.(SBP parts, bicycle chain)

2. Use 11-tooth sprocket on jackshaft and 76-tooth sprocket on drive ring= 6.91:1.(Pocketbike parts, strong 8mm chain)

3. 4 X 6.91 = 27.64

4. 22/30 = 1.36(Your bike chainring and cassette-1st gear)

5. 27.64 X 1.36 = 37.6:1.(Brutal acceleration!)

6.6th gear sprocket is 16-tooth. 22/16 = .73:1; 27.64 X .73 = 20.18:1.....

7. 6th gear is 20.18:1

In 6th gear, 50mph @ 13,000rpm.

7th and 8th gear is for cruising at highway speed.

Now you're SMOKING!

Unsure if bike chain and cassette will withstand this awesome power.

You need to jump into the forum for more feedback on this!