(agent orange special) What could possibly go wrong?

well the little 29cc bike is being retired. it is a sad day.

BUT, dont fear, my projects always come back better.

in this case, i have an almost brand new 5 hp briggs. it has less than an hour of use, and looks factory, no dents not even any dirt packed in the fins, it just happens, that it will fit in the frame of the old 5 speed bike. now i know what you all want to know, and that is, it it gonna have gears? that is a definate yes. i feel that with this power, the gears are gonna be fairly shallow, but i have an idea to combat that. it is gonna be a street bike, as much as that pains me, but the casette doesnt have a creeper gear. i did the math, and i need a 6 to 1 for dirt use, but that will be very hard to make. i can make an about 5.5 to 1. (with a jackshaft) which should work ok. im gonna have about 65 ft lbs of torque, and with pedals, you can make more, so i hope i wont break the chain. its gonna have a centrifugal clutch, because there is no room for a cub cadet, or belt clutch. im gonna leave the governer in, and leave the engine 100000% stock. i need help connecting the throttle cable, on the below tank bracket. i really need a picture. speaking of pictures, i have mocked up the engine. let the build begin.

I am open to any advice, from the people that know about high power, and gears.

 

[Sidewinder Jerry]

than disaster strikes. im motorin along, 6th gear, to the bar, when i grab 7th. when i do, the chain overshifts, and grabs on something or another. i let off, but the weight in. the rotating assy, tries to rip the wheel out of the carriers. when it cant, cause it is blocked in there, instead, it bends the frame into an S shape. this in turn slams the tire against the opposite frame tube, locking it up, and slamming me into the handlebars. i managed to recover it, and didnt wreck, (see im not an unskilled driver), but the skid mark is like 50 feet long lol. I had to carry it about a mile back. also destroyed my brand new tire. broke the chain for the second time.

You pushed things into too high of a ratio; you were also doing a lot of cross-chaining as well. The more you cross chain the less torque you can load onto the chain. This is where my 4-speed 34-16 freewheel could've helped.

 

[2speedboi]

This guy really does have that 4 speed cassette idea working and it outta be considered.

You wont loose to much top end with that.

 

[redneckracing674]

cross chaining?? whats that? i broke the chain again

 

[Sidewinder Jerry]

Here's an example of cross chaining using a 3x7 what many call a 21-speed. Cross chaining would be little little or big big; 1(7) or 3(1).

 

[redneckracing674]

i still dont understand. like too shallow ratios? i was thinking about a 40 chain casette, with a widened shifter, and a cheesy chain, that flexes alot, along with a massive spring in the derailuer

is the re like a heavy bike chain? i know there is like 35h, and 40h, that get almost 2x as strong.

 

[Sidewinder Jerry]

i still dont understand. like too shallow ratios? i was thinking about a 40 chain casette, with a widened shifter, and a cheesy chain, that flexes alot, along with a massive spring in the derailuer

is the re like a heavy bike chain? I know there is like 35h, and 40h, that get almost 2x as strong.

I use a Shimano HG71 chain. On a 3x7 ideal alignment would look like this 1(2), 2(4), 3(5) notice how the chain is straight.

This is what extreme cross-chaining [1(7) or 3(1)] looks like compared to ideal alignment. Notice the lateral stress that gets put on the chain.

 

[Sidewinder Jerry]

I put color coding on my shifters and can do all shifting with my left hand. I use a triple chainring shift kit. The only time a front chainring is shifted is when either in rear sprockets (3) or (5). Notice how the chain is always in a fairly straight line. Only the slightest of cross chaining.

 

[redneckracing674]

that makes sense. you think i should add a few small gears. that does make sense, since i mostly pull the pins apart in the chain, and only once have i actually ripped the links in half. i need spring tension to keep it from bouncing, and too much, and the spring cant pull it into high gears. i need a massive spring, and a suicide shifter, since if break my thumb trying to shift that big spring

 

[redneckracing674]

i have tried kmc hp20, and z series. ill dig around, to see what i have that isnt stretched. maybe i should widen the shifter, and run 40 chain, on a bike chain freewheel

 

[Sidewinder Jerry]

i have tried kmc hp20, and z series. ill dig around, to see what i have that isnt stretched. maybe i should widen the shifter, and run 40 chain, on a bike chain freewheel

The chain won't match up to the spacing between the rear cogs