Rigged Gearbox?

[skid20]

Your yamaha 125 (assuming its a yz125 two stroke) will make at least 20hp, your clone makes 6.5, the yamaha will wind out past 8k, the clone, governed at 3,600, you can ungovern it but then the risk of throwing a rod or the dippers is fairly high. The clone is splash lube, air cooled, yamaha is liquid cooled (assuming its newer than early 80's), 2 stroke so no crank case oil. If you want me to keep going i can, theres no competition.

Now if they were rated at the same hp, and redlined at the same RPM then that would be ok, but would still take up more room.

I'm going to upgrade several things on the clone so I'm not worried about damaging it. Also I'm not trying to compete with the 2-stroke, I'm aware that they produce massive hp in a compact package.

I guess I should of just asked if it would improve the overall speed of my project and left it at that.

this is a 70's model 125 (free) I was told it has wall damage possibly a crack....and the crankcase has a shoddy patch someone put on it (probably dropped). I'm just trying to increase the speed that I can get out of my clone I have a TAV with a 48t x 40 sprocket on an 18 dia tire and only get about 45mph. If there is any competion at all it would be between the TAV and the Yam tranny.

and yes it is because it would be cool to shift some gears on a bike with a %!*$ utility engine. And besides when I'm done with it you won't even be able to tell it came from a Yamaha.

 

[theo]

If you are going by hp I would rather have a 20 hp twin 4 stroke with electric start hooked up to that bike tranny than a 125cc 20 hp 2 smoke. The torque and bottom end would be awsome. I.m talking about off road of course, for pavement then the 2 smoke would be better.



theo

 

[crazycart]

Have you ridden a 20 hp 2 stroke? Somehow i doubt it, because if you did, you'd want that.

 

[Raywelder]

If you are going by hp I would rather have a 20 hp twin 4 stroke with electric start hooked up to that bike tranny than a 125cc 20 hp 2 smoke. The torque and bottom end would be awsome. I.m talking about off road of course, for pavement then the 2 smoke would be better.



theo

Now your talking!

and like Krunch said, you can have a 20hp briggs, and a bike engine that puts out 20 hp, but the bike engine will crank out 8k rpm while the briggs may only be pushing 4k.

 

[Kaptain Krunch]

Have you ridden a 20 hp 2 stroke? Somehow i doubt it, because if you did, you'd want that.

Exactly. Although ifs its a 70's air cooled 12-15hp would be more realistic.