Yamaha Jog 100cc Dragster

[fabster]

Longer 7mm studs to match the cylinder.



2Fast 47mm crankshaft



Metrology for future reference

[jackrides]

Beautiful 45 degree crosshatch!

[fabster]

Yeah, 2Fast parts are of awesome quality.
Massimo takes pride in his products and it shows.
Small details here and there that put him on top.

[fabster]

Some small intake mods.
I'm running a Keihin 33mm, and the intake was designed for 28mm I believe.















It's coming along !

[808ministroke]

VERY INTERESTING, as I myself am currently running a 33mm Keihin. Mainly because it is the only genuine pwk carburetor I have (other than the subpar polini)[*cps are nice but polini doesn't make a great pwk]. plenty of real dell'ortos and round slides....
I also am running a stage six intake although a different style and for Piaggio.

I noticed right away that the intake was a choke point when I put on the right size rubber boot thingy.
I actually had a friend 3d print a peice to sit in the carb after the slide on the engine side to taper down to 28mm.I have yet to pick it up or test fit it but your route would probably be superior. I have vforce reeds aswell and removed the stuffer because that too was too small a diameter.

I assume ur using vforce reeds aswell, do you think that a normal unported intake would be able to utilize that extra diameter or will the reeds themselves not allow for that much flow?
I know their are too many variables to answer that reasonably lol.

[fabster]

Feb 29, 2024 22:18:00 GMT -5 808ministroke said:

VERY INTERESTING, as I myself am currently running a 33mm Keihin. Mainly because it is the only genuine pwk carburetor I have (other than the subpar polini)[*cps are nice but polini doesn't make a great pwk]. plenty of real dell'ortos and round slides....
I also am running a stage six intake although a different style and for Piaggio.

I noticed right away that the intake was a choke point when I put on the right size rubber boot thingy.
I actually had a friend 3d print a peice to sit in the carb after the slide on the engine side to taper down to 28mm.I have yet to pick it up or test fit it but your route would probably be superior. I have vforce reeds aswell and removed the stuffer because that too was too small a diameter.

I assume ur using vforce reeds aswell, do you think that a normal unported intake would be able to utilize that extra diameter or will the reeds themselves not allow for that much flow?
I know their are too many variables to answer that reasonably lol.

This is the intake/reedblock I was running on the 2Fast setup.
R&D Italia, made with a Stage6 reedblock, machined to be clocked at 90 degres. The crankcase is also machined to allow it.
To my knowledge, this and the MXS Racing kit are pretty much the best on Minarelli Horizontal engine. I can't say for Piaggio engine...





Now, if you're tapering inside the carb, you're already reducing the MM of the carb. Testing will tell, but if your setup can benefit of the 33mm, then why not use it fully ?

On this 2Fast 100cc setup, I tried both 33 and 35mm Keihin, and kept the 33mm on
Real carburetor are more consistent. There is a reason they are more expensive, and it shows. Power wise it's the same, but reliability is up and that alone is worth it. I woundn't mind a real Dell'Orto either. Like you, I don't f*ck with copies and replicas anymore.

Do the reeds stay on the reedblock when you remove the stuffer ? If I remember correctly, on some Vforce the stuffer is what holds the reeds.

[fabster]

Completed V1 Engine

[fabster]

This is the first version of the frame, back in 2020

[808ministroke]

awesome I'm redoing my front stem to get rid of bad play and these pictures are perfect for a reference thanks, looking good 👍

[hippo008]

Very nice work being done here. I love seeing really custom builds done at the limits of these little motors, very interesting stuff.

I wonder how reliable a setup like this is? Like how long will this cylinder, piston and crank last. I assume not very long given how hard its going to be pushed and the RPM's you will be targeting.

[fabster]

Mar 26, 2024 10:14:36 GMT -5 hippo008 said:

Very nice work being done here. I love seeing really custom builds done at the limits of these little motors, very interesting stuff.

I wonder how reliable a setup like this is? Like how long will this cylinder, piston and crank last. I assume not very long given how hard its going to be pushed and the RPM's you will be targeting.

More durable then people could think.

On the first page, you can see my sleeper 100cc 2Fast Bugeye Zuma. I put a new ring each 1500km. If I remember correctly, I did 4000km+
The crank is still running strong, sold to someone else.
On a street setup, wear is limited because we're not WOT all the time (and don't need to be because there is enough power).

On my drag setup, I would say I change the ring every year. It sees more dyno mileage then track hahaha

[fabster]

All new panels





Difference between the Stage6 quick action throttle and OEM. Because of the larger circumference, you don't need to turn the grip as much to raise the slide in the carburetor

[fabster]

On 2 wheels







New everything

[Lucass2T]

Nice build, but whats up with those chopper handlebars?
Are you planning to be a human air brake halfway down the strip?😂

[Timmer]

I’m wondering, whats the weight on those full wheels? Would a spoked wheel not be lighter (and thus less mass to spin?)

Love the topic so far, some nice stuff going on here!