Speedway Scarab project

[2SlickNick]

https://youtu.be/0EQt5vkMwMQ

I wanted to share my new project with you guys. I figured if I am going to create a Facebook page called " American Minibikes " I would have to at least own an American minibike Lol... I thought this would probably make a great bike for flat track racing, but I think it would be better as a cruiser and just all-around good minibike.

 

[2SlickNick]

It really stinks that someone cut the motor plate, because they also cut the stock hole where the jackshaft mounted. Not sure if I will weld a jackshaft bracket on or try to use it with a TC...

 

[2SlickNick]

Well it looks like I do have to weld a jack shaft bearing holder back in place.
I am guessing if I want to use a torque converter, I am limited to using a 20 series only, because 30 series would probably hit the frame. Can anyone confirm this?

Or I guess I could use a centrifugal clutch and jack shaft set up. Has anyone done this?

 

[2SlickNick]

I was doing some wire wheel work on the frame today and found a serial number up by the neck .
20672
I also cut out a bracket for the jack shaft bearing holder and will be getting that welded in shortly.
I'll post another video of my progress as I get more progress done Lol...

 

[Itype2slo]

What motor was original Sachs Tecumseh or fugi those are neat bikes:thumbsup:

 

[2SlickNick]

Not sure, but I think it was a tecumseh...

 

[2SlickNick]

Well it looks like I do have to weld a jack shaft bearing holder back in place.
I am guessing if I want to use a torque converter, I am limited to using a 20 series only, because 30 series would probably hit the frame. Can anyone confirm this?

Or I guess I could use a centrifugal clutch and jack shaft set up. Has anyone done this?

Anyone have any info on TC for speedways?

 

[2SlickNick]

Let's see if this kart calculator app is going to work out here. This is the gearing I am going to run on my scarab until I get the torque converter.


KartInfo by kartcalc.net:

[FONT="Verdana"]
[B][U]KART[/U][/B]
[INDENT][I]Kartname [/I]: [B] Speedway Cc JS [/B]
[I]RW diameter [/I]: [B] 16 in[/B]
[I]Weight [/I]: [B] 300 lbs[/B]
[/INDENT]
[B][U]ENGINE[/U][/B]
[INDENT][I]Engine type [/I]: [B] Pred [/B]
[I]HP [/I]: [B] 6.5[/B]
[I]Torque [/I]: [B] 9.48 ftlb | 12.86 Nm[/B]
[I]RPM [/I]: [B] 5600[/B]
[I]Governor removed [/I]: [B] true[/B]
[I]Assummed HP [/I]: [B] 7.18[/B]
[/INDENT]
[B][U]TRANSMISSION[/U][/B]
[INDENT][I]System [/I]: [B] Clutch & Jackshaft[/B]
[I]Clutch sprocket [/I]: [B] 10[/B]
[I]Jackshaft in [/I]: [B] 17[/B]
[I]Jackshaft out [/I]: [B] 12[/B]
[I]Axle sprocket [/I]: [B] 50[/B]
[I]Final Ratio [/I]: [B] 7.08:1[/B]
[/INDENT]
[B][U]PERFORMANCE[/U][/B]
[INDENT][I]Wheel Torque [/I]: [B] 67.15 ftlb | 91.05 Nm[/B]
[I]Acceleration [/I]: [B] 10.79 fps² | 3.29 m/s²[/B]
[I]Top Speed [/I]: [B] 37.65 mph | 60.59 km/h[/B]
[/INDENT]
[/FONT]

 

[jim85541]

I would think with the angle on the motor plate a TC would fit pretty easy. On some you have to slice a piece off the TC backing plate, but with the angle you might not have too. You can not use the included mounting plate and make your own. Just keep the center to center distance the same as stock. You can change center to center as long as you use one of the standard measurements so the belts fit. Comet has a list of those specs. A clutch works, but a TC is so much better.

 

[2SlickNick]

I can almost run the 30 series. I agree TC is best. I have made my own jackshafts and had to measure for appropriate size belt.


I may have to notch about 1/8 the quarter inch off of the motor play if I want to do a 30 series. But I would much rather purchase another 20series. Until then I will use JS, I like jack shaft set ups for modified motors. Depending on this bike, it may occasionally see the flat track.

 

[ole4]

I use salsbury 330 or comet 340 tc on speedways.

 

[2SlickNick]

Well it looks like my 20 series torque converter 6" driven unit rubs the swing arm axle. So sad - I really wanted to run a TC and not clutch and jackshaft.

 

[chrisr]

On my speedway, I went with a comet 30 the driven is run on the outside of the frame. I had to move the engine to the left, but it works good with the Tec 3.5hp.

 

[2SlickNick]

That's one way to do it...
I thought about elongating the holes on the axle swing arm to compensate but that will be cutting it close to edge. Unless I get a 5" salsbury TC I will just run the JS. I plan on doing 6.5:1 ratio.

 

[ole4]

My 6inch driven clears swing arm axle easily. Are you sure you don’t have a 7inch driven? I am putting another speedway together now I’ll take some pics for you later. I make my own swingarms but the axle location is stock.

 

[Ajf]

My 6inch driven clears swing arm axle easily. Are you sure you don’t have a 7inch driven? I am putting another speedway together now I’ll take some pics for you later. I make my own swingarms but the axle location is stock.

They changed the jackshaft location in 72 in order to use the larger diameter Fairbanks driven. His is a 71 and it used a 5” driven made by speedway.

 

[Ajf]

Look at the distance of the cutout for the clutch to the end of the motor plate. First is a 71 and the 2nd is a 72. 70 and 71 can’t use the 6” clutch.

 

[2SlickNick]

Thanks again for your help Aaron.

 

[2SlickNick]

My 6inch driven clears swing arm axle easily. Are you sure you don’t have a 7inch driven? I am putting another speedway together now I’ll take some pics for you later. I make my own swingarms but the axle location is stock.

Yep definitely sure it is a 6".

 

[2SlickNick]

View attachment 106425
Look at the distance of the cutout for the clutch to the end of the motor plate. First is a 71 and the 2nd is a 72. 70 and 71 can’t use the 6” clutch.

Oh yeah you can see the difference...