79cc MTB official build thread

[ultralight01]

I swear, it was totally worth it. Besides the rag joint, there's not really any cheaper options if you don't have a rear disc hub. Maybe $40-$50?

Hey, I'm goona have 500-600 in this build when its over, about the price of a moped. But this can go everywhere, without a license or registration. Plus, I get to build it. I want it To LAST, not like my 2 stroke kit bike. And the power of this engine would tear out my spokes with a rag joint.

 

[TheNecromancer13]

^^ 66 dollars?!! Sixty-SIX DOLLARS?!! Good lawd have mercy on our souls!

That's nothing. I actually went a step further and got custom sprockets made by rebelgears for my last bike because I wanted a 40t 420 chain sprocket with a hard coat that would bolt onto a 5/8" mini hub. Cost me about $80 just for the one sprocket, but it was worth it. Here's a pic of the sprocket:

EDIT: I can't wait till I can start machining my own sprockets.

 

[ultralight01]

I mean, I'm going to be using this thing a ton. Don't want it breaking on me.

 

[Tony01]

Xct forks are the lowest of the low. Worse than rst low ends. If you're set on 1-1/8 swap it for an xcr. Or go with an xcm in 1". Xct < xcm < xcr.

 

[ultralight01]

Xct forks are the lowest of the low. Worse than rst low ends. If you're set on 1-1/8 swap it for an xcr. Or go with an xcm in 1". Xct < xcm < xcr.

It's that bad huh? Probably not as bad as my Walmart bike fork...

 

[curtisfox]

This is getting interesting, got to watch it closer. Looking good so far..............Curt

 

[ultralight01]

Thanks Curtis! I'll be back home on the 22nd and working on this. Man, I just went cycling for 20 miles, there is definitely some benefits to normal cycling! But that seems not what this forum is about exactly.

 

[Potato_In_Exhaust]

I tried 'pedaling' for about half a block and got tired, said SCREW THIS!......... dumped the clutch, and yelled out, "Woo-Hoo!!".

 

[ultralight01]

Well, It's easy to pedal an 8lb racing road bike...

 

[curtisfox]

Ya! i pedal everyday when it's not raining or snowing, these old bones need it ............Curt

 

[mobike91]

How far have you gotten on your bike since your last post? Iv gotta say, im really impressed with what you've done so far and how custom you are building your bike especially at your age. You must have a good amount of resources at hand and some good teachers to have helped you know how to use so many tools and such. I got into engine kit bicycling when I was 17 cause I lost my license. Now I'm 26 and just play with them for a hobby. I built a 2 stroke recently that was geared down so bad you had to pedal it to 20 then hit the motor lol. It does 50 at about 3/4 the Rpms from max. It's on a 700c style hard frame bike. I like your build so far. I just ordered a 79cc 4 stroke kit to play with next. Found a nice trek disc brake bike to build it on too. Btw I'm in Lebanon Oregon.

 

[ultralight01]

Hi will,
I appreciate the post. I've been in Cali for two weeks and I'm on my way back Wednesday.
My father had a lawn business for 10 years and has collected a lot of tools for working on his commercial equipment.

As far as tools go, I taught myself with the help of some forums like this one. I'm a fast learner, and engines were like Legos to me.

As far as resources go, I'm thrifty. But I also made a nice chunk of cash from rebuilding go karts up to about four months ago when I sold my racing kart.

I'm ordering parts for this bike still. I have about $100 in parts to order until it's perfectly finished. I'll update as I add the headset, handlebars, alternator, etc.

I'll be looking forward to your build too. I was inspired by TheNdcromancer13, another Oregonian in Portland that made a trek 79cc.

 

[ultralight01]

Slowly progressing. Had to machine an adapter for the sprocket adapter. Haha. It was for a 1.5" hub, and mine was like 3/4 of an inch. That took like 5 hours to perfect. Also got the new extra large headset in, by cutting a few slots to make the head tube larger.. I've been pretty busy on other stuff, but I'll get to finishing this soon.

I'm thinking of making fiberglass panels to hide the engine mount and some other messy bolts and such. Maybe a convex headlight shroud on the front to.

 

[ultralight01]

Progress vid:
https://www.youtube.com/watch?v=b4XsgQuVrn4