Two Stroke Mini Bike

[Poboy kartman]

At least I have a pot to piss in and a window to throw it out of.

That's cool.....I have indoor plumbing and a toilet....dang...boy....you didn't just walk into that one....you RAN in!

 

[landuse]

I like the use of pots and pans in this build

 

[Poboy kartman]

I like the use of pots and pans in this build

Yep....you never know what Brett is gonna cook up next!

 

[Desertduler]

Thanks guys.

---------- Post added at 03:45 AM ---------- Previous post was at 03:41 AM ----------

Yep....you never know what Brett is gonna cook up next!

Will you make a cover to hide all those spaces in the block behind the pot?
I guess they would help for cooling, or also just collect dust dirt and rocks.
Maybe some stainless screen.

Its like a Kelly Wood thing.... With a cooking theme

No, they will be exposed.

 

[Desertduler]

I took the mini bike out for a maiden voyage today, it runs great and has tons of power with excellent low end torque plus it rips out great on the top end. I pulled some hills and the engine ran cool without any problems. I will post a video at a later time.

 

[machinist@large]

Wheres the video!!!!
Is the video done yet????
PICTURES!!!!!
PICTURES!!!!!
PICTURES!!!!!

Is that enough to get our point across???

 

[itsid]

^^ what he said!

'sid

 

[Desertduler]

Here is the difference between a float needle seat which is to be used with fuel pump delivery on the left (1.5mm) on VM Series Mikuni Carburetors and the one on the right is (2.0mm) which I had to use on this mini bike because I am using a gravity fed fuel delivery with the fuel tank above the carburetor. I took a spare aluminum VW crankshaft pulley that I had laying around the shop from my buggy racing days and wit a little machining and altering I turned it into a secondary starting device should I need it. This engine starts so easily either by push starting the mini bike or wrapping a rope around the modified VW pulley and giving it a yank. Lots more testing today, the foot pegs work awesome, the rear brake shoes are camming over sometimes under hard braking which I can fix I did not want to get too crazy with this thing without wiring a kill switch up because if by any chance the throttle stuck on this thing and you had no way of killing the ignition you would be in for one wild a$$ ride! I will post a helmet cam video soon, I am busy right now with other things like converting a friend of mine engine over to reed valve induction so that we can get our lake bed racing going again this year.

 

[chancer]

That thing looks Good!
So with the VW Pulley, Does that Nix the POT from Yesterday?
Looks better this way anyway.

 

[Desertduler]

That thing looks Good!
So with the VW Pulley, Does that Nix the POT from Yesterday?
Looks better this way anyway.

Thanks, I am going to make a different chain cover now that I am using the VW pulley as a back up starting device, on asphalt and concrete I can bump start the engine over easy, on gravel and dirt it is tougher to do hence the added starter pulley. I would rather carry a piece of rope in my pocket just in case I need to start the engine in a bad location but at least the pulley is far away from my leg. I still need to finish capping the exposed flywheel nut on the other side of the engine, I am going to machine a cap to cover the nut, no big deal. I can say that this thing turns a lot of heads and is a blast to ride! Not your every day power plant for sure.

 

[chancer]

So... How fast is it?
Or you probably figured the gearing and RPMs
What do you think it will do WFO?

 

[landuse]

I assume the cable ties are just temporary

 

[Desertduler]

So... How fast is it?
Or you probably figured the gearing and RPMs
What do you think it will do WFO?

I don't know yet, every time I try to ring it out there are cars in the way, I am going to have to take it out somewhere and ring it out so I can check the main jet and read the spark plug and to see where the engine's high rpm air fuel ratio needs to be, I have the low and mid range jetting and settings good and I know that the main jet is a tad rich which is good because from there I can jet down and get the jetting right for maximum rpm without burning the engine down, that's the key to keeping a two stroke alive and putting some power down, correct jetting and needle settings, that is why I have many jets and needles and needle jets and different air slides with different cutaways. The engine is well behaved with a linear power band and it has some real good torque without a peaky hit. Give me some time and I will jet the engine correctly and then post a video with a GPS speed. But remember I did not build this engine for high rpm output, I wanted more pull off of the bottom to the mid range and I am using a small carburetor on this engine for higher intake velocity at lower rpm's and good pull from the bottom, I can tell you this for a fact though this engine just the way it is right now would spank most modified utility engines with aftermarket parts put into them and it will do it all day long without any concerns about durability issues, this mini bike is not for kids or the timid I will just put it that way for now plus I paid 30.00 for this engine and it is loaded with goodies in it's stock form, forged piston, forged aluminum connecting rod with roller bearings, a full circle forged steel crankshaft mounted in ball and roller bearings and a 75 watt 12 volt lighting coil and the ignition has an mechanical advance that can be tailored to ones liking plus the engine is 47 years old which I would call vintage and it is like brand new inside all within factory specs and it still has the original cross hatch in the cylinder wall!


---------- Post added at 04:02 AM ---------- Previous post was at 04:00 AM ----------

I assume the cable ties are just temporary

Yes, Lol, they are tape for now.

 

[chancer]

Oh yeah I remeber that part:
"But remember I did not build this engine for high rpm output, I wanted more pull off of the bottom to the mid range"

Everybody always talks about Speed. and it is easy to forget, When thinking about a "Built up Engine",
That it was also "Purpose Built".
Carry on.

 

[bob58o]

I don't know yet

Thanks for such a detailed, informative response to a simple question.

 

[Desertduler]

Thanks for such a detailed, informative response to a simple question.

You will have to excuse me bob, sometimes I get carried away with maybe to much information and details.

 

[bob58o]

You will have to excuse me bob, sometimes I get carried away with maybe to much information and details.

Please don't hold back. I feel like I'm stealing awesome stuff just reading about the things you do.

 

[chancer]

Please don't hold back. I feel like I'm stealing awesome stuff just reading about the things you do.

Thats what I do!

 

[Desertduler]

Thanks guys.

 

[Desertduler]

Here is a little road test with a uphill run. The air fuel ratio on the top end is rich hence the engine going flat on the top end which I will change.
https://www.youtube.com/edit?o=U&video_id=MDXNftDfldU