Two Stroke Mini Bike

[chancer]

I was wondering similar to Sid. Or is there not some compromise between 54 inches and Nothing?

 

[Desertduler]

I have thought about tilting the engine forward more but then the oncoming air would not run through the cylinder cooling fins and I would risk overheating the engine and then I would have to use the diaphragm carburetor because of the angle of the intake port in the cylinder and then I would have to seal the throttle shaft and choke shaft in order to keep the dirt out of the engine plus the pipe would have to spiral like a snail in order to get 54 inches of it under the seat. I have shortened and modified the silencer and created a open area inside along with a silencing section out the back and I have painted the middle section with flat black high temperature paint and I left the end caps unpainted and I have it mounted up with a rubber vibration isolator.

 

[Desertduler]

I was wondering similar to Sid. Or is there not some compromise between 54 inches and Nothing?

Not for a tuned pipe it has to be exact, it would be senseless to build and expansion chamber that was the wrong configuration, lets just see how it runs without one for now, I have other builds upcoming that I will build expansion chambers for, the mini bike would look silly with 54 inches of expansion chamber. I guess I could build one that went straight out the back just for fun with no bends, that would be easy but ugly!

 

[Desertduler]

Let me put 54 inches in perspective in relation to this mini bike, here is how long the expansion chamber would have to be if it was exiting straight out the exhaust port to the rear of the mini.

 

[chancer]

Just get a Trailer. LOL
Or better yet you could borrow "2Slicknicks" Side car!

Just kidding. The KTM pipe looks cool anyways.

 

[Desertduler]

Just get a Trailer. LOL
Or better yet you could borrow "2Slicknicks" Side car!

Just kidding. The KTM pipe looks cool anyways.

Believe me, I wanted to build a pipe for this engine on this mini bike but it would look horrible, I am going to use this mini bike out on the lakebed along with the karts.

 

[NewbCarter]

Need a seperate minibike for the exhaust

 

[Desertduler]

Need a seperate minibike for the exhaust

That is what I am saying, too much pipe for the size of the mini bike indeed.

 

[Poboy kartman]

Just bend it over for a sissy bar!

 

[itsid]

or add some skatewheels for a drag bar..

hundreds of options with this one Bret

I thought it'd be a "quick laps around the block" mini bike,
but if it's indeed a "let's plow the desert" mini bike... That KTM exhaust seems to be the way to go indeed.
especially since you'll likely need the space in front of the engine for a nice big foam filter

'sid

 

[Desertduler]

Just bend it over for a sissy bar!

Lol, yes, a heated sissy bar!

---------- Post added at 06:36 AM ---------- Previous post was at 06:31 AM ----------

or add some skatewheels for a drag bar..

hundreds of options with this one Bret

I thought it'd be a "quick laps around the block" mini bike,
but if it's indeed a "let's plow the desert" mini bike... That KTM exhaust seems to be the way to go indeed.
especially since you'll likely need the space in front of the engine for a nice big foam filter

'sid

You are exactly right! I have a dual stage foam air filter on the way for this engine, I am sure that this thing will have enough power to have some fun with.

 

[Poboy kartman]

Just what ya need....something to keep your back warm in the desert!

 

[landuse]

Is the tread on the tyres aggressive enough for desert riding?

 

[Desertduler]

Is the tread on the tyres aggressive enough for desert riding?

For cruising the dry lake bed in the desert they will work fine, this thing has zero suspension and it would not do too well over the rough terrain!

Here is the front wheel bearing spacer that I have machined out of aluminum, these have to be made to the correct dimension in order to spread the side load force evenly between the two bearings so that they share the load together. The ball bearings should have zero preload on them after the axle is tightened down, these spacers are in contact with the inner bearing race, the rear wheel has the same set up. I cut down the axle material and threaded the axles 5/8 NF, I am using steel lock nuts and hardened washers on the axles. Here is also a photo of the rear exhaust mount that I made and slotted on my mill, the exhaust rubber isolator mount lock nut can be loosened when the engine is moved forward for chain adjustment then of course tightened down along with the engine mount bolts after the chain adjustment is set.

 

[Desertduler]

So I wanted to hear how this muffler was going to sound so I bolted on the old snowmobile engines recoil-rope pulley and taped the gas tank down and plumbed a fuel line up and poured in some mixed fuel and flipped the choke on wrapped the rope around the pulley and gave the rope a yank and the engine stater right up! The rear wheel is not bolted down tight so it is moving around a little in the video. I am waiting on more parts so that I can continue.
https://www.youtube.com/watch?v=z3-CjU9uriU

 

[rushking19]

Sounds good I was waiting for you to rev it tho

 

[Desertduler]

Sounds good I was waiting for you to rev it tho

I am waiting for a 1 inch twist throttle to come in the mail and I need to wire up a kill switch plus it is kind of hard to pull the throttle cable that I had hooked up with one hand while I was filming, it does rev up though and sounds pretty good.

 

[ezcome-ezgo]

This thread is so informative I feel like I should be paying tuition.

 

[Poboy kartman]

This thread is so informative I feel like I should be paying tuition.

You're supposed to be! Send it to "The Poboy Fund"!

 

[Desertduler]

This thread is so informative I feel like I should be paying tuition.

I hope that I do not bore you with details ez, sometimes maybe I explain too much, I can tone it down a bit.