Two Stroke Mini Bike

[Desertduler]

locking buddy?

we want to see the painted result as well (well... I do!)
I'd also love to see a desert lap when you dialed in your jetting and such..
and I doubt I'd be the only one here.

basically.. I'd like to see this thread living for another page

So, if you really want to have this thread closed, I will; but I'd rather not
your call.

'sid

Ok, I will keep posting then. I have a cross country excursion that I have planned with this little meanie through a volcanic region out in the desert that might be of some interest to some just to see how this thing will survive and if I have all the bugs worked out on it. The main logistical problem I have doing this excursion is fuel range because of the small tank I have on this little bike but I can pack more fuel safely and it should not be a problem. I will pack tools and spare items along with extra tubes with a small inflation device which I carry when I am racing motorcycles. I have made a rear chain guide which is spring loaded that I have been testing because I have had the rear chain derail before over rough terrain and so far with the chain guide that I made installed the chain has not derailed.

 

[chancer]

But But I already IBTL!!!
JK. I wanna see it finished too. Or a new Thread Chronicling "The adventures of 2 Stroke Mini"

Carry on!

 

[Desertduler]

After much testing today I am going to try a different exhaust system. I was doing some jetting runs and I decided to disconnect the front part of the muffler and separate it from the main body and try a run, this thing about threw me on my a$$ so the muffler that I am using is restricting the power output of the engine a lot. Back to the drawing board with the exhaust system, I just might have to spend the time and curl up 54 inches of expansion chamber under the seat and out the back of the "Meanie Bike".

 

[chancer]

That is so amazing, that exhaust on a 2 stroke makes that big of a difference.

 

[Desertduler]

That is so amazing, that exhaust on a 2 stroke makes that big of a difference.

Try it sometime, (Two Stroke Engines before and after with the correct exhaust tuning) you would be amazed! BIG difference with two stroke engines, just another reason I use two stroke engines on my rides, just with the correct exhaust system one can gain tons of power and I don't mean just a little bit. A$$ whoopin tons! I took a stab at this exhaust system and got it wrong. I will fix it and make it right.

---------- Post added at 06:45 PM ---------- Previous post was at 05:58 PM ----------

I have owned and raced quite a few dirt bikes in my time both two and four stroke engine powered machines and let me tell you the difference between a 500cc open class two stroke motorcycle and a 500cc open class four stroke motorcycle, they are not even close to being the same animal, you have better have a lot of guts and a set of big balz to hold the throttle W.F.O. on a two stroke open class bike! I still have a four stroke racing bike and a two stroke racing bike. The modern day Supercross bikes are all four strokes because the factory Honda Team decided that they would try and change the Supercross world by boycotting two stroke bikes when in reality 250 two stroke bikes were spanking their 450 four strokes on the track and in the early stages of the draw back away from the two stroke engines on race bikes they did indeed pit the 250 two stroke bikes against the four stroke 450 bikes in order to give the four strokes a chance, yes you heard it right it is called the laws of physics if you think that a four cycle engine that is naturally aspirated can make as much peak power and torque as a tuned two cycle engine then you are mistaken, that is why with all due respect to all small four stroke engine lovers I don't use them because they bore me and they are not thrilling to me. Pour tons of money in them and you still have questionable reliability and not so much power gain per dollar that is spent to do so.
You can listen to Destry Abbott he has raced both two and four stroke bikes and he is now a four stroke guy because that is what the open class bikes are now days four strokes and he is forced to ride them. I have raced in some of the series of races he has raced in but he is a National Rider.
https://www.youtube.com/watch?v=O7h9XhsDt3Y

 

[chancer]

But Abbot just said 4 stroke is the way to go? yet wondering where the tech on the 2 stroke may have gone.
Rather than Factory Sanctioned Bike racing, A good place to look would be the Crazy Backflipping Freestyle Motocross bikes. What are they using. I would guess 2 strokes. Seems like you would need that instant power and torque to get a bike to back flip and do the amazing things they do in a tiny arena.
Am I correct?
BTW
Not to school the teacher. but I think We tried to tell you this when you decided on the exhaust. At the time I was just following the logic I have learned from you. LOL

 

[Desertduler]

Rather than Factory Sanctioned Bike racing, A good place to look would be the Crazy Backflipping Freestyle Motocross bikes. What are they using. I would guess 2 strokes. Seems like you would need that instant power and torque to get a bike to back flip and do the amazing things they do in a tiny arena.
Am I correct?
BTW
Not to school the teacher. but I think We tried to tell you this when you decided on the exhaust. At the I was just following the logic I have learned from you. LOL

You are right and I should have listened to what I told you guys!
I am not a teacher just a learner!
And you are correct with the freestyle riders using two strokes. And KTM still makes two stroke bikes and there is a whole bunch of ex four stroke riders going back to them (Two Strokes) in desert racing.

 

[chancer]

I understand your Dilema though. 54 inches of pipe twisted under a minibike frame just doesn't work.
I will be interested to see what you come up with. There must be some sort of compromise between your 54" computer model and just the existing silencer.
Good thing you did not lock this thread yet!

 

[Desertduler]

Just for kicks, watch this video of Jonny Walker racing and winning this Erzberg rodeo in 2015 on a KTM 300 XCW two stroke motorcycle like I own and it is very capable of putting some serious whoop a$$ on a lot of four stroke race bikes, mine is my favorite race bike of all time.
https://www.youtube.com/watch?v=4j6dyAMrPZU

---------- Post added at 07:21 PM ---------- Previous post was at 07:20 PM ----------

I understand your Dilema though. 54 inches of pipe twisted under a minibike frame just doesn't work.
I will be interested to see what you come up with. There must be some sort of compromise between your 54" computer model and just the existing silencer.
Good thing you did not lock this thread yet!

Yup, we will see, but it will be worth it.

 

[Desertduler]

I have modified the internal baffles of the muffler that I am currently using and the engine now makes more power and revs higher. I have a expansion chamber design rough drafted out that will fit in the rear open space of the frame which I will make later. I will be posting some videos of the mini bike with the new found power that I have achieved from modifying the muffler. This thing rips!

 

[NewbCarter]

Is there any estimates on how much power does it make after all the mods ?

 

[Desertduler]

Is there any estimates on how much power does it make after all the mods ?

Nothing earth shattering but some and some is better than none, we will see how much more I will get after I have made an expansion chamber for this thing and give it a test run, remember I am not looking for a huge improvement or gains in upper rpm ranges but after altering the baffles in this muffler I did gain some more power with engine rpm over rev. This engine is only a three port two stroke.
https://www.youtube.com/watch?v=5YU0csqX2Bw

 

[itsid]

judging by the video, it's quick

I love the whizzing of a two stroke, I'm eager to hear the difference using an expansion chamber.

'sid

 

[NewbCarter]

It still moves very nicely and sounds cool in the process .

Tho question : did u experience any overheating issues ?

 

[Speedbob712]

Awesome.. Cant wait to see yours threw.
All my friends say im crazy and i cant do that!! I want to put build this into a mini bike. Defiantly going to have to build my frame. Its a 69-70 Rotax. I say to **** with them.

 

[chancer]

Well with that motor, Dont worry about building a frame, just buy one, But Build the Motor.
Those things are cool

 

[rushking19]

I have modified the internal baffles of the muffler that I am currently using and the engine now makes more power and revs higher. I have a expansion chamber design rough drafted out that will fit in the rear open space of the frame which I will make later. I will be posting some videos of the mini bike with the new found power that I have achieved from modifying the muffler. This thing rips!

Hmm so baffles mufflers do work on 2 strokes meaning mine should run good with that muffler I have

 

[Desertduler]

Two Stroke Minibike Update

It has been awhile since I have posted so I will post the results thus far with the out come of my 293 Sachs two stroke engine that I modified and installed on a Bonanza frame. After much testing in the desert on different terrain I have found this engine to provide plenty of torque with a 7:1 reduction to pull you about anywhere you want to go without any problems at all even with free air cooling and ambient temperatures over 90 degrees Fahrenheit. The foot pegs and brake pedals work awesome so as your feet do not slip off of them in rough terrain. The engine pulls the mini bike through sand very easily even without a C.V.T. which I found amazing. The only problem I encountered was if the rear tire hit a rock real hard the rear chain sometimes would come off because the tires sidewall would pucker enough to hit the drive chain and derail it off the rear sprocket but I will rectify that problem by installing a narrower tire on the rear the same size that I have on the front.

 

[bob58o]

Still looks awesome!
How've you been?

 

[Desertduler]

Still looks awesome!
How've you been?

Great bob thanks! I will tear this thing back apart soon and clean it all up and decide on tuned pipe which might wind up looking like a dogpile all curled up under the seat.