Help choosing engine

[Sdannenberg3]

So I am going to buy a dirt bike engine as some of you may already know. I dont have much experience with engines at all so my question is what are the benefits to a 2 cycle vs. a 4 cycle of the same size? (125cc)

I know how 2 and 4 cycles work, but like is there more hp gain in the 2 cycle 125cc vs the 4 cycle 125cc? The reason I ask is because I dont want to get this 4 cycle and have it be slower than I expected. How fast do you think I can get it up to?

http://phoenix.craigslist.org/evl/mcy/887808223.html

Also, he said that it runs but it wont idle. That should be an easy fix right? Dirt carb? adjust idle mixture?

So should I got for it for $300?

 

[crazycart]

That's not worth it at all. Those pit bike engines only make about 8-10 hp. It really depends on the bike, A 125cc 2 stroke off a newer yamaha, kawi, or honda that is liquid cooled, will absolutely rip. Makes upwards of 25 hp. If your gunna go 4 stroke id get a 250cc+

 

[Sdannenberg3]

Well the engine I have on my kart now is only a 6.5hp and its fine. I just want to shift. So wouldnt 8-10 be alright? And not to mention if its geared then I can go faster than 30 like I do now.

Plus I can use the brakes, intake, carb, exhaust, and engine. And then maybe get a bigger engine.

I like, 2 strokes, but I hate how loud and annoying they are, not to mention you have to mix gas and oil.
But if it is gonna be less powerful than my HF 6.5hp then i wont do it.

 

[crazycart]

It would be a bit more powerful, but they are cheap. I just don't think its worth 300 bucks.

 

[Russ2251]

Horsepower is Horsepower, 2 or 4 cycle.
2 cycles just get you there faster.
I don't understand the problem with mixing.

 

[Sdannenberg3]

Well i found one for $200 but it had a crack in the crank cover.
http://phoenix.craigslist.org/wvl/mcy/888214681.html
And nothing is wrong with mixing. id just rather not. its easier to have 1 gas can with gas that I can put into any of my machines. and then I dont have to keep buying oil. And 4 strokes get better gas milage i hear? And what about the noise? Neighbors would really hate me!

 

[crazycart]

That cover can be welded, take it to a shop and have them weld a plate on it. That looks like a four stroke...with a 2 stroke pipe...odd.

 

[2or3wheels]

yeah and some 2 strokes are quieter. the weed wacher i have is stupid silent.

 

[Sdannenberg3]

Thanks, but again I find myself just being REALLY eager to get myself an engine! Im just gonna wait some more and see if I cant find a bigger engine, Maybe even 2 stroke to pop up. See here I am paying for the actual bike to be in good condition, but I dont care about the bike.

I also want to find a bike with hydraulic brakes and possibly even electric start.

 

[Russ2251]

I look for performance, something a 4 cycle cannot provide unless heavily modified (there goes gas mileage).
2 cycles are half the weight, smaller, and have far fewer moving parts and are therefore more reliable.
Advantages of 2 cycles far outweigh disadvantages.
If properly maintained will out last Otto cycle based engines.
My 2¢.

 

[Sdannenberg3]

So why dont they use 2 strokes anymore? Just because of noise and pollution?

 

[Kenny_McCormic]

So why dont they use 2 strokes anymore? Just because of noise and pollution?

EPA BS, Alphabet gang out to ruin your day.

 

[Sdannenberg3]

Well who is in charge? Cause i think they must be the only 10 people in the world who dont like 2 cycles.

And this leads to another question, Is there a way to make a 2 cycle even quieter then it is off of a dirt bike?

 

[Russ2251]

I make my 2 cycles as noisy as possible.
All are either straight piped (good) or megaphoned (better). Some of them just pour straight out of the cylinder. Too much power loss when muffled. I run my engines in a non-residential area so noise is not an issue. Lucky me.

 

[Sdannenberg3]

I wish I could do that. I can, but I also will be in a residential area sometimes...