Dirt Rider Magazine

two-strokes are cheaper. for a normal piston and rings job,a two-stroke is less than $200 while a four-stroke is more, i believe. for a devastating failure and complete engine rebuild, a four-stroke may be $3000 vs a 2-strokes $700 approximatey. hope this helps.

I broke a valve 3 weeks ago so I think I can tell you how much it cost to rebuild the topend of a 4 stroke.
I'm about $750 into the topend because I have to replace the cylinder head, if you take the $518 for the head out it's really not that bad, but I'm doing it all myself. $100 worth of tools , if you already have a box full, will be enough for you to do it on your own. I hear guys saying 2 strokes are easy to work on, I have never owned one but the 4 stroke really doesn't seem so hard. Mind you I have NEVER worked on a bike before, manual in hand I think i could do anything lol.

It really depends on how much you can do yourself. A normal top-end as mentioned will be cheaper on the 2-stroke especially if you need to have valve work done on the 4-stroke and don't have the necessary tools/skills to do a good valve job.

If you grenade the motor; then the 2-strke wins hands down.

It all depends on how hard you ride it. I do mine on my YZ250 every 30 hrs or 1 year. But i dont race it. Ill let the 4 strokers awnser this. Just wanted to get back to you.

wel, i dont know how much i can help, im a beginner rider who weighs nothing and i can t utilize the power like faster riders can. im not much of a revver, more of a midranger, or a lugger in some turns. The only time i rev it out is when i panic rev and on the straights and all.four-strokes can go longer on top-ends than two-strokes, but i only ride once a week and about two hours worth of riding. i also missed 6 weeks off this summer with a broken wrist, so, i haven't had to do a top-end yet. lets just say, they are like a car battery: the run perfectly fine, until the day they die in heavy traffic.

YEah thats why I like to get it in every year unless I dont ride it much. Its pretty easy to tell when your valves are needin some adjustment too.

this is one of the main reasons i want a two-stroke. on a 2-stroke, oh man it seized, oh well, break out the spare top end and break it in 2 hours later. on a 4-stroke, oh !@#$%^&* it seized, 2 weeks in the shop and $2000 later you go and break it in.

Again we're back to what you can do yourself. I have no idea what the shop would charge me but a full topend rebuild on my 4 stroke is going to cost me about $750. I'm doing everything myself and that includes a $518 cylinder head. For the havoc I wreaked on my head, I don't think that is too bad. My problem was I lost a radiator cap in a spill and didn't notice. Had that not have happened I bet I would be riding right now.

Hare said it best.

Thanks for all the input!

They are about the same price in the long run. Take this from an owner of both. They both have their advantages and are fun. I ride my bikes harder than Evil Kneivel too.

it was a joke! not that hard but a lil hard. lol

mine did and do. all my racing buddies do. then maby we just ride them to hard or something. not how many hours do you put on your bike? usually my buddies go out for sunrise to sunset. thats a lot of wear and tear.

If your 2-strokes were blowing up at 20 hours you (or who ever worked on them) was doing something very wrong.

My current '06 YZ-250 has a little over 55 hours (actual running hours on motor) and is going strong. Its going to get a top end this fall just because I don't like to go over 60.

If you were to pull the piston and rings on your YZ-450 at 100 hours, while it may be running well I'd be willing to bet the ring gap is now out of spec and you are getting more piston rock in the bore than you should.

The point of top-end work is to change them out (4 and 2 strokes) before thay wear out and have failure.

Since you haven't taken yours down (apart) and measured you really don't know what shape the piston and rings are in.

If you aren't running it hard you may get 100 hours from it OK, but not if its been run very hard at high rpm's.

150 actual running hours either way is likely too long and if it does grenade the piston it will be major $$$

me too. unless you ride an XR, those numbers are unrealistic.

My wr is supposed to be 13500 and the new 150f are like over 14000

8,600 is the peak actually...haha, you got schooled. well, not really, what is 100 RPM anyways?

im talking peak power, not redline. the peak power is lower than the redline in most cases.

yes, you are about right. most 250Fs are around there.

I would look for the newest 2 stroke you can find, but its an expensive hobby no matter what bike you get.

Dont fall down stairs

piston n rings cost the same for both,but more can go wrong with a 4 stroke

mx guys do tend to lay down marginally faster lap times on 4 strokes

you arent racing MX sean. you're drag racing from the sounds of it.

my first MX, will be in spring at budds creak here in Maryland don't know if I'm ready but im going hard