Clutch it right and jet the carb properly and it should last a long time or at least until you need another topend.Topends should last at least two good hard ridding seasons or close to 150-200 hrs

 

Well I guess I will be getting close to needing my topend redone soon. How hard is it to do it on this 4-wheeler?

 

With a manual you can get it apart in about an hr.Once you get it bored and the parts to go back it takes about 2 hrs.Then about 3-4 hrs breakin time.Very important on rebuilt 2strokes is the break in.

 

You have to bore the cylinder out?

 

<div class="FTQUOTE"><begin quote>Originally posted by: derekmman

You have to bore the cylinder out?</end quote></div>

Take the cylinder off.Take it AND the piston to a reputable shop,have them mic the piston and cylinder to get what your clearance is now,have them order the correct size of Wiesco piston and bore and hone to fit.
If you just ring it it may last a ride or two but not long.If it is worth doing it is worth doing right.

 

Well micing is a must when rebuilding an engine, that is why a questioned boring it out, it seemed as if you were saying to bore it everytime. I have rebuilt about 10 engines but all but one have been 4 strokes. Out of those nine 4 stroke engines 7 needed boring out only due to long service time. And the only 2 stroke I have rebuilt was a weed eater engine and it didn't needed boring. I guess what I am trying to say is that, do 2 strokes only have a service life of around 200 hours, when 4 strokes get tenfolds more?

 

i just rebuilt the topend on a 96 400L. there wasnt anything wrong with it even tho it still had the original piston and rings. 2 cycles get a good amount of service life as long as they arent hopped up and in turn running hotter temps than what they were designed for.

 

You can get more life out of a 2stroke but from what I have had it seems like 200hrs is a good amount of seat time.Plus all of mine have been modded.And yes you will have to rebuild a 2stroke more often than a 4stroke.Once you take the cylinder off you will see why.The piston gets beat on the front and the back more so the more hrs you get on it.