New top ends?

[R E A L]

I am not sure if this is the right place to post this but, I have been looking in cycle traders and stuff to buy a used dirtbike and poeple have been saying that they have new top ends on their bikes. I was just wondering if someone could explain to me what this is.

 

[Studboy]

A new topend is typically: New piston, rings, wristpin, wristpin bearing, and gaskets. It is basically everything on the top end of the connecting rod.

 

[dan4011]

its a good thing for a used 2 stroke bike to have

 

[R E A L]

How do you tell if you need a new one? Is it expensive?

 

[Studboy]

If the bike is low on compression, or if the topend has been in there for more than a year or two, then it needs a new topend. On a 250, it will run you $~120 to do it yourself (it's not too difficult).

 

[R E A L]

low on compression???? sorry, I do not own a bike yet but I am trying to learn as much as possible for when I finally get one.

 

[mxmatthew]

youll gradually loose power from low compression and the bike will be easier to kick over.

 

[Studboy]

And harder to start. Also, a piston when left in service too long will develop stress cracks and break destroying your top and bottom end.

 

[R E A L]

ok I understand now.

Thanks a lot guys,
Jeff

 

[KTA]

When the piston comes to the top of its stroke it compresses air inside the chamber for combustion. If the piston or piston rings start to wear the amount of compression will slowly decrease. Eventually you will get to a point where the bike runs poor or possibly will not start. When this happens a new top end is needed. New top ends are a good things and are usually changed based on the hours the bike has been ridden. Normally a 250cc 2stroke will get between 40 and 60 hours of ride time depending on how hard you ride. Smaller bikes will get less time, larger bikes will get more.

 

[R E A L]

k , thanks