2 Stroke Rebuild questions

[RotaryRolla]

I've ridden a 2 stroke but never owned one. Lately i have been considering buying one. Before i do, i wanted to ask a couple of questions.

1. how often do they need a rebuild if you like to race/ride casually?

2. whats the standard cost of a rebuild and what does it entitle?(ie. what needs to be replaced/how long does it take)


thanks for any help.

 

[YZ165]

Depends on the bike, are you talking 125, 250, or 500?

 

[91-YZ250-Chris]

yes, i was wondering this, I have a yz250 and i want to know when to change out the rings and when to do the piston

 

[Senior KX Rider]

Top end for a 250 will run about $100 and I usually do mine once a year in the off season. I figure about 40 or 50 hours. Depends a lot on your riding style

 

[RotaryRolla]

yeah i meant YZ 250. thanks for the imput.i will probably be picking up a '99 YZ250 tomorrow. i rode with some hair scramble guys today on the sand and they said i was doing pretty well, so i think ill get something more competitive.

 

[kickstartkx]

Depends mostly on your riding style and the oil and the amount of it.
dont go any longer that a year of normal riding because when those pistons wear theil start work hardening them selfs and crack and usualy that means truble

 

[fishy7509]

how often should u rebuild a 100

 

[kickstartkx]

same as a 125 a year at the most or when evver the compression goes down

 

[fishy7509]

my yz 100 doesnt seem like it has much power any more does that mean it needs a rebuild. also the guy i bought said he thought it was bored .60 over how do i find out for sure. and what do i need to rebuild it just the piston and rings? do i need a new head gasket . would i go to my local shop to get these things or can i order them offline.

 

[nickyd]

order them online, not offline...sorry...couldn't resist....sounds to me you need to buy a manual....if you are asking how do you know if its bored .60 over, I'm guessing you don't have a micrometer nor a bore gauge...if not, and you are insistent on doing your own top end...put the cylinder and piston yourself and take it to a shop - have them do the measurement and order you a piston and gasket set....at that point, you might as well spend the extra $50 and let them deal with the labor...if you are in or around NJ, you can bring it to my shop. Also, if its bored .60 over and worn - you will probably have to either buy a new cylinder or have it sleeved back to stock - neither option is cheap.

 

[JayP0629]

yea, i am looking at a yz 250----2003 and it has a ton of after market parts on it and the dealer says the top end has never been redone... i called another dealer and they said...WORST CASE

 

[JayP0629]

is about 550.00 if u have the motor out of the bike. u will have to put it back in, they the carb back on it..i think i would spend the extra 100 to have them do that for me

 

[ocotillowellsrider]

Once a year replace the piston and check the cylinder for scratches and scuffs. Buy yourself a manual, some box wrenches, a measuring caliper, and teach yourself. It will save you money in the long run because you won't have to pay $50 or 60 extra dollars everytime you do the top end. Not to mention that if you get good at it- charge your buddies a twelve pack and you have free beer(or coca-cola). About $100 bucks in parts and get dirty. If the cylinder is questionable, take it in to the shop and ask them.

 

[Rcannon]

I say learn the top end. I have a full garage of stereo equipment nd a lifetime supply of yamalube R just because I learned how to do this. None of my buddies know how.

My speciality seams to be those italian Lems and Cobra's. Those small racers eat pistons!


Very easy job with the exception of the circlips. The small engines have even smaller clips.

Even though I have rebuilt close to 30 top ends, the twop strokes still amaze me. With the top end broken down you are looking at 6 or 8 parts wondering "how the hell does this even run???" There just does not appear to be enough parts to do anything with.

 

[nickyd]

My speciality seams to be those italian Lems and Cobra's. Those small racers eat pistons!
Very easy job with the exception of the circlips. The small engines have even smaller clips.
.

You can say that again....the first time I did a PW50 (this is after many other top ends on my bikes/friends bike,etc)....I swore I'd never ever do one again....but I have...those little circlips test my patience (and my fat fingers)....