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Title says it all. Got to do one or the other whats best????? Ordered new piston will be in soon. Need help on the right or best way.

Replate.

Got a pic of your cylinder walls?

Can get you one, But whats the best way? My cylinder has a scratch in the back side of it. Cost to plate about 200 and to bore & sleeve 250. Whats the best?

You want to replate for the simple fact that your bike will run cooler and it wears so much better than a sleeved cylinder.... so much less frequent rebuilds....

thanks will replate.

i paid 160 for the replate from powersel I believe (recommended by RBD, so good enough for me )

I have a sleeved cylinder, and have no problems. Sleeving has some advantages, in that once it's sleeved, you'll NEVER need to worry about it again. Sleeves can be honed over and over, electrofusion can not. You'll be replating every few pistons, but with a sleeve that won't be a problem anymore. Lots of people run sleeves, there's nothing wrong with them.

BS. A sleeved cylinder is sleeved because it is trashed.... that is the only reason to ever want a sleeved cylinder.

A sleeve changes your porting... for the worse. A sleeve can shift. A sleeve wears more than twice as fast as a plated cylinder.

As a matter of fact... even if your cylinder gets a gouge in it... have it welded, bored and plated over a sleeve.

Unless something goes terribly wrong, an aftermarket plating job will last as long as you own the bike, and for as many pistons as you decide to replace. On the KDX, a good replate job and a forged piston and you will be good for YEARS. A sleeve will wear much quicker. Softer metal wears faster. Simple, no?

The ONLY benefit of a sleeve is the ability to bore to the next oversize without needing a replate WHEN (not if) it wears past the service limit. This is a moot point on the 90 kdx, since you can't run an oversize piston without sacrificing the powervavles anyway.

Sleeves can be honed over and over

Until you cant get a piston to keep the clearance correct. Then if you overbore the ports need work, too. At that point your looking to re-sleeve. Not the preference I would take. Like you said, I'm sure you are fine, but like inda said there is lots to go wrong with a sleeve job.

Nothing wrong with an iron bore or iron sleeve in an engine designed for it, but I would never have a factory plated powervalved cyl hogged out and sleeved. I've actually had an iron sleeve in an air cooled kart motor plated Chuck pistons through it willingly without touching it. Lots of car racers building trick stuff are going that route, too. Aluminum blocks with plated cyls. Re-ring regularly with no special tools, with the motor in the car. Now, for that plated aluminum 2-cycle v-8.

Now...take an accident prone motor like a lot of 4-cycles (esp these beefed up industrial motors we see in karting), in which you can get many pistons, and have a small failure that can be bored out, you are ahead cost wise over a plated bore....but if you're one of these guys you must not care about cost either, or you'd be running a 2-cycle (sorry karting semi-off topic)

I rode 2 years a cylinder stock with Wiseco piston.
I rode 3 years a nickasil replaqued cylinder with Wiseco piston.
Now I ride a sleeved cylinder bored from the stock 6900 to 7000 with Wiseco piston (216cc to 223cc!!!!).

I can't tell a difference between the 3 about wears or bad experience...

But, I can tell you: I really like the 1 more HP with the 223cc

With a 49 rear sprockets, RB-Designs head and Carb, VForce3, FMF Rev, steering damper, KX forks with enduro valves, etc.... torque monster with top-end too