not going into detail now ,but the repair shop(for my pinon bearing, right side of crank) told me it was ready to pick up,, got there and saw my case,crank, rods all ready to go but no pistons,, ends up the "tech"got them mixed up w/ the other junk and tossed them,,the owner overnighted new in box "kb" pistons... (rings,wrist, pins, lube, etc.ect) all the right size(standard..i saw the std. stamp on my old ones,) and the box denotes standard pistons . its going in a 97 evo.. any word of wisdom be for i put them in???? if they are junk ill buy good ones. thanks dave

 

Keith Black has been making pistons for a good while, I don't have any personal experience with them but I don't recall anybody talking bad about them. More than likely better then stock.

 

Joke has been that KB stands for Ka-Boom.
We have 80" Evo new on the shelf, and will not install them.
Scott

 

I have no experience with them installed in a v-twin, but I know what kind of mess they make inside of a small block Chevy when they shatter. Their Hypereutectic piston is very brittle.

 

Some shops like them others do not. I have only used a few sets in very mild evo set up, per the customers request. price wise you are close to the cost of a true forged piston.

CP pistons, JE pistons, Wiesco all good parts.

 

thanks everyone,going to ask some other shops in the area,,, see what they say..dont know if these are keith black but they say K-B proformance pistons...thanks again

 

I have built many race car engines and the problem that most have with KB pistons is they dont read the instructions on gapping the rings. The top ring is closer to the top of the pistion than other manufactures, which they say is more efficient. But this also make the top ring run hotter causing more expansion of the ring. The instructions call for a larger top ring gap than what is ussally standard. Otherwise the ring expands when it gets hot butts up and tightens up in the bore and ripps the ring lands apart, this hard aluminum alloy then breaks appart and destroys everything it gets caught in. A forged piston on the other hand in a failure will hold together and cause a lot less damage.
I have seen many KB pistons live forever if properly gapped, but also there have been quite a few failures from people who have not read directions and gapped like an ordinary pistion (too tight).
I my self would run forged pistions they are not much more money and the way an air cooled engine expands and contracts it would give you a better saftey margin.
Then again the stock pistions are cast and I have heard no problems with them.
It could be that they cant sell the KB pistions, so they are willing to give them to you. But who knows?
If they are gapped right they should be fine.
But do what makes you feel comfortable, after all its your bike and they lost your pistions, so its not unreasonable to request the very same for repacement.
Good luck

 

thanks for the input, think ill READ all instructions and FOLLOW them.Time to get to work, i want to ride this year,, thanks dave

 

I agree. I prefer Wiesco.

 

KB pistons also are prone to failure with pinging/detonation/improper tuning. They are fragile due to the high silicon content. Not a good mix with an air cooled engine. I would stick with a good forged piston personally................if your from NH then talk to RR cycles about em, they won't recommend them for vtwin, most reputable shops won't.