[oscarodster]

I am in the process of upgrading my 06 deluxe from 88 to 95. What do you think of KB PISTONS KB348. Bore=3.875, Stroke= 4.000, Comp. Ht.= 1.27. As in my past thread, (Upgrade kit). Any suggestions will be appreciated.

 

[ceraaa42]

Doesn't KB stand for "Kaa Boom"?

 

[Nitram_b4]

Doesn't KB stand for "Kaa Boom"?

I hope not, I have KB's in mine.
I have heard stories about all manufactures. been told KB piston will pop their tops, I guess I will find out
I have also read about thousands of people that have KB pistons in their cars, trucks, bikes. that is a **** load of blown pistons if the stories are true

Here is another story about another manufacture here http://gma.yahoo.com/okla-woman-shoots-kills-intruder-911-operators-okay-091106413.html
Point is if I did not do a little research on my own I would be worried about using anybody's equipment, from Harley to KB

 

[DEW2112]

KB forged going in my 103" build, just got done checking deck height ( front = -.002", rear = -.001")

 

[Nitram_b4]

what you gapping the top ring at?

 

[DEW2112]

what you gapping the top ring at?

They are @ .018" right out of the package which is fine with me.

 

[claydbal]

Doesn't KB stand for "Kaa Boom"?

hehehe. yep

 

[bigpete1]

Doesn't KB stand for "Kaa Boom"?

only if you do not read the instructions and not propely set ring end gap especially top ring ,i have installed a bunch of them no issues at all ,thanks pete

 

[Dyna Ryda]

I hope not, I have KB's in mine.

Here is another story about another manufacture here http://gma.yahoo.com/okla-woman-shoots-kills-intruder-911-operators-okay-091106413.html
Point is if I did not do a little research on my own I would be worried about using anybody's equipment, from Harley to KB

That link is a story about a woman that shot and killed a guy breaking into her home. Good story, but has nothing to do with pistons:beer:

 

[dsvracer]

I have used a lot of the KB pistons with no problems. However if you do not read the directions and set the top ring gap accordingly they could have issues. They WILL NOT work if they are gapped wrong. The top ring is supposed to be gapped at .026" anything less and you will have a problem. dsv

 

[2wheelrider]

I've used them on older motors, shovels mostly. My choice for TC motors would be J&E or CP pistons. They cost more but you get what you pay for. Wesco would be my choice for a budget build. Read this
http://www.nrhsperformance.com/tech_hypers.shtml

 

[DEW2112]

I have used a lot of the KB pistons with no problems. However if you do not read the directions and set the top ring gap accordingly they could have issues. They WILL NOT work if they are gapped wrong. The top ring is supposed to be gapped at .026" anything less and you will have a problem. dsv

Hypereutitic maybe, not forged.

 

[Don Dorfman]

I have used a lot of the KB pistons with no problems. However if you do not read the directions and set the top ring gap accordingly they could have issues. They WILL NOT work if they are gapped wrong. The top ring is supposed to be gapped at .026" anything less and you will have a problem. dsv

listen to this guy he is right on the money
Also a little extra gap will not hurt anything or loose any power. I have set them at .030
Understand that the rings are the conduit that takes the heat from the piston to the cylinder wall and when the ring fit if right they will get hot as they should. They expand and that gap diminishes. so don't worry and don't get stingy on the gap. Run them with confidence.

 

[Nitram_b4]

Mine are set to .023, KB states .019, but I agree larger gap, and I don't know WTF happened with the link I copied

 

[DaleW]

What possible reason could there be to have to check the ring gap?If manufacturers cant sell a product that can be fitted for standard use without having to be modified, then they dont deserve to remain in business.

 

[Don Dorfman]

Their forged VS hypereutectic cast pistons have different end gap specifications and the number I referenced is for the cast pistons.

 

[notsip83]

Have used the KB pistons since they were introduced in 1996. Have probably bored & fit the KB pistons in over a thousand sets of cylinders. The KB348 piston is a hypereutectic piston that has a longer skirt than the "Slipper" style forged piston that is also offered by KB and Wiseco. With the "Slipper" style piston which has a shorter skirt length you will probably have piston slap noise issues at operating temperature where you won't have with the Hyper KB348. We have bored and fit hundreds of the KB348's before Wiseco developed their slipper piston and to this date have never had a complaint or issue with them. If were asked which piston to use on a non racing application we always suggest the KB Hypereutectic pistons.

With the Hyper piston you can run the piston to wall clearance a lot tighter than a Forged piston.

On installing the top ring, you must follow the instructions closely as previously suggested, using the Hyper piston the piston dome will not absorb the heat that a Forged piston will, therefore the heat radiates to the top ring and causes the top ring to grow more which causes the end gap to close.

Hope this info is helpful.

 

[DEW2112]

These are the pistons I just pulled out of my 95" build with 32000 miles on them, the front piston went KA-BOOM, not sure why.

 

[notsip83]

Did the rod bearing go south on you. By examining the picture this is a typical result of rod bearings failing and the rod hitting the piston. Can't tell by the picture but which side of the piston did this happen on, Major Thrust side or the Minor Thrust side?

 

[DEW2112]

Major thrust side. Rod pin bushings looked and felt fine with the pin in. Did notice that the front rod was blue at the crank pin but read in the manual that was normal, not sure.