Kawasaki Flat Top Pistons... Source/Information?

Roo

it's all good
Site Supporter
I have a Lamey motor I hydro locked. Sending the crank down to get rebuilt.

Really should put new pistons in once I get the crank done....

I bought the motor used and it had flat-top pistons in it...

Wondering which model/kawi flat top pistons to source out or would work out? Or should I say, what are people most commonly running flat-top wise?


Regards,
Andrew
 
Last edited:

Waternut

Customizing addict
Location
Macon, GA
I thought only Wiseco pistons were flat tops. I also believe they are the only forged pistons available.

Did you break something when you hydro locked it? I've sunk my engine a few times and the only thing I've blown out is the head gasket.
 

Roo

it's all good
Site Supporter
Motor is completely apart.

One look at the crank, and you will notice a very, very bent rod.

Pistons I guess could be reused, but the one has some skirt roughness from lack of lubrication. Cylinder walls are fine and still look mint but plan on honing real quick, possibly bore and go up in piston size if I'm feeling nasty.

Pistons that I took out are Pro-X (stamped on bottom) look to be cast, no forged. I would just search for the part number stamped on the piston but while I am at the office, I am just wondering what other options there are.
 

Roo

it's all good
Site Supporter
Roo, I was wondering what it costs to replace a rod. I need to do that and didn't know what to expect. Also, where did you send it to???

I haven't sent it out yet, but was planning on sending it down to Crankworks because of the many recommendations that comes from this site about them.

I am done riding for the season so I am taking my sweet old time doing it, and also throwing around different ideas.

Replace a rod (tear apart/assembly) with the rod was around $300 I believe I was quoted.

Mine will require a complete rebuild with all new bearings and rods, as the bearings on mine are not spinning very nicely/smoothly on the end of the crank that had the rod damage. That was around $700 I believe which included tru'n, balancin', etc...
 
If the crank had yamaha or kawasaki 133 rods you probably have a ProX Kawasaki piston. The Prox 20mm pin pistons only went to 81.5mm the 22mm pin pistons go to 83mm from Prox. If they are bigger you have something different.
 
thanks

I haven't sent it out yet, but was planning on sending it down to Crankworks because of the many recommendations that comes from this site about them.

I am done riding for the season so I am taking my sweet old time doing it, and also throwing around different ideas.

Replace a rod (tear apart/assembly) with the rod was around $300 I believe I was quoted.

Mine will require a complete rebuild with all new bearings and rods, as the bearings on mine are not spinning very nicely/smoothly on the end of the crank that had the rod damage. That was around $700 I believe which included tru'n, balancin', etc...
 

Roo

it's all good
Site Supporter
All kawi pistons are flat tops?

Stampings on my current Pro-X pistons are 'prox 3718', which are 0.75 over.

Bumping to 85MM pistons would put me slightly over 860CC which would be awesome, but the question is can this cylinder be safely bored to 85MM? Looks like there is a good amount of sleeve material left but I have never seen big-bore sleeves so nothing to compare to...

Guess I'll have to post a picture when I can.
 

BROSS

The future right here
Location
Lake Norman, NC
I have 85mm R&D pistons in my 61x bigbore, Riva and R&D pistons are made by Wiesco, they are a little different. All Kawasaki motors have flat top pistons, but the boost port in the Kaw is wider than the Yam, so the ring end gap is real close to comming out the port. This is the whole reason I found someone that made a Yamaha flat top piston. Like Supertune said get the pistons from Randy at that price!! I paid $199 each from LPW in the spring.
 
R&D flat tops use the Kawasaki design top. Which really has a very very slight dome to it...around 2 degrees if you laid a scale on it. Yamaha's is much much more pornounce maybe like 12 degrees.
Riva made flat tops that were truely FLAT across the top of the piston.
 
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