Flat Top Piston Question

[#ZERO]

I'm looking for a picture of a Kawasaki flat top piston that has been trimmed down for use in a Yamaha engine.

Does someone have a template or measurements for trimming the skirts on a Kawasaki flat top piston?

 

[#ZERO]

Where can I purchase some 85mm R&D Dominator pistons cheaper then 400 bucks? :banghead:

I can buy two Kawasaki flat tops for the price of one Dominator piston.

 

[yamaboy2000]

purchase a 4mil base spacer plate from racers-edge(dasa) or riva and throw some domed pistons in there, I doubt you will even notice a difference... and just think of how many over bores would be possible using pro-x pistons(not to mention money saved), the cylinder would most likely out last you and me..just a thought:smile:

 

[#ZERO]

I already have the northwest dominator sleeves and the port timing is almost perfect for a 5 ~ 6mm stroker with flat tops.

I hate using spacer plates because it's just some more o-rings to leak.

Your right about the dome pistons being more common with sizes but I like the idea of having the wrist pins closer to the piston tops.

 

[Kaveman]

Be careful using Kawi pistons. According to Jr., the piston ring alignment dowels need to be removed and repositioned to line up between the ports on the yamaha, at least on my Dasa pv. I have an 85mm dominator that came out of a 6mm stroker with the stock length rods that has been modified to clear the crank. Let me know if a pic of it will do you any good.

 

[#ZERO]

Be careful using Kawi pistons. According to Jr., the piston ring alignment dowels need to be removed and repositioned to line up between the ports on the yamaha, at least on my Dasa pv. I have an 85mm dominator that came out of a 6mm stroker with the stock length rods that has been modified to clear the crank. Let me know if a pic of it will do you any good.

I have pictures of the dominator pistons but none of the Kawasaki flat tops that have been modified.

Thanx... I'll have to check out where the ring gap lines up on the sleeves, I imagine this would be a real problem on the lameys because of all the transfer ports.

I might just have to make the skirts the same length as the dome tops and trim the bottoms to match the contour of the sleeves.

 

[#ZERO]

I found a template if anyone wants to trim their Kawasaki pistons for use with the Yamaha crankshaft. It's taken from a Riva flat top or R&D Dominator piston. If you print it out on a piece of 11" long paper the template diagram should be 10-1/2" for an 85mm piston. Line the seams up with the arrow on the piston top or the in the middle of the exhaust side skirt. You will need to trim the edges off both piston skirts front and rear. Also here's a picture of what the template should look like installed on an untrimmed Kawasaki flat top piston.

 

[ArtMaybee]

which piston are you modifying? CR500? 951?

 

[masterblaster]

I lucked out and found a guy selling a buncha r&d/riva pistons on ebay and grabed them up but since then ive never seen them cheap anywhere again. We have a few guys running kawi flattops in cylinders where the ring ends are over ports and have some serious time on them with no issues,I wouldnt sweat it.

 

[MTRHEAD]

Yes - Dominator, Riva, and other SJ pistons started life as kawasaki's and were machined. The early versions did have the pin's moved and the later ones had them installed in the Yamaha position. The bosses underneath were wider to accomondate this.

Food for thought - I've been running Kawasaki flat tops in my GPR1200 without any pin relocations for 3 year at 7900 rpm max. The ring ends do cross through the rear ports (cylinder is similar to a Lamey) just need to chamfer everything. Ideal? No, but 99% of all race GPR's in the day had Kawasaki OEM flattops in them. The flattop big bore by Riva had the pins moved same with 87mm Group K's

 

[feartheride]

Be careful using Kawi pistons. According to Jr., the piston ring alignment dowels need to be removed and repositioned to line up between the ports on the yamaha, at least on my Dasa pv. I have an 85mm dominator that came out of a 6mm stroker with the stock length rods that has been modified to clear the crank. Let me know if a pic of it will do you any good.

I will have to keep this in mind Lamey has kawi flat tops and is due for a rebuild soom ,,5 yrs on the original pistons..yikes lol

 

[Jr Freestyle]

I will have to keep this in mind Lamey has kawi flat tops and is due for a rebuild soom ,,5 yrs on the original pistons..yikes lol

5 years @ 1 tank a season, they probably still look new...haha