hi Guys! I was wondering if the kawasaki 550 piston port and reed valve engines have the same pistons? Also do any of you guys know how much you can mill off the cylender deck befor the compression gets too high for premeum gas? one of the drag racing guys in town here has milled .136 (almost 3/16ths) off his but he is running VP race gas.
550 pistons
- Thread starter pistonslap
- Start date
WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
Piston port engines use single ring pistons,reed engines use dual ring pistons,the ticket is to use the dual ring pistons in the piston port engine.
- Location
- Mount Albert, Ontario
In regards to milling off the cylinders, maybe this info will relate a little bit.
Instead of milling the cylinders, I have always heard you can mill a stock head about .040" to .050" and still safely run pump gas. If you measure a stock head, the shoulder depth from the flat part of the head to the edge of the dome is usually about .070". Make sure you measure this first. If the head has already been cut a little, you don't want to go a full .050" because you'll end up removing too much material. You can safely take off the whole lip, but be sure not to cut into the dome. If you take off the whole shoulder, it usually results in too much compression for pump gas though. You want about .020" shoulder to still run pump gas. Keep in mind these measurements are for stock piston port pistons. If you use reed pistons, this might change the above measurements because they usually generate higher compression in comparison to piston port pistons.
Stock reed motor pistons with dual rings will fit into a stock piston port bore, but they might be a little tight in some cases. Many guys swap in stock reed pistons when their stock piston port pistons are worn out. At one point I read the stock reed piston is about .005" larger in diameter than a stock piston port piston. So a reed piston will likely work well in a worn out stock piston port bore.
If that guy milled .136" off his cylinders, those pistons must be pretty close to smacking the head unless he's had the domes recut.
Instead of milling the cylinders, I have always heard you can mill a stock head about .040" to .050" and still safely run pump gas. If you measure a stock head, the shoulder depth from the flat part of the head to the edge of the dome is usually about .070". Make sure you measure this first. If the head has already been cut a little, you don't want to go a full .050" because you'll end up removing too much material. You can safely take off the whole lip, but be sure not to cut into the dome. If you take off the whole shoulder, it usually results in too much compression for pump gas though. You want about .020" shoulder to still run pump gas. Keep in mind these measurements are for stock piston port pistons. If you use reed pistons, this might change the above measurements because they usually generate higher compression in comparison to piston port pistons.
Stock reed motor pistons with dual rings will fit into a stock piston port bore, but they might be a little tight in some cases. Many guys swap in stock reed pistons when their stock piston port pistons are worn out. At one point I read the stock reed piston is about .005" larger in diameter than a stock piston port piston. So a reed piston will likely work well in a worn out stock piston port bore.
If that guy milled .136" off his cylinders, those pistons must be pretty close to smacking the head unless he's had the domes recut.
WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
Also you run into cranking issues with a 550 and super high compression,a newer style starter will solve that problem but don't even consider going that high on the compression using that older style stock starter,it would take a battery like an odyessy to crank it over enough to start been there done that.
ok, sweet! thanks alot this is exactly what I needed!