KX Riders

Maintenance & Technical => KX500 Original => Topic started by: vagassasson on August 11, 2014, 12:16:57 PM

Title: anyone care to explain this piston?
Post by: vagassasson on August 11, 2014, 12:16:57 PM
(http://i.imgur.com/peSgMww.jpg)
Why does the piston on the right have a big hole in the side that goes almost all the way to the middle. It has the same hole on both sides. I am new to working on k5 motors so if this is a really stupid question just delete this thread.
Title: Re: anyone care to explain this piston?
Post by: vagassasson on August 11, 2014, 12:19:27 PM
It also has a set of groves machined in the ring area of the piston
Title: Re: anyone care to explain this piston?
Post by: stujordan on August 11, 2014, 12:27:18 PM
Holes I guess are for cooling....

Grooves r for the rings? ;)
Title: Re: anyone care to explain this piston?
Post by: Motorrad on August 11, 2014, 12:37:23 PM
Holes for weight

Groves?
Title: Re: anyone care to explain this piston?
Post by: vagassasson on August 11, 2014, 12:40:20 PM
If you zoom in really close to the rings on the right there are 5 small groves cut in between the ring groves and 5 more above the ring groves +1 more below the ring groves
Title: Re: anyone care to explain this piston?
Post by: vagassasson on August 11, 2014, 12:58:53 PM
(http://i.imgur.com/8VBRpBC.jpg)
Factory piston
(http://i.imgur.com/FU16F56.jpg) other piston
Title: Re: anyone care to explain this piston?
Post by: stujordan on August 11, 2014, 01:07:45 PM
Id wager they are for trapping oil and hot gases....think of them as built in micro-rings....anyone got a better guess?
Title: Re: anyone care to explain this piston?
Post by: vagassasson on August 11, 2014, 01:15:42 PM
Id wager they are for trapping oil and hot gases....think of them as built in micro-rings....anyone got a better guess?
I was thinking the same thing but I had never seen a piston like it before so I had to ask
Title: Re: anyone care to explain this piston?
Post by: stujordan on August 11, 2014, 02:43:53 PM
Are u going to a larger bore or just replacing the piston?

What brand is that piston?
Title: Re: anyone care to explain this piston?
Post by: vagassasson on August 12, 2014, 01:31:47 AM
I bought a used piston and cylinder off eBay.  This is the piston that came with the cylinder but as you can see its already pretty wore out
Title: Re: anyone care to explain this piston?
Post by: Speedway73 on August 12, 2014, 05:36:34 PM
Piston on the right looks like an older Wiseco. The tiny grooves were marketed as "anti-detonation" grooves I believe.