KX Riders

Maintenance & Technical => KX500 Original => Topic started by: medicman on January 05, 2011, 12:42:03 PM

Title: New top end
Post by: medicman on January 05, 2011, 12:42:03 PM

Hey guys forgive my retarded question. I had my top end sleeved a few years ago (i know dumb), I seezed the original piston at glamis a few years back and did the rebuild my self. I just ordered a Kx500 piston an put it in. The bike ran good. I recelty seezed the bike again (lost compression) so....my question is do I need to measure the cylinder and find the right size piston or can I just order the standard size/stock piston. I know I can have the cylinder bored, but then I would need a larger piston correct? You guys rock thanks for the helping a newb :-D

Title: Re: New top end
Post by: sandblaster on January 05, 2011, 06:41:22 PM

I have rode several sleeved bikes.
I always warm them up very gently, I have them jetted correctly, and run a quality 40:1 mix.
They will usually last a good long time.
Yes, I would rather get one chromed.
In your case you need to know how bad the damage to your cylinder is.
If it is normal galling then chances are you could go 1 size over and be fine.
If it has scoring or pitting then you have to know what size it will be after the damage has been machined out.
Many shops will not even bore your cylinder unless they have the piston you are going to run in it so that they can be sure to bore it to the correct size.
If your going to have it bored locally I would take it in with a list of oversized pistons that are available and ask them what size to get.
I'm sure they will be happy to help you.

Title: Re: New top end
Post by: medicman on January 06, 2011, 10:06:16 AM

Thanks for the info brother! Ill see what the shop says. I live by pro circuts shop, am gonna take it there.

Title: Re: New top end
Post by: sandblaster on January 06, 2011, 01:30:26 PM

Perfect  :-D

Title: Re: New top end
Post by: Polar-Bus on January 07, 2011, 10:37:04 PM

I believe you are not supposed to run OEM rings (which are designed to run with a nikasil type plated cylinder.  To my understanding sleeves are made of cast iron, and can be re-bored as needed, but you also need to run a piston ring that is designed for a softer cast iron liner ? Do you have a sleeve installed that's been previously chromed ?

Title: Re: New top end
Post by: medicman on January 08, 2011, 08:27:02 AM

To my understanding its just a cast iron sleeve. Has not been borred out yet. Am willing to pay the money to have it done right, hoping that pro circut can do it right. Am in so cal, if you guys have any better ideas of who to take it to. I just want the bike to be bullet proof reliable which it pretty much has been for me so far.