KX Riders

Maintenance & Technical => KX500 Original => Topic started by: texranger on December 22, 2021, 07:35:45 AM

Title: KX500 Cylinder question
Post by: texranger on December 22, 2021, 07:35:45 AM

Hi folks,

I'm pretty new to the green machine; purchased an 1989 KX500 a couple of weeks ago that was parked due to a piston skirt giving up about 10 years ago. I've been slowly tearing up apart the engine to do a complete rebuild and I have a question about the cylinder. I'm not sure if the cylinder is steel lined, electrofusion or Nykasil. I have cleaned the cylinder the best I could and when using a magnet it stick in some of the areas. Can somebody help me out here?

Thanks!

Title: Re: KX500 Cylinder question
Post by: KXDINO on December 23, 2021, 07:56:28 AM

Sleeves are easily seen from the joins top and bottom of barrel as around the ports were one that isnt wont have this , just imagin they have to bore the barrel out to press a sleeve in .i prefer to recoat a barrel over a sleeve as they transfer heat better , lighter , and will last a long time with regular air filter maintenance , another thing that wears top ends out faster is not warming the engine up before full power runs.

Title: Re: KX500 Cylinder question
Post by: texranger on December 23, 2021, 10:58:23 AM

Thank you Dino; I've seen re-sleeved cylinders in the past and this one has definitely not been sleeved. Yesterday I've measured the bore and I get under 86mm pretty much everywhere. I'm wondering if I can send the cylinder to a company like Millennium for them to inspect and advise if a simple bore clean up and recoat is doable in order to keep it under 87mm.   

Title: Re: KX500 Cylinder question
Post by: KXDINO on December 23, 2021, 05:34:52 PM

Go the whole hog , get a recoat you be better off in the long run , another thing to check is crank seals and rod play if the engine being sitting 10 years , seals minimun. if it was me i would get crank re balanced useing wossner rod kit ,seals , new tranny bearings and seals . i even polish the tranny parts for easier shifting well worth it .A bit more preparation at this stage resuits in a nicer bike to ride.

Title: Re: KX500 Cylinder question
Post by: texranger on December 27, 2021, 01:55:20 AM

Yes sir! - I'm sending the jug to Millennium for a recoat. The crank is getting rebuilt as well. I ended up going with a Vesrah rod kit so hopefully that will work out OK. Pretty much the entire bottom end will get serviced...seals, bearings, etc. I was not aware about polishing the tranny parts but will look into that.   

Title: Re: KX500 Cylinder question
Post by: motorman455 on December 28, 2021, 02:29:39 AM

I put a Vesrah rod in mine and its a 525, ported and 14:1 compression.  No issues with a over a 100 hours on it so far.