jetting for 6200-10k above sea level.

[81cr450]

Back out 2 1/2 & turn it in to where it sounds best. If your getting surge/run on with the 62 go up another size.

but it hit 110  ,  thats low borderline even cold. Sounds like its due

Before anything else it would pay to go through with a leak down test as low as the compression is

http://www.kxriders.com/forums/index.php/topic,4378.0.html

http://www.kxriders.com/forums/index.php/topic,6608.0.html

[bjohn07]

I threw the carb back one. Gonna run it tomorrow and get it up to temp and go from there.   
Thanks.   

[Foxx4Beaver]

but it hit 110  ,  thats low borderline even cold. Sounds like its due
Before anything else it would pay to go through with a leak down test as low as the compression is

+1...just freshen it up now while it's winter....that way you have ALL this upcoming season to ride worry free   ...you will thank us!

[bjohn07]

but it hit 110  ,  thats low borderline even cold. Sounds like its due
Before anything else it would pay to go through with a leak down test as low as the compression is

+1...just freshen it up now while it's winter....that way you have ALL this upcoming season to ride worry free  ...you will thank us!

so ive never rebuilt a dirt bike 2stroke.  not saying that i cant do it, been building small block v8s and hd motors for years.  but when you say freshen it up are you mainly talking about ring replacement to help bring that compression up,  do the cyclinders use a sleeve replacement or a coating.  and the rest im sure ill just try to find specs and replace bearings and such as needed.      any top end build kits you would reccomend as far as brand?

[Foxx4Beaver]

If you can rebuild a s.b. v8,you can easily rebuild a two stroke!.Here's a little helpful info,courtesy of the site.
http://www.hallbergs.net/kx500/

I would pull the jug and inspect the nickel plating for flaking and wear...but it's sounding like you need a re-plate and new piston/rings...at least that is the way I would go.And while the jug is off,you can feel if there's alot of slop in the crank bearings...good chance there is...which means splitting the cases...and if that's the case,you might as well do a complete overhaul...which would run roughly about $1400,give or take.I know this is probably NOT what you want to hear...and I'm just basing this on "worst case scenerio"...there's a chance you might be fine just getting the jug re-plated and new piston/rings/gaskets for $600 give or take.I don't think just replacing the rings is gonna be a good solution,I'm thinkin "mo money".
These guys do good re-plating..
http://www.powersealusa.com/
...and they will/can supply you with a piston if you ask for one.I myself,and a few others on here are running Wossner pistons...and I've had excellent luck with it.  
 

[81cr450]

If you can rebuild a s.b. v8,you can easily rebuild a two stroke!.Here's a little helpful info,courtesy of the site.
http://www.hallbergs.net/kx500/

I would pull the jug and inspect the nickel plating for flaking and wear...but it's sounding like you need a re-plate and new piston/rings...at least that is the way I would go.And while the jug is off,you can feel if there's alot of slop in the crank bearings...good chance there is...which means splitting the cases...and if that's the case,you might as well do a complete overhaul...which would run roughly about $1400,give or take.I know this is probably NOT what you want to hear...and I'm just basing this on "worst case scenerio"...there's a chance you might be fine just getting the jug re-plated and new piston/rings/gaskets for $600 give or take.I don't think just replacing the rings is gonna be a good solution,I'm thinkin "mo money".
These guys do good re-plating..
http://www.powersealusa.com/
...and they will/can supply you with a piston if you ask for one.I myself,and a few others on here are running Wossner pistons...and I've had excellent luck with it.  
 

BIG X 2

Replate , piston, main bearings & seals if your lucky . You will be happier with a good running bike over a mostly worn out 1

[bjohn07]

thanks for the info.    i didnt think it would be that much.  if im gonna pull it apart i might as well redo it.  i might just wait. got a deployment coming up so it will prob be after that. 

[bjohn07]

holy moly!    i used to pay 250 to get all 8 sleves coated and honed and pistons coated for nitrous.  granted it was 5 years ago i was expecting it to be 70 most for a single cylinder at the most.       looks like i better start putting aside a rebuild fund. might as well do it right.

[Foxx4Beaver]

holy moly!    i used to pay 250 to get all 8 sleves coated and honed and pistons coated for nitrous.  granted it was 5 years ago i was expecting it to be 70 most for a single cylinder at the most.       looks like i better start putting aside a rebuild fund. might as well do it right.

Now you're talkin..."do it right"!!
One more thing you will not want to skimp out on...is a GOOD pair of riding boots,you'll need em to kick over a fresh K5...or...the consequences could be quite painful!

[bjohn07]

So got my new exhaust orings on.  New fuel and air filter. Didnt start it. It was in the 20s and 30s yesterday. But after putting fresh gas and the carb back on i noticed a steady flow of fuel out the bowl overflow?  Makes me think the float is sticking or height is wrong.  what is the height supposed to be?

[bjohn07]

compression psi at temp was right under 145.  with the jet change, (carb was pretty clean already)  and a float height adjustment, new plug and air filter the bike is running like a 500 should.   wheel up, going sideways in dirt.  feels right. got the exhaust o rings changed also but it is still leaking oil from the weld at the front mount.  probably gonna jb weld it and call it a day.      a little bit of surging only in neutral, not sure if this is a carb issue or a cable issue. but i cant adjust the idle at all. not sure what the deal is.