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New KX500 converted to snowbike owner with some questions

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Bcsnowbiker:
Hey everyone,
New KX500 owner here, that I have converted to a snowbike. I have owned some big bores way back in the past, a PE400 and a couple IT465's but never a 500. Kind of dates me I know...
I've ridden and raced dirt bikes for over 40yrs, snowmobiles for 30, but snowbiking to me is the new latest greatest thing. I've been interested in snowbikes for years, and I always said the day I build one it has to be a 2 stroke 500. I picked the KX for the powervalve and Nickasil cylinder.
Bought a 91 in decent shape for the vintage. Tore it down to the frame and rebuilt the bike but left the motor alone as everything was in spec and decent looking on the top end, bottom end was still tight. I figured I only had a half dozen rides on it this year anyways, so ride it stock and find it's short comings. As far as add ons engine wise so far I got some new rads, a PC Plat 2 pipe, snowbike intake and an Intellajet carb set up for altitude adjustment. A Scalvini carbon shorty silencer is on the way as well.
So the bike rips, and makes a perfect snowbike. I can pull 4th gear up huge alpine bowls (it's big mountain riding where I live in BC). My only complaint is the top end signs off too soon. Bottom to mid are a monster, but missing some top for those big long pulls. As a caveat I have not pulled my PV apart yet to assure proper operation.
So on to my questions. Summer is here, I have a bit of play at my main bearings at the FW and it is time for a full motor rebuild. Easy parts, rebuild and balance crank, replace all bearings and seals, replate cylinder, new piston etc. Possible clutch rebuild, PV assembly, hopefully trans is happy.
My questions come to porting, head work and timing. Two things I want to keep with a snowbike in remote big mountains is easy starting and reliability. She's a one kick wonder right now and reliability? well it is a 91, enuff said.
What kind of squish is considered tight but reliable on the KX5? On my RM250 I shoot for 1.2mm but thinking a little extra clearance on the KX wouldn't be a bad idea. My thought was to have squish tightened but then the head recut to stock or slightly higher compression.
Porting ideas? Again nothing too crazy but looking to keep what I have down low and adding a bit more to the top.
Anyone play with their ignition timing much? Particularly retarding timing looking for top end.
Fuel wise I have some leeway as I have access to Avgas and typically run it 50/50 in the KX now.
Thats all I got for now, I'm sure more later.
Cheers  8-)

reklessj:
Welcome aboard man!! Sure you will love that thing once ya get her all straightened out. Check this out http://www.kxriders.com/forums/index.php/topic,16933.msg137454.html#msg137454 and maybe pm member 1901306708 I think he's the man for SNOWBIKE tuning a K5

Bcsnowbiker:
Thanks man. I've read through this thread and pretty much anything I could find here and on KxGuru.
1901306708 is pushing the limits of the motor more than I would like to,but I should shoot him a PM, I'm sure he has some good ideas.

Bcsnowbiker:
Figured out how to post a photo here. From last week and last ride on the snowbike this season.

Foxx4Beaver:
Welcome aboard!

Nice pic!

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