1990 KX500 SF conversion, few Q's

[174ktm]

So I have been collecting KTM parts for a while and recently purchased a 1990 KX500.
Will be building this bike for next year ice racing season.
-2014 KTM (frame, swingarm, subframe)
-2013 KTM shock
-2016 KTM 4CS forks
-2008 KTM triple clamps

KX500 plan (items not purchased)
-44 mm Lectron carb
-AJ FMF pipe,
-Prox basket/inner hub
-new intake (does a person go Rad Valve/Vforce 3/stock?)
I'm sure I read somewhere the Vforce3 didn't fit correctly, but Im not sure
-Wossner piston
-Ported and Polished

Kickstart is very worn, buy new KX500 or will some other KX/KXF be a better fit?
Decompression required?

Thanks for your input

[umberto]

Sounds like a fun project.  Sandblaster is building a 2016 KTM conversion as well.  It seems like it is pretty straightforward if you start with a 450.  Here is a link to the thread if you want to look through it. 

http://www.kxriders.com/forums/index.php/topic,16691.0.html

It seems like most guys use the stock 500 kickstarter.  In fact, there have been a couple of KTM/KX 500 conversions on the site that used the stock kicker without issue.  As for the compression release, I would highly recommend it anyway.  It makes kicking the big 500 a lot easier.  Larry Weichmann on this site does a really nice job.  Here is a link to his thread:

http://www.kxriders.com/forums/index.php/topic,6445.0.html

[174ktm]

Thanks for the intel.
Just bought a pipe and silencer from AJ waggner (Flea-bay).
Plan on doing a bike tear down this week.

The frame is a 350, so I know it's not a drop in. I do have a 08 300 frame here that I plan on using the frame rails like the 2016 250 conversion above. (that green frame is sweet)

I have done 2 CR500 AL conversion for myself and built another for friend. I always wanted a KX500 again here I am, all in at this point.

[sandblaster]

Sweet.
I'll be watching your build.
The best bang for you intake buck is a V-Force 2, not the 3's and definitely NOT a Rad valve

On the kick lever parts, I would buy new if I had the option but I do have some used one's in my K5's..
In the very least, get a new return and thrust spring for it.

Decomp?
Depends...
Even on a stock engine I run a decomp head.
It's easier on me and it's easier on the components.

What do you plan on doing for your engine?

[174ktm]

where does one buy a Vforce 2?
New kicker will be placed on my OEM list

Plan for the engine right now is:
-Stock bore
-Port and Polish
-Re-shape the head + decomp
I need a hard pulling mid to top power engine.

I will be looking for someone to do the porting and head mods.

[174ktm]

Update -
Not much of a update, this Canadian winter is causing havoc on my riding right now. Have not taken my 500 engine out yet because of the winter blues, but have been collecting a few parts over the last few months
-New FMF SH pipe and PC silencer
-New Vforce 2
-Lightly used Hinson clutch basket
-New shifter
-DP clutch pack
-Degree wheel
-New Kicker and intake

Took the ignition cover off tonight and gave the crank a wiggle up and down and there is small amount of play (1 - 2 mm), engine will be split.

[sandblaster]

Yep... That is a typical KX500 with a few miles on it.
Since you are splitting the cases you may as well do it right and replace everything that you can still buy...
What you can't buy, get it rebuilt...

[174ktm]

Got the motor out and pulled the jug,
Cylinder(jug) looks newer than the rest of the bike 9.5/10
Power valves look good (gears) 9/10
Cylinder head seen a explosion of a piston, 5/10  
Piston 86mm, I think its a Wiseco
Head gasket is a 1mm
Connecting rod is got some play for sure. I will get the motor split in a day or two

Degree wheel misplaced (Wifey)
I didnt a chance to get any measurements.

I have my eye on a 1999 KX500 in really good shape, might pick it up this week if I can figure out a way to sneak it into the garage and add it to the bike collection before wifey can do a dirt bike count.

[umberto]

Got the motor out and pulled the jug,
Cylinder(jug) looks newer than the rest of the bike 9.5/10
Power valves look good (gears) 9/10
Cylinder head seen a explosion of a piston, 5/10 
Piston 86mm, I think its a Wiseco
Head gasket is a 1mm
Connecting rod is got some play for sure. I will get the motor split in a day or two

Degree was misplaced (Wifey)
I didnt a chance to get any measurements.

I have my eye on a 1999 KX500 in really good shape, might pick it up this week if I can figure out a way to sneak it into the garage and add it to the bike collection before wifey can do a dirt bike count.

Distract her with flowers.  It works for me.