Author Topic: 07 KTM 250sxf/500kx conversion  (Read 22776 times)

0 Members and 1 Guest are viewing this topic.

Offline umberto

  • Administrator
  • Hero Member
  • *****
  • Posts: 2,485
  • First Ride 02-02-19
Re: 07 KTM 250sxf/500kx conversion
« Reply #15 on: September 06, 2016, 03:06:48 AM »
You're building quite the stable of cool KTM/K5 conversions.  We'll need pics of this build also.   :-D
Perhaps I have a dirt bike addiction?

03 KX 250/88 KX 525/2017 KX250F - Goliath
17 KX250F/04 KX250
04 KX 250 - Lunchbox's Bike
05 KX 125/144

Offline Foxx4Beaver

  • Hero Member
  • *****
  • Posts: 8,945
  • James Stewart DID NOT invent the scrub!!..JoJo
Re: 07 KTM 250sxf/500kx conversion
« Reply #16 on: September 06, 2016, 06:47:30 AM »
Fox - Just trying to help out the next guy that might try one of these, as it seems its the small things that are the things that seem to be the issues that need figuring out.

I know....and a fine job you did. :mrgreen:
all good.
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #17 on: September 26, 2016, 02:47:51 PM »
Update-

Not much has happened lately, using my buddies garage for the project so the last few weeks hes needed it. Exhaust is done and mounted but really not happy with it. Sticks up above the rear fender, needs some pipe cut down and a mount made. With that said, its not a high priority and can be done when ever.

For those that might be trying to run the G2 2stroke perch and PWK39 (or other PWKs ?) I ended up using a Motion pro T3 #10-3000. Threads into the carb cap and the perch and solves the WOT if the cable gets pulled. This cable is for KTM 2strokes and is 5inches longer then there stock cable, and is about factory length for the two Kx500 cables I have here.

Just need a day to put it all back together, mount the two perches and prey like hell it starts up lol. Getting excited, should have been done by now. Hopefully get to ride it a bit then I will tear it all down for powder coating this winter and take care of any details that need to be addressed.

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #18 on: October 02, 2016, 10:47:42 AM »
Update:

Bike runs, no leaks, started 3rd kick and idled somewhat lol.

Still lots of small things to do along with getting jetting correct. I did ride it around a bit and it seemed pretty boggy in the bottom end but seemed to clear up some in the higher rpms. Also seemed to power out pretty fast. Most certainly not a wheelie monster yet lol

I was ear to ear smiles when she started and idled.

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #19 on: October 08, 2016, 07:25:12 PM »
Update:

My buddy and I worked on my jetting today, started off at 168/58 needle in 3 clip, 1.5 out on the air screw which was my base jetting. I was running extremely Rich. We started leaning things out and at this time we are at 158/42 , needle clip in the second from the top 1.5 out on the air screw.

Mid has cleaned up tremendously, still a little bit fat down low. Going to hopefully try a 40 tomorrow and see if that helps.

Offline Smokinbigbore

  • Newbie
  • *
  • Posts: 2
Re: 07 KTM 250sxf/500kx conversion
« Reply #20 on: December 17, 2016, 11:27:59 AM »
Build is looking great! I am creating the same monstrosity- 2007 450 SXf with 1985 KX500.
I have made an adapter plate to convert the carb boot to the later 6 bolt later type. I've also got the later Kehin carb also(1994). I used a 2007 300 exc air box boot to connect box to carby which fits perfect.

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #21 on: June 16, 2019, 11:46:08 AM »
LONG OVERDUE UPDATE! -

SO a lot of things went sideways on me on this build.

1. Lost compression out doing final jetting. Don't know if I ran it to lean or what. Was able to limp the bike home. Looking back, was probably low compression to begin with as it wasn't to hard to kick over.

2. Had my jug bored out for a 87mm Wosner piston. Went to install and ring gap was all wrong and to wide. Come to find out the guy that bored it went to far so I had to much slop. Had to take it somewhere else a yr later to bore it once more to 87.5. New Wosner piston of course.

3. When I had the motor out I said aww screw it Ill have the frame and some misc parts Powdercoated Kawi Green. Powdercoat Shop screwed the pooch and I lost my VIN. 7months of back and forth with WSP and a drive finaly across the state and I was able to recover my VIN....it now looks like a drunk 3yr old punched the numbers into my frame. WSP....if your read this figure out a new system.


Where I am now! -


1. Motor is put back together minus the head which is currently with our very own Larry getting his work done.

2. Just picked up a older PWK 38 airstriker to replace the pwk39

3. Figure out a better airfilter system - looking at going pod with cover or possibly a newer airstriker that is shorter to allow the ktm boot to fit better.

4. Fix my muffler mounting, guy that welded up my stinger went all free lance on me. Need to cut the welds and redo it so I dont have to cut the rear fender to fit.

5. Buy supermoto tires to put on my Behr Supermoto wheels

6. Wire up the bike for the street and get in inspected and get a plate.

7. Terrrorize the back roads!!!!

On a side note, Ive been searching some starting points with this carb for the 5-hundy. Theres nothing wild about my motor 1.5mm over with some porting in the jug. The airstriker currently has a #6 slide, and r1172n needle. There are some scratches on the front of the slide, nothing you can feel. I have read about useing the Yamaha needle and thats about it. Also heard the STIC metering block is the tits...just dont have the coin for that right now.

Offline dave916

  • Hero Member
  • *****
  • Posts: 544
Re: 07 KTM 250sxf/500kx conversion
« Reply #22 on: June 17, 2019, 01:33:03 AM »
jetting i would be starting AROUND 1368n needle  52piloT 170main

Check the metreing block oing before you start {youtube it}

Offline umberto

  • Administrator
  • Hero Member
  • *****
  • Posts: 2,485
  • First Ride 02-02-19
Re: 07 KTM 250sxf/500kx conversion
« Reply #23 on: June 17, 2019, 03:44:35 AM »
jetting i would be starting AROUND 1368n needle  52piloT 170main

Check the metreing block oing before you start {youtube it}
Mine was bad on my carb before I changed over to a Lectron.  Changing that o-ring made a big difference.
Perhaps I have a dirt bike addiction?

03 KX 250/88 KX 525/2017 KX250F - Goliath
17 KX250F/04 KX250
04 KX 250 - Lunchbox's Bike
05 KX 125/144

Offline dave916

  • Hero Member
  • *****
  • Posts: 544
Re: 07 KTM 250sxf/500kx conversion
« Reply #24 on: June 17, 2019, 06:13:14 AM »
jetting i would be starting AROUND 1368n needle  52piloT 170main

Check the metreing block oing before you start {youtube it}
Mine was bad on my carb before I changed over to a Lectron.  Changing that o-ring made a big difference.
Most metering block oring seals are leaking on secondhand pwk /  3 or four differant points where the leak 


https://www.ebay.com/itm/Jet-block-o-ring-1-Keihin-PWK-33-41-carburetor-35-36-38-39-40-mid-body-gasket-/201306545569

the price of them seems to gone up over the past  months :-)

Offline dave916

  • Hero Member
  • *****
  • Posts: 544
Re: 07 KTM 250sxf/500kx conversion
« Reply #25 on: June 17, 2019, 06:15:55 AM »
What kind of gasket carb sealer does everbody  use to hold oring in position for fitting?

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #26 on: June 17, 2019, 01:08:09 PM »
Will definitely look into the metering block oring. Thanks for the heads up on that one.

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #27 on: June 17, 2019, 01:11:17 PM »
jetting i would be starting AROUND 1368n needle  52piloT 170main

Check the metreing block oing before you start {youtube it}

Keep the #6 slide as well?

Offline dave916

  • Hero Member
  • *****
  • Posts: 544
Re: 07 KTM 250sxf/500kx conversion
« Reply #28 on: June 20, 2019, 10:15:54 AM »
jetting i would be starting AROUND 1368n needle  52piloT 170main

Check the metreing block oing before you start {youtube it}

Keep the #6 slide as well?

never noticed much differance with slides / 6 or 7 fine

Offline hunter

  • Jr. Member
  • **
  • Posts: 25
Re: 07 KTM 250sxf/500kx conversion
« Reply #29 on: July 21, 2019, 08:44:52 AM »
Update:

1. Head came back from Larry. Its so d**n nice I almost didn't install it. It also makes everything else look like crap lol. Thanks Larry!

2. Good call on the Meteringblock oring. I barely touched it and it broke apart. New o-ring and 1368n needle clip on center with 168/52 installed. Couldn't find a 170 local to me.

3. Got the Top end done, motor is in bike. Need to order some new rubber mounts for the radiators.