Author Topic: 2003 KX 250 SF Conversion  (Read 161575 times)

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Offline zz3gmc

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Re: 2003 KX 250 SF Conversion
« Reply #150 on: August 28, 2015, 12:29:18 PM »
I was going to use it thinking it was a 86mm piston. Thanks!

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #151 on: August 29, 2015, 01:23:46 PM »
I got the new piston installed today and was able to fire it up.  I only rode it up and down the driveway, but what a difference!  I think this motor is going to live up to my expectations.  I am still missing a tiny part on the KIPS linkage that should be here Tuesday and I will be done with the motor. 

Funny story from my build today.  I installed the circlip on one side of the piston and then installed the piston on the wrist pin.  When I was trying to install the second circlip, it slipped out of my hand and disappeared.  I stopped everything I was doing and started making search circles in my garage.  About an hour later I gave up after verifying that it was not in the cases (I had stuffed rags all around the piston).  Luckily I had a new circlip left over from another job, and it appeared to be the same size.  I started trying to put it in, and it just wouldn't seat.  I tried several different ways and still nothing.  I got a little frustrated, and decided to compare the clip with the one I had installed, but the wrist pin wouldn't budge back out the side where I was trying to install the spare clip.  I went ahead and removed the clip I had put in on the workbench, and the wrist pin came out.  As I was looking at the piston, I finally caught a glimpse of something metallic in the groove where I had been trying to install the spare clip.  The original one hadn't slipped out of the piston and flown off, it had actually flown in and seated.  That's why the wrist pin wouldn't budge, it was installed and ready.  I guess maybe it's time for some glasses for the garage.   :-D

I should have everything finalized and ready for next weekend.  A ride video should be coming. 
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 sandblaster

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Re: 2003 KX 250 SF Conversion
« Reply #152 on: August 29, 2015, 03:00:23 PM »
Glasses stink but it's nice to see what your doing  :-D
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #153 on: August 29, 2015, 03:03:37 PM »
Getting old sure isn't for sissies.   :-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 umberto

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Re: 2003 KX 250 SF Conversion
« Reply #154 on: September 02, 2015, 07:04:43 AM »
I got the exhaust valve working and was able to fire it up last night.  Unfortunately, it feels like it has low compression.  I think that my cylinder was more worn that my calipers were showing.  I'm going to test it with my handy dandy compression tester, but it looks like I get to tear the motor back down and get the cylinder re-plated.  Yay!  One day I swear I shall ride this thing! 
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

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Re: 2003 KX 250 SF Conversion
« Reply #155 on: September 02, 2015, 07:12:53 AM »
I got the exhaust valve working and was able to fire it up last night.  Unfortunately, it feels like it has low compression.  I think that my cylinder was more worn that my calipers were showing.  I'm going to test it with my handy dandy compression tester, but it looks like I get to tear the motor back down and get the cylinder re-plated.  Yay!  One day I swear I shall ride this thing! 

Did u check ring end gap in cylinder?

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #156 on: September 12, 2015, 06:36:56 AM »
I sent my cylinder to Millennium Technologies and sure enough, it was completely worn out.  They are going to sleeve it to 86 mm, then bore it back to 88 mm so I can use my Wossner piston with some new rings and gaskets.  Hopefully I will have it back in a few weeks and can finally ride the beast as God intended.  

Meanwhile I was able to build a new pipe mount in Light Welding 2, and the instructor was nice enough to weld up the missing silencer mount on the subframe.  Here's a pic of the pipe mount.  It's made of 3/16" plate with a 1/2" solid steel pipe that I threaded to accept a 6 mm bolt.  I braced the post from the side with some 1/8" solid bar for added strength. On the back I welded some more ?/?" stock on to keep the mount from moving around when bolted up (it fits flush against the stock raised pipe mount).

I attached the stock rubber mount to this mount, and it made a lot of difference in the amount of movement in the pipe.  I still need to clean up the welds and paint it.





 
« Last Edit: January 05, 2018, 02:40:49 PM by umberto »
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 umberto

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Re: 2003 KX 250 SF Conversion
« Reply #157 on: October 12, 2015, 04:47:55 AM »
Got a box in the UPS delivery today.  After I unpacked it, look what I found...



Now if I can just sneak out of here without anyone seeing me...
« Last Edit: January 05, 2018, 02:41:09 PM by umberto »
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 umberto

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Re: 2003 KX 250 SF Conversion
« Reply #158 on: October 12, 2015, 05:28:06 AM »
While I was waiting on the cylinder, I got a chance to rebuild the forks and shock.  I also replaced the linkage and swingarm bearings, and added new brake pads.  The bike is ready to go, now I just need to assemble and re-install the motor.

Of course my son's swim season just began, so I don't have a free weekend to ride the beast until probably Thanksgiving.  But:

« Last Edit: January 05, 2018, 02:41:30 PM by umberto »
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 sandblaster

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Re: 2003 KX 250 SF Conversion
« Reply #159 on: October 12, 2015, 05:30:17 AM »
Nice!
 :-D
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #160 on: October 12, 2015, 05:35:31 AM »
I thought that guy was funny.  He's some sort of TV Preacher, but he reminds me of a young Martin Short.   :-D

Millennium did a really nice job on the cylinder.  I know you know this Sandblaster, but for everyone else Millennium just started offering sleeving services as well.  They're a great company to deal with, and now they can do everything in one place.  Bonus!
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 umberto

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Re: 2003 KX 250 SF Conversion
« Reply #161 on: October 12, 2015, 06:31:42 AM »
I got my face painted, camo on, escape route planned, and was making my run to freedom to install my cylinder when my wife reminded me that tonight is parent teacher conferences at the school.

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 sandblaster

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Re: 2003 KX 250 SF Conversion
« Reply #162 on: October 12, 2015, 06:51:19 AM »
 :lol:
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #163 on: October 12, 2015, 02:46:54 PM »
Parent teacher conferences went really quickly this year.  In and out in one hour.   :-o  I have twins and they have a couple of shared teachers, so I could kill two birds with one stone.  Managed to sneak into the garage for a couple of hours and got a ton done.  I am down to refitting the exhaust (I need to make a new silencer mount because I fixed the missing tab on the frame), adding fluids and kicking the snot out of her.  Unfortunately it was too late tonight, so I will make a run at it tomorrow.

« Last Edit: January 05, 2018, 02:41:48 PM by umberto »
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 umberto

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Re: 2003 KX 250 SF Conversion
« Reply #164 on: October 13, 2015, 02:46:20 PM »
I was able to get some more done on the bike tonight.  I got all the final bits installed and rolled her outside to see what happens when she's kicked over for real. Started on the third or fourth real, full kick (I think I solved the compression problem for sure).  I had the wife video it running for a bit. Sorry it's so dark, I had to do it quickly before the neighbors got together a lynch mob.  :-D

https://m.youtube.com/watch?v=x0UVfU_Fl3Q&feature=em-upload_owner

All that's left is to put on the new ASV levers and ride the snot out of it.
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