Author Topic: 2003 KX 250 SF Conversion  (Read 236538 times)

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Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #195 on: January 03, 2016, 12:03:00 PM »
I think your doing a great job.
Just keep doing what your doing  8-)
Thank you Sandblaster!  I'm starting to understand why you guys love these big two strokes so much. They're a blast to work on and ride.  Of course I couldn't have built it without all the help you guys gave me.
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 #196 on: January 08, 2016, 09:59:17 AM »
So I have two more modifications I would like to do to my bike before I tear it apart and powder coat the frame.  One of those things is to address the carburetor issues I have been having.  Foxx suggested I get a Lectron carb, and after hearing his and other's positive thoughts on them, I decided that it would work well with my setup.  I spoke with Dennis at Packard racing and ordered a carb custom set up for my altitude and motor setup.  It arrived along with a new throttle housing (more on that later) that must be used with carb.  Dennis suggested that I first boil the intake and carb together for a five minutes so the rubber would relax to the larger size of the new carb and not crack.  I purchased a new intake from Kawasaki and waited for the wife to leave the house so I could steal her pot and stove.  I measured the water to make sure it hit the carb where it needed to, got it boiling, and then perched the carb on top of the pot so that just the intake and carb horn were in the water.  It looked something like this:



I had previously modified the new intake per Sandblaster's instructions to use the VForce 2 reeds that came with my motor.  I bolted that all up to the intake and began the process of shoe-horning the carb into the now very small space.  A couple of tips if you are going to do this swap:
1. Buy longer bolts for your clamps, the carb is larger than stock
2. You will probably have to move your airbox boot clamp, as it won't fit below the carb anymore due to a larger bowl.  I used an allen bolt on top of the clamp to make it easier to tighten.  
3. Put your throttle cable in first, you won't be able to work on it after the carb is in.

The carb takes up nearly the entire area, and it a bit of a bear to get in place.  There is a little bit of room for the throttle cable at the top, but it is a tight fit.  

The darn thing looks cool on the bike:



Now I was on to the throttle.  As I put the new housing on my handlebar, I ran into a problem.  The throttle housing is made by Magura, and is round all the way around.  This doesn't allow any room for the front brake lever to move.  I called Dennis, and he suggested that I use the stock housing if I could.  Unfortunately, the new throttle cable does not have the screw in adjuster/stop like the stock cable.  I was able to make it work by cutting the adjuster/stop off the stock cable and making the following modifications:

1. I cut a long slot lengthwise with a Dremmel tool and a cut off wheel.  I also sanded the end flush so I could drill it out larger.

2. I put a nut on the shaft and used that to hold it in a vise without crushing it closed.  I then drilled the end out to just over 1/4" so the new cable would slip in.



3. I cut housing and the adjustor/shaft down so that it did not pull on the throttle when fully closed.  I made sure that you could tighten the adjuster/stop down all the way without it interfering with the cable pivot.



Voila!  Now I am ready to see if it will run.  Unfortunately I have a swim meet to go to this weekend, so a ride report will have to wait a bit.

Have a great weekend everyone!
« Last Edit: January 05, 2018, 02:44:39 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 #197 on: January 08, 2016, 10:02:52 AM »
If anyone is looking for Packard's website, here it is again:

http://packardracing.com/start.php?page=categories.php
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

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Re: 2003 KX 250 SF Conversion
« Reply #198 on: January 09, 2016, 01:00:00 AM »
I missed this...good to see you went with the Lectron, which size is that?....I'm very curious to see how well your fuel mileage/consumption is gonna be.
nice job with the throttle housing too.
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #199 on: January 09, 2016, 01:51:14 AM »
I'm embarrassed to say I forgot. We talked about the setup, and Dennis said we'll use this carb, and I kind of forgot.  I'm going to call him on Monday to update him on my fix, so I'll ask him the size and specifics. He's a super nice guy.

I'm interested in the fuel consumption as well. The Lectron looks a lot larger than the stock carb, and I'm already short on fuel with the 250 tank. It might be time for an oversized tank. 

I'll keep you posted once I get a free moment to ride it again.

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 tobys 2 strokes

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Re: 2003 KX 250 SF Conversion
« Reply #200 on: January 09, 2016, 03:50:29 AM »
Your going to like tuning it :-o
you have to remove the slide for every adjustment with my ziptie tank its a pain in the butt and the one in my T4 is worse you have to remove the carb every time other than that the are great.

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #201 on: January 09, 2016, 04:57:54 AM »
This conversion is so tight, I have to disassemble this bike to do just about everything anyway. I'm pretty excited to ride it.  I think my old carb was worn out a bit, so this should really wake her up.
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 DoldGuy

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Re: 2003 KX 250 SF Conversion
« Reply #202 on: January 09, 2016, 05:45:46 AM »
That is a 44 Lectron, Packard can (or could) turn down the O.D. Of the carb to fit the stock intake boot just as the PWK.

Umberto, I hope your cable setup works well for you, if you have issues, I posted about the cables I had made specific to the KX500 using a Lectron & the stock throttle assembly, which fits very well.

I'm also curious about your PWK that was on your 500, have you pulled the main jet block off to inspect its o-ring (has 2 security torx bolts holding it on)?

DoldGuy
Its Never too Late to Have a Happy Childhood!

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #203 on: January 09, 2016, 05:54:19 AM »
Thank you for clearing the carb size up Doldguy. We talked about a lot of different things, and I was more focused on tuning and installation. Plus I have the attention span of a gnat.  :-D. Dennis did turn it down quite a bit, but he still recommended boiling it for long term. It's close, but just a bit bigger. The throttle cable works really smoothly so far, but I'll keep an eye on it. I don't want to hang a throttle on something this fast.

I'm at a swim meet with my son today, but I will take a look at the stock carb when I get home tomorrow. I am assuming it is worn because it ran so much better with Danger's carb on it, even though the jetting was close in both carbs.
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 alexander-vmann

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Re: 2003 KX 250 SF Conversion
« Reply #204 on: January 10, 2016, 10:40:38 AM »
new carb? now im kinda jealous :-D cant wait to see goliath run wide open :-o
KX 500 newbie

my bike: 1993 kx500

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #205 on: January 14, 2016, 09:32:24 AM »
So I finally got a chance to fire Goliath up with the new carb, and dear Lord did that make a difference. No more hesitation at low rpm. It lit the rear tire up going out of my driveway like a funny car. I think I'm going to like this bike even more now.  :evil:

I also ordered an IMS 3.1 gallon tank.  I got it in black, which is custom order, so it may take up to eight weeks to get here. I guess I'll just have to stay close to home for now.  :-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 DoldGuy

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Re: 2003 KX 250 SF Conversion
« Reply #206 on: January 14, 2016, 12:47:40 PM »
That's Great News! Do you know what needle he sent with the carb (4-2Xl,5-2Xl) ? Also don't forget if/when you get time, check the main jet block on the PWK (I am a Curious George  :roll:)

DoldGuy
Its Never too Late to Have a Happy Childhood!

Offline umberto

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Re: 2003 KX 250 SF Conversion
« Reply #207 on: January 14, 2016, 01:13:30 PM »
I kept telling myself to write down the needle, because everyone seemed interested on the last Lectron thread.  I remembered that I wanted to write it down, right as I finally got the carb in the intake boot.  I couldn't bring myself to take it back off. I still haven't talked to Dennis about my throttle fix, so I'll call tomorrow and get the needle when I update him.

I've got the old carb on the workbench. I'll get some pics on Saturday to satisfy your curiosity. I'm curious to see what's going on in there as well.
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 #208 on: January 15, 2016, 07:11:41 AM »
I spoke with Dennis this afternoon, and he told me that he had installed a 5-2 needle in the carb.  My riding areas vary from 450 to 1100 feet above sea level (if I don't go up a mountain near my parent's place), if that helps any.
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 #209 on: January 17, 2016, 07:28:05 AM »
One of the last things I wanted to do to Goliath (I'm starting to like that nickname) was to add a Trail Tech Vapor computer.  The reason I wanted one is to be able to monitor the engine temp, but having a tachometer and speedometer is nice too. While I had the tank off for the carb swap I went ahead and put the tachometer lead on the plug wire, and covered it with electrical tape to keep it place.



The temperature gauge uses a sensor that goes in the radiator hose.  I had to use a tube to connect my radiator hose originally, so I just replaced the tube with the sensor.  It works really well.



The last piece is the wheel speed sensor. To fit it, you must drill a hole in the caliper mounting bracket and use the included self tapping screw. Because I am using the oversized rotor, I had to adjust the mounting spot quite a bit. I used some electrical tape to hold the sensor in place so I could test to make sure it worked. I ended up on the opposite side from where the recommended, but it seems to be working fine.  



I mounted the computer behind the handlebars, hoping It would protect it from roost and wrecks.  



I took the bike around the block to test everything, and I was amazed again at how well the carburetor works.  It is about 40 degrees outside, and the bike started, idled, and ran so crisply. Best modification I've ever made to a bike.  I desperately need to go ride this dude.  Hopefully I'll have some time next weekend.
« Last Edit: January 05, 2018, 02:45:32 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