Author Topic: KX500 Powered Quadracer 250R  (Read 39292 times)

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Offline Goat

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KX500 Powered Quadracer 250R
« on: January 13, 2014, 05:30:02 PM »
I started building this thing last winter but never had a chance to start a build thread. There isn't a lot of pics as I have had phone issues and lost most of them. Got a new phone and it takes way better pics than any other phone I've had. Anyway...

Had a 87 K5 engine in a 92 frame with a bunch of 87 /88 parts attached to it. It didn't ride very well and didn't run very well either. Found some cracks in the frame and decided I needed to do something different with it. So I started pulling it apart.



2 days after setting the engine on a shelf my buddy called and said I got you a 85 quadracer 250 for cheap. Complete minus jug, head, and brake pads. Sold all the suzuki garbage I didn't need and started to get the fab gears turning.

After staring at it for a day I went and bought an 8ft chunk of 1" diameter 1/8" wall tubing to strengthen the frame with. Ended up only using about 4 feet of the tubing. Once all that was reinforced to my liking I cut the front engine mount tube just above where the exhaust port on the k5 engine wouldn't hit it. Then I cut 2 pieces of the new tubing and put a nice bend in each one to end up with a wishbone support like the bike had. Welded that in and set the engine in. Swingarm needed no modifications for the engine to fit. I was impressed with how easy it went together from there.

Once I got the engine sitting in there I had to figure out engine mounts. Lower engine mount needed moved forward half inch or so. Used 1/8" flat plate for front mounts. Drilled and bent accordingly. I made the head stay brackets the same way.

Now that the engine is in. Chain lines up perfectly. Now the fun part... How do I get the giant K5 pipe to fit :P This took the longest. I wanted the pipe to fit in a way that I wouldn't burn my leg and prefer it to exit out the left side so it wouldn't cause issues if I ever wanted to put rear fenders on it. Originally I used part of the K5 stock pipe and part of a quadracer pipe. Engine would run but wouldn't rev above 3k rpm. So I started researching pipe design. Ended up buying a program for building pipes. Learned a lot playing with that program. I contacted Sanblaster to see if he could keep an eye out for a junk pipe I could cut up. He had one off his personal bike that he hooked me up with for an excellent price as always. Used most of that pipe and part of the quadracer pipe I originally used. Fabed up some exhaust mounts and fired it up. Ran good and made it up to around 8k rpms.

Now its time for a test ride... Needed some jetting done but it was pretty solid. Vibrations were horrible though. My feet and hands vibrated so much I'd lift my feet and let go of the bars. Ended up removing the head stay brackets to see if that helped any. It got rid of probably 70% of the vibrations so it never went back on.

I noticed trans oil looked grey so I decided it was time for a rebuild, crank seals and crank bearings. New OEM rings, OEM seals, and high end bearings from a driveline shop I visit frequently. Now it's running better. Re-jetted again and it's an awesome beast.





It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline Goat

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Re: KX500 Powered Quadracer 250R
« Reply #1 on: January 13, 2014, 05:46:08 PM »
I forgot to mention the original carb boot was rotted pretty bad and would interfere with the exhaust so I bought a brand new KXT250 intake off ebay.

I noticed if you're WOT for 1/4 mile or so it would want to fall on its face like it ran out of Fuel. It was fine in short stretches but anything over 1/8th mile it would run lean.



So I started looking for something sturdy enough to make a intake spacer out of to level the carb position a little. I found some PVC sheet laying around in one of my cabinets so I traced the reed cage onto it and cut 2 pieces out. Then took them to the sander to make them thinner on the bottom than the top. The next part is why I buy drills with a level on them. Clamped the 2 pieces together on the bench marked the spots where the holes needed to be on the engine side flipped the pieces over and marked where they needed to be for the intake boot. Leveled my drill and started boring the holes. Put them on for test fit and it made a considerable difference. Still need to do a little fine tuning to them but they are working fine. Gonna take a little more material off the bottom to level the carb a bit more. Once it is where I need it I will have someone machine the spacer out of aluminum so it's one piece.

« Last Edit: January 13, 2014, 06:19:51 PM by Goat »
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline Goat

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Re: KX500 Powered Quadracer 250R
« Reply #2 on: January 13, 2014, 06:17:17 PM »
Forgot to mention the shift lever needed to be extended 1.5" so I could get my foot between it and the footpeg.





Here are pics of the extra support pieces too.







This project is far from done. I have works shocks that came with the quad that need rebuilt, frame a-arms, and swingarm need powder coated, and seat needs reupholstered. Not sure what colors I want to go with yet. Any ideas?

Got bored and tired of not being able to ride because the snow is too deep si I built some brackets and bought some used skis off a Ski-Doo.







I didn't get a pic but the sand shark paddles work way better than the sedona tires. I should have video to post when the ol lady gets home in the morning.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline sandblaster

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Re: KX500 Powered Quadracer 250R
« Reply #3 on: January 13, 2014, 06:56:19 PM »
I can't wait to see it.
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline motopunk

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Re: KX500 Powered Quadracer 250R
« Reply #4 on: January 13, 2014, 07:41:04 PM »
goatzilla in the snow ...  :-D  ...  long time ago i´ve seen a snow-kit for quads that made it loking like a fourwheel-skidoo ... 

cant wait to see this project finished... blue and white would be a great color for it, but please without the suzuki-seat cover...its a goatzilla now...  :wink:
big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

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Offline Foxx4Beaver

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Re: KX500 Powered Quadracer 250R
« Reply #5 on: January 14, 2014, 01:03:37 AM »


that's cool!...I'd be a little confused at first if I saw that thing coming head-on rippin down a snowmobile trail.
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline sandblaster

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Re: KX500 Powered Quadracer 250R
« Reply #6 on: January 14, 2014, 03:11:40 AM »
Goatzilla!!!!!
I like it  :-D
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline motopunk

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Re: KX500 Powered Quadracer 250R
« Reply #7 on: January 14, 2014, 05:26:21 AM »
Goatzilla!!!!!
I like it  :-D


very simple story to this name .. 6 or 7 months ago i´ve seen a suzuki ltz500 2stroke-quad and that was called "quadzilla" ... 
goats quad starts to be a unique build, so it needs a unique name like this...  :mrgreen:

hope that goat will like this name too...  :wink:
big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

---  www.der-motopunk.de.tl  ---

Offline Goat

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Re: KX500 Powered Quadracer 250R
« Reply #8 on: January 14, 2014, 07:21:20 AM »
Lol I do like the name. I'll have my seat cover done at an upholstery shop so they can put the name in the seat cover.

Here is a couple videos for you guys. Head gasket started leaking coolant down the side of the jug by the last video. I guess Windrosa doesn't make a good head gasket. So now I need to find a good one.

Sedona tires on back. They work but not real good.
https://www.youtube.com/watch?v=kc-TOz97Y5k

Sand Shark Paddles work much better.
https://www.youtube.com/watch?v=g9wpie0WBN4

Head gasket started to leak and at the end started overheating
https://www.youtube.com/watch?v=euTRvTw-7XU&noredirect=1
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline sandblaster

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Re: KX500 Powered Quadracer 250R
« Reply #9 on: January 14, 2014, 07:25:42 AM »
I guess Windrosa doesn't make a good head gasket. So now I need to find a good one.

Cometic  :-)

You need to make your vids public...  :-o
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Goat

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Re: KX500 Powered Quadracer 250R
« Reply #10 on: January 14, 2014, 07:39:33 AM »
Thanks SB. Vids are Public now.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline Foxx4Beaver

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Re: KX500 Powered Quadracer 250R
« Reply #11 on: January 14, 2014, 07:42:55 AM »
Thanks SB. Vids are Public now.

still sayin "Private"
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline Goat

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Re: KX500 Powered Quadracer 250R
« Reply #12 on: January 14, 2014, 07:47:19 AM »
Try again. Apparently it didn't save settings the first time.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline Foxx4Beaver

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Re: KX500 Powered Quadracer 250R
« Reply #13 on: January 14, 2014, 07:51:24 AM »
you're good....that thing goes pretty good with the paddles...how's it doing wheelies?
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline Goat

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Re: KX500 Powered Quadracer 250R
« Reply #14 on: January 14, 2014, 07:58:17 AM »
Snow is over a foot deep out in the field. It definitely needs more than 8 paddles per tire. Can't get wheelies out of it. on pavement it will break the tires loose all the way through 4th gear. I do plan to get a bunch of different size rear sprockets and play with it until it goes the way I want. My rear shock is also pretty spongy so that is another reason for no wheelies yet.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.