CRF450R / CR500 Supermoto Project

Discussion in '2 smokers' started by J Banning, Dec 17, 2013.

  1. J Banning

    J Banning Been here awhile

    Joined:
    Oct 9, 2007
    Oddometer:
    156
    Location:
    Newark, DE
    I’m building aluminum framed CR500 supermoto based on a 2004 CRF450R chassis.

    Even though this isn't my first supermoto, I'm super excited. I've had a couple really fun KTMs, the last being a KTM 525SMR, but that bike was set up for smaller kart tracks, high maintenance and really expensive to fix. After the motor needed to be freshened up and the parts bill was 2/3 of what the bike was worth, it sat. Eventually I came to the realization that it was worth a lot more in parts than whole so I parted it out.
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    Meanwhile, during the last year or two I've been doing more and more track days on my GSX-R 600 Suzuki. I've been having a lot of fun with that... but I miss the supermoto. This summer I had a chance to ride my buddy's highly modified Husqvarna 510SMR at NY Safety Track and that made me decide that I *HAD* to have another one...

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    I wanted a new supermoto. This one though had to be fast, but it also had to be easier and less expensive to maintain than my old KTM. I wanted it for track days and possible racing on road courses, not the tight motard/kart tracks I used to ride. I want to ride it on road courses like Summit Point Shenandoah, NY Safety Track and Jennings GP. I want the bike to run 120 mph.

    And so the project began...

    Finding a chassis
    I started with a street legal CRF450R in supermoto trim I found a few hours from my house. It’s a very clean, low hour unmolested bike. The seller was really bummed after the sale that I was gonna tear it apart, but I know the end result will be well worth it. As soon as I got the bike home I had it titled and tagged before I took it apart.

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    Before I tore into it though I had to take it for one short ride around my neighborhood. I was impressed. It had more power than I was expecting! Verified on GPS the bike would do 103 mph as I bought it. Not bad. (for what it’s worth, the Trailtech speedo was within 2mph of the GPS top speed)

    <iframe width="420" height="315" src="//www.youtube.com/embed/cKwHLC7WH7A" frameborder="0" allowfullscreen></iframe>

    Parting it out
    After that first ride I pulled it into the garage, put it on the lift, and pulled the engine, carb and exhaust.

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    I sold them all off, ending up with just a rolling chassis.

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    Time to find a CR500!
    I then began my search for a CR500 engine. At first I was thinking I'd go just for a motor but after some research and seeing what complete motors were selling for I figured I could get a complete running bike for not much more. In addition that would also get me the carb, exhaust, ignition and throttle.

    Before too long I found my bike, a 1999 Service Honda CR500AF. I got it from a guy who bought it four years ago and due to a bad knee was never able to ride it. It just sat in his warehouse collecting dust.

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    A nice bonus was that it came with a supermoto wheelset and a bunch of new Honda hardware.

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    Since the bike hadn’t been run in four years I took it home and changed the oil, cleaned the carb, put a fresh plug in it.

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    After it all went back together all it took was three good kicks and the engine was running…. and damn, it sure sounded good!

    <iframe width="560" height="315" src="//www.youtube.com/embed/opKmXsztY5U" frameborder="0" allowfullscreen></iframe>

    Sell off what I don't need to fund the rest of the project
    Now that I knew it would start and I could run it through all the gears I then pulled everything I needed (engine, carb, exhaust, ignition, throttle) and then list the rolling chassis for sale.

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    Learn new skills
    I should also mention that while all this was going on I also managed to find some time to have a good friend start teaching me how to TIG weld (I'm already pretty good with MIG). I'd like to weld the CRF frame up myself, but I’ve still got a LOT to learn so I think I’m just gonna have to let him do it. I’ll do all the cutting and fitting though.

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    What's next?
    I'll be ordering motor mounts and aluminum stock for the frame this week. The swingarm bushings I need should be in by the weekend, so I hope to have the motor at least sitting in the CRF frame by next week.

    With that being said, that's where I am now with this project. ;)

    Stay tuned for more updates!
    #1
  2. J Banning

    J Banning Been here awhile

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    Good news and bad news...

    The good news:
    When I bought that CR500AF it came with a second set of supermoto rims. The rear was a 17x5" and I hoped it would fit on the CRF to replace the 17x4.25" rim and 150 tire. This week I took a closer look and found that the axle diameters were the same and when I mounted it up the spacers look like they'll put the sprocket and rotor in the right spots! I have a new 160 rear and tube laying around so this weekend I'll see if I can get it mounted up to know for sure.

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    The bad news
    Taking a closer look at the CR500 motor i found a HUGE crack on the intake side of the piston skirt. I guess I'll be doing a top end a lot sooner than I was planning :mad:

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    But there is some more good news...

    • I got a complete '98 CR250 airbox off eBay for $30 shipped. The boot, metal base, cage and bolt will work on my 450 airbox.
    • I ordered a airbox adapter plate, motor mounts, coil mount and exhaust mounts from http://conversionparts500.com.
    • I ordered the correct swingarm spacers needed to properly space the engine in the chassis from http://rockymountainatvmc.com

    :D
    #2
  3. J Banning

    J Banning Been here awhile

    Joined:
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    Oddometer:
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    Location:
    Newark, DE
    Made some good progress with the frame !

    Removed the subframe, airbox, shock and swingarm.
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    Broke out the reciprocating saw and bi-metal blade and cut off the forward and lower motor mounts.
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    Put the new swingarm bushing in (moved stock one from right to left and then put a new 59mm one in the right side) and set the motor in the frame. The bushings appear to have done their job and the sprocket is aligned with the chain guide.
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    The whole "Y" section needed to be cut and moved up about 4 inches so that there will be room for the exhaust to bolt up to the engine. I marked lines where I wanted to cut.
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    A reciprocating saw with a NEW bi-metal blade made quick work of that aluminum tubing.
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    Next step was to use an electric die grinder to grind out the welds on the big end and pull out the remains of the downtube.
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    It took a while but I finally broke through all the welds. Doesn't look half bad.
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    That's all for now. Stay tuned for more updates this coming weekend.

    :cool:
    #3
  4. onetravdown

    onetravdown I can't ride where?

    Joined:
    Jul 27, 2007
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    Nice work! Subscribed!

    Sent from my SAMSUNG-SGH-I747 using Tapatalk
    #4
  5. 225

    225 Been here awhile

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    Mar 13, 2012
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    158
    Location:
    New Orleans
    I'm glad to see a thread on this. You still have your DRZ I seen last summer at the Gap?

    Good luck with the build. Maybe you can show Lee a thing or two LOL
    #5
  6. rpmwfo

    rpmwfo Been here awhile

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    Jul 8, 2011
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    135
    Why not just run the Service Honda as a SM?
    #6
  7. J Banning

    J Banning Been here awhile

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    Oct 9, 2007
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    Newark, DE
    The DR-Z400SM was a loaner bike from a friend. It was fun at The Dragon and I made the Killboy highlights on it.

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    #7
  8. J Banning

    J Banning Been here awhile

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    Oct 9, 2007
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    I don't have a title for the Service Honda, but I do for the CRF450R... plus the CRF is already street legal and inspected in my state. CRF is a newer ('04 vs '99) and very low hour bike.
    #8
  9. onetravdown

    onetravdown I can't ride where?

    Joined:
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    It's been about 12 hours since you started this thread. Is it built yet?
    #9
  10. anonny

    anonny What could go wrong?

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    :lurk. In
    #10
  11. D.T.

    D.T. Difficult but useful

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    Aug 1, 2004
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    Moneyapolis, MN

    :lol3


    Looks like a wheelie machine!
    #11
  12. jar944

    jar944 Been here awhile

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    Looks good.

    You might want to do your motor work (if you still plan on it) while you have the cylinder off.
    #12
  13. bykpimp

    bykpimp Live and let ride

    Joined:
    Oct 18, 2006
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    Santa Cruz Ca
    Very cool!!!!! I feel you on the price of 525SM's I had a pretty nice one a few years ago with all the bells and whistles.......I couldn't give the thing away so I parted it.

    Funny I should find this thread as I'm going to go have a look at Alloy framed 5hunny in the morning. Keep up the good work!!!!
    #13
  14. FJ_Kevin

    FJ_Kevin Been here awhile

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    Maryland ==> originally from Long Island
    Nice work... I'll be watching too!:thumb
    #14
  15. Fener6

    Fener6 The Container Man

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    Gates of Hell
    Sweet. Will you be taking that to NJMP?

    Edit: Ahh Banning, just realized the name. I've heard the name somewhere b4, can't put my finger on it. You know jshep or pete? Pete stopped doing track, but jshep is going at it hard this past year.
    #15
  16. BigDave75

    BigDave75 Will Work for Food!

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    In. :clap:clap:clap
    #16
  17. bobfab

    bobfab Long timer

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    Westminster CO
    Looks like a fun project, i saw the chassis for sale thread and was wondering !! :lurk
    #17
  18. J Banning

    J Banning Been here awhile

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    Oct 9, 2007
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    Newark, DE
    Well, it's been a little while so I've got a bunch of updates...

    After about a month of private messages, reading threads and collecting photos I finally started the fab and welding of the frame. Boy, did I underestimated how long it would take! Between cutting out the factory "Y" and mounts, grinding the frame and "Y" smooth, sourcing, measuring and cutting billet pieces for the frame and head stay and then welding everything together I figure that's a solid 24 hours labor. That doesn't count the cutting and welding of the radiator fittings, so that might be close to another 10 hours. This is my first conversion, so I could do it again in maybe 2/3 the time but I'm just saying the first time around took a lot longer than I was expecting.

    Grinding the frame smooth where the old motor mounts were...
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    Trimming more off the "Y" and then we used a mill to remove more material from the inside so it would slide onto the downtube better...
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    I got two pieces of billet aluminum. One was used to fill the gap in the two lower frame rails. The ends of that were milled to fit down inside the factory hollow tubes...
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    Once they were tack welded in place we fitted the new motor mounts...
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    We then finish welded the motor mounts and the rest of the frame. I will eventually grind most of the welds smooth and get the frame powder coated...
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    The other piece of billet aluminum was cut and then drilled to use as a headstay mount. At this time we also welded the coil mount...
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    After the welding was done we tore into the motor. Aside from having a big ass crack in the stock piston and a blown crank seal, everything, including the bore looked really good (it is still the stock bore). Just to be safe I replaced the stock crank and main bearings with new OEM Honda parts and the OEM piston was replaced with a new Wiseco.
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    I haven't put the motor together yet. Still waiting on crank seals, new clutch, water pump rebuild kit and for me to get around to porting the cylinder before machine work to it.

    Finally, I was able to get that spare 17x5" rear wheel and 160/60/17 rear tire mounted up and fitted on the bike. I've got plenty of tire clearance between the tire and frame and as long as I can adjust the spokes enough to offset the rim another 3-4mm I think I'll have minimal chain rub on the tire.
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    The picture doesn't show it, but this new tire/rim combo just looks so much better than the little 17x4.25 and 150/60 tire I had before. Hopefully it will help on the track too.
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    That's all for now! :D

    -B
    #18
  19. J Banning

    J Banning Been here awhile

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    Oct 9, 2007
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    Newark, DE
    Yes, as long as it'll run over 110 mph I'll have it at NJ Motorsports Park. Not sure I know those guys though. Hit me up on Facebook. Always looking for new people to ride with!
    #19
  20. 225

    225 Been here awhile

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    New Orleans
    Looking good!
    #20