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Thread: Buyer looking for input on a CR500 conversion

  1. #1
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    Default Buyer looking for input on a CR500 conversion

    So I had an SXV550 which was a beast to ride, but an equally beastly bike to maintain. Sold it a couple months ago and have been looking for a replacement.
    Came across a RMZ 250 with a CR500 engine in it, and had some questions for you knowledgable people:

    Having never ridden a two-stroke, how would it fare on larger tracks (more road racing style)?
    Where should I start in terms of questions with the fabrication - as in, what would be involved in that kind of conversion?
    Any difference in years of CR500 motors with gearing, etc.?
    Other things I should look out for?

    Thanks ya'll!

  2. #2
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    Default

    Well, I did find this ...


  3. #3
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    Classic sportbike vs motard track vid. He kills em' under braking and through the turns, they disappear down the straights, just to be reeled back in. Now tell me, why do people ride sportbikes? Gearing and jetting would be most critical with the 2stroke on a big track/street. Use a high quality premix around 36:1 and you should get good reliability. Plus, a 2stroke is cheap and easy to rebuild vs 4stroke.
    Last edited by exit90a; 11-04-2011 at 04:40 AM.
    2007 RXV550SM/2007 KTM 690SM
    NO REMORSE / NO REGRET Previous Supermotos: 2008 SM510R

  4. #4
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    Keep the pilot circuit a little too rich. That will save your bacon if you chop the throttle at high speed. Also keep the idle speed high, that will keep the engine lubricated when you chop the throttle. I am certain these bikes were never really intended to exceed 100 MPH. A lot of typical motocross logic does not apply here. If you spin this sucker up to top speed and shut off the throttle with the idle set low and the pilots lean, you will either seize the piston or melt the piston and smear aluminum over the rings and smush them in. It is really easy, due to the speeds the bike can run with gearing, to drive the engine with the rear wheel. When the rear wheel drives the engine (instead of fuel driving the engine) the engine stops being lubricated. Chopping the throttle is just something that happens. You really need to keep the idle high and the pilot circuit rich to keep from breaking the engine. This is what I did on my 1986 CR500 shortstroke. I would recomend a long stroke engine as you can still get parts for them.

    http://www.supermotojunkie.com/showt...n-CR500-motors

  5. #5
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    That's some good info right there ... thanks Tank.
    It's a moot point, though. I can't get it plated up here (canada), so I'll just have to drool over it from a distance.
    Anyone in the Pacific Northwest, though, check out this ad:

    http://seattle.craigslist.org/sno/mcy/2683501853.html



    Quote Originally Posted by TankerBEAN View Post
    Keep the pilot circuit a little too rich. That will save your bacon if you chop the throttle at high speed. Also keep the idle speed high, that will keep the engine lubricated when you chop the throttle. I am certain these bikes were never really intended to exceed 100 MPH. A lot of typical motocross logic does not apply here. If you spin this sucker up to top speed and shut off the throttle with the idle set low and the pilots lean, you will either seize the piston or melt the piston and smear aluminum over the rings and smush them in. It is really easy, due to the speeds the bike can run with gearing, to drive the engine with the rear wheel. When the rear wheel drives the engine (instead of fuel driving the engine) the engine stops being lubricated. Chopping the throttle is just something that happens. You really need to keep the idle high and the pilot circuit rich to keep from breaking the engine. This is what I did on my 1986 CR500 shortstroke. I would recomend a long stroke engine as you can still get parts for them.

    http://www.supermotojunkie.com/showt...n-CR500-motors

  6. #6
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    Quote Originally Posted by T-rex View Post
    That's some good info right there ... thanks Tank.
    It's a moot point, though. I can't get it plated up here (canada), so I'll just have to drool over it from a distance.
    Anyone in the Pacific Northwest, though, check out this ad:

    http://seattle.craigslist.org/sno/mcy/2683501853.html
    Oh man, if only i wasnt deployed. That'd be a ripper for sure. I've ridden CR500AF's in the dirt, but i couldnt imagine what trouble i would get into on the streets.

  7. #7
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    Default

    Plenty of info here and on cr50riders. All of us bought them or built them and sold them shorty after for good reason. Search here for satans Supermoto.
    Last edited by 06-530rr; 11-05-2011 at 10:38 PM.
    2006 husqvarna 530rr. AKA "dirtyfivethirty" or "freight train " Formerly known as Alohar1

    www.FastBikeIndustries.com www.ksrwheels.comwww.balidogrefuge.com

  8. #8
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    Here is satans Supermoto. Plated too
    2006 husqvarna 530rr. AKA "dirtyfivethirty" or "freight train " Formerly known as Alohar1

    www.FastBikeIndustries.com www.ksrwheels.comwww.balidogrefuge.com

  9. #9
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    haha thats my bike on craigslist.
    2010 yz450
    2010 r1
    05 crm500 plated supermoto
    86 xr600
    74 mx250

  10. #10
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    Quote Originally Posted by alohar1 View Post
    Plenty of info here and on cr50riders. All of us bought them or built them and sold them shorty after for good reason. Search here for satans Supermoto.
    Why does everyone get rid of their cr500's right after the build? Too much trouble?

  11. #11
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    i will tell you why im getting rid of mine. the 500 is far from smooth cruising on the street. yes it has lots of power and it goes fast. but you have to either be all in it or not at all. you cant just cruise at 1/4 throttle going down the road. they want to surge, plus my hands and feet go numb after about an hour on it. but for the track it would be awesome its just not a very practical street bike. if i had the money to keep it and sumo my 450 i would.
    2010 yz450
    2010 r1
    05 crm500 plated supermoto
    86 xr600
    74 mx250

  12. #12
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    Moto said it. It's not a cruising SM. On or off. If it was for the track without a doubt I would have kept mine. Or if I could have both. I would have kept mine. I couldn't justify keeping a 15k Supermoto that I ride once a month. It's tough to beat a 4 stroke SM for street duty. Now off road or track... I'm a smoker boy all the way!!
    2006 husqvarna 530rr. AKA "dirtyfivethirty" or "freight train " Formerly known as Alohar1

    www.FastBikeIndustries.com www.ksrwheels.comwww.balidogrefuge.com

  13. #13
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    Quote Originally Posted by alohar1 View Post
    Here is satans Supermoto. Plated too
    Jesus I still love that motorcycle.

    So far, none of your complaints about your Sumo CR500 would deter me. I would however balance the crank for sure. I've ridden a 500AF with a balanced crank and it's a pussycat.

    I would however go w/ the KX500 mill for obvious reasons. The PV valve gives it a dramatically wider, longer, and stronger powerband. I'd probably add the 550cc kit as well.

    My only concern, and it's a big one, is about mpg. My FI SMC gets an honest 45-54mpg riding it quite hard. I've heard rumors that the 2 stroke 'tards only get like 15mpg!!! Is that true?

    Thx.
    2008 KTM 690 SMC, MX-Tech suspension, full FMF exhaust, DNA filter and modified airbox, Tune ECU, tubeless tire conversion w/ Michelin Power Pures.

    2008 KTM 300SX (started life as a 250SX).

  14. #14
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    Quote Originally Posted by T-rex View Post
    Well, I did find this ...

    I really enjoyed that video. That Frenchman (I think) 'tard rider really smacked those road bikes around.
    2008 KTM 690 SMC, MX-Tech suspension, full FMF exhaust, DNA filter and modified airbox, Tune ECU, tubeless tire conversion w/ Michelin Power Pures.

    2008 KTM 300SX (started life as a 250SX).

  15. #15
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    Default cr500

    I finished mine 6 months ago. KX is not as reliable as the cr, Power valves are good but take some maintance espeically if you dont jet properly which can be time consuming as well. If you look at a KX con rod they are way smaller than a cr around the piston pin area, this can pose problems when riden hard. They are one ugly motor. To put them into any frame is a mission because of the rear swing arm bolt and motor mounts.
    A 93-01 cr motor rear swing bolt will bolt straight into any ali cr or crf frame.it is a matter of spacing it right and cutting out the front mounts. It is alot more complicated than that but it just gives you an idea of what is involved.
    People tend to spend alot of money but dont understand what is involved when building one. They port the max out of them and runthey run like shit. eg on or off,. If they spent the money to port it to run smoother which can be done with the right choice in carb you would have a bike that would cruise along at highway speeds.

  16. #16
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    Default cr500

    There are many frames to use for your build CR 250 97-99 bit old now and not worth the troulble, 00-01 better frame still old, CR250 02-07, Nice frame good handling. The 00-07 will take a crf front end and motard wheels.
    CRF250 04-05, would probably stick with the later cr250.Crf 05- on, all good.
    Crf450 02-04 nope, Crf450 05-on all good. Many pick the Crf250 I like the 450 for one reason there bloody easy to work on if done right. changing jets on my cr is a pain. Mind you I dont know whether they handle as good.

  17. #17
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    Default cr500

    If you gonna build one, build it for what you want, nice ported motor that is able to run on the track and still behave. Many have built them thinking it will be the altermate but then sell them because they have nt taken the time to understand what they want, then lose thousands because it not what they want. I love my cr I cruise, I hoon and do what ever I want. I ride mine I always get off with a grin on my face, you that grin when you first got laid LoL

  18. #18
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    Quote Originally Posted by Oldie 30 View Post
    I ride mine I always get off with a grin on my face, you that grin when you first got laid LoL
    Yeah man. Truly a fun bike to ride. Wheelie city................

    I enjoy most when children come running from the yards to see what's approachimng.
    Passing between the high school buildings at lunch, just rolling along in 1st gear is also a thrill. Everybody stares.

    But yeah............ an honest 15mpg.
    and yes, the balanced crank is well worth the effort.
    Sure thing, the GSS mild porting works well w/the tweeked timing and the tuned jetting. Though it blurbles and lurches at part throttle/mid RPMs, just lie any other 2T.
    I usually run a couple gears higher to lug the engine (feels more thumper-ish) when trying to be pedestrian friendly.
    The correct gearing (very tall gearing) can give semi-comfy highway cruising at 65MPH, but vibes are still present (yet the mirrors aren't blurred at all).

    The all out insanity of the thing does spawn evilness.

    If you want one, get one and satisfy the urge.
    Everyone needs to be subjected to a CR500 at least once in their life.

    Power valve?
    These things don't need a power valve.

    01 CR500af 83 XL600 hooligans 83 CR480
    97 VFR750 CB1100F 93 Honda Sportster
    74 Suzuki Titan
    75 H1-F 75 RD350
    74 MT250 75 XL350 93 Ducati fighter

  19. #19
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    The frame its self dictates what fabwork is needed.
    Some frames are quite easy.

    Mine started from here.............

    ..



    If you're thinking at an already-done bike, then take a friend to check it out.
    Look for overall cleanliness in the build. Check the welds to see if they're really ugly (or really nice) 4 eyes are better than 2.

    If you're looking to build one.............. good luck.
    01 CR500af 83 XL600 hooligans 83 CR480
    97 VFR750 CB1100F 93 Honda Sportster
    74 Suzuki Titan
    75 H1-F 75 RD350
    74 MT250 75 XL350 93 Ducati fighter

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