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CR-500 HP / vibration?

jski

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Apr 5, 2001
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#1
I was wondering if it is possible to get 80+hp from a CR-500? The reason I am asking is I built a 1987 500 hill shooter for sand racing and was wondering what hp is possible out of the 500 running on gas because I am looking to build a new combination and want to get he most out of the motor. Also, with regards to vibration how does the choice of frames change vibration for example if I was to use a frame other than the CR-500 frame how would the vibration change because I have heard that putting the 500 in other frames worsens the vibration?

Thanks
 
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#2
Yes, the well modified CR5 engine is capable of 80HP on race gas.

The frame mass will be the main issue with vibs. As a general rule, but not hard and fast, the lighter you go, the more vibes you will feel. Resonant frequencies come into play, so it is possible to have a very heavy frame vibrate in sympathy at a certain RPM. Keep everything rigid and tight!

Thinking aloud, I wonder how rubber engine mounts would work on the CR5 engine?

Chris
 
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#3
We have a 1999 CR500 that has ports polished, V force reeds and head skimmed 1mm. This has been dynoed at 72 Hp on pump (95 octane) gas
 
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#6
Last CR 500 I had vibrated more than my old roached one,Sent crank to falicon in florida www.faliconcranks.com VIOLA- burly yet smooooth.
 

jski

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#7
Thanks,

Eric regarding the vibration question I guess I should have worded that better as what I really wanted to know is do the OEM's design the frame around the motor to dampen vibration? The reason I ask is that I have seen a couple quad's with CR-500 motors that have vibration problems along with probelms of the frame cracking. Also, have you ever ran any modified CR-500's on the dyno and if so what could one get from a modified CR-500 on gas? Thanks as I have heard so much good about your work on here with bikes I was wondering if you have built high hp drag motors as well which was the reason for the question.
 

zero_it

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May 20, 2000
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#8
Has anyone ever ridden an open class MXer that didn't vibrate???

The last CR 500 I rode in the sand almost knocked my eyeballs out into my goggles!
 
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#9
As I mentioned the mass of the frame affects the vibe level. Also the size of the frame matters. If the frame is compact with the large mass areas close to the engine, the engine/frame assy will have more vibes.

Chris