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I have a custom made 02 cr500AF .So the bike is basically a cr250 but the cr500 motor adds 7lbs more to the total weight of the bike .I weigh around 215 and ride at carnegie (lots of hills ) and the ocassional ride in the forest (single track).I am an ok rider ,I dont race but my freinds who I ride with race D36

(B class)and win and (A class) and win .I want to keep the valving stock (I might redo it later) but the stock springs are way to soft .Yesterday I did a little 30foot road jump and on the take off I allways preloand my suspension to get more height ,and the forks blew throught the travel WAY to fast (it was kinda scary) I had the fork compression a 5 out form all the way hard and the rebound was at like 10-12 out.

Thanks alot

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Well, taking your weight plus the 7 lbs and running it through a spring rate generator for a '02 CR250. Here is the results:

Your stock fork spring rate is.....45kg/mm

Your stock shock spring rate is....4.9kg/mm

Your recommended shock spring rate is....5.096kg/mm

Your recommended fork spring rate is....0.46004kg/mm

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There is more than simply weight to be taken into account here. The rotational mass of the 500 engine is far greater as is the power output. Hence you will find the gyroscopic forces generated by the motor will require additional attention. The added chain torque will also compress the shock more easily under acceleration. The extra horses will naturally make the bike lurch in choppy terrain.

The Duck

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Good point! At any rate, you can see that stiffer springs are in the future. How stiff, I don't know. Even using the ones I listed would be a huge improvement I'm sure.

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I would recommend the same fork springs as Jeff mentioned, but I would bump the rear up to a 5.4kg/mm.

Take Care, John

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