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2011 YZ250F suspension setup for 125lb rider

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Hi, I'm new to this group and to suspension work on big bikes so go easy on me :o)

 

I have a 2011 YZ250F with 12 hours on it that my son wants to set up for motocross. Its all stock and he's having a hard time with the stiff suspension.

I ordered a new (takeoff) 4.7 ti rear spring from a 2010 YZ125 and some new .428 front springs (1C3-23141-D1) off eBay for a starting point. Hope to get them any day now.

Since I'm into the forks to change the springs, I was thinking of trying  a lighter oil like Bel-Ray 2.5w fork oil? Good... Bad...? 

 

Will I still need to revalve the bike or can I get away with spring change only? - Jeff

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You need softer springs imo and a re valve

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Softer then 4.7 shock & .428 forks ? (Stock is 5.3 shock and .449 forks)

 

Also any valve stack recommendations/mods with the lighter springs?? 

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My chart says 0.39 and 4.4

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Were do you the "chart" that has this info on it?

Any charts with stack info? - Jeff

 

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Race tech do a kit with suggested shim stacks , the chart I have is from k tech in the UK , race tech also has a on line spring guide as does a few others like mx tech

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We (Race Tech) recommend a .416 for the forks, your .428's should be in the ballpark and make a noticeable difference.

 

On the shock we're recommending a 4.7.

 

So looks like the springs you have coming should definitely help.  A quality oil will also make a noticeable difference.  Not all oils are created equal.  While the Race Tech oil is a bit spendy, I've seen our techs in R&D rebuild the same set of forks with our oil and with another leading brand.  While the other brand was extremely sticky, the RT oil had way less stiction.  If you can't get your hands on the RT oil (you can email me to order with a TTalk discount to chris@racetech.com) your next best choice will be Spectro from our testing.

 

I would try just the springs first, let him ride it.  I'm sure it'll already be worlds better, but if he's still wanting more, you'll want to look into a revalve.  With his light weight, the stock valving is definitely not setup for him.  If you are into doing your own valving, you can order a Gold Valve kit (again use my email and mention TTalk for a discount) and it comes with all the parts and settings you need to revalve the forks.  If you'd rather have someone with experience do it, there are a couple of great Race Tech Dealers up in Minnesota (Vaith's Cycle and PDR Performance) who can help you out or you can send it out to us in California.  PDR and Vaith's are at quite a few D23 events trackside and both have excellent reputations.

 

Feel free to shoot me an email with any other questions and I can get you my cell number to call if you want to discuss further.

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