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Spring Rates for my Style, Level, and Weight... ???

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Ok so I just read about 50 threads that pertained to this subject give or take... 

My Specs:

Weight: 210

Riding: mostly fast aggressive woods/trails with some tight technical stuff as well - maybe every so often a little track riding.

Skill - I used to race Open Class B in TT Scrambles and Hare Scrambles 

Age - 50 (Don't think that's relevant though as I still like to fly through the woods with my hair on fire :D  )

 

Here's my Situation - Picked up an 08 CRF450R where the PO was 290, and raced MX - C Class, and classified himself as a "Slow" C rider. He had the suspension reworked at JM Suspension in IL (Matt Borgic) - Shock main shaft and fork sliders are gold nitrate coated , revalved,.. resprung,.. blah blah - 

The guy had the factory springs still, so I have them as well (47 and 5.5 I believe..)

I spoke with Matt at JM and he said he could re-do the suspension for me no prob,.. 400.00 to revalve, rebuild, re-spring - Didn't think that was too bad at all. So I'm going to do that this winter, but in the mean time..

 

I went ahead and put the stock rear spring back on the shock and set the sag (104mm w/ around 28mm of free sag) - The aftermarket rear spring was 7.25!!! . The fork seals were leaking so I'm going to go through them and probably put the Stock springs back in them as well for the time being.

 

I guess my question would be this: Is it more important to have the spring rates directly in relation to your actual weight,.. or does that vary given the type of riding you'll be doing..?

Meaning - Since I'm going to be doing mostly woods riding and trails and fire roads type stuff,.  would the facotry springs suffice for me at this time until I can send everything off this winter and have it totally gone through for "Me"? Matt's suggestion for my weight and riding needs would be: 49/5.8 (?) and around 360cc of oil (?)

 

Any thoughts and experiences on this would greatly appreciated!

Thanks

Rick

 

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5 hours ago, WERNER1 said:

Matt's suggestion for my weight and riding needs would be: 49/5.8 (?) and around 360cc of oil (?)

 

I think he's dead right. With the .49s, Id probably put 4mm of preload in them at your weight (spacers) but you can do without.

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cool thanks! I'll be redoing the forks this weekend hopefully... and then send everything off over the winter.

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Ok,.. So I'm FINALLY getting around to rebuilding my forks  (Tonight actually!) .. so I was going through all of my info on this and came across some variances in fork fluid volumes (?)

 

I was reading though the Honda Service manual for the 07/08 CRF450R and it says the "Standard" Fork oil capacity for a bike after 07' is 13.75 oz. ( 406.6 CC's) ... The min/Max according the manual is: 10.9=322cc / 14.2=419cc - So I'm guessing with me using the factory fork springs (approx. for a 180 lb rider - I'm 210 ) that 360 cc is still going to be good ?

Also, it seems like I remember reading about adding a bit more fork oil to the inner damper section than is recommended, but I cant remember why for some reason, and I can't find that info any more... anyone care to confirm or deny that one? :D ... maybe it was just for bleeding purposes or something as shouldn't any excess be forced out upon inserting the damper assembly inside the tube and screwing it in (It drains out of the weep holes or something (??))

 

Thanks,
Rick

 

 

 

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On 8/8/2017 at 3:38 PM, WERNER1 said:

My Specs:

Weight: 210

Riding: mostly fast aggressive woods/trails with some tight technical stuff as well - maybe every so often a little track riding.

Skill - I used to race Open Class B in TT Scrambles and Hare Scrambles 

Age - 50 (Don't think that's relevant though as I still like to fly through the woods with my hair on fire :D  )

Howdy, I've been revalving my own suspension on my 08 CRF450 with Dogger's help.  I got some heavy shock and fork springs left over from a spare set of suspension I snag off Ebay this summer.  The guy was selling for a friend and told me it was "for a 200-210lb 30+ amateur B rider".  I've already picked up a stock 03 shock spring, but still needing some stock fork springs (I'm 170 lbs).  Maybe we can do some trading?  I've already reworked the shock so the spring is off, but still need to open up the forks.  Probably will be doing that in the coming weeks after MX season comes to a close in my neighborhood at the end of Oct.

As for your other Questions: fork oil height, I'm running 405 for Mx at 170 lbs, you might want to trend a bit more than that if you thinking of riding both woods and track.  Hopefully one of the suspension gurus chimes in.

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16 hours ago, WERNER1 said:

Ok,.. So I'm FINALLY getting around to rebuilding my forks  (Tonight actually!) .. so I was going through all of my info on this and came across some variances in fork fluid volumes (?)

 

I was reading though the Honda Service manual for the 07/08 CRF450R and it says the "Standard" Fork oil capacity for a bike after 07' is 13.75 oz. ( 406.6 CC's) ... The min/Max according the manual is: 10.9=322cc / 14.2=419cc - So I'm guessing with me using the factory fork springs (approx. for a 180 lb rider - I'm 210 ) that 360 cc is still going to be good ?

Also, it seems like I remember reading about adding a bit more fork oil to the inner damper section than is recommended, but I cant remember why for some reason, and I can't find that info any more... anyone care to confirm or deny that one? :D ... maybe it was just for bleeding purposes or something as shouldn't any excess be forced out upon inserting the damper assembly inside the tube and screwing it in (It drains out of the weep holes or something (??))

 

Thanks,
Rick

 

 

 

Yes, the little bit extra you put in the inner chamber helps with the bleeding process, particularly when you put the basevalve back on. You want the extra oil height so that when you push the base valve in, the air gets pushed out....if that makes sense. Otherwise I'd the oil height is low, you'll have a pocket of air stuck between the oil and the basevalve.  The extra oil can be dumped out (via the two opposing holes towards the top of the chamber) after the basevalve is tightened and the damper rod pushed through it's stroke. 

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FooBarr - Thanks for the offer, but I've already got everything done and back together right now,.. I don't plan on taking the forks back off until I send them in to get all reworked this winter. You mentionedd "Dogger",.. is that "Don M."?... Can't be to many "Dogger's" out there :D Maybe see if you can confirm brand and specs on the springs (?)

 

MX/SX/21 - I went with the recommended amount in the damper and went with the high side measurement before I put the damper valve /cap back in/on - Man was it tough getting that cap pressed down to start threading it in to the outer damper housing! .. but my measurement was right at 1-3/4" (Mine is an 08 so it's a bit different than the 07's) Everything bled out find.

I ended up going with my suspension tech's recommendation on the oil volume = 360cc so we'll see how that pans out on this next ride.

Moving on to installing the new radiators, Trail Tech 70W kit w/ stator and weighted flywheel,.. 

 

 

 

 

Forks Resized.jpg

Fork Internals Resized.jpg

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