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Author Topic: CRF250L or CRF 250 Rally suspension  (Read 1857 times)

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Offline deapsquatter

Re: CRF250L or CRF 250 Rally suspension
« Reply #40 on: January 07, 2019, 06:03:59 pm »
A few month's back I got Martin at http://www.mpcustomvalve.co.za to build a shock for my CRF250 Rally. I'd heard good things about the CTP (close to perfection) shocks and decided I'd rather have him build me one of these as apposed to try and improve the stock shock. As most know by now the stock shock is incredibly soft and bouncy. It offers no adjustment except for very limited preload.

Before I spoke to Martin I (with the help of a friend) took some measurements to establish the sag of the bike with the stock shock. First we adjusted the shock for maximum allowed preload. Rider weight (no gear) is 80 Kg. Results were as follow:

OEM SHOCK MAX PRELOAD
Static60mm
Rider125mm

Not even in the ballpark.

Left the bike with Martin for 2 days so he could take measurements and then waited a few weeks for him to work his magic. This would be the first time he built a shock for the CRF Rally. Here is a pic of the new shock with grey 6.5 kg/mm spring.



Martin warned me the 6.5 spring would probably still be a bit soft but its the only one he had in stock with the needed measurements. So we figured we would give it a go while new springs were on there way from Ohlins. Result:

CTP SHOCK PRELOAD 30 - 40mm
Static25mm
Rider95mm

Much better! We did however have to add a lot of preload (the new shock body has a lot of thread for adjustment) and even then rider sag was still a bit high. The target was 80mm - 90mm. It also didn't leave much room for some added weight from luggage. So when the Ohlins shipment arrived I picked up a 7.5 spring.





CTP SHOCK PRELOAD 20mm
Static23mm
Rider86mm

Result! This time we did not have to add as much preload and the sag figures were where we wanted them. Sitting on the bike one could get definitely notice the increased height and I could no longer flat foot. Even riding you could feel the added height. Not surprising given we went from rider sag of 125mm to 86mm a difference of 39mm! The CTP shock comes with with 59 clicks of rebound adjustment. I'm currently still playing around with this but suffice to say that having almost zero rebound damping on the stock shock the bike feels far more stable over bumps. Previously it would come back at you like a pogo stick! I wont go over the benefits of having correctly set sag - I'll leave that as an exercise for the reader :) Other benefits of this shock:
  • Given MP Custom Valve built it they can easily service/modify it.
  • A remote reservoir can be added later if required adding compression adjustment.
  • That cool Ohlins mustard colour spring ;)

I paid just under R7,000. Given the end result and compared to some other options I'm happy with that. Also I can now do this without bottoming out  :thumleft:



Thanks Martin at MP Custom Valve. It was great working with you.
PS. I'll be in touch to sort out the front  :biggrin:
« Last Edit: January 07, 2019, 06:05:27 pm by deapsquatter »
 

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Re: CRF250L or CRF 250 Rally suspension
« Reply #41 on: January 07, 2019, 09:35:20 pm »
Great feedback, this upgrade is a must imho
Little by little, one travels far
J.R.R Tolkien
 

Offline blauth

Re: CRF250L or CRF 250 Rally suspension
« Reply #42 on: January 08, 2019, 08:48:17 am »
deapsquatter; don't be in too much of a hurry to upgrade the front. Ride it like that a little first. I think I've only bottomed mine (I weigh 92kg) out about once or twice over 14000km. It's nice and plush like it is now and works surprisingly well.

I love my upgraded shock (Wilbers from an XR650L - preload and rebound only). I found I left the rebound setting half way for quite a long time but I wasn't really happy with it like that because the compression damping was actually too much making the shock a bit harsh. I then set my rebound damping to the softest (most rebound) and this affects the compression damping characteristics too (making it softer) and now my bike feels spot on.

My sags are probably about the same as yours now, maybe a touch stiffer (I'll need to measure to be sure).

I'm sure you'll attest to the fact that this upgrade transforms the bike. It really feels like an overweight dirt bike now.

Offline deapsquatter

Re: CRF250L or CRF 250 Rally suspension
« Reply #43 on: January 08, 2019, 09:02:58 am »
deapsquatter; don't be in too much of a hurry to upgrade the front. Ride it like that a little first. I think I've only bottomed mine (I weigh 92kg) out about once or twice over 14000km. It's nice and plush like it is now and works surprisingly well.
I have noticed the front seems to be working a bit harder now that the bike is riding more upright. Its not terrible but obviously there is room for improvement.

I love my upgraded shock (Wilbers from an XR650L - preload and rebound only). I found I left the rebound setting half way for quite a long time but I wasn't really happy with it like that because the compression damping was actually too much making the shock a bit harsh. I then set my rebound damping to the softest (most rebound) and this affects the compression damping characteristics too (making it softer) and now my bike feels spot on.
I found the same. To much rebound and it gets way to hard on the compression.

I'm sure you'll attest to the fact that this upgrade transforms the bike. It really feels like an overweight dirt bike now.
Oh yes  :thumleft: