So I just put my SP forks onto my MC28 and compared to the SE forks the difference in the rebound (or the force that they spring back) seems to be a lot. The SP forks hardly seem to shoot back half as much as the SE forks. I wonder have I done something wrong or are they like this. I have the preload set to two visible lines and no matter what I set the Blue rebound adjusters to its still not great.
_________________
John 3:7

to measure the oil level do I push the stanchion all the way down into the fork leg? with no springs?

Snap!
I was just reading about fork set-up at the same time. http://www.nsr-world.com/tuning/250-tuning/suspension/
I also found this tutorial on the Tyga website which easily explains how to take an oil level reading.
http://tyga-performance.com/images/00psm/02tpfitman/08fitmantuning/14mc28frontfork.pdf

Thanks max. Thats the guide I was following. I wish they had more pictures 😕

okay I opened them back up and double checked everything. I set the height to 145mm and it feels a bit better but still not as strong rebound as the SE forks. I just want to know is that normal for the SP forks

prelude2.2 wrote:okay I opened them back up and double checked everything. I set the height to 145mm and it feels a bit better but still not as strong rebound as the SE forks. I just want to know is that normal for the SP forks

I can't comment on the SP forks per se, but what grade OIL have you put in? also have you tried adjusting the rebound damping adjuster and if so what happens when you take it to the max. setting?

As Max said, what grade oil you using, remember these bikes were designed for Asian lightweights, so the recommended oil might not be heavy enough for us European heavyweights!!!!!, not saying we are all lardasses.
_________________
Proud Father of , 05 ktm 400exc supermoto 2018 honda crf rx supermoto

Im using 10wt Rock Oil. There doesnt seem to be much of a difference between the Max and lowest setting

ok so I stripped them again. inspected everything, including inside the dampers. reassembled and went by Oil Level (145mm) fully compressed with no springs. put it all back together as per spec and they seem a lot better. Still no where near as much rebound spring in them compared to my SE forks but they seem much stiffer and I cannot bottom them out under my own strength.

While the MC28 SP forks are generally considered a better [cartridge type] design, the adjustment of them all (R6K, MC21SE/SP, MC28SE/SP) is hampered due to a poor needle design. That's why you don't really feel much difference between MIN and MAX settings.

I need to talk to Suspension Steve at HEL sometime, and see if maybe it's possible to offer a reprofiled needle or something. I'll need to get hold of a spare fork sometime for him to take a look at, and then convince the boss to let us have one of the CNC lathes for a couple of hours.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

prelude2.2 wrote:ok so I stripped them again. inspected everything, including inside the dampers. reassembled and went by Oil Level (145mm) fully compressed with no springs. put it all back together as per spec and they seem a lot better. Still no where near as much rebound spring in them compared to my SE forks but they seem much stiffer and I cannot bottom them out under my own strength.

My dim and distant memory recalls that 12.5w might be a better choice of oil (attained by mixing 10w & 15w, make sure the oils are compatible, same brand/type usually is)

Also just thinking about this...how confident your SE forks were not already a "sorted" set...stiffer springs, re-valved etc?

We always use 12.5W Rockoil in the NSRs. Suspension isn't my strong point though, and happy to admit it, but I believe a lighter oil is only more suitable once the shim stacks [and probably spring rate] are properly sorted. It's OK if you're 65kg soaking wet, but for most of us slightly more portly westerners, the suspension generally needs a little "help"!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

I have 10wt in them. would it make that much of a diffidence? I am about 90kgs

prelude2.2 wrote:I have 10wt in them. would it make that much of a diffidence? I am about 90kgs

If anything I think 10w should make them rebound "quicker" than 12.5w, which is your issue right? The SP forks are rebounding much more slowly than the SE's.

It's a tough one as I suppose you don't know how well or poorly your SE forks were working in the first place, and you are using them as a benchmark.

I think one of the guys who has experience of both sets of forks or a suspension specialist needs to jump in here...what should the rough rebound rate be on SP forks? can they be re-assembled in such a way that would create slow rebound?

-

(just a thought is there any mileage in rebuilding your SE forks with fresh oil so you have a direct comparison?)

I actually rebuilt my SE forks when I got them some years ago. And there is probably less than 1000miles on them. The SE forks seem to be in great working order and the internals seem pristine (I had them totally apart this week). The specific issue i have is that my SP forks after the rebuild do not "shoot back" after being compressed like the SE forks do.
It is very noticeable but is this the norm for SP forks. I am so worried of a low side caused by the forks bottoming out because I have Repsol SP fairings on the bike