[Dom Thompson]

I Fitted some Ikon progressive front fork springs to a 2015 scrambler and have been trying to dial them in...

I cut the stock spacer down to 46mm to account for the longer springs (stock spring was 327mm and the ikons are 518mm) which made the spacer finish more or less level with the top of fork tubes and did not alter the oil level. I noticed noise coming from the spings when I compressed the forks so pulled the spings out checked the oil levels which was 280mm from the top of fork tubes which seemed really low as I had thought the stock level was 123mm for the Scrambler? Anyway so I toped up the 10wt oil to 165mm and rode for a bit and the front and was super firm and i was not getting much sag (70kg ridder) so I cut the spacers down to 36mm and still is pretty harsh on small bumps. Considering lowing the fork oil level to say 190 to 180mm or shortening my spacer more so there is minimum preload when forks are fully extended. If anyone else out there has any experience or advice on the matter it would be appreciated.

Dom

 

[Boy Racer]

Hi Dom,

I have NH front springs which are a copy of the Ikon's in my 2015 Scrambler.

I played around with different spacers but I just used plastic tubes as easier to cut and I don't like chopping stock stuff up, but that's just me. After I got the level right I used spacers supplied by NH plus some washers (I think as it's a while ago now).

This photo is how the stock set-up looks after the cap is removed, this is the level I ended up using.

This next photo shows my spacers bringing it to stock level. These are 34mm long.

Note the large washer is still being used between the spring and spacer, could be your noise if this is missing?

The oil level needs to be done with the forks out and standing upright without the spring in, I would take this opportunity to replace the oil. I also played around with oil weight and amount, ending up using a lighter oil and lowering the level, but I can't remember to what level. If changing oil rates around you need to stick to the same manufacturer as the weights vary from one to another.

I hope this info is of some use to you.

Cheers,

BR.....

 

[Green01SprintST]

Fork oil level is set with the forks standing straight up, compressed, with springs removed. Spacers should be long enough to provide some measure of spring compression when the forks are fully extended; I wouldn't go any shorter than flush with the top of the fully extended fork leg. The length of the fork cap and washer will provide the required spring compression. Also, always put a washer between the spring and the spacer. I also use a washer between the spacer and the fork cap.

 

[Dom Thompson]

Thanks for the replys. Going to pull the forks out and go down to a 5 wt oil and have a play around with the oil level. I will leave my spacer as is for now as they are probably at minimum proload at 36mm all ready. Good point about not cutting the stock spacers down. Would have been good to have them as a reference or if I need to put them back in one-day. Once i get to it Il let you know what end up with.

Thanks Dom

 

[[email protected]]

Fork oil level is set with the forks standing straight up, compressed, with springs removed.

This is very important. It sounds like your fork oil level of 280mm was based on an incorrect measurement procedure. So when you added oil, you probably got close to locking the compression ability of your fork. Your fork oil level creates a certain amount of "air spring", which rapidly adds a spring-like effect once you get towards the limit of compression to prevent mechanically bottoming out. If you added too much oil, which is incompressible for our purposes, you have no air spring and your harsh ride is likely a factor of your fork having a reduced travel.
Your new springs being longer, resulting in more spring and less of the thin-walled aluminum spacer displacing the fork oil, reduces the air spring slightly faster than stock during compression. Something to consider when you want to fine-tune the feel. My Progressive springs are beefier and longer than the stock springs, and I'm at 150mm for fork oil level measured per the above procedure.

 

[Dom Thompson]

Hi [email protected] thanks for the input, I think could be on the money about the incorrect measurement.. Did you go with a 5wt or 10wt oil with 150 measurement?

 

[[email protected]]

Did you go with a 5wt or 10wt oil with 150 measurement?

The standard 10W is still in the forks. I've been on the fence about adding emulators or a full cartridge kit, which is to say I haven't decided what to do next with the front end, so I haven't messed with the oil weight either. If you find that 10W is too harsh and 5W too soft, and you have the time and inclination to mess around, you can mix them and they should mix linearly, that is to say 50/50 = 7.5W, 75/25 = 8.25W, 25/75 = 6.25W. Not sure you'd be able to tell the difference, but it's something you could try before you go drilling holes in your damper rod and dropping $200 (in the US) on emulators, shipping, etc. Always use the same brand, as oil weights are a range and brand X 10W could be the same as brand Y 15W.