Excess preload on Sachs Open chambers

[Marty Moose]

I pulled down my 2016 Sachs forks off my 350rr to revalve them after 10hrs I have a good idea of what I like and don't like about them. One of the issues was excess preload on the springs this is a fairly well know issue. Mine were 12mm preloaded 4-5mm is a much better idea.In order to achieve this you don't need to cut any spacers just remove two washers.

The first one to remove is the one on the left the large alloy spacer that sits on the spring seat.



The second one on the right is from under the fork cap there are two washers in there I removed the thicker one.

Once this is done you need to make a washer to fit over the spring seat as the spring onto an alloy seat is not a good idea. I used a race tech spacer washer I ground out the centre a bit a nd relieved one edge to fit the rounded edge of the spring seat. The pic is the original alloy spacer and the new washer.



The bike rode much nicer and was more settled in corners with this mod. Forgot to mention this makes the preload just over 4mm and would help some of you guys complaining of harsh suspension.

MM

[Knox Enduro]

I may have to look into that mod, it seems to be a growing consensus that the Sachs Forks have to much pre load.
Thanks for the pics.

[Marty Moose]

I rode it the next day the bike felt better in ruts more settled on the entry into the corner = more traction. I also mapped the std shim stacks and can post up if you like I'm going to revalve mine.

MM

[Johnny Depp]

Good find. Thanks, I'll try it soon.

[jump64]

Thanks for the information, just curious if you have had the fork apart again after riding it for a while? Is there any wear on the spring seat from the steel washer rubbing on the alloy seat?

I purchased different springs for my brothers new 300 and they are 467mm vs the stock at 461mm. Measuring preload this comes out to 16mm on his bike, which seem like a lot. I was told by a tuner to cut down the upper nylon spacer? Or should I be looking to do something similar to what you have done to reduce the preload? Do you know if anyone is making preload spacers for these forks?

[Marty Moose]

The seat looks fine I've had the forks apart many times Twowheels on here I think was going to make some spacers or at least I sent him the std spacers measurements and that was his intention maybe he will read this and respond

MM

[dirtbird]

Its common to have a top-out spring inside the cartridge.
While 12mm preload may be alot, 5mm looks too little.
In case of hard rebound you may have the spring bouncing in the seat as the top-out spring is momentarily uncompressed.....

[twowheels]

The seat looks fine I've had the forks apart many times Twowheels on here I think was going to make some spacers or at least I sent him the std spacers measurements and that was his intention maybe he will read this and respond

MM

The projects keep piling up ... making 7mm shims, tools for the new closed chamber fork, adjustable mount upper triples for the TM ... gotta get back to these spacers

[GMP]

Stock preload on my brother's set was 14mm which is ridiculous and probably a big part of the poor stock manners some report. Also, the stiffer springs I originally got from Steve were a larger dia than stock, did not fit the shoulder of the spacer, had excessive clearance to the spring guide, and a lot of friction on the lower tube ID. This is on a '14 fork, maybe others are different? We were both a little confused at this point. After some measuring I found that the stock '14 Sachs spring shares EXACTLY the same dimmensions as a Marzocchi 45mm Shiver spring, so thats what ultimately went in @ 4mm preload with a trimmed spacer. Haven't ridden them yet but the feel a lot more normal bouncing them on the floor.

[jump64]

Thanks for the information, here is the spacer I am wondering if it is alright to cut down? Or if I should go with a smaller preload spacer at the bottom?