Sach forks topping out? E.g. Clunking when fully extended?

[betajuice]

thanks for the tips. well, back from the suspension shop and feeling like an idiot.... doh!

turns out i simply needed to bleed the air out of the forks. the pressure was making the forks top out more than normal and they said the design of the sachs forks seems to have slightly longer springs than probably needed which makes them top out a bit more than the average fork. they reckon with decent top out springs there should be no issues, but agreed that if the 2015 springs and earlier were low quality jobbies then it's not surprising if they are failing on some bikes. they are getting the later model springs and will fit them for me next time i'm up there.

moral of the story?

bleed the forks regularly.

if you get that clunking sound regularly with 2015 or earlier sachs forks, stop riding. your springs have probably gone and will mash your shims etc. get the 2016 springs.

[GMP]

Wow, I would think you would notice the performance on the small stuff go to crap from pressure buildup long before it overwhelms the top out spring. I'll bet you have light rebound valving.

[Johnny Depp]

Never had one bit of pressure build up in my '15 Sachs. Got rid of the bleed valves after one got damaged. Lots of pressure seems odd?

[Johnny Depp]

BJ, any update? I have heard a top out noise very rarely on jump take off, it is so seldom I am not sure I want to tear the forks apart again?

[betajuice]

BJ, any update? I have heard a top out noise very rarely on jump take off, it is so seldom I am not sure I want to tear the forks apart again?

all good thankfully. the suspension tuner did say the design of the sachs forks will mean the odd small clunking sound that is not a concern... he told me the exact reason but i've forgotten. something about the main spring being a tad longer than normal and so there's a bit of extra pressure than usual when nearing full extension?

but he said usually the only guys likely to break the top out springs occasionally would be the supercross guys doing those massive jumps constantly.

[GMP]

Well thats just excessive preload then, nothing special and dealt with with spacer length adjustment. I know they come preloaded a bit much. Add the sloppy rebound and there is your answer, especially if the top out springs are really a question.

[Marty Moose]

Well thats just excessive preload then, nothing special and dealt with with spacer length adjustment. I know they come preloaded a bit much. Add the sloppy rebound and there is your answer, especially if the top out springs are really a question.

GMP is the rebound on the post 15 bikes as sloppy as the previous 4 hole rebound piston on the earlier models? I've not pulled my 16 forks yet but have ok rebound control between 6-8 clicks out so its still a bit sloppy. If they run the same bleed shim on the comp face as the 15 then this will exaggerate this I think. Have you pulled a 16 set of forks apart yet?? The 16 shock is pretty good std responds well to clicker changes.

MM

[GMP]

No idea, only had '14 Sachs apart.

[Dyrtmon]

Okay - I have what appears to be a dumb question as I'm no suspension expert:

What is a top out spring? I have had my Sachs forks apart on my 13 300RR and there's only one spring - is that the top out spring?

BTW, during last weeks desert ride I did notice an occasional clunk upon full extension, thought maybe I had a loose handlebar mount but all was tight. Think I'll delve into the forks but need to know what a top out spring is first.

I also ran across a youtube vid that showed the complete breakdown and re sealing of a Sachs fork but can't find it....Anyone know of that vid?

thx

[mtdirtbag]

Jim; would it be the vid on Stillwell's site?