Ohlins help - preload adjuster

[dukey33]

I was doing some maintenance on the LT and was curious to see how much preload adjustment I was getting out of the rear Ohlins. To my surprise, it moves very little when the adjuster it turned all the way in, almost imperceptible!. More data: there is very little resistance to turn the knob until is it about 1.5 turns from bottomed-out.

First, I assume the collar should move most of the stroke of the locator pin when dialed up from zero to maximum, about 3/4 inch?

Second, while I have seen instructions on this forum on how to refill the original BMW preload adjuster with oil, but have not seen a similar procedure for doing this on the Ohlins. I know to rebuild the shock itself requires special equipment that pulls a vacuum on the chamber, but does refilling the preload collar need a vacuum pull-down too?

Yes, I realize I should have the entire shock (and front too) rebuilt and that will take care of everything (unknown mileage), but I can't plunk down that kind of coin right now so I'm looking for any thing I can do myself until I win the lottery. Also the shock response is okay so it's not dangerous or unwieldy to ride as-is, but I'd like to get the pre-load adjuster working.

Thanks.
have a safe and happy New Year.

[jzeiler]

Dave,


I have them but have not tried that. There is no Nitrogen in the preload so it should work the same a s the stock unit for re-filling. I have considered replacing the Ohlins pre-load adjuster unit with the one from the stock shock as it has an indicator and it is a bigger knob. Just have not gotten around to it yet.

[dukey33]

Thanks John.

That make sense. I actually hadn't looked at the refill procedure for the OEM shock but agree the same could be applied to the Ohlins adjuster.

I went into the HOW and did see this in Post No. 278384 by bmwmick in the preload adjuster servicing thread:
Ive re-filled my Ohlins Type 4 preload adjuster once in 30K miles. IF it is a Type 4, the small countersunk screw in the preload adjuster remote can be removed and you can add oil there. It is a LOT more difficult than refilling the stock shock because the hole is tiny.

Looks like I'll take a closer look and give it a try. Thanks again.

[yechave]

The dealer swapped out the preload on the OEM shocks on our LT a couple of weeks after we bought it, which did nothing for $75.

The new Ohlins does not have any indicators showing where the knob is set, which I don' really care for. The preload mount had to be ground down to fit the bike.....which I thought was odd considering what they cost.

At 41k miles, the OEMS were totally shot. The original owner did tow a trailer, have no idea if that makes any difference. The new Ohlins are excellent, with the exception of the rear spring being way too stiff. Not sure I am willing to take it off to have it changed. Works great two up, but brutal solo riding.

The R1100Rt we had before this, had an outstanding OEM shock system, and I still feel it rode better for us than the LT does, but without the luxury of more room, better overall performance etc. You just happen to sit in a different position, which is tougher on the back for those of us that have had surgery.

Almost wish I had not thrown out the OEM's, but there is only so much room for all the stuff.

[dukey33]

Update:

Well, I tried the refill as described by bmwmick. There is an Allen screw on the side of the adjuster and another Phillips screw just above it. I was able to drip jack fluid into the lower hole after loosening the upper one to let the displaced air out.

But now the adjuster does a funny thing. There is resistance beginning about 1/2 turn from the first detent (good), and resistance all the way until the adjuster bottoms (also good), but there is also just as much resistance when turning the knob back out. :confused: Is this normal for the Ohlins adjuster? I'm guessing not.

And the final outcome.....it still does not seem to move the preload collar. :mad: I'm expecting there is a lot of air trapped in the system since the fluid level was so low, there was only resistance for the last 1.5 turns before I put in more fluid. Now I'll have to figure out how to bleed it.

[dukey33]

Epilogue.

I figured out why there was so much resistance in turning the adjuster either direction. I'll just say, do NOT turn the adjuster knob if you have the small Phillips screw removed.

I refilled the adjuster cavity by slowly dripping jack oil into it and then turning the adjuster out a little until the fluid was pulled down, then a little more fluid, followed by another turn of the knob. In the end, I was able to get enough oil in it to pump the collar out about 2mm. An improvement over before I started.

What I did next you may or may not want to try. I progressively added more fluid by pumping up the collar and then jamming it so some of the oil volume was held in the collar as I backed out the adjusting knob. In doing so I could get more fluid into the system. I eventually worked up to about 5mm of movement before I got tired. I think this is still only about half of what it should be capable of.

If someone has an idea how to bleed the air out, please share. I even tried suspending the adjuster as high above the shock as possible and leaving it there for a day to let the trapped air accumulate at the high point, but I don't think it worked.

Well, I know I can get oil into the adjuster and I know the adjuster isn't stuck. :cool: