Sunday, March 18, 2012

R1100S winter rebuild - part 5

Next move of this rebuild is about putting the front end back together. With fork parts all over the floor, some repainted, some new and ready to fit, it's time to reassemble the whole lot. But before event thinking about bolting the the fork legs back on the bike, there are a couple of tasks waiting to be accomplished : 
- fork needs to be serviced, 
- upper and lower yokes need their ball joints replaced,
- and new front shock has to be fitted.

Let's start with the front shock. The nicely engineered Bitubo finally gets its chance to replace the old looking Showa. It's been set up to standard trim for compression, rebound and spring preload, but it's been lengthened 6mm. It's one of the benefits of this shock swap, I was really into trying to find a front shock which length could be changed. So the Bitubo ticked all the options where even the Öhlins does not allow a length change.

The poor Showa next to the new Bitubo

The new shock in place

Next were the yokes and their ball joints. As proper tools were missing to extract the ball joints from the yokes and to screw them back to the correct torque figure, these parts were taken to the nice and knowledgeable guys at Metal Machines. It took them less than 1 minute to unscrew the ball joint from the lower clamp, but they gave up on the top clamp, smartly stopping before things go terribly wrong ... well at least for the bike parts, because one of the guys almost broke a finger working on that. They finally advised I should go to a BMW shop, which I can't blame them with as to every specific parts, their specific tools. So it's finally a mechanic at Europ Touring BMW dealer in Arras who replaced the ball joints in less time than it  took you to read this sentence.

The yokes with brand new ball joints

Eventually, the BMW emblem bought months ago has found its place

To the fork rebuild now. One of the legs had a fried join, making oil spill all over the tube. There was only  this small part to replace, but the fork has been completely serviced anyway : oil, joins, and washers were changed with new material.

Old and worn parts

Nice and shiny new ones

The reassembled fork legs look like the following. What you seen on the first picture is a long plastic tube that fills the fork internals so only 170ml of oil is needed. This system has been kept on R1100S up to 2002 before the idea of having this tube in the fork has been abandoned.

With all the big parts ready or even fitted, the front end could be put together again starting with the yokes, then the fork legs and finally putting back the mudguard, front wheel, steering damper and brake calipers. The same steps in pictures :

Again, new parts where the bike deserves it

The R1100S has a front again, but the rebuild process is still far from being complete as coming posts will confirm.

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