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There are quite a few options for improving the suspension on a GS. Mostly these involve changing the whole shock absorber - all of these are quite expensive, ranging from around £250 per shock for a Hagon, up to around £650 per shock for a Wilbers or Ohlins. Personally I have not had much to complain about the OEM Showa shocks, especially as I do not ride the GS off-road (at least not intentionally!). At 54000 miles I had the original rear shock rebuilt by MCT in Stowmarket, and fitted a replacement front shock from BMW (the cheapest option at £160). By 84000 miles both these were feeling a little tired and I intend to get them rebuilt again in the near future, but thought I would try replacing the springs first with some Hyperpro progressive springs (ordered from Motorworks for £163). I had fitted some to my last Yamaka FJ1200 and they had greatly improved the ride and handling so was interested to see what difference they might make to the GS. They came with a set of Hyperpro spring compressors (£70 but £60 back on return) and an instruction booklet, which was variously helpful.
My first task was to get the bike from outside the house into the garage - not as easy as it sounds as my garage is only a lockup a couple of hundred yards from my house, and the road up to it was sheet ice for the week before Christmas. Eventually we had something of a thaw after Christmas and I managed to get the bike inside, although it was till covered in road grime and very dirty (the outside pipe was frozen too).
1. In the garage - note the snow outside!
2. Hyperpro springs and spring compressor kit.
3. I decided to remove the front shock as it is far easier and I suspected it would be more simple to take apart.
4. First job is to remove the panniers, seat and tank to gain access to the upper nut. This is a 15mm nut, for which you need a 15mm ring spanner, as you need to hold the 5mm allen bolt in the top of the shock while undoing the nut. After undoing this you need to undo the lower bolt - a 15mm nut and 14mm bolt, and remove the bolt. You should then be able to work the shock absorber off the wishbone and remove it from the bike.
5. The standard Showa front shock absorber and replacement Hyperpro spring.
6. The next job is to fit the shock absorber into the spring compressor, using the additional collar so it sits on the spring, and then compress it by turning the 17mm nuts on each side in turn until the collet on the shock is released.
7. Remove the collet and then release the spring compressor and take the old spring off the shock absorber.
8. Front shock absorber taken apart.
9. After cleaning and checking the shock over, fit the new Hyperpro spring (closer coils at the top) to the shock and reverse the compressing process to refit the collet.
10. Refit the shock absorber to the bike, not forgetting to first fit the rubber spacer, and then refit the bottom bolt - I found I had to use a screwdriver to lift the shock slightly while fitting the bolt. After loosely fitting the nut, I then refitted the upper nut, and then tightened both up.
11. The refitted shock absorber.
Then I set to stripping down the back of the bike to get at the rear shock - this involved removing the auxiliary tank, sidepanels, exhaust catalytic converter and stubby pipe, and rear wheel. As you can see from the photographs it was all pretty grubby although I cleaned some of it as I went along.
12. Undo the allen bolt (?7mm) holding the rear shock absorber to the swingarm.
13. To access the upper bolt I found I had to first remove the two seat brackets on either side of the bolt. 15mm spanner and socket to remove the bolt. With a bit of persuasion to release it from the swingarm the rear shock absorber then dropped out.
14. This is where I got a bit stuck. The Hyperpro handbook showed a numebr of different shocks, but none were quite the same as this Showa unit. I did a search for posts on the UKGSer site which is usually a great source of answers - unfortunately the only thread about this I could find was from a few years ago when a guy had put up the same question and then later posted that he had found out how to do it - but didn't explain how!
15. Looking at the shock I thought this was the right way way to compress the shock and that I had to release the large nut below the bottom eye. I did not have a spanner to fit this, although a 7/8 AF spanner was close and helped me work out it was 22mm. I went and bought a 22mm spanner but could still not get the nut undone. I did another search and only found a few references to getting other people to fit the springs, one of whom was a company called Calsport in East Birmingham, not far from me. Looking at their website I could see they sell Hyperpro springs so gave them a ring. Craig could not have been more helpful and said if I bought the shock over he would fit the spring while I waited.
Calsport is located at the back of an old industrial estate ans resembled something from one of those car films like Fast and Furious, with a number of very fast looking Mazdas and TVRs filling their workshop, and a few bikes on the side. Craig explained he had fitted springs to several BMW shocks, and used to have an 1150GS himself. I explained how I thought it came apart - he said he had made that mistake the first time he had done one - don't undo that large nut, he said, it releases all the gas from the shock!
16. Turning the shock the other way up, he fitted a different castellated collar inside his much larger bench compressor and compressed the spring. He then undid the small grub screw in the picture and used two small bent screwdrivers to release the large circlip, seen halfway up the shock end in the picture. Releasing the compressor enabled him to take the end with the remote adjuster still connected off the shock and then the spring.
17. The shock apart - all that was needed to do was to refit the Hyperpro spring and the job was nearly done - but oh no, that would have been too easy!
18. This is what you do not want to see - oil on the shock and piston (there was more but Craig had wiped it clean before this photograph). Compressing the shock without the spring fitted showed not only was there not much oil in the shock, most of the air had disappeared as well. That would explain why the suspension felt so rubbish then!
19. The old and new rear springs.
There was only one thing to do - I rang MCT in Stowmarket to arrange for them to rebuild the shock. They were a bit concerned that it had failed after only two years, since they expect them to last longer, but I did explain it had covered 36000 miles in that time. I boxed up the shock with the Hyperpro spring and sent it off to them. Guess I had better spend the time waiting for its return cleaning the rest of the bike...
20. Posted the shock to MCT on Friday, they phoned me the following Wednesday to say it was done and it arrived back the next day. As well as servicing the shock they replaced the bush and seal, polished the piston and adjusted the remote adjuster which had not been doing very much before - with carriage and VAT it came to £123.60. I also sent the Hyperpro compressor kit back to Motorworks and by design or accident they credited me with the whole cost of £70. Needless to say I had not got round to cleaning the bike at all but I just needed to refit the shock, and attend to all the other jobs I had decided to look at while taking the bike apart, like the non functioning horn and speed camera detector and why my fog lights kept blowing a fuse...