BMW K bikes (Bricks)


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tinyspuds

tinyspuds
Life time member
Life time member
I have fitted a new Ramshox jobbie. The OEM was shot and (mostly because I can’t resist tinkering, but also because I thought it might produce more lateral stiffness) I went for the 1” shorter version. Inspection of the old shock shows a slight curvature of the piston rod, so upgrade was probably timely.

Initial impressions/impact:

I can throw my leg over the bike from the ground rather than the pegs!

The shock appears to be excellent quality and is a thing of beauty (thanks for the recommendation Dai).

The suppliers have been very professional - although I did pose a question last night so I’ll report on their post-sales performance next week.

I have been very pleased with the set up of the outfit since my initial remedial work, nothing unpredictable and one handed steering at 60 on good highways. 

On rough roads however the sidecar dominated handling by its agressive reaction to less than smooth surfaces. I assumed this was down to chair tyre pressure and torsion bar shock preload issues, both of which I was experimenting with. However, even with the new rear shock set at almost zero preload the behaviour on rough roads is greatly improved.

I was concerned that reducing the rear height might adversely affect steering geometry. However, initial runs still at minimal preload, show no return of the nasty headshake I spent a lot of time tuning out.

One problem that I hoped the new shock might help with was the feeling that the bike leant out too far on the adverse camber (I had previously set the bike to zero lean out without much improvement). Unfortunately, this condition feels much worse. I can’t persuade myself that it has anything to do with a shorter shock, so today I will crank up the preload to max and see what that does.

TBH that deterioration seems so extreme that I’m wondering if I’ve screwed up a support setting during the shock change (I took advantage of the changeover to lube the final drive splines so the bike was jacked up for a couple of days putting increased pressure on the chair).

For those that helped out with my very noisy top end, which I have also been working on since my Snowdonia adventure, Olaf called it right as a faulty injector. I had the injectors cleaned and rebalanced by Injectortune (fantastic service and result (please moderate out if endorsement not allowed)). Power delivery is silky smooth now and the death rattle has completely disappeared.

Thanks as always for everyone’s help and support.
Stu


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106.
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
2000 Hayabusa with Charnwood chair, Wasp forks and EZS wheels.
    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
No worries on spruiking a company that gives good -whatever they do. It it helps another member, and that goes for weeding out the poor services too, then all the better.

Congrats on making progress.
cheers


__________________________________________________
Patience is something you admire in the driver behind you and scorn in the one ahead.
~Mac McCleary
1977 R75/7-100, '93 K11/K12 Big Block, '95 R100 Mystic, '96 K1100RS, '98 K1200RS, '06 K1200R & '09 K1300GT. Projects: 1993 & '96 K1100RS, & 1st '98 K1200RS.
The Mystic, Big Block, 2nd K1200RS, K12R & K13 are running & ridable.
    

3Back to top Go down   Rear shock upgrade and injector clean Empty Excessive lean out resolved Wed Mar 06, 2019 2:59 am

tinyspuds

tinyspuds
Life time member
Life time member
tinyspuds wrote:I have fitted a new Ramshox jobbie.

One problem that I hoped the new shock might help with was the feeling that the bike leant out too far on the adverse camber (I had previously set the bike to zero lean out without much improvement). Unfortunately, this condition feels much worse. I can’t persuade myself that it has anything to do with a shorter shock, so today I will crank up the preload to max and see what that does.

TBH that deterioration seems so extreme that I’m wondering if I’ve screwed up a support setting during the shock change (I took advantage of the changeover to lube the final drive splines so the bike was jacked up for a couple of days putting increased pressure on the chair).


Hmmm. Schoolboy error but probably worth a mention. 

After cranking up the preload I did a quick check of the lean out angle. It was way off and I spotted that the front mount for the upper strut had rotated around the chassis member, effectively increasing the distance between chair and headstock. I’m pretty good at giving the bike a visual before going out, esp. with things I’ve adjusted or replaced, but hadn’t noticed this problem before. The lean out problem did seem to get progressively worse in adverse camber driving (noticeably m’ways) and I now suspect it was re-setting at rest. Perhaps the one inch shorter shock and the preload adjusting had prevented this natural correction.
I’ve re-set the lean and tightened up the fitting. A 30 mile run suggests it’s transformational.
I have a couple of ideas to (reversibly) prevent a recurrence.

You have been warned (but maybe it’s only me that would get into such a mess in the first place) Embarassed.

Stu



Last edited by tinyspuds on Wed Mar 06, 2019 3:01 am; edited 1 time in total (Reason for editing : clarity)


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106.
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
2000 Hayabusa with Charnwood chair, Wasp forks and EZS wheels.
    

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