BMW K bikes (Bricks)

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1Back to top Go down    Rear shock upgrade and injector clean on Sat Mar 02, 2019 6:49 am

tinyspuds

tinyspuds
Silver member
Silver member
I have fitted a new Ramshox jobbie. The OEM was shot and (mostly because I canít resist tinkering, but also because I thought it might produce more lateral stiffness) I went for the 1Ē 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 Iíll 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 canít 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 Iím wondering if Iíve 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 everyoneís help and support.
Stu


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LLís.
2007 HD883 Sportster. Bobbed and bettered.
1954 Royal Enfield 350 Bullet. Original.
    

2Back to top Go down    Re: Rear shock upgrade and injector clean on Sat Mar 02, 2019 7:18 am

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


__________________________________________________

1987 K100RS, '89 K100 w/K1100RS engine, '93 Framed K11/K12 engine 'Big Block', '09 K1300GT, '07 K1200R, '95 R100 Mystic & '77 R75/7.

    

3Back to top Go down    Excessive lean out resolved on Wed Mar 06, 2019 2:59 am

tinyspuds

tinyspuds
Silver member
Silver 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 canít 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 Iím wondering if Iíve 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. Iím pretty good at giving the bike a visual before going out, esp. with things Iíve adjusted or replaced, but hadnít noticed this problem before. The lean out problem did seem to get progressively worse in adverse camber driving (noticeably míways) 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.
Iíve re-set the lean and tightened up the fitting. A 30 mile run suggests itís transformational.
I have a couple of ideas to (reversibly) prevent a recurrence.

You have been warned (but maybe itís 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 LLís.
2007 HD883 Sportster. Bobbed and bettered.
1954 Royal Enfield 350 Bullet. Original.
    

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