BMW K bikes (Bricks)

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1Back to top Go down   Frame/engine mount Empty Frame/engine mount on Tue Oct 29, 2019 4:14 pm

tinyspuds

tinyspuds
Gold member
Gold member
Hi all,
Spent the day divorcing my sidecar from the K, dropping the sub frame and removing the trans for a spline lube. Found heavy oil soiling in the bell housing so Im assuming I have a leaky main seal - but that can wait a few days.

The side car subframe shares the OEM engine/frame mounts at the front and uses an 8mm 10mm allen head bolt (not the fancy cap loc bolt).

This bolt (LH side) spins easily but will neither tighten nor back out. It feels like its stripped or sheared) but it wont extract with a magnet or with me pulling on the (otherwise unfastened) subframe.

Does anyone know if the engine case hole is directly threaded or is there a threaded interference fit bush inside the hole that may have come loose or possibly even, does it sound like a failed helicoil?



Last edited by tinyspuds on Tue Oct 29, 2019 5:16 pm; edited 1 time in total (Reason for editing : thanks to Glenn)


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

2Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Tue Oct 29, 2019 5:08 pm

glennpm

glennpm
Silver member
Silver member
Hi,

Are they the 10mm, not 8mm bolts numbered #1 and #2 in this diagram? If so I believe that the engine block mount tabs have a nut on the opoosite and inside of the bracket to accept these bolts. I used these mount points for my Flexit sidecar.

https://www.realoem.com/bmw/enUS/showparts?id=0513-USA-02-1987-K589-BMW-K_100_RS_83_0502,0503,0513_&diagId=46_1268

Try to pry under the bolt head or your captured bracket at the same time you are un-threading. Sometimes this will be enough to get off of the thread stripped portion of the bolt.

Glenn



Last edited by glennpm on Tue Oct 29, 2019 5:25 pm; edited 1 time in total

    

3Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Tue Oct 29, 2019 5:22 pm

tinyspuds

tinyspuds
Gold member
Gold member
Thanks Glenn, now you have confirmed the case is threaded I’ll attack it accordingly. I’m guessing the additional sidecar stress has killed it, although I’m surprised it hasn’t shown up in handling/vibration.
Back on it tomorrow, Cheers, Stu


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

4Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Tue Oct 29, 2019 5:25 pm

glennpm

glennpm
Silver member
Silver member
Hi!

Check my edit ;-) I think this is a bolt and nut attachment. I have many pictures of my Flexit bracket building, checked them and think their are inboard nuts for both of these frame to motor front mount points.

Glenn

    

5Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 2:49 am

charlie99

charlie99
VIP
VIP
yes bolt and nut attachment

good advice glen


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OFrame/engine mount Au-log10

"redframe" rs "bitsa"  with many contributions from the k100 community ,,with many thanks
    

6Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 3:52 am

tinyspuds

tinyspuds
Gold member
Gold member
Thanks Guys, After a day of hassling with the sidecar and transmission I probably wasn’t seeing straight yesterday. Back on it today and get that clutch out.
Cheers.


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

7Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 8:03 am

glennpm

glennpm
Silver member
Silver member
Excellent!

    

8Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 12:30 pm

tinyspuds

tinyspuds
Gold member
Gold member
Hmmm, interesting.
This may be one of those cross over year issue things as Ive certainly got other bits on an early 85 RT that aren’t the same as the years around it.
The RH mount is definitely into a blind hole that runs under two longitudinal ribs on the top of the crank case. I used this set up as my reference as the LH side is buried under plumbing and TB mechanism.
The LH bolt runs through a crankcase tab to a nut (which is completely hidden from view).
I’ve struggled to find pictures or descriptions of this set up.
Thanks for your help.


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

9Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 3:13 pm

charlie99

charlie99
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VIP
forgot I took this pic ...hope it helps

Frame/engine mount 20190243


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OFrame/engine mount Au-log10

"redframe" rs "bitsa"  with many contributions from the k100 community ,,with many thanks
    

10Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 3:24 pm

tinyspuds

tinyspuds
Gold member
Gold member
Thanks Charlie
That looks exactly as I have on the LH (valve) side. Your pic looks like the RH side is either internally threaded on the crankcase tab or maybe could hold a captive nut between the two ribs. Either way I can tighten or loosen that one using the bolt head only but looks like I’m going to have dismount (at least) the injector rail to get at the LH nut.
Oh well. Certainly better than helicoil.
Stu


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

11Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 3:37 pm

charlie99

charlie99
VIP
VIP
there is usually a little wiggle room under the radiator core , so you should be able to place the nut through there , if you have the radiator cover off ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OFrame/engine mount Au-log10

"redframe" rs "bitsa"  with many contributions from the k100 community ,,with many thanks
    

12Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Wed Oct 30, 2019 3:40 pm

tinyspuds

tinyspuds
Gold member
Gold member
@charlie99 wrote:there is usually a little wiggle room under the radiator core , so you should be able to place the nut through there , if you have the radiator cover off ?
Great tip Charlie! The nut isn’t even off so I’ll see if I can get a wrench on it via the rad.
Stu



Last edited by tinyspuds on Wed Oct 30, 2019 3:41 pm; edited 1 time in total (Reason for editing : Cant spell own name :-()


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

13Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Thu Oct 31, 2019 11:45 am

glennpm

glennpm
Silver member
Silver member
Good picture from Charlie,

If the left hand mount on your motor is tapped and stripped, I would tap it out from 10mm to a 12mm rather than using an insert. With the sloped gusset on the motor mount bracket, you can probably not get a nut to sit squarely.

Glenn

    

14Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Thu Oct 31, 2019 3:59 pm

charlie99

charlie99
VIP
VIP
hi glen, I don't think a 12mm bolt will fit through the frame ,  some later frames have rubber isolation on the front mounts and a 10mm ferule through the rubber.

 just a heads up


Frame/engine mount 20190157


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OFrame/engine mount Au-log10

"redframe" rs "bitsa"  with many contributions from the k100 community ,,with many thanks
    

15Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Thu Oct 31, 2019 4:01 pm

glennpm

glennpm
Silver member
Silver member
Yeah, that wouldn't work! Good call.

Glenn

    

16Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Thu Oct 31, 2019 5:54 pm

Dai

Dai
Life time member
Life time member
@glennpm wrote: With the sloped gusset on the motor mount bracket, you can probably not get a nut to sit squarely.
File the sides off the nut, as in - been there, done that Very Happy


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

17Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Thu Oct 31, 2019 6:00 pm

glennpm

glennpm
Silver member
Silver member
Hi,

I've done that too for smaller angles, like on a slope of structural steel. I just had an idea though that could work, use a threaded coupler.

8MM threaded coupler

    

18Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Fri Nov 01, 2019 7:45 pm

Packo

Packo
Silver member
Silver member
As the LH side mount is a thru hole taking a 10mm bolt and nut but a bit longer than the factory job to accomodate the subframe I have sacrificed a cheap ring/open end spanner for this purpose. On loan at moment otherwise I would post a photo. From memory I think it was 17mm and I thinned it down with the grinder and tweaked the angle slightly until it fits easily. To put it back just silicon the nut in the spanner and hold it in position and turn the bolt until tight, just don't use too much silicone as you only want to hold the nut until you get a couple of threads started.


__________________________________________________
______________
 
83 K100 HRD Outfit
77 R100RS
1992 K1100 Outfit
1983 K100
    

19Back to top Go down   Frame/engine mount Empty Re: Frame/engine mount on Sat Nov 02, 2019 12:05 pm

glennpm

glennpm
Silver member
Silver member
Regarding holding the nut in the wrench, I use blue masking tape, a loop around the wrench and push the tape over the nut to hold in place. The tape is easy to remove once you have the engagement started. For obscure locations, I sometimes wrap a loop of tape, sticky side out, to hold the nut on my finger tip or screwdriver until I can get it started.

Glenn

    

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