BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


tborosak

tborosak
active member
active member
Hi Guys,

Unfortunately my finished custom build has hit a bit of a bump as my rear seat that I got from cafe4racer.eu has spilt in half. I have emailed the company to get a resolution however they have now ignored me and took down the pictures of my bike on their website when I said that I never gave permission for them to use my pictures. 

So I brought several parts off this company a fibreglass seat, rearset and exhaust system. They all fitted on well but after riding for a while I have noticed some major flaws. the rearset isn't solid and flexes a lot when trying to change gears so you are trying to force it into gear. Ended up machining my original rearsets and they worked a dream no problems at all so wasted money on the rear sets off cafe4racer. the exhaust was all good however it doesn't slip on properly to the valves causing the bike to back fire like crazy every time I back off or drop down a gear. I ended up welding the 4 smaller exhaust pipes into the connection and then cutting the muffler off and stretched out the pipe on the end to change to over to a slip on pipe which now has fixed the problem and works a dream. However I have left the worst for last I hit a speed bump last weekend and from the impact it has spilt my fibreglass seat in half. I have emailed and contacted cafe4racer.eu about this As the seat is not in stock and was finding out when they will be back in stock. However I got a shitty response back saying "Hi Thomas really sorry to hear that , seems that some reinforcement  brace from back side within frame would be necessary also you have mounted there  license plate holder that could have also have influence on back weight ..…. , unfortunately producer has a big delay therefore   those are out of stock currently… really cannot assume when back in stock".


So I wrote back asking if they could contact their producer to find out a rough date as I'm looking to still buy the seat not get it replace and wrote in the email that I didn't recall them asking for permission to use pictures of my bike on their website. Unfortunately since then they have not replied to my emails and have taken down the pictures of my bike. It's left quite a sour taste in my mouth as I kinda put up with their product and modified it to make it work but getting a response back like that and not willing to help at all with getting a new seat. 


Really this post is just to make people wary of cafe4racer.eu but also does anyone know of someone in Australia - Queensland area that can mould up a new seat from my old one or even fix it so looks new again? 


Cheers Thomas  K100 RS 1985 Custom Build CAFE4RACER problems  Img_5011
K100 RS 1985 Custom Build CAFE4RACER problems  Img_5010
K100 RS 1985 Custom Build CAFE4RACER problems  Img_4210[url=https://servimg.com/view/19848557/102]K100 RS 1985 Custom Build CAFE4RACER problems  Img_5012 [/url]


__________________________________________________
BMW k100 RS 1985 (Cafe Racer)
 
TOM Wink

https://www.instagram.com/tomborosak/
https://www.instagram.com/tomborosak/
    

chris846

chris846
Life time member
Life time member
Hi Tom, I ordered the same seat unit a while ago after seeing yours and liking the look of it.

The first one arrived in a box that had been damaged in transit. The seat unit had started to split along the horizontal join, similar to yours but not as bad (the seat is made from upper and lower halves, bonded together with something that looks like epoxy). I emailed the company and a replacement arrived within 36 hours. I thought that was impressive service.

It is a solid i.e. heavy seat unit. So I can see how it needs to have a good set of mountings to cope with its own weight. How have you mounted yours? I'm using M6 rubber bobbins for the two pre-drilled holes that are inside the hump, plus I've made a further two rubber blocks to take the weight under the actual seat part.

I would've thought that you could have a go at rejoining the two halves back together?


__________________________________________________
The Longest Lunch
    

Dai

Dai
Life time member
Life time member
@chris846 wrote:The seat unit had started to split along the horizontal join, similar to yours but not as bad (the seat is made from upper and lower halves, bonded together with something that looks like epoxy). I emailed the company and a replacement arrived within 36 hours. I thought that was impressive service.

It is a solid i.e. heavy seat unit. So I can see how it needs to have a good set of mountings to cope with its own weight. How have you mounted yours? I'm using M6 rubber bobbins for the two pre-drilled holes that are inside the hump, plus I've made a further two rubber blocks to take the weight under the actual seat part.
IMO not really the point Chris. It might look good, but introducing a serious stress point by bonding the upper and lower halves is extremely bad design. You have a front part that flexes X amount and a rear half that only flexes Y amount. With reasonable usage it's going to split at the intersection, period. You, as the builder, should not have to spend the time you did spend working out where to support it to prevent the bond line from splitting again. At the very least it should have been moulded so that a 'lid' at the very top of the hump was bonded to the 'box-shaped' hump. That would have put relieved the stresses that are in the current design and made it very much stronger. Even moulding it as a one-piece unit (like Rickman and Degens used to do) and then adding the base later would have removed that problem. As it is, the design is production speed over strength.

Confession: my experience of glassfibre mouldings is restricted to building canoes (kayaks) but we had to take all of this into account when moulding storage areas into the bodies.


__________________________________________________
'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)
    

chris846

chris846
Life time member
Life time member
Fair comment, the seat base and the base of the hump are moulded as one piece - more or less a flat tray with raised edges. The dome of the hump seems to be bonded on top of this. Both sections, especially the 'tray' base are quite thick and heavy - 15mm in places. I'm curious about how Tom mounted his, because I can see how the weighty hump section - eight to ten inches in length - overhangs the two pre-drilled mounting holes in the floor of the hump (I think these are aimed at the cross member on the OE frame, although mine doesn't have that). This could explain the failure, particularly the short part of the crack right at the front of the hump on Tom's unit. If that's the case then I'll be adding an outrigger, further to the rear so's the hump is no longer cantilevered.
But you're right, if the above guesswork is correct, then the seat unit should come with some indication of what mounting is required.


__________________________________________________
The Longest Lunch
    

tborosak

tborosak
active member
active member
Hi Chris 
Yes mine sounds very similar to how you have mounted your seat I have put rubber bushings in between the frame and the seat and have bolted it through the two pre drilled holes with washers in between so there isn't too much stress on the two small holes . However there isn't any support for the part that extends over the wheel as I didn't think that the tail tidy would be too heavy for the seat (as no one sitting on the hump etc).


I was going to rejoin the seat with fibreglass cloth and resin however was hoping to just buy a new one and then put some extra fibreglass and resin around the joins inside the hump to give some reinforcement (just for peace of mind). Also I was going to take the tail tidy off the rear set all together and fabricate a rear wheel tidy to reduce any weight on the rear seat.


__________________________________________________
BMW k100 RS 1985 (Cafe Racer)
 
TOM Wink

https://www.instagram.com/tomborosak/
https://www.instagram.com/tomborosak/
    

chris846

chris846
Life time member
Life time member
That confirms it - even with a tail tidy & number plate (which can't be the heaviest of things) the weight of the hump is too much for itself.

Shame you had to discover that weakness after all the work you put in. But (here's the optimist talking) the next version will look just as good as the original, but will be even better! I wouldn't bother ordering another unit - it'll have the same weakness, whereas if you set about improving & refinishing the one you've got it'll be much better, and it'll be a bit more 'yours'.

Meanwhile I'll be revising my own build.


__________________________________________________
The Longest Lunch
    

tborosak

tborosak
active member
active member
yeah that's what I'm thinking too will just end up fixing this one I have now up and see if it is possible to find a local company to mould up a new seat from the old one. 

Though while I have the bike apart can look at tidying up other items on the bike too haha looking to bring my front headlight down a little bit as a little high and looks odd. Then make a bracket for the number plate to wrap around the wheel.


__________________________________________________
BMW k100 RS 1985 (Cafe Racer)
 
TOM Wink

https://www.instagram.com/tomborosak/
https://www.instagram.com/tomborosak/
    

8Back to top Go down   K100 RS 1985 Custom Build CAFE4RACER problems  Empty custom tail section on Sun Apr 21, 2019 7:41 pm

Kerrylohrey

Kerrylohrey
active member
active member
Hi mate , we do have a problem here in Aus. regarding good custom parts, all the bits i needed mostly came from overseas, i fabricated my tail section from 2 mm alloy sheet then formed another piece which is currently being upholstered. Alloy doesn't require the support that glass does but its a bit harder to work with i guess. hope you get a resolution. I would post a pic but im buggered if i can figure out this computor stuff yet. ha! ha!

    

tborosak

tborosak
active member
active member
Thanks Kerry
Yeah it is quite hard here to get any modified parts however I knew what I was getting myself into when buying the K100 nothing was going to be cheap haha. My old man is a fitter and turner plus welder so he helped with a lot of the customization on this bike. Though that's what we were leaning towards doing an alloy seat but will see if I can get this one moulded if not I will just repair it and make it nice again. However the actual seat we are going to make alloy now so it has a nicer shape and sits better into the fibreglass moulded seat and fuel tank. 
Hopefully you figure out how to sort the computer out and show us your pride and joy.


__________________________________________________
BMW k100 RS 1985 (Cafe Racer)
 
TOM Wink

https://www.instagram.com/tomborosak/
https://www.instagram.com/tomborosak/
    

Kerrylohrey

Kerrylohrey
active member
active member
Will get my wife to assist with the photo stuff, i don't understand all the computor stuff very well , rather be out in the shed. My build has been totally by myself, welding painting etc wanted to keep the back end as small as possible hence the home made tail section.
Will get a few photos soon, regards Kerry

    

Kerrylohrey

Kerrylohrey
active member
active member
Hi Tom, think i figured how to add a photo of my KK100 RS 1985 Custom Build CAFE4RACER problems  20190415

    

tborosak

tborosak
active member
active member
Kerry that looks awesome love it! Very clean and tidy I like the height and positioning of your headlight. I am looking at moving mine down a bit as I set it too high and looks a little odd haha. 


__________________________________________________
BMW k100 RS 1985 (Cafe Racer)
 
TOM Wink

https://www.instagram.com/tomborosak/
https://www.instagram.com/tomborosak/
    

Kerrylohrey

Kerrylohrey
active member
active member
Hi Tom , thanks for your comments re my K, the beauty of these home custom jobs is that we can all interpret the style we carry in our heads. Your bike is very "balanced", great work Tom !!

    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum