planning to build a better guibo/flexible disc coupling

[munkeeboi83]

I was at a motorcycle meet last night and I was admiring one of the member's frame sliders for this Triumph Daytona 675 on how quality and clean looking the design was. What surprised me was that he designed and CNC machined it all himself. We talked about the different uses of Delrin, which is a relatively lightweight and super duper strong plastic that is used as ball bearing replacements and also frame sliders for bikes. The nice thing is that it can be easily machined. Please see the link below if you want more info.

Anyways, he showed me some of the various bike parts he machined out of Delrin and also billet aluminum and they were all pretty impressive. He showed me a flex disc coupling he made for a C5 Corvette and it looked almost like the flex disc couplings for our E12s. I recently replaced the flex disc coupling a few months ago. Upon taking my E12 into the shop to fix an electrical problem with the alternator, I discovered when it was on the lifts that the flex disc coupling was broken and cracked again. I know that replacing the flex disc couplings/guibos every few years is a normal thing for us Bimmer enthusiasts, but what about having something about the same weight but a lot more solid, harder and stronger. He also does reinforced aluminum inserts for where the bolts go thru.

I'm prob going to purchase a guibo online and have my friend take measurements and make me a guibo and do some testing. Although this is a very hard material, he says there is no transfer vibration. If everything works out well, I guess I can let you guys know in a couple weeks after he makes a prototype for me to install.

Does anyone need to replace their guibo or flex disc coupling that's located in SoCal that would like to do some testing with their E12? I guess I could mail it out too if people in other parts of the country would be interested.

http://en.wikipedia.org/wiki/Polyoxymethylene_plastic

[alotawatts]

Replacement guibos (aka Hardy Disk's) for older BMW bikes and no doubt Isetta's can be purchased in rubber and what looks to be some kind of a resin ...sort of a honey color. I have one for my R27...will add a pic here soon.
I would stay with the stock hard rubber/hockey puck guibo for E12.

[GripGreg]

Just to pick your brain, alottawatts, why would you stay with the rubber guibo?
Thanx for your contributions,,,,Greg

[alotawatts]

Here is a pic
1st pic - 2nd row - Hardy Disk
http://www.flickr.com/photos/roundel/page2/

These older bikes came with this Vollkollen (sp?) type pictured.
There was a service bulletin where they went to rubber for exported bikes to tropical places..... odd.
I cannot think of any reason to not use rubber as engineered for E12's.

[DMS]

Hmm only if it keeps breaking with increased power I'll upgrade but I like to keep in mind that this is one of the protective measures at hard launches for my drivetrain. But ofcourse I'd like to see your results!

[munkeeboi83]

@alottawatts I noticed your pictures of BMW motorcycles. There were some vintage BMW bikes at the Coast Motor Werk event that I was at over the weekend. There was even a BMW bike with a side car. The owner was giving the kids at the event rides and popped up the side car when he turned hard for the older kids. I love the look of vintage style cafe racers.

I was speaking to Pierre over weekend at the Cars and Coffee meet in Irvine and also at the Coast Motor Werk event and he explained to me that I improperly installed my guibo/flex disc coupling, so that's why it was starting to shred after only a few months.

Anyways, I'm going to try to get some pictures of the Corvette C5 guibos that my friend made. Pierre was telling me that Delrin (very hard, temp resistant plastic) might be too stiff and cause too much vibration. Much like changing out your suspension bushings and engine mounts to hard polyurethane (Energy Suspension, etc.) Although my friend has said otherwise that the Delrin does allow for some flex, I guess I'm going to get a flex disc coupling and let him take measurements and see how it turns out. The hard black rubber that the guibos come in does have a good amount of flex and they should be handle high hp cars. I don't have too much experience, so I came on the boards to ask you guys.

Anyways... do you guys have any ideas for things we can make out of Delrin for our E12s or CNC machined aluminum? If you guys have some ideas or designs, perhaps I can get a group buy for you guys if you guys are interested. I have a few ppl who have access to CNC machining, equip to anodize it to any color, laser engraving for labels, etc.

Some ideas I had so far were:
- battery tie downs (Delrin or Alum)
- custom pulleys (Alum)
- various mounting brackets, ex: the plastic tab for our radiator fluid reservoirs (Delrin)
- shifter components

[GripGreg]

I hope you didn't remove the metal band before installing the guibo!!
I thought there was info in FAQ, but, I guess not.
Glad you made it to the OC. Greg

[Jeff Dennis]

Munkeeboi,
Thought I would share here is a photo of my 1979 Moto Guzzi... I love the style of late sixtes English Cafe Bikes.
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[alotawatts]

@alottawatts I noticed your pictures of BMW motorcycles.

Those are not my pictures..... but this one is :

[Jeff Dennis]

Nice R27...

[Blaise]

Since we are sharing motorcycle photos...

<a href="http://picasaweb.google.com/lh/photo/5F ... site"><img src="http://lh6.ggpht.com/_UZQuuBHQvx4/TFouh ... o.jpg"></a>

<a href="http://picasaweb.google.com/lh/photo/E_ ... site"><img src="http://lh4.ggpht.com/_UZQuuBHQvx4/TFouh ... o.jpg"></a>

<a href="http://picasaweb.google.com/lh/photo/wp ... site"><img src="http://lh6.ggpht.com/_UZQuuBHQvx4/TFouh ... o.jpg"></a>