I am hacking my K100. The rear wheel is now a Mini Cooper wheel with a 185/65 R15 tire. I am making a 4 into 1 collector and routing the exhaust away from the wheel/tire. My question is, can I just use a can from a Jap liter bike, or do I have to use something tuneable like a SuperTrapp? I don't know how smart the K bike fuel injection system is. Any advice will be appreciated.

Thanks,

Mike Lydon

The muffler from a jap 1 litre is ok just noise factor may need to be dealt with according to what you like and as for fuel injection it should be ok as it is basicly an air in and appropiate fuel for mix.

Hi Mike,
I'd like to see some pictures of your rear wheel arrangement. Have you spaced out the wheel to get clearance for a 185 tyre?
I use a 145x15 on a Wasp wheel, but there is not much clearance at the swing arm.
Cheers,
Paul.

Paul,

I am using a 5.5 x 15 Mini Cooper wheel. The reason for the 185/65 size, is I wanted to keep the tire diameter about an inch under the non stock wheel/tire that I had (160/60 R16), and the front and sidecar wheels are 185/60 R14. I did not want a visible difference in tire width. To make it work with the stock rear brake, I had to add a 12mm spacer to the wheel adapter that I have. I am using a wheel adapter that was donated to the project. If I had made my own, I would not need the spacer, as it would have been built in to the adapter. If you need info on the wheel adapter, I may be able to help you.

Mike

Thanks Mike,
Useful information on rim size and tyres. I use a standard profile rear tyre to keep the diameter reasonable but a 60 profile on the front.
Keep us up to date with all your sidecar mods, with pictures if possible.
Cheers,
Paul.

Paul,

You can see progress photos at www.hpsidecars.com. Poke around the general discussion area, the technical discussion area, and the photos section.



Mike

I'm only assuming you need to modify or re-route the exhaust for the sidecar set-up. It has been well proven and documented that no other exhaust makes better power than the stock unit. BMW were very clever, they managed to design an exhaust system that was both quietest and best for power. The only benefit of any aftermarket units was in weight savings (approx 4 kg) and visually some were more appealing.

Thanks Mike,
Your hub-centre steering looks superb and I'll follow your progress with great interest.
I've added that site to my 'short cuts' so when I've got a bit more time I'll delve a bit deeper. (I'm off camping again shortly......no forum for a couple of days, how will I cope?)
Cheers,
Paul.

Dennis,

The ONLY reason I am changing the exhaust is for tire clearance. I really like the sound of the Staintune, and it is much more esthetically pleasing than that UGLY stock muffler.



Mike