First, the 'treats reed kit' aka 'tomos alukit machined for puch exhaust flange' has a major design flaw, the deck height is about +3-4 mm from the top of the piston. Ohnoes! Low compression to be sure, which is a major bummer for a kit with awesome bottom end. I built one of these a few months back and tried a couple different things to get it in spec, but the easiest solution i found was a super-duper high compression head.
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| From Puch 'treats' reed kit - Noah Bern |
These are machined from puch Magnum heads, which fit the fins relatively close
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| From Puch 'treats' reed kit - Noah Bern |
Not perfect, but the performance increase is noticeable. Starts much better, timing is more predictable, and it feels like it has way better torque, but that's hard to claim without a dyno. Anyhow, about 4 of these are in testing and have been running great.
That build also made me re-think a big problem area for owners of magnums. Over the years I've tried a few different ways to mount maxi exhausts onto magnums, including flat brackets with bends, different shims, etc, and nothing has been satisfactory in terms of looking clean, simple, and fitting a variety of different bikes, kits, and pipes. Finally I came up with this little guy:
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| From Puch 'treats' reed kit - Noah Bern |
Simple, elegant, and the test models seem to fit most magnums. The only one that had complications, i believe was crashed because the pipe was all chewed up and the arm was bent.
The final version is much more professional looking and entirely made of stainless steel and aluminum, with plated grade 5 and grade 8 fasteners. I dont have a picture handy, but there will be one up on treatland when they get them in.
Awesome!! that head is just what i've been waiting for :)
ReplyDeleteHey! That Magnum exhaust mount is exactly how I had mine. Grade 5 hardware is a MUST, I've sheared a few grade 3 bolts. Love your work.
ReplyDeleteThanks grreat blog post
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