enfield bullet trials

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Bobber-job
Posts: 17
Joined: Tue Jun 03, 2014 9:14 pm

enfield bullet trials

Unread post by Bobber-job » Mon Jan 11, 2016 3:46 pm

Hello Ive been trying to find a trials exhuast for my '92 500 Bullet- something like the works trials bikes used to have. the Hitchcocks ones stick out a bit at the front - any ideas? ta Martyn

Coxy
Posts: 202
Joined: Sun Mar 29, 2009 11:05 am
Location: Sydney Australia

Re: enfield bullet trials

Unread post by Coxy » Wed May 11, 2016 12:22 pm

Make one, Got a mate with Oxy welding gear then have a look into "sand bending" gives better than Mandrel bends with no section area change and is not that hard to do especially for a single cylinder jobby.

Right size pipe cap one end and fill with dry sand pack it in with a broom handle and then seal with a wooden plug driven in with a mallet, the sand maintains the round section of the pipe and then heat till red hot and bend to suit your needs.

If for instance the pipe needs to be say 48 inches long then add at least 2 to 3 feet extra length so you have something to grab and use for leverage, secure one end in a pipe vice like the chinese cheapies you see in machine mart and heat where required to then bend to the desired curvature.

Any machinist can make the flange if required or if a slip fit pipe like some triumphs then nothing else needed and you will end up with an exhaust header that fits exactly where you want it, Has no section change affecting flow rates and unlike so many pipes made up of welded together mandrel bent sections there is no weld inclusions inside to impede flow.

Believe me find a mate with the gear and have a play it is not anywhere near as hard as people may think, One little hint when trying to figure out what bends you need what I do is find the appropriate diameter flexible aluminium corrugated ducting like many cars use for the heater ducting circa Cortina's and others of that era under the dash facia and use that to bend yourself a 3D template as the aluminium tube retains whatever shape you bend it to and does not kink perfect for the job, Then just copy your template and as you lay it alongside the new pipe you can see where and by how much it needs to be bent.

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