The rear of the exhaust seems to be a "semiside". Is this from Librands, I know you cut off some. Does this stop exhaust fumes coming back, into the cockpit.
No - it's a homemade system using pipe bought from eBay (see the first post for the component parts). The bit I cut down was the long pipe - I expected to trim a bit as I'd ordered a longer length than needed using the old adage of 'it's easier to take off than to add'.
To be honest, didn't have an issue with fumes from the old rear system, just fancied a side exit (and it meant I didn't have to bend a pipe to negotiate the rear axle),
