Thumper Diaries

Thumper Diaries

About the blog

This blog is to be a diary of our activities and the trials and tribulations of owning a Royal Enfield Bullet 500.

For spares and such, I normally go to Hitchcocks Motorcycles

For a complete log (linked index) of all the posts in this blog, go here: Diary log






Removing the PAV

CustomisationPosted by exile Thu, February 06, 2014 16:29:29
What is a PAV? It's a Pulse Air Valve that takes some unburned fuel and air mixture from the intake manifold and redirects it to the exhaust pipe just after the outlet port.
It is a device that supposedly will cause any unburnt particles in the exhaust to be burned and thereby reduce emissions. Nice, if it works. Which I don't entirely believe.
If your national rules don't require it, then neither do you. I don't. So off it comes as it restricts the exhaust.

Removal is a piece of cake. No electrics involved, it merely unscrews from the exhaust pipe and the valve in the tool box. Unscrewing the armoured pipe will allow you to remove the valve from inside the box. The whole removal takes seconds rather than minutes. There are some resulting holes to be filled though.
One in the toolbox, one on the exhaust and one on the inlet manifold.

The inlet manifold is a bit of a quandry. I don't trust the EU with their regulations and such so I decided to keep the little brass tube that works as the outlet from the intake manifold, intact. So I cut off a half inch of the neoprene tube that connected it to the PAV and screwed a slightly oversized screw into it. This becomes, effectively, a cap for the outlet which, by its removal, will allow me to reverse engineer the job if time and conditions dictate.

The toolbox was blanked by two oversized steel washers and a rubber washer, all held in place by a through bolt creating a sandwich of washer, toolbox, rubber washer and steel washer. The rubber washer is mainly for waterproofing. A dab of black gloss and the job is a good 'un.

The exhaust pipe hole is blanked by a purpose made cap purchased from Hitchcocks.

For now, at least, my winter modifications are complete. I want to ride Thumper now I've done with the tinkering. A wash and a good polish is all he needs but that will have to wait until the sun is shining again.







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