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Made an air filter for Dommie 99

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Cobbled this together from a threaded ring, welded on extension tube and a Ramair oval filter, better than nothing I guess 

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That will keep the rocks out ,and treble the life of rings and bores. Back in the day, Norton would say a filter is not needed in the uk. But they had no idea we would be still running the bikes 60 years later. And they made much of the profit on sales of parts ,which are now very scarce ,particularly cylinders.

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The nicely welded ally tube that comes off the Monoblock ignores one carb basic. At the bottom of the inlet there is two holes leading to the float area. If these are allowed to breath outside the air cleaner tube there is often a modest increase in engine pick up, especially at lower engine speeds.This is a common fault with the fitting of 'go faster' air tubes onto concentric carbs. The genuine AMAL version puts these same holes to the outside air, carb works properly. 'Go faster' air trumpets look good do nothing.

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Hello Alan not sure if you are saying i have done a bad thing but with the monobloc it is not possible to fit an intake tube that does not encompass those holes, unlike a concentric. The screw on ring was an Amal part

In reply to by peter_brown1

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Good idea and an effective well made setup Peter, thinking of doing something like this on my Atlas special. Can,t recall if the pilot and needle jet air intake holes Alan mentions are the same on Monoblocs but Concentrics do indeed work properly using filtered air rather than direct from the outside. Big advantage is the air being filtered, essential in these circuits

Even Amal offset long velocity stacks benefit from this.I made up a custom K&N filter for my 850 using modified screw on rings as you have. It filters air to both the stacks and the pilot and needle intakes similar to yours. Works superbly with good power, economy and a reliable idle

The Mk3 850 also has an excellent oil tank breather takeoff that I connected to the back of the filter. No oily fumes or dripping hoses. Not sure this would work on your bike

 


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