Air/filter/airbox assembly

Previously wrote:

I own a 1976 850 Commando Roadster, the previous keeper has removed the airfilter assembly and has fitted a K and N filter - runs fine but I would like to go back to standard, I have looked on e-bay and I wish I hadn't as one is featured - some sort of "alien" type that comes in at over £250.

What I need to know please is:

Will the 750 Commando airfilter assemblyfit my bike - are the airfilter assemblies all the same or amI tied to a specific one for my model? thanks

If you've got a Mk 3 then you'd probably find the original air filter would be the plastic black box type.I've justput the earlier type air boxon my Mk2a, which also originally had theblack box. It fitted without a problem: the only thingI chose to do was drill some additional holes in thebackplate so I could use the existing screw holes in the battery tray.

I would certainly not pay £250 onebay; I got mine for half of that from Andover Norton and it's a nice piece of kit. I've found Nick to be a great help at AN.

Hope that helps.

Ian

The black box filter is a devil of a job to instal anyway. Legend has it that the frame was built around it.

You can indeed use the 750 / 'non A-suffix' 850 air filter with the paper element and these are available from various suppliers, including in stainless.

The Mk111 850 battery tray is slightly shorter on the front lip and from memory you'll have to space out the filter back plate slightly. If it hasn't already been done, you may also need to find a way to locate the battery more positively as the original air box has a retaining function.

If you assemble the filter on the bike using the top mounting, you'll soon see where it has to be spaced to set the back-plate vertically.

Original filter back plates have a lug for the ignition switch which can easily be ground off.

Your carbs will originally have been fitted with the cut-away spray tubes and associated needles. It may be worthwhile checking what is fitted. My preference is for the earlier type full tubes and needles where the black box is no longer being used.

I think that you'll find it easier to set the carburation cleanly with the early filter than with the K&N. You can use the jetting for the Mk2 (not 2A) as a starting point - 260 main jet, 3 1/2 slide cutaway.

Without even looking, I bet that airbox on ebay is being sold by Norvil? An absolute ripoff again. I restmy case.

Regards, Paul.

Previously wrote:

Without even looking, I bet that airbox on ebay is being sold by Norvil? An absolute ripoff again. I restmy case.

Regards, Paul.

I have concerns over Norvil's approach to selling on Ebay. They have every right to move-on used stuff which isn't good enough to put on their rebuilt bikes. The problem comes with the sheer volume ofparts which are listed at vastly over-inflated prices. Fair enough, they usually have the 'or best offer' tag, but their strategy gives the impression that they aretrying to influence the market price for used parts by creating an artificial 'ceiling.' I'm sure that they are not trying to kid anyone that the buy-it-now price is truly representative of the realistic value......

Still, the value of anything is determined by the price someone is willing to pay, and if I were running a business I suppose I'd try to maximise returns.

As always, 'caveat emptor' - 'let the buyer beware.'

ps I'm considering changing my black airbox (with its pathetically small filtration area) for an earlier type. Offers based on £200 most welcome!!

pps I've often found that many new parts sold by various sellers on Ebay can be bought more cheaply from the 'usual' suppliers, so don't get carried away by auction fever!

Allan.