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Air filter on single Monobloc 99

Submitted by bruce_mitchell on Mon, 14/07/2014
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Heavy Twins

I would like to add an air filter to my single Monobloc 99, has anyone done this? There is very little space between the carb and the battery box which is mounted further forward than the oil tank. What filters has anyone used that fit?

thanks Bruce

Submitted by robert_tuck on Mon, 14/07/2014

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I have a filter box fitted between the oil tank and battery,its a tight fit and expensive to buy from Norville, There is no dedicated filter for it and its a devil to fit after a lot of "fetlling". Not worth the bother.Fit a piece of hose and a cone filter.

Submitted by richard_rumsey on Mon, 14/07/2014

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Previously Bruce Mitchell wrote:

I would like to add an air filter to my single Monobloc 99, has anyone done this? There is very little space between the carb and the battery box which is mounted further forward than the oil tank. What filters has anyone used that fit?

thanks Bruce

Submitted by Xanna_jeannett… on Tue, 15/07/2014

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Previously Bruce Mitchell wrote:

I would like to add an air filter to my single Monobloc 99, has anyone done this? There is very little space between the carb and the battery box which is mounted further forward than the oil tank. What filters has anyone used that fit?

thanks Bruce

Well Bruce In my Amal big Catalogue Amal Made a Type 96 air filler for all twin engines some have called this the pancake filler , so contact Amal or keep a eye on Ebay or its a case or looking round Auto jumbles

Yours Anna J

Submitted by bruce_mitchell on Tue, 15/07/2014

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Our experience here (Canada) is the cone filters plug up very quickly. I have a pancake filter but it doesn't fit the space, I'm trying to deteremine if it's thicker than the type 96, from the photos I can find it isn't.

thanks, Bruce

Submitted by bruce_mitchell on Tue, 15/07/2014

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Previously robert_tuck wrote:

The pancake filter will not fit between oil tank and battery box.

Correct, I have just verified that.

Bruce

Submitted by neil_wyatt on Tue, 15/07/2014

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The std pancake is too thick. But there was a slimmer one, I have one and when I find it I'll give the dimensions.

Nice to have it re-made in stainless.

Submitted by bruce_mitchell on Tue, 15/07/2014

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Previously neil_wyatt wrote:

The std pancake is too thick. But there was a slimmer one, I have one and when I find it I'll give the dimensions.

Nice to have it re-made in stainless.

Any part number or identification on it would be very helpful!

Submitted by neil_wyatt on Tue, 15/07/2014

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I don't recall a part number on it as Martin Bratby, who I bought it from told me it was an Amal proto type.

I'm not aware of any difference in the gap between end of carb and oil tank / battery box standard set up be it wideline or slimline.

I'll have a look for the missing filter body this Sunday.

The threads BTW are imperial and also fit the Mk 1 concentric 626.

Submitted by robert_tuck on Wed, 16/07/2014

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Previously neil_wyatt wrote:

I don't recall a part number on it as Martin Bratby, who I bought it from told me it was an Amal proto type.

I'm not aware of any difference in the gap between end of carb and oil tank / battery box standard set up be it wideline or slimline.

I'll have a look for the missing filter body this Sunday.

The threads BTW are imperial and also fit the Mk 1 concentric 626.

Norvile made some,I have one on my 99DL, Between the oil tank and Battery (there is no battery Box on the DL just a platform and clamp).

The box needed redrillig to match up with the oil tank and some reshaping to get the parts to fit together. The filter element is a carved up part from something else.The carb needs an adaptor to replace the bell mouth and a rubber connector (this part is made a bit loose and does not seal) The rubber also fouls the oil tank flange. The fixings are a bit of an afterthought and likely to vibrate loose and enter the motor.It will deflect rocks from entering,but filter? no i don't think so.

Submitted by gordon_johnston on Wed, 16/07/2014

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My 99 and Atlas never had air filters and bore wear hasn't been an issue. Perhaps living in Scotland where water ingestion is more of a problem than sandstorms is a factor. Oddly enough the only one of my bikes which has needed a rebore in living memory is my BSA A7 - the only one with an airfilter - a splendid Vokes microvee device.

Submitted by david_cooper on Wed, 16/07/2014

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My 1963 (88SS) came with single carb and an air filter between the battery box and oil tank. The filter is semi-circular with a tube out of the flat diameter face - a snug fitting alloy tube went on that and was threaded onto the carb bellmouth thread. Some bikes have a plate fixed to the oil tank (or maybe battery box), to bridge the gap. There's a hole in the middle of the plate to allow the filter tube to pass through. Maybe someone knows hos long that detail lasted? Did it go when the 'SS' models appeared?I see to remember the filter element was an old BMC Mini type circular filter, cut in half.Everything is currently packed away pending delivery of a new garage in a couple of weeks so I can't measure it.My Lucas RITA now lives in that gap and I use a pair of cone filters. It's a compromise to squeeze them in since I have concentrics which stick out further than monoblocks I think. Especially when twinned. But with single monoblock there should be more space.

Submitted by david_cooper on Wed, 16/07/2014

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There was an article in Jampot some years back by a British motorcycle designer industry insider who described comparison tests with and without filters. With filters the oil stayed cleaner and the engine life was maybe doubled at no discernible loss of performance. They did not fit them as standard because the customers wanted their bikes to looked like race bikes - which did not have them. So a) there was little customer demand, and b) they saved money and c) engines wore out quicker so they sold more bikes. This was in England where it isn't generally too dusty (although with so much coal being burned the city air was a lot dirtier then than now).

Submitted by bruce_mitchell on Wed, 16/07/2014

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Previously neil_wyatt wrote:

I don't recall a part number on it as Martin Bratby, who I bought it from told me it was an Amal proto type.

I'm not aware of any difference in the gap between end of carb and oil tank / battery box standard set up be it wideline or slimline.

I'll have a look for the missing filter body this Sunday.

The threads BTW are imperial and also fit the Mk 1 concentric 626.

There is a gap difference on mine, I can't see how to change that as the battery box is bolted at the bottom and top and there is very little room behind it before it hits the frame.

Submitted by bruce_mitchell on Wed, 16/07/2014

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Previously David Cooper wrote:

There was an article in Jampot some years back by a British motorcycle designer industry insider who described comparison tests with and without filters. With filters the oil stayed cleaner and the engine life was maybe doubled at no discernible loss of performance. They did not fit them as standard because the customers wanted their bikes to looked like race bikes - which did not have them. So a) there was little customer demand, and b) they saved money and c) engines wore out quicker so they sold more bikes. This was in England where it isn't generally too dusty (although with so much coal being burned the city air was a lot dirtier then than now).

Engine life nearly doubled... that seems worth it!

Bruce

Submitted by Xanna_jeannett… on Wed, 16/07/2014

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Previously Bruce Mitchell wrote:

Our experience here (Canada) is the cone filters plug up very quickly. I have a pancake filter but it doesn't fit the space, I'm trying to deteremine if it's thicker than the type 96, from the photos I can find it isn't.

thanks, Bruce

Type 96 is the thin type air filler but the original ones are hard to find now,

you have to look on ebay or auto jumbles sales and keep your eye and ear on the look out for one yours anna j

Submitted by bruce_mitchell on Mon, 28/07/2014

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I have just acquired an air filter box off of ebay, a Volkes, it appears to have very little use if any and fits exactly between the oil tank and battery box and the two tabs on it line up with the threaded bolt holes on the back of the oil tank. Add some foam and we're there!

thanks all, Bruce

Submitted by bruce_mitchell on Tue, 03/02/2015

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Previously neil_wyatt wrote:

I don't recall a part number on it as Martin Bratby, who I bought it from told me it was an Amal proto type.

I'm not aware of any difference in the gap between end of carb and oil tank / battery box standard set up be it wideline or slimline.

I'll have a look for the missing filter body this Sunday.

The threads BTW are imperial and also fit the Mk 1 concentric 626.

The gap is because I have an Atlas tank!

Bruce

 


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