99S differences

Previously wrote:

Anyway, here's my query... I had an idea to change it to single carb, and bought the manifold listed in my parts book - Pt. No. 18242 to do this. However the vertical stud spacings (ie on the head) are farther apart than on this manifold. Does anyone know if a manifold is available to convert this head to single carb? When I asked Mick Hemmings he suggested scouring the autojumbles, which I get very little opportunity to do.

I have one with the vertical spacing at 1 5/8th in or about 41mm. I just tried it on a head that I had handy in the garage and it fits. Any good to you?

Cheers

Alan

Hi Alan yes that would be great. I've tried to pm you but it says it can't find a valid email address? Anyway if ok with you could you txt 07725748587 so I can ring you later?

Thanks

Martin

Hi Patricia

RGB sell the manifolds (might have to open them out to 1 1/16" - don't know how they come). Sorry if this duplicates another answer in this enormous thread.

Are you absolutely certain that you bought a new 99SS with a single carb in 1961? Do you have any photographs?

Mine came with a single carb manifold when I bought it in 1979, and I would like to keep it that way, if any new ones were shipped like that.

Steve

Hi, back in 1961 I bought a 600 SS from Hooleys in Nottingham, at that time there was quite a lot of experimenting going on, one was to upgrade the piston to 8. 3/4 to 1compression, another as you have said was to put siamese pipes on, twin carbs were not fitted as standard at that time, there were many conversions brought out but try and get one now is almost impossible, many who have carburettor problems on Amal Monoblocs tend to over tighten the nuts holding the carb on to the engine, this has a tendency to distort the facing and that allows air to seep inbetween the facing, that causes the engine to run lumpy or to keep cutting out, no alteration of the mixture screw will cure this until the facing is leveled again, so now is my question to anyone reading this, can anyone tell me where I can get the twin carb conversion from.

Hi Ron

I have a 99SS engine just a few numbers away from yours (but this is not the number used in the log-book as being the 'engine number') see attached pic.

It has been suggested that the 'SS' was added by owners later (to kind of turn base metal into gold) but the pictures are too similar to make that likely.

My bike was first registered in 24th August 1961 as a 600cc 'Super Sports'

The differences from a standard 99 are,

The cam is high-lift, stamped 'X1'

The inlet tracts are opened out to 1/ 1/16" and polished

The pushrods are fatter, like a Commando.

There is a tiny BSS stamp on the top of the barrels (I think they have wider pushrod tunnels)

There is a tiny SS stamp on the underside of the head

From a road test in 1961 the valve springs were the later, shorter and stiffer 'dual rate' types.

From the spares book it looks as if the pistons could be the same as a standard 99, but the 88SS pistons differed from standard 88's

(this odd - someone knowledgeable will correct this point) Oddly, the spares book offers hi-comp pistons for the 99 Std and D/L, but not the 99SS.

I'm not sure about the bulge issue, not sure what I am comparing with, but I do believe that my engine is exactly like yours.

It has distributor/coil ignition

The pressure relief valve is different (but I don't know how - but they have different part numbers)

The timing cover has provision for a rev counter

There is a tacho drive nut on the end of the camshaft

The valves were the same size as standard 99's.

If you are anywhere near London we could compare them

Steve

Hi Adrian, As this thread is still ongoing. The attached pic of my engine block may help.

I have rebuilt this engine from sump plug to head steady and at the time tried to pin down details of the spec. There seems to be quite a bit of âmisinformationâ to put it politely, around.

The 99ss 600cc had coil ignition, as far as I can see externally, the basic 600ss engine will look the same as standard of that year. You need to get inside to check things out, the camshaft was the main difference. Valve timing can be checked but unless you are up on 50/74/82/42 and things its not easy.

Ron.

Previously wrote:

Previously wrote:

Previously wrote:

Hi again, another query , my 99SS engine should have the camshaft etc of the Manxman, should it also have an SS head , by the NOC , May issue , the head information in it says SS heads have horizontal mounting studs, mine has the vertical stud configuration, have I the wrong head please.

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The factory built 99SS models, that were catalogued and available to Joe Public for a little under two years,were all stamped with 99SS on the back of thecrankcases. As opposed to just 99 or 99C on the other 600cc engines.

As part of the deal, you got an SS camshaft from the 650 engine as well as 650 barrels, 650pushrods, twin Monobloc 376 carbs plus the option of a siamesed or standard exhaust. The most notable diffference between the 650SS and 99SS was the cylinder head. The 650 had the new splayed exhaust and twin carb job with horizontal carb mounting studs. The 99SS was sold with the old standard 1960 style 99 head with the old exhaust ports and mounting studs for the 2 into 1 car manifold. Although, mounted in this area was now a special adapter which fitted between the head and allowed the use of twin carbs. Strangely, in this head you had the bigger inlet valves of the 650 and some earlier 88 &99 heads plus the shorter but stiffer 650 type of valve springs. Coil ignition was used for these engines.

Of interest, the 1962 sales brochure shows the 88SS wearing the 650 type of SS cylinder head but mentions that the 99SS has the standard head. John Hudson once told me that the last couple of dozen 99SS bikes produced by the factory were actually fitted with the SS head but were never released to dealers as it was quickly realised that any of the previous 99SS bikes, stillavailable,would then never sell. Which begs the question of what happened to these proper 99SS specials? Where the bikes re-engined with650SS motors and sold as such or just dismantled for spares?

FUNNY OLD WORLD ISN'T IT, WE MEN REFER TO OUR MOUNTS AS 'SHE' BUT ANNA MUST REFER TO HER MOUNTS AS MEN.... REFERING TO THRASHING AND NUTS ? HOPE THATS OK TO MENTION

Hopefully attached is a photo of the 1959 to 1963 cylinder head usedon the99SS engines. Both the road and off-road Nomad version had this motor but with carb, ignition and other small differences.

Hello Phil, the 650 barrels are 7mm longer than the 99 and the 99ss have ak2FCmagneto. I owned one back in the 70s and raced it too- I thrashed the nuts off it, but it just came back for more - what a bike! I wish I had NOT SOLD ITwhat aFOOL I was! Yours Anna J dixon

Hello well I like my men like a Norton beefy and plenty of vibes!