Silencers for the Heavy Twins

Previously steve_marshall wrote:

Just reading this thread today when I got back my re chromed 99SS silencer after 4 months away at the re-chrome. I was given this silencer, along with small bore Siamese pipes and the original 99SS engine with my Com-Dom in 1979, so I think it is the original 1961 99SS item. it is exactly 25 inches long, and has a long welded and ground seam along the underside (see photo) . Internally there is a disk at the outlet end with a small central hole through which you can see all the way along the silencer. Remains to be seen how crisp (or not) the exhaust is in action.

Vic Willoughby's 'The Motor Cycle' 1961 road test attributes most of the extra performance of the SS to the Siamese pipes and silencer, and you have to agree that it is strange that if the Siamese setup is so much more powerful (and you would think cheaper to produce) it was only offered as no-cost option. I don't have my parts book with me, but I think it is a different part from the RH standard Dommi part. In the first edition he says that this Siamese setup is the only reason the 99SS has the same maximum power as the Manxman but retains more useful torque lower down the rev range.

You can only imagine what a Manxman with a Siamese exhaust might have gone like, Norton probably suppressed it on public safety grounds.

Steve

well how do you make out the (99SS) as the same power as a 650 Norton Manxman when the (99ss) had 43bhp , and the Norton Manxman has 52bhp I think there a big difference in the power out put, don't you, and it was only some of the 99SS had 2 in to 1 pipes this was just a marketing trick.

Hmmm ComDom: sounds like a safe bike........

My 650ss with a knocking motor and 99 head, yet produces fantastic performance with a single carb but alsothe 2-1 system. Maybe there is something in it. Will be some machine (64 bottom end) if I ever get to fix it,

Talking of pipes for the record: Armours tell me they have Dommie down pipes in Stainless but only Chrome silencers.

On closing, I understand that someone put a Morini V twin engine in a Norton frame. Guess what they called it?

well there the ones that started all this silencer and exhaust pipe mess in the first place, with making the Wrong type of silencer and exhaust pipes the bends are wrong on the exhaust pipes and the silencer have big seam on the under side , wear the original did not have a seam there were welded seam , and the cone end is not right as well , and the baffles are not the right type so you get poor performance, this all to do with back pressure in the exhaust system, this over time leads to poor carburation and unburnt fuel and sooty exhausts and carbon build up on your valves and pistons , too get the right carburation take off the exhaust and run the bike with out them on , and you then see the colour of the flame patents , get the right colour of flame a nice mid blue , then your going places , this is how broad tack racers tuned there bikes in the mid 1920s this just like your car if you put a poor exhaust on it it will not perform its just like sticking a potato up the tail pipe, yours anna j

Previously steve_marshall wrote:

Isn't the Gunsons Colortune plug the way forward to observe the flame colour running the engine with with yer actual silencer fitted? Available at £27.10 from all good eBays.

Anna - I have to say I was a little disappointed with your restrained response to my risible 99SS/Manxman power claim.

Steve

Well since I had a (99SS) and Now a Norton Manxman 650 , I would know, and there both very good motorcycles in there own way, and at lest they both have the legendary featherbed slimline frame and you cannot argue with that, can you, happy Christmas

A Jap carb? No street cred there...........

British carbs for British bikes.

well how about senspray carburettors or Gardner carburettors or wal-phillips or almac are these any good for you,

Armours made me up some chrome small bore siamese pipes about 6 months ago, and they look really good. I had to provide the exhaust ring to them in advance for the RH pot, as it is captive.

Was it a Morton or a Norini?

Armours have made Nothing They use other suppliers or exhaust makers to make up something special. they have no tooling, these are the real facts . and most of there exhausts are copies of some else after market copy . most Triumph and BSA exhaust are easy to get . as a most AJS and Matchless /and Commando but when it comes to dominator they failed there is NO Folded seam on bottom of the Original dominator silencers from 1956 to 1970 but there is a welded seam running down the length of the bottom . them chromed over

You see in photo 681 the silencer on the right its the original one and the one on the left is a after market one with a folded seam on the bottom , note the original one is a welded seam and have a more rounded cone end . yours anna J

The parts book says

22790 Silencer L or R 88, 99 Std and D/L

23767 Silencer RH 650 Std and D/L

The SUPPLEMENTARY LIST for 1961/62 Models 88ss, 99ss and 650ss says:

23767 Silencer, R.H. (for exhaust pipe 24021) 1962 88ss and 650ss

and 23767 Silencer (for Siamese Pipes 23830/1) 1961 88ss; 61/62 99ss.

So it looks like all 650's and all SS's (88,99,650) had the same RH silencer, with or without the siamese pipes. Norton only made two options.

Well your parts book will not say is parts numbers 23174 RH and 23437LH these are the Manxman silencers very special made just for the Norton manxman only. and there very hard to get your hand on them. no one has ever made any for the after market . there is only the originals hand made by bracebridge street craftsmen .

AS you see in this picture 273 the original silencer for the right hand side that just come from Quality chrome in Kingston upon Hull after re-chroming at a cost of £160 there work is very good with a very thick lair of chrome on its silencer they remove all the old chrome first and them polish it up for the nickel bath its first nickel plated for 2 hours in that bath then it gone back to the polisher for the next stage then on the the chroming bath were it spends 3 hours in there to get a real nice thick lair of nickel chrome on then back to the polisher for the final polish a lot of work for one silencer thats what you pays your money for good quality work and long lasting too. there top men in there trade . I have seen them do this work as spent time with them doing this type of quality workmanship , and quality chrome as never lost even a washer or nut. or screw and there the only ones in this area that can do real Gold plating using real gold in there process. yes someone as had there Lambrettor parts Gold plated and engraved the art work is just out of this world. just take a look on there web site. well were going of topic yet again . but its in my story on chroming a silencer. these silencer are from Sweden from a good Friend how i will always be indeted to him. he has his own norton museum.