Stewart Developments England- 2/1 manifold

Hi Steven,

Are you following me ??

I have just found one of these things as well, and questioned the same point. Unless you have a one piece gasket it won't seal, and the two flanges that we use on the Commando will fall down, only one screw in each! So I feel that it can't possibly seal nicely with only two screws. You may have to machine the inside face flat first before boring it. You first, let me know how you get on.

Cheers

I Have drilled the extra holes in the centre of the manifold as the carb and filter present quite a downward force when fitted and the two outer screws will be working quite hard to support the weight. You will probably need to use a ball ended allen key to tighten the socket screws. Use a small dab of loctite for peace of mind but don't worry too much about dropping them as they won't get too far down the inlet tract. If you use the original screws you can recover them with one of those telescopic magnets. If you go for stainless steel this tends not to be magnetic (or not as much) and as such a little more difficult to recover.

Dave Evans

Previously wrote:

Previously wrote:

Hi Steven,

Are you following me ??

I have just found one of these things as well, and questioned the same point. Unless you have a one peice gasket it wont seal, and the two flnges that we use on the Commando will fall down, only one screw in each ! So i feel that it cant possibly seal nicely with only two screws. You may have to machine the inside face flat first before boring it. You first, let me know how you get on.

Cheers

Hans,

Have been discussing this with John Dunn who also has one on his bike. he suggested and i followedhis advice on maching the manifold flat. this was accomplished with valve lapping compound on a flat plate of glass. it was off, arched in the middle. as i understand it he used two of the regular gaskets stuck to one side with instant gasket or possibly found a single gasket for an atlas from one of your favorite stockists. My 62 Atlas has an Amal 2/1 manifold and i just reused that gasket with some gasket stuff. drilling extra holes is up to you, i dont think its necessary if you fit it carefully. If you do drill it be carefull not to drop the screws into the engine whilst fitting it. you'd be turning the bike upside down eh? LOL.

John said he drilled his manifold, your call...

I dont know of any reason why the one piece gasket would be better, just easier to fit.

havent heard many on thetopic yet, maybe others will join in???

I have the same 2-1 manifold and made a gasket out of some thickish gasket material that I had in the workshop, it's held on with just the 2 screws with no problems.

Previously wrote:

Previously wrote:

Previously wrote:

Hi Steven,

Are you following me ??

I have just found one of these things as well, and questioned the same point. Unless you have a one peice gasket it wont seal, and the two flnges that we use on the Commando will fall down, only one screw in each ! So i feel that it cant possibly seal nicely with only two screws. You may have to machine the inside face flat first before boring it. You first, let me know how you get on.

Cheers

Hans,

Have been discussing this with John Dunn who also has one on his bike. he suggested and i followedhis advice on maching the manifold flat. this was accomplished with valve lapping compound on a flat plate of glass. it was off, arched in the middle. as i understand it he used two of the regular gaskets stuck to one side with instant gasket or possibly found a single gasket for an atlas from one of your favorite stockists. My 62 Atlas has an Amal 2/1 manifold and i just reused that gasket with some gasket stuff. drilling extra holes is up to you, i dont think its necessary if you fit it carefully. If you do drill it be carefull not to drop the screws into the engine whilst fitting it. you'd be turning the bike upside down eh? LOL.

John said he drilled his manifold, your call...

I dont know of any reason why the one piece gasket would be better, just easier to fit.

havent heard many on thetopic yet, maybe others will join in???

I have the same 2-1 manifold and made a gasket out of some thickish gasket material that I had in the workshop, it's held on with just the 2 screws with no problems.

I also use this setup with an RGM manifold on my 750, just 2 screws and no problems plus no risk of dropping screws into the motor,,,,,,,,baz

I have used one with just the two screws without problems. However, it niggled me as imperfect engineering (but aren't Nortons all imperfect engineering?) and I eventually got hold of a 650 one with 4 mounting holes which I subsequently fitted and is still on the bike. My Stewart Developments manifold is now lurking somewhere on a shelf.

i used a su carb on my commando with only 2 fixing holes for 15years.no problems/// made a slightly thicker gasket and checked both surfaces were flat.i bolted it on using allen head set screws making sure all the threads in the head were used.

Previously wrote:

Just got hold of a 2/1 manifold for my Commando. set up for a singleAmal. It only has two mounting holes, I've one on my 650 (an Amal)that has twoadditional holesinside the manifold. Has anyone run a 2/1 with only bolt holes on the outer flange? can't decide if I should drill two more holes to get the best air seal or if it will work as is.

Well I've just bought one of these and as yet not fitted the bloody thing, some say they are ok with two outer bolts some say not, and seeing as my motor runs well on twin carbs, I think I will leave her as she was meant to be! As I see it in my many years of using amal carbs is as long as they are not worn out then they should and will work OK.