OEM short open exhaust for sale

TonyA said:

Hello , I just saw the 2in. Head pipes ! That’s huge , I wonder how it affects the power band ? Looks like one piece header and muffler , very interesting.

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Spotted that as well Tony; that’s 6-7mm greater in dia than the OEM downpipes. No idea how that might affect running.

That said, they look well made and are bespoke so no doubt the manufacturer will be able to mirror standard header dimensions.

I’m going to make contact and find out whether Alldens is interested in developing a set for the Commando. I’ll keep the forum updated.

Stephen_Spencer said:

Spotted that as well Tony; that’s 6-7mm greater in dia than the OEM downpipes. No idea how that might affect running.

That said, they look well made and are bespoke so no doubt the manufacturer will be able to mirror standard header dimensions.

I’m going to make contact and find out whether Alldens is interested in developing a set for the Commando. I’ll keep the forum updated.

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Thanks for doing that. I received a response from Alldens on Facebook and was told when they get a Commando 961 in house it will be done and he will make jigs for production. I am interested in the 2in. Diameter pipes with hangers that fit the Commando mounts. I measured the OEM head pipes on my 961 and they are 1.75in. Diameter already.

TonyA said:

Hello , I just saw the 2in. Head pipes ! That’s huge , I wonder how it affects the power band ? Looks like one piece header and muffler , very interesting.

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2" ID pipes with no internal baffles will definitely produce less back pressure than the standard 1.75" pipes. This will effect the EFI tune on a Domi. It may result in just a small drop in low rpm torque/power. Of course the Domi EFI module may be able to adapt. I'm sure the effect will be even more pronounced on a Commando. The Commando is a bit of a different animal since it has a cross-over connection between the two exhaust pipes.
It will be interesting what results after the switch.

TonyA said:

Thanks for doing that. I received a response from Alldens on Facebook and was told when they get a Commando 961 in house it will be done and he will make jigs for production. I am interested in the 2in. Diameter pipes with hangers that fit the Commando mounts. I measured the OEM head pipes on my 961 and they are 1.75in. Diameter already.

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That’s good news Tony; looks like it’s already in hand. I’ll contact them as well so they can see there is some wider interest.

May be a safer option to request that the header pipes mirror the dimensions of the OEM pipes - they’re bespoke so I guess he can do that easily enough. Why risk introducing the potential problems BT mentions. They may also need to take account of the differences in rear hanger sub frame - single/duel seat

The open pipes will be popular with some, but way too extreme for the majority I reckon. They’ll sell more if they include a removable baffle. Not sure how to describe the finish on the original pic - brushed? They could be a polished option easily enough - additional cost of course.

A bigger primary pipe diameter on the 961 is going to make it feel weaker than it already does.
Even a 1.75” primary is too much.
I never measured the I.D. of either the Domi and Comm header pipe, but a 2 into 1 would make the bike feel more responsive low in the rpm range.

The only effect I feel between my commando and domi are noise. Any performance differences are probably just placebo effects.

NorTriDuc said:

A bigger primary pipe diameter on the 961 is going to make it feel weaker than it already does.
Even a 1.75” primary is too much.
I never measured the I.D. of either the Domi and Comm header pipe, but a 2 into 1 would make the bike feel more responsive low in the rpm range.

The only effect I feel between my commando and domi are noise. Any performance differences are probably just placebo effects.

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I would order mine with baffles . I wonder if he would make a 2 into 1 for us ?
Finally an interesting topic for us to talk about. !

TonyA said:

I would order mine with baffles . I wonder if he would make a 2 into 1 for us ?
Finally an interesting topic for us to talk about. !

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Or, how about one of these?

TonyA said:

I would order mine with baffles . I wonder if he would make a 2 into 1 for us ?
Finally an interesting topic for us to talk about. !

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Did you ever get the chance to have the stock head flow tested or ported?

BritTwit said:

Or, how about one of these?

View attachment 124628

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Who are those from?

NorTriDuc said:

Who are those from?

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Unknown.
A vintage racer - John Snead on this site, knew another racer who liked his 961 and proposed the system.
But it went no where. Only one was made for John.
Petty really.

NorTriDuc said:

Did you ever get the chance to have the stock head flow tested or ported?

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No flow testing. I did make some measurements of the port diameters. The MCT head has larger ports at the valve seat and the bowl. I will try this head without any other changes. I have also ordered a set of 90mm bore pistons through JS Motorsport . I sent him my stock pistons to work from .