OEM short open exhaust for sale

[Stephen_Spencer]

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.

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.

 

[TonyA]

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.

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.

 

[BritTwit]

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.

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.

 

[Stephen_Spencer]

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.

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.

 

[NorTriDuc]

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.

 

[TonyA]

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.

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. !

 

[BritTwit]

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. !

Or, how about one of these?

 

[NorTriDuc]

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. !

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

 

[NorTriDuc]

Or, how about one of these?

View attachment 124628

Who are those from?

 

[BritTwit]

Who are those from?

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.

 

[TonyA]

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

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 .

 

[BritTwit]

Petty really.

Should have been Pity not Petty, oh well.
Was a beautiful design and I would love to get a set made.
I tried a few places, even guys that do custom Harley pipes, but couldn't get anyone to build a set for me.

 

[TonyA]

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.

Do you mind measuring the OD of the pipes ? I would like to know how the Primary pipes compare between the Commando and the Domi 961 mega exhaust. Thanks in advance.

 

[TonyA]

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

This is what I have found so far. Comparisons between the 2015 961 head and the 2010 and earlier MCT 961 head :

Measurements were carefully taken :

It shouldn't be difficult to see this but valve head shrouding is much worse on the newer 2015 head :

This is what RWHP (73.44) my 961 had in July 2024 . I will be going back to this same shop when I complete this work .

Just because I don't post doesn't mean I'm not doing anything .

I suspect it was the MCT head that broke the Bonneville salt flats speed record.

 

[TonyA]

This is what I have found so far. Comparisons between the 2015 961 head and the 2010 and earlier MCT 961 head :

Measurements were carefully taken :

It shouldn't be difficult to see this but valve head shrouding is much worse on the newer 2015 head :

This is what RWHP (73.44) my 961 had in July 2024 . I will be going back to this same shop when I complete this work .

Just because I don't post doesn't mean I'm not doing anything .

I suspect it was the MCT head that broke the Bonneville salt flats speed record.

With the amount of speedometer error these instruments have you would have to see 140mph on your speedo to be anywhere near that .

 

[NorTriDuc]

Do you mind measuring the OD of the pipes ? I would like to know how the Primary pipes compare between the Commando and the Domi 961 mega exhaust. Thanks in advance.

I measured both my commando and domi. Both are 1.75” O.D. at the header