Place your bets again...

Right then ladies,

I now have a set of balanced MK3 down pipes to test on the Dyno (thanks Sam) and a wonderful looking Maney system (thanks Chris) and my own unbalanced pipes.

The two stock Norton systems will be tried with stock peashooters.

The Maney system will be tried as is.

Any bets on what the differences will be on the Dyno??

Fast Eddie said:

........Any bets on what the differences will be on the Dyno??

Click to expand...

Damn Eddie I really don't have clue this time, except to say that My money would be on the Maney set up. I do have one question though, are they all 1 & 3/8ths?

If the Maney headers protrude into a chamber rather than match a perforated tube then my money is on the Maney (assumes no other settings are altered).
Ta.

Right-O welding exhaust is my kind of crudeness - so I vote the factory pipes will give best kick off to upper mid range with torque then the Maney system will take off with maybe 5-7 hp boost. Maney turns his to intended 7200 + as you know racers and rules and a decade ago made 100.7 hp he said. I used to pay $250 a pull on a V8 size dyno so what this cost you so we can appreciate your efforts for us more. I'd sure like to $end Peel 1.5" orappy looking 2>1> Dunstall longdong hollar megaphone for comparision as that was was what pissed me off I could not stay in seat in lower gears then pleased me other cycles had to back off d/t wheelies aiming for same turn bottle neck. Would be funner if you could barrow a sound level meter too.

If you can see all the way through stock peashooters, I'd bet that there's not a big difference as long as the test motor is stock, not jetted or leaned on in any way. A non-resrictive or less-restrictive exhaust will make a couple more bhp than a restrictive or more-restrictive one. Once you star making other mods (jetting, cams, valves, more compression) the effect of losing the restriction will be increased. Overall length and volume will affect at what rpm best power is produced.

The system that will make the most power will be the system that is best matched to the specs of the engine. Jim

Quite right Jim, to make the betting fairer I should state that the ginea pig is an 850 with 10.5:1 CR, JS 1 cam, 35mm FCRs, RH10 head.

My bet: Most power, Maney system. 2nd balanced stock 3rd individual stock 2nd and 3rd may be close to even once the heat from the balance pipe begins to wash back between the exhaust ports and block cooling air.

The thing I have noticed on outboard 2 smokes to 4 cycles is often the experiments are distinctly worst than stock till dialed up/dn by this and that on whims or insights to suddenly WTFUP or give up on that basic idea to start over.
The other thing I noticed was the higher performance engines react more dramatically to poor or good exhaust than lesser engines. So if one system arrangement really disappoints take it as hay mixed with pony poopoo > being evidenc of some real horses just waiting to be let loose.

I don't know which one will be better, but I am interested in the numbers.
Although the comparison is relative, I have a 750, JS1, single TM40, Big Bore exhaust and an assumed CR of 10 to 1.
Eddie, when will your report be returned?

OK, unless you have some big valves stuck in there I would say the 1 3/8th headpipe system will make more power up to over 6000 rpm where the larger pipes of the Maney system will take over. That is if the 1-3/8 inch system has straight through mufflers. Jim

If you mean a Maney system similar to the one in this video. I suggest it will rev out well even beyond 7000 RPM. However best torque will be around 6500. My feeling is the pipe diameter is too large. The two separate pipes will probably give more top end regardless of pipe diameter, however the power band will be harsher. The cam timing should probably be advanced for the Maney system, and the bike geared upwards a bit for the extra torque. You've said you are using 35mm carbs, however you haven't said the port diameter. If you've gone above 30mm, your motor becomes more top end and the pipe needs to suit it.

https://www.youtube.com/watch?v=S509LGFabCw

pete.v said:

I don't know which one will be better, but I am interested in the numbers.
Although the comparison is relative, I have a 750, JS1, single TM40, Big Bore exhaust and an assumed CR of 10 to 1.
Eddie, when will your report be returned?

Click to expand...

Pete would you please clarify something. When we talked about your bike (or one of your bikes) in late February 2015 at the link below, Eddie stated he had a JS1 and you offered that your ride had a JS2 that was installed in an advanced position. In earlier posts I believe you've referenced a JS1 in your bike. So possibly you've got multiple bikes, multiple cams or a memory as bad as mine. Please clarify. Thank you.

http://www.accessnorton.com/radiused-cam-raced-years-bean-oil-t21574.html?hilit=pete.v js2#p282166

WZ507 said:

pete.v said:

I don't know which one will be better, but I am interested in the numbers.
Although the comparison is relative, I have a 750, JS1, single TM40, Big Bore exhaust and an assumed CR of 10 to 1.
Eddie, when will your report be returned?

Click to expand...

Pete would you please clarify something. When we talked about your bike (or one of your bikes) in late February 2015 at the link below, Eddie stated he had a JS1 and you offered that your ride had a JS2 that was installed in an advanced position. In earlier posts I believe you've referenced a JS1 in your bike. So possibly you've got multiple bikes, multiple cams or a memory as bad as mine. Please clarify. Thank you.

http://www.accessnorton.com/radiused-cam-raced-years-bean-oil-t21574.html?hilit=pete.v js2#p282166

Click to expand...

Sorry, WZ507, that was surely a typo back then. I have the one bike with the JS1.
Anyhow and for what it is worth, it is my opinion that after owning a running the JS1, I know the JS2 would be too much for the street.....for sure!

pete.v said:

WZ507 said:

pete.v said:

I don't know which one will be better, but I am interested in the numbers.
Although the comparison is relative, I have a 750, JS1, single TM40, Big Bore exhaust and an assumed CR of 10 to 1.
Eddie, when will your report be returned?

Click to expand...

Pete would you please clarify something. When we talked about your bike (or one of your bikes) in late February 2015 at the link below, Eddie stated he had a JS1 and you offered that your ride had a JS2 that was installed in an advanced position. In earlier posts I believe you've referenced a JS1 in your bike. So possibly you've got multiple bikes, multiple cams or a memory as bad as mine. Please clarify. Thank you.

http://www.accessnorton.com/radiused-cam-raced-years-bean-oil-t21574.html?hilit=pete.v js2#p282166

Click to expand...

Sorry, WZ507, that was surely a typo back then. I have the one bike with the JS1.
Anyhow and for what it is worth, it is my opinion that after owning a running the JS1, I know the JS2 would be too much for the street.....for sure!

Click to expand...

Can't argue there Pete. JS states the JS1 as being "hot street and all around racing for 4 or 5 speeds with strong mid range".

When I dyno'd mine last time it had a perfect linear power curve from 3000 to 6200, at which point it simply levelled out until 7000. So, in other words, JS claim for the JS1 is bang on. I would still actually like to know what the JS 2 would Dyno like, but its probably not something I'm gonna try considering the work involved in doing so.

Pete, in answer to your earlier question about my intake ports, my head is a stock RH10 so I have 30mm ports.
When I look at the Dyno graph, it really looks to me that the head is a bottleneck at 6200. I wanted to address this last winter but did not have the time to do so. Hopefully I'll be able to do so next winter, then I just have to decide between a Comstock head job or a Fullauto (I keep changing my mind on that one as Jim knows too well)!

So, until then, I just intend to play round with exhausts, velocity stacks, and settings. All in the interest of 'adding to the body of knowledge" of course...

pete.v said

Eddie, when will your report be returned?

Click to expand...

So when are you going on the dyno Eddie? I'm really looking forward to hearing the results.

Would the Maney system suit your engine with the 30mm intakes? Probably. I think that the Maney exhaust will still give you the highest bhp, followed by the balanced and then the none-balanced, not sure about torque?

Not wishing to deviate much, but as I've said before, my 2-1-2 gave a noticeable increase at the higher end of the revs, so logically as the Maney is designed to extract/assist making power this should "win," although I appreciate what comnoz has said

The system that will make the most power will be the system that is best matched to the specs of the engine. Jim

Click to expand...

It's a pity that you don't live nearer to me as you could've whacked my "Dunstalesque" pipes on........unless your passing Leeds before the test. I could always post them to you I suppose, but they do take a bit of fitting. How much time do you have on the dyno?

Reggie said:

pete.v said

Eddie, when will your report be returned?

Click to expand...

So when are you going on the dyno Eddie? I'm really looking forward to hearing the results.

Would the Maney system suit your engine with the 30mm intakes? Probably. I think that the Maney exhaust will still give you the highest bhp, followed by the balanced and then the none-balanced, not sure about torque?

Not wishing to deviate much, but as I've said before, my 2-1-2 gave a noticeable increase at the higher end of the revs, so logically as the Maney is designed to extract/assist making power this should "win," although I appreciate what comnoz has said

The system that will make the most power will be the system that is best matched to the specs of the engine. Jim

Click to expand...

It's a pity that you don't live nearer to me as you could've whacked my "Dunstalesque" pipes on........unless your passing Leeds before the test. I could always post them to you I suppose, but they do take a bit of fitting. How much time do you have on the dyno?

Click to expand...

Short answer to 'when?' Is hopefully within the next 2-3 weeks. I am still very busy with work, and the Dyno's 'calendar' also gets booked up, but I hope to find a 'slot' soon.

I reckon I'll be on the Dyno for half a day or so.

No plans to pass by Leeds I'm afraid, but thanks for the offer. You could always come down here... Make it a full day on the Dyno playing with yours as well!!

Fast Eddie said:

Pete, in answer to your earlier question about my intake ports, my head is a stock RH10 so I have 30mm ports.
When I look at the Dyno graph, it really looks to me that the head is a bottleneck at 6200. I wanted to address this last winter but did not have the time to do so. Hopefully I'll be able to do so next winter, then I just have to decide between a Comstock head job or a Fullauto (I keep changing my mind on that one as Jim knows too well)!

So, until then, I just intend to play round with exhausts, velocity stacks, and settings. All in the interest of 'adding to the body of knowledge" of course...

Click to expand...

That is interesting because I have the RH1. All that has been done is .040 off the face, some intake manifold matching and of course comnoz doing the guides.

pete.v said:

Fast Eddie said:

Pete, in answer to your earlier question about my intake ports, my head is a stock RH10 so I have 30mm ports.
When I look at the Dyno graph, it really looks to me that the head is a bottleneck at 6200. I wanted to address this last winter but did not have the time to do so. Hopefully I'll be able to do so next winter, then I just have to decide between a Comstock head job or a Fullauto (I keep changing my mind on that one as Jim knows too well)!

So, until then, I just intend to play round with exhausts, velocity stacks, and settings. All in the interest of 'adding to the body of knowledge" of course...

Click to expand...

That is interesting because I have the RH1. All that has been done is .040 off the face, some intake manifold matching and of course comnoz doing the guides.

Click to expand...

RH1 also has 30mm ports, is that correct? If so, you've got the one to have it seems (if you read through Comnoz head flow thread that is).

I will be really interested in the effects of each setup on midrange, which for me seems to be a lower area with each passing year!
I am really starting to get addicted to the pull of the 850 from 3,000 rpm and don't much enjoy riding bikes that must be revved to make power.
So although the top HP number is the one we all tend to fixate on, the midrange is what most of us ride. Most often the things that give a big top number suck the life out of the midrange. But not always. Higher compression helps all over whereas , as we now know thanks to Comnoz, big ports tend to kill the lower and middle ranges. Having said that, my 850 is a MK3 with the 32 mm ports and it seems to pull extremely well in the midrange. It has a bit of a compression bump from a thin head gasket, some open pipes and that is about it. Perhaps midrange could be even better with an RH10 30 mm head on there.
I really don't know what works on a Commando to enhance this midrange, but then, for the 850 at least, it just needs to be left intact.
Even my BMW 1200rt riding friend was impressed with the way the near stock 850 Commando effortlessly catapults out of corner without the need for screaming revs.

Nigel pointed out that with the stock 850 engine the squish band is too wide to be of help. The skinny head gasket on my bike seemed to really wake it up, far more than the half point compression gain should have accounted for. Perhaps the difference was due to moving from a non functioning squish to one the is close enough to add some zip. I confess that I did not measure it last time the head was off. The main goal there was to finally get an oiltight, compression tight installation. Perhaps the wake up was due to simply getting a properly sealed head, finally!

I have read that the squish band , when set in the working range, adds mostly to the midrange and does very little if anything at the top. Some racers even machine existing squish bands away to get a more revvy engine, though they might be misguided.
The squish band for Nortons came from sometimes janitor Leo Kuzmicki of later Hillman Imp fame, and first was tried, with great success, on the racing Norton Manx. The Manx has good top end but is also an allover engine that can really accelerate out of a corner.
Many have copied that Manx Squish combustion chamber, including Reg Orpin with his Orpin Velos, one of which won the 1967 Production TT.

Glen