Inlet upgrade?

Al's#5 said:
Really am tempted to continue with the LET IT BREATH mods by adding another intake to the airbox and removing the cat but, just back from a spin and it's running great. Shortened exhaust now burbles on coming down the box and it's pulling fine right through the rev range, as high as I need it anyway. Pondering the airbox, it has a 62mm opening which should be adequate, restricted under the seat yes but plenty of gaps enough to cope, at least for my requirements.
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Will be booking a Dyno run with the new setup so wait and see what that brings forth. I have put the original separator back in place but am contemplating an easy way to make a more effective one something like an inline filter with inverted cones inside to persuade the oil to return. Without factory separator my catch tank had something like 100ml of grey emulsion after 100miles! I had just done oil change so it might have been disposing of a bit of oil it didn't want. Still thinking about that grey emulsion going back into the engine......
Inlet upgrade?
 
Fast Eddie said:
Venting the crankcase to the rocker box and then venting the rockerbox to atmosphere surely has to be the sensible plumbing option on these motors?

Doing that is effectively using the rocker box as an oil separator.

I can’t imagine there’s that much oil thrashing around in the rocker box to allow much oil egress via the breather pipe ?
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That was the way all the bikes came out first. (I know you know that) They used the rocker box banjos and then to the airbox . There STILL was oil getting to the air box. My bike was worse with the original way using rocker box/banjos. The real problem is the excessive clearance piston to cylinder creating all the extra pressure. There were so many issues its hard to keep track :
wet sumping , too much oil pump leakage back to sump (mine did this) , weak scavenge (got a new oil pump worth every penny) , oil tank over filling , and lastly piston/cylinder/rings clearance . My bike as sent to me as new would have put 200~300 ml of oil into the airbox in 350 miles of riding (75 mph) and many 961 did this . Now it deposits 13~20 ml in 350 miles (75 mph). And I still have the original pistons/cylinder only a re-ringing at 6300 miles . I know you know this FE , but there are 961's out there that get virtually NO oil in the air box . Norton needed to reject all of the out of spec pistons/cylinders , but whoever built the engines didn't and passed them through.
 
Clive said:
Will be booking a Dyno run with the new setup so wait and see what that brings forth. I have put the original separator back in place but am contemplating an easy way to make a more effective one something like an inline filter with inverted cones inside to persuade the oil to return. Without factory separator my catch tank had something like 100ml of grey emulsion after 100miles! I had just done oil change so it might have been disposing of a bit of oil it didn't want. Still thinking about that grey emulsion going back into the engine......
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The original separator has a baffle in it too, you can't see through end to end . How will you tune the engine ? Just going to see what the changes bring you ? You can put on a Dyno Jet Power Commander and tune that way , Its not too much money and easy to do. I am still waiting for my dyno time , if you can believe !
 
Classic Moto Morini 3½ & 500's have what is called a "Labyrinth" in the crankcase breather hose (which is larger that the 961), but it would be pretty easy to replicate. The Morini Riders Club recently got some 3D printed. As you can see each disc has an opposing flat to the next..

Inlet upgrade?


I'm not sure it would help on the Norton though. By restricting the airflow it may make matters worse.
 
TonyA said:
That was the way all the bikes came out first. (I know you know that) They used the rocker box banjos and then to the airbox . There STILL was oil getting to the air box. My bike was worse with the original way using rocker box/banjos. The real problem is the excessive clearance piston to cylinder creating all the extra pressure. There were so many issues its hard to keep track :
wet sumping , too much oil pump leakage back to sump (mine did this) , weak scavenge (got a new oil pump worth every penny) , oil tank over filling , and lastly piston/cylinder/rings clearance . My bike as sent to me as new would have put 200~300 ml of oil into the airbox in 350 miles of riding (75 mph) and many 961 did this . Now it deposits 13~20 ml in 350 miles (75 mph). And I still have the original pistons/cylinder only a re-ringing at 6300 miles . I know you know this FE , but there are 961's out there that get virtually NO oil in the air box . Norton needed to reject all of the out of spec pistons/cylinders , but whoever built the engines didn't and passed them through.
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After 350 miles (not real bad) :


https://www.accessnorton.com/proxy.php?image=https%3A%2F%2Fi.vgy.me%2FBzwhNN.jpg&hash=a20a8b87123e43bef81b792e17111ff6
 
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Nice one Tony, pretty much what mine looks like. Mostly just water vapour as you would expect. I was actually surprised when I rerouted the breather system back to the factory original that it worked (as in using the rocker cover banjo's). I think they just changed so many things that they never thought to go back and see if the original breathing layout was actually ok once the real cause of the problems had been identified.
 
iwilson said:
I think they just changed so many things that they never thought to go back and see if the original breathing layout was actually ok once the real cause of the problems had been identified.
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I think you hit the nail on the head there. Big time.

Not a phenomenon limited to Norton either, I see it all the time in numerous companies, it leads to confusion and a profound lack of understanding of the functionality of the systems concerned. So when the one person who does understand it leaves... problem solving becomes little more scientific than that ‘pin a tail on a donkey whilst blindfolded’ game that kids play !!
 
Mines back to standard. Got rid of that ugly oil air separator. Reinstalled the banjo bolts in the rocker box. Running like a dream. Nearly up to 20,000 km.
 
Okay so here is the dyno run with my new slightly larger injectors and K&N (other intake filters are available) filters. The bum dyno seemed to give me more of an an urge opening the throttle mid-range and it seems to pick up better at the top end which is kinda explained by the increased midrange torque and the top-end gains. It is still leaning off at the top end so I may look at the next size injectors up.

The second 25% throttle setting run shows on the a/f graph very nicely how the ECU goes from closed loop to open loop.

The intake noise is quite loud and I think I would struggle to get it through at my local track. As you normally do not get to hear the true sound of a 961 on open pipes while riding a dyno run is worth it just to hear that gorgeous howl!

The dyno centre can program Power Commanders and said they would look into this and were confident they could smooth out the power/torque curve, but they knew someone with a Domi who had got a richer map from the factory which really improved things. So altogether some progress but more to go....

Inlet upgrade?


Inlet upgrade?
 
Interesting...so where is the switch from closed to open loop? Would a power commander help with top end lean-age....lol! Vs a bigger injector which I would assume would give you an across the board increase...so it could sort out the top end, but you’ll be running too rich lower down....
 
Vernon240 said:
Interesting...so where is the switch from closed to open loop? Would a power commander help with top end lean-age....lol! Vs a bigger injector which I would assume would give you an across the board increase...so it could sort out the top end, but you’ll be running too rich lower down....
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If you look on the lower line of the second graph which is the air/fuel ratio there is a step around 5300 rpm. This is where the ECU stops looking at the lambda sensors and just squirts the juice in based on the the other sensors but does not check what's coming out the exhaust. If you look at the lean peak around 2500 rpm they said this is where the Euro emissions test looks. Ahem.

I didn't check the new injectors with the standard airbox which I intended to do but I suspect I could probably go for some slightly bigger ones. I was thinking that at tickover the Lambda based closed loop running should adjust for the bigger injectors itself? They said that with a power commander they would disconnect the Lambda sensors but I'd need to talk to them more about this. There is still this fabled richer map available from the factory which would be the ideal solution and if we're looking at a Power Commander install and setup I wonder if the money is better spent on an SCS ecu....
 
Clive, mine was set up by the factory for open shorties and de cat. So I imagine this must have been a fairly rich map. Nevertheless, after track sessions the plugs clearly looked lean. So I’m guessing my AFR must have looked a lot like yours.

Your first graph is showing it lean above just over 4,000rpm. And it gets leaner. Not only I’d this throwing away power, it’s causing heat. I think your graph is really quite lean for an air cooled engine.

I’d seriously investigate the Power Commander if I were you. I don’t think that bunging in random bigger injectors is the answer matey...
 
Clive said:
If you look on the lower line of the second graph which is the air/fuel ratio there is a step around 5300 rpm. This is where the ECU stops looking at the lambda sensors and just squirts the juice in based on the the other sensors but does not check what's coming out the exhaust. If you look at the lean peak around 2500 rpm they said this is where the Euro emissions test looks. Ahem.

I didn't check the new injectors with the standard airbox which I intended to do but I suspect I could probably go for some slightly bigger ones. I was thinking that at tickover the Lambda based closed loop running should adjust for the bigger injectors itself? They said that with a power commander they would disconnect the Lambda sensors but I'd need to talk to them more about this. There is still this fabled richer map available from the factory which would be the ideal solution and if we're looking at a Power Commander install and setup I wonder if the money is better spent on an SCS ecu....
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I saw that, but that looks far too high. I'm not saying it's wrong, but that is pretty (very) high in the rev range to still be on closed loop and not 'on the map'...but that was 25% throttle, so that could be the explanation? As you say, a definite step though! the lean condition 2500 rpm is noticeable on the first chart though!

Yep, the closed loop situation 'should' take care of low revs/throttle openings...but that graph with the step so high up has kinda made me think 'when does closed loop kick in?' Under those conditions, you would think that it would cover a lot of riding, speed wise, but if it's also based on throttle position as well (which I highly suspect..or input from a MAP sensor that also would indicate load...not sure if yours has that) it may be the ratio of closed loop vs open loop/map operation could significantly change in 'real world' riding conditions, especially on the track with wider throttle openings. Also, I'm not saying this will happen, but I used huge injectors in a V8 I built..they were so big (flow wise) that I could not get them to a level where I could get the mixture anywhere near reasonable. I had control over injector duration and even on a the minimum, I was way too rich...had to buy new injectors, as the ones recommended were essentially programmable buckets!

Still frustrating no one can have a peek at the mapping and alter with your current ECU. I would (and have) gone with the SCS ECU. I know it's a significant expense, but if your local company are happy to map with the SCS, I'd be tempted. You could also think about wide band sensors....start doing some data logging....tweak things yourself! You know you want to! I'm always weary of the lessons I've learnt...trying to do things economically, finding that they are just a little too compromised and finally biting the bullet and doing it the way I knew in my heart of hearts, should have be done...would have been cheaper in the long run as well.
 
Yes it's most prominent on the 25% throttle. I am still learning about the principles involved here and so far the changes have resulted in a better riding experience and I quite like the appearance so the cost/benefit is acceptable. I have now got another bike to prepare for the track so performance improvements should really be spent there although I'm thinking that a dabble with even bigger injectors, which can be got cheaply as good condition second hand, might be worth trying and the search for the elusive richer factory map. Heard it was last seen riding around Castle Donington on a unicorn.
 
Clive said:
Yes it's most prominent on the 25% throttle. I am still learning about the principles involved here and so far the changes have resulted in a better riding experience and I quite like the appearance so the cost/benefit is acceptable. I have now got another bike to prepare for the track so performance improvements should really be spent there although I'm thinking that a dabble with even bigger injectors, which can be got cheaply as good condition second hand, might be worth trying and the search for the elusive richer factory map. Heard it was last seen riding around Castle Donington on a unicorn.
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AKA the unicorn map!
 
Clive said:
Okay so here is the dyno run with my new slightly larger injectors and K&N (other intake filters are available) filters. The bum dyno seemed to give me more of an an urge opening the throttle mid-range and it seems to pick up better at the top end which is kinda explained by the increased midrange torque and the top-end gains. It is still leaning off at the top end so I may look at the next size injectors up.

The second 25% throttle setting run shows on the a/f graph very nicely how the ECU goes from closed loop to open loop.

The intake noise is quite loud and I think I would struggle to get it through at my local track. As you normally do not get to hear the true sound of a 961 on open pipes while riding a dyno run is worth it just to hear that gorgeous howl!

The dyno centre can program Power Commanders and said they would look into this and were confident they could smooth out the power/torque curve, but they knew someone with a Domi who had got a richer map from the factory which really improved things. So altogether some progress but more to go....

View attachment 79676

View attachment 79677
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A almost 5 HP gain at 5000 rpm ! And a solid 3 HP on top end. Really good but there is more to come , Get the power commander you will be happy ! I think your exhaust is holding back power too (Shorties will make more power) . And a big thanks for doing this and showing us your results . I will follow up asap with my efforts !
 
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