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Re: Needing Air to go really fast
...OK, here we go, we got a real pressure cooker going here
Two down, nobody on, no score, bottom of the ninth...
Some science from the 21st century...
An AMAL 32mm (1_1/4") carburettor throat was connected to a vacuum cleaner.
All body orifice that could leak air were sealed except the carburettor throat.
A gauge was fitted to the jet holder post.
The jet holder was assembled with a 260 ml/min main jet only but no needle jet or needle were fitted.
All throttle slide orifice were sealed so air could only pass beneath them through the throat.
A standard 3.5 cutaway alloy slide and a polymer 3.5 cutaway slide with fitted air flow channels were used.
The spray nozzles used were the flat top and the stepped types.
The slides were assessed to determine when the greatest Bernoulli effect was achieved for both slides using the flat top nozzles. The spray nozzles were exchanged for the stepped nozzles and the trial repeated for both slide types.
Result:
Maximum Bernoulli effect occurred with either slide type set at 6.5mm (1/4") regardless of nozzle type fitted i.e.
1. at 20% of throttle slide opening, or
2. throttle slide lip approximately level with the top of the spray nozzle, or
3. at the point of transition from cutaway to needle (parallel section) and needle jet (disclaimer: according to AMAL notes), or
4. equivalent to 13mm arc rotation of the throttle grip.
The attached photos show the measure of available vacuum, the set-up and achieved results.
The point that the Bernoulli effect began between 0 to 6.5mm for any combination of slides and nozzles could not be accurately determined due to the lack of gauge discrimination.
Conclusion:
1. The polymer slide with fitted air flow channels showed significantly increased Bernoulli effect regardless of spray nozzle type fitted.
2. The Bernoulli effect generated by the standard alloy slide was marginally increased by use of the stepped spray nozzle instead of the flat top type.
You may now quote/misquote/misrepresent/fabricate stuff based on the above for decades to come!
Ta.
...OK, here we go, we got a real pressure cooker going here
Two down, nobody on, no score, bottom of the ninth...
Some science from the 21st century...
An AMAL 32mm (1_1/4") carburettor throat was connected to a vacuum cleaner.
All body orifice that could leak air were sealed except the carburettor throat.
A gauge was fitted to the jet holder post.
The jet holder was assembled with a 260 ml/min main jet only but no needle jet or needle were fitted.
All throttle slide orifice were sealed so air could only pass beneath them through the throat.
A standard 3.5 cutaway alloy slide and a polymer 3.5 cutaway slide with fitted air flow channels were used.
The spray nozzles used were the flat top and the stepped types.
The slides were assessed to determine when the greatest Bernoulli effect was achieved for both slides using the flat top nozzles. The spray nozzles were exchanged for the stepped nozzles and the trial repeated for both slide types.
Result:
Maximum Bernoulli effect occurred with either slide type set at 6.5mm (1/4") regardless of nozzle type fitted i.e.
1. at 20% of throttle slide opening, or
2. throttle slide lip approximately level with the top of the spray nozzle, or
3. at the point of transition from cutaway to needle (parallel section) and needle jet (disclaimer: according to AMAL notes), or
4. equivalent to 13mm arc rotation of the throttle grip.
The attached photos show the measure of available vacuum, the set-up and achieved results.
The point that the Bernoulli effect began between 0 to 6.5mm for any combination of slides and nozzles could not be accurately determined due to the lack of gauge discrimination.
Conclusion:
1. The polymer slide with fitted air flow channels showed significantly increased Bernoulli effect regardless of spray nozzle type fitted.
2. The Bernoulli effect generated by the standard alloy slide was marginally increased by use of the stepped spray nozzle instead of the flat top type.
You may now quote/misquote/misrepresent/fabricate stuff based on the above for decades to come!
Ta.
This is getting interesting.
Exploring places never seen before.
If measuring doesn't show a difference, where do we go from here.
A dyno run or 2, with air/fuel measurement may show something. ?
We have seen a couple here before, but they didn't specifically explore for this.
Some dyno charts did show a big dip in power not far into the rev range, we recall.
And a dislike for large throttle openings low in the rpm range....
My parts book stops at 1973, can anyone say for sure if all 850s got the same carbs,
or did stepped spray tubes only go into some years/models ?
I'd assumed they all got the same thing, but is that so.
Exploring places never seen before.
If measuring doesn't show a difference, where do we go from here.
A dyno run or 2, with air/fuel measurement may show something. ?
We have seen a couple here before, but they didn't specifically explore for this.
Some dyno charts did show a big dip in power not far into the rev range, we recall.
And a dislike for large throttle openings low in the rpm range....
My parts book stops at 1973, can anyone say for sure if all 850s got the same carbs,
or did stepped spray tubes only go into some years/models ?
I'd assumed they all got the same thing, but is that so.
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Rohan said:
We're a small part of a process to dissipate energy into space as radiated heat.
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Rohan said:
Ah, but you asked about us here, not them there.
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Rohan said:
According to the parts books, and also Amal's Norton factory spec. sheet, there's no evidence to suggest that 850 carbs were fitted with anything other than the stepped 928/107 spray tubes and 928/104 needles and, although the build numbers did change, this seems to have been nothing more than an alteration of main jet size to suit 'A' and non-A Mk2 models etc..
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Anonymous
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Re: Needing Air through the pin holes
Things to do tomorrow, perhaps.
Investigate the effect on air:fuel ratio of throttle slide cutaway (1st transition from pilot circuit) from fully closed throttle to approximately 6.5mm slide opening. This is when the one-way airflow through the pilot mixing chamber at idle transitions to both pin holes flowing air:fuel mixture from the pilot circuit due to the Bernoulli effect created when the throttle slide just begins to open. Sketch-up make help to clarify - it does for me
.
Ta.
Things to do tomorrow, perhaps.
Investigate the effect on air:fuel ratio of throttle slide cutaway (1st transition from pilot circuit) from fully closed throttle to approximately 6.5mm slide opening. This is when the one-way airflow through the pilot mixing chamber at idle transitions to both pin holes flowing air:fuel mixture from the pilot circuit due to the Bernoulli effect created when the throttle slide just begins to open. Sketch-up make help to clarify - it does for me
.Ta.
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Very little if no sucktion by spray tube chimney-Bernoulli effect with slide low down or cutting a fuel path lower would not spill out the extra enrichment over standard tall flat top. The fuel rises to spill out d/t piston decent lowering below ambient in fuel bowl- not the air flow past top of spray tube- at least in very low throttle opening. The foam mix volume of the pilot mix chamber is so tiny it would only work for one jug inhale then I think it floods with fuel. Shoot if really wanted a punch in simple ole Amals, rig up a can of brake cleaner or NOS. As noted success will be noticed by fear/craving of throttle snaps below 60 or so.
L.A.B. said:
Thanks Les, solves that bit.
I wonder if John Healey is wrong about Commandos meeting some sort of emissions test ?
I sort of think that 1973 is (much) too early for any sort of smog standards (?).
1978 comes to mind for some reason, without looking into it.
Wasn't there discussion that Commandos couldn't have met these regs - if they had still been in production.
And, I rather think that emissions testing doesn't cover accelerating vehicles anyway, that would be tough to meet, for anything.
Acceleration requires richness, the antithesis of smog reduction.
It was steady state cruising where the focus was.. (??).
And, the Mk 1A, Mk2A and Mk3 were for NOISE REDUCTION purposes, with quieter blackcap mufflers and air cleaner arrangements.
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Rohan said:
The only emission requirements as far as I know, related to noise output before US EPA regulations for motorcycles kicked-in from, I believe, 01/01/1978 hence the introduction of the cleaner-burning Triumph T140E (Emission) model for the US market where T140V and TR7RV models manufactured after that date could no longer be sold, and which John Healy is certainly aware of.
Thanks again Les for the clarification.
So is Mr Healey spinning us a yarn then about the purpose of the stepped spray tubes - and Ludwig following in his footsteps !
Leaning it out to solve a flatspot just seems soooo wrong, ESPECIALLY in the new larger motor.
So is Mr Healey spinning us a yarn then about the purpose of the stepped spray tubes - and Ludwig following in his footsteps !
Leaning it out to solve a flatspot just seems soooo wrong, ESPECIALLY in the new larger motor.
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Anonymous
Guest
Thanks for that L.A.B.L.A.B. said:
I understand Norton Commandos ceased production in 1975 therefore questions and answers regarding Triumph emmision control features from 1978 may best be suited to an original 'Pub' thread discussion. I am encouraging of Rohan to initiate an original thread in whatever relavent section he chooses.
Ta.
This seems to follow on logically from where we have been travelling.
Despite your best efforts to derail it.
Your posts bear no relation to the opening of this thread either - combat crankcase breathers.
A misnomer right from the start, since all 72's got it.... !
Despite your best efforts to derail it.
Your posts bear no relation to the opening of this thread either - combat crankcase breathers.
A misnomer right from the start, since all 72's got it.... !
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needing said:
I don't agree, as it strongly suggests that any reference to the Commando being "leaned down due to meet EPA requirements" is likely to be inaccurate at best, so I don't think even you can dismiss the information as irrelevant. Leaned down, yes, but to suit the noise restrictive intake and exhaust systems.
(John's reference to the T150 having sloped spray tubes is certainly an error, as the sloped spray tubes were only introduced during T160 production-again nothing to do with EPA but part of the "Economy kit" (along with the 5-ID ring needles and 4.0 cutaway slides) introduced to reduce the T160's horrendous fuel consumption during the fuel crisis of the mid-'70s).
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Anonymous
Guest
Hi L.A.B.
I had hoped to maintain this thread as a discussion of improvement to the flow of air in a Norton Commando above and below the piston crown. To my thinking, the stepped spray nozzle is just another tuning component available in today's world.
The thread is in danger of degenarating into on-dit regarding who said what and why they may have said in response to prevailing global economic conditions as a result of the '1973 Arab Oil Embargo'.
Would you mind terribly moving that discussion with Rohan to the 'Pub'? Thank you in advance.
Ta.
I had hoped to maintain this thread as a discussion of improvement to the flow of air in a Norton Commando above and below the piston crown. To my thinking, the stepped spray nozzle is just another tuning component available in today's world.
The thread is in danger of degenarating into on-dit regarding who said what and why they may have said in response to prevailing global economic conditions as a result of the '1973 Arab Oil Embargo'.
Would you mind terribly moving that discussion with Rohan to the 'Pub'? Thank you in advance.
Ta.
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