Needing Air

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Aha. Should be 3 to 5 inHg (76 to 127 mmHg).
Previous post edited.
Ta.
 
Re: Needing Air without alloy in combustion chamber.

Hi.
Viton quadring cemented into 32mm AMAL carby to act as throttle slide seat/seal
1. to compensate for AMAL alloy slide skirt not being flat (brass also shown)
2. to ensure idle air flow is only through the pinhole ports
3. raise the air flow (above idle) closer to the spray tube height
4. reduce skirt breakage.
Ta.
 
Combat crank case breather.
Reverted to the 4-petal-reed-valve.
The steel balls in the Combat breather tower worked fine but for the noise!
The 'honking' of the reed valve is preferable to the 'rattle' of the balls.
Ta.
 
needing said:
Combat crank case breather.
Reverted to the 4-petal-reed-valve.
The steel balls in the Combat breather tower worked fine but for the noise!
The 'honking' of the reed valve is preferable to the 'rattle' of the balls.
Ta.
Click to expand...
I am sure you mean the "1972 crank case breather" and the "1972 breater tower", right? Lets be clear here, the "Combat" was an abomination on top of the 1972 Commando.

You speak of the Combat a bit heavy with reverance, but in reality, being desirable is questionable at best.

Other than that, how ya been?
 
This thread began with the intention of improving the breather.
I wondered at the outset if the mass of a 9/16 ball could track the crank pulses, or just fly around ineffectively.
Apparently the results are: it worked fine but for the noise.

Needing, did you get a chance to obtain any evidence that the breather lowered the crank pressure?

Stephen Hill
 
Stephen Hill said:
This thread began with the intention of improving the breather.
I wondered at the outset if the mass of a 9/16 ball could track the crank pulses, or just fly around ineffectively.
Apparently the results are: it worked fine but for the noise.

Needing, did you get a chance to obtain any evidence that the breather lowered the crank pressure?

Stephen Hill
Click to expand...

Hi Stephen.
Yes, the engine inlet at the inlet rocker cover had 2 inHg vacuum (down from 3 to 5 inHg with 4-petal reed valve).
Not as effective but 2 inHg is still enough for the catch can oil extraction circuit to operate.
This was with 2 balls. I considered spring loading a ball but that defeats the simplicity goal and risks spring breakage into the engine. All in all, empirical proof that my reed valve is the better of the two options.
Ta.
 
Re: Needing Air to lift oil

New rings installed and 4-petal-reed-valve refitted.
Cool air flows into engine and out via reed valve.
Solenoid cuts cool air flow when catch can level rises and resultant vacuum draws oil into the oil tank.
Screen shot of onboard sensor readout shows engine vacuum at 3000rpm.
Hobot, how much vacuum do you hope the exhaust airflow may create? I don't think a Norton exhaust pulse (even 2into1) could get near 2 inHg.
Ta.
 
Re: Needing Air to lift oil

needing said:
Hobot, how much vacuum do you hope the exhaust airflow may create? I don't think a Norton exhaust pulse (even 2into1) could get near 2 inHg.
Click to expand...

Some agricultural machinery uses exhaust gas flow to vacuum power large swirling air filter centrifuge thingys.
Lotta power in that system, although obviously engines are larger too.
 
Re: Needing Air but not the noise.

I have some trips planned for the next 12 months now that the engine is run-in so looked to reduce exhaust note/noise upon my ears at cruising speed. They are detachable and dyno runs planned for various other tweaks will determine their effect (or not) on tuning.
Ta.
 
Boy does that take balls to show here but does make perfect utilitarian sense & glad not permanent welded on like my suzuki, which was too restricitve quiet so popped 4 .22 hp in to make two .38 holes that gives more distinct lower note and darn if not a bit more spunk down low. Factory black cap mufflers are also available in case eggs thrown at gatherings.
 
Re: Needing Air not in oil tank.

Oil tank temperature sender calibrated to thermometer.
4-petal reed valve fitted to breather tower.
Breather/oil extraction system allows oil tank fill to return inlet (no cappuccino).
Ta.
 
hobot said:
Boy does that take balls to show here but does make perfect utilitarian sense & glad not permanent welded on like my suzuki, which was too restricitve quiet so popped 4 .22 hp in to make two .38 holes that gives more distinct lower note and darn if not a bit more spunk down low. Factory black cap mufflers are also available in case eggs thrown at gatherings.
Click to expand...

Hi hobot.
The exhaust noise is so much reduced by the elbows on the pipes that I can hear every little engine tinkle and twitter.
Stirs the leaf litter up pretty good too!
Ta.
 
Re: Needing Air through oil.

A thought for the day.
Most crankcase oneway breathers that I have seen on this forum have the outlet above the inlet (exceptions I spotted are the sump plug breather type and a XS650 type that a scandinavian? chap fitted the other way - there may be more). So, oil will flow or accululate in most oneway breathers and the reed valve assembly will become submerged in oil.
My latest version follows the higher outlet convention (the earler in-catchcan version was in air above the oil level). This does not seem to negatively affect function but I notice the (submerged) reed valve no longer 'honks' at kick-over. I suspect oil damped reed valves may actually seal better and the oil cushioning help to prolong reed life.
Ta.
 
A check valve anywhere in the exit path will lower case below ambiant but maybe not as much as if right in the case oil level. Btw a wider IS tank blocks a lot of the engine valve train noise and extends the time of road trace flowing. Also was pleased with exht wrap as took out the thin metal clang of exht blasts which allows more distinct valve train ringing head if squated at front and no skin marks if pressed against it checked up under tank for electriclal connections. A big wind screen takes a lot of wind sense/noise out too so have to watch speedo for sense of how fast entering turns.
 
Re: Needing Air to go with the fuel flow

Club run today and 160 km from home and the bike starts coughing and spluttering while cruising at 110 kmph.
Switch to reserve, no change. Backed off, ok for a moment then same. Rolled the throttle on, ok while accelarating then same same. AFR had gone from a constant 13.5:1 to 9.1:1 at cruising. Bloody jet holder loose again! Pilot circuit ok, main jet still functions, needle jet is 5+ threads lower than it should be. Twice in one calendar year and I'd nipped them up tight and filed/centrepunched the joint last November. Now I'm drilling, grinding and grubscrewing this design flaw from existence tomorrow.
Ta.
 
Re: Needing Air but not leaking around the throttle slides

A good pair of 32mm carby bodies (with 850 spray nozzles) arrived today (1st job is grubscrew the jet holders :D ).
They came with 32->30mm tapered manifolds. Have you fitted such manifolds and carbies to a 32mm ported head?
My first thoughts are that the taper may improve consolidation/direction of the air:fuel charge and that the annular step may act to dissapate the valve slamming pulse (perhaps improved by offsetting 1mm to create a D port).
Practical application experience would be great. Dyno results even better.
Ta.
 
gortnipper said:
Hmmm do a search for some of JimC's posts IIRC he has some test results.
Click to expand...

Thanks gortnipper. Will do.
I have seen IIRC before in threads. What does is stand for?
Ta.
 
needing said:
gortnipper said:
Hmmm do a search for some of JimC's posts IIRC he has some test results.
Click to expand...

Thanks gortnipper. Will do.
I have seen IIRC before in threads. What does is stand for?
Ta.
Click to expand...

In this context, probably 'If I Read Correctly'

But it could mean 'If I really care' !!
 
needing said:
gortnipper said:
Hmmm do a search for some of JimC's posts IIRC he has some test results.
Click to expand...

Thanks gortnipper. Will do.
I have seen IIRC before in threads. What does is stand for?
Ta.
Click to expand...

IIRC = if I recall correctly
 
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