Measured Air/Fuel Ratio for Optimization

hobot said:

At lower rpm like most street bikes live in, the headers can back wash by the sonic and mass flow reflections all the way back out carb throat so O2 sensor not that good but near WOT. Highest EGT Peel produced was 1375'F measured by temp needles in each header 10" from exhuast ring bolt. If Canaga could get O2 to help dial in touchy over carbed engine then maybe us lessor experienced can too. The one wire type will heat by exhaust only as C'do's owners not that worried to heat up enough for cold start EI fueling by using the polarity sensitive 3 wire type, nor likely must spare electric current to heat it much anyway. Its takes a fairly long study to see what's up with all the little to big factors to rely on O2 sensors of various types. Color tune plug kit likely more useful for low down rpm dial in, if not just going by ear and feel as traditional.

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All of those choices should be used to get the most info and verify O2 sensor results. Most manufacturers say that readings can be irratic at lower RPM's. Still provide very useful information particularly when installing different brand delivery system from stock. Makes sense for race tuning also. These systems have become relatively inexpensive and more accessable so why not?

1375 F 10" from exhaust ring is really hot...combustion temp might not get that high...was this on pump gas? Normally asperated? You weren't running lean were you? :wink:

dennisgb said:

hobot said:

At lower rpm like most street bikes live in, the headers can back wash by the sonic and mass flow reflections all the way back out carb throat so O2 sensor not that good but near WOT. Highest EGT Peel produced was 1375'F measured by temp needles in each header 10" from exhuast ring bolt. If Canaga could get O2 to help dial in touchy over carbed engine then maybe us lessor experienced can too. The one wire type will heat by exhaust only as C'do's owners not that worried to heat up enough for cold start EI fueling by using the polarity sensitive 3 wire type, nor likely must spare electric current to heat it much anyway. Its takes a fairly long study to see what's up with all the little to big factors to rely on O2 sensors of various types. Color tune plug kit likely more useful for low down rpm dial in, if not just going by ear and feel as traditional.

Click to expand...

All of those choices should be used to get the most info and verify O2 sensor results. Most manufacturers say that readings can be irratic at lower RPM's. Still provide very useful information particularly when installing different brand delivery system from stock. Makes sense for race tuning also. These systems have become relatively inexpensive and more accessable so why not?

1375 F 10" from exhaust ring is really hot...combustion temp might not get that high...was this on pump gas? Normally asperated? You weren't running lean were you? :wink:

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It's not unusual to see the headpipes glowing a bit under heavy load on the dyno. There isn't enough cooling air to keep them cool. 1350 to 1500 degrees on the thermocouple is not uncommon although that's pretty hot for a Norton..
When I was tuning the blown Ecosse the Ti headpipes would look almost translucent during a hard pull. Scary stuff. Jim

comnoz said:

When I was tuning the blown Ecosse the Ti headpipes would look almost translucent during a hard pull. Scary stuff. Jim

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Now you went and done it! That's some serious name dropping there. Like 200 hp isn't enough?

pete.v said:

comnoz said:

When I was tuning the blown Ecosse the Ti headpipes would look almost translucent during a hard pull. Scary stuff. Jim

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Now you went and done it! That's some serious name dropping there. Like 200 hp isn't enough?

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He wants to drop the blower on the next one and add a turbo. Then go for 300+.
About 1/4 of that pegs my funmeter. Jim

1375 F 10" from exhaust ring is really hot...combustion temp might not get that high...was this on pump gas? Normally asperated? You weren't running lean were you? :wink:

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Peel was mostly fed 91 octane no-lead no-booze pump gas through 34 Miki Carb right out the box no dialing in at all, as only intended to break in then change to the standard wisdoms of power sets ups here.
So almost 1400'F scared me at first till I looked up air cooled aircraft racers to see they got like 1600'F exht temps! Heads got to 425'F when maxing out. Peel was accidental combo that performed better after 80's mph than my poor wimpy 70/hp/365lb/6spd/9000 rpm+ SuVee, which fucked with my head no end at first besides about running out from under me till I got my P!! dragster planting reflexes re-established - but by golly didn't take me long to exploit that power with even better bigger performance jump in tri-linked power handling plus like 70's lbs removed. Weighed about 40-45 lbs more than Ludwig's Twiggy C'do. Peels 2-1 pipes essentially burnt/oxidized chrome off to the Y junction 18" from head, with O2 bung just beyond that 3-4".

I've a set of old rusty 750 headers with O2 bungs and temp needle holes in them if anyone wants to experiment to dial in and observe scope of volts/O2 in wide running ranges then put back nice pipes. i was is/am planning a pass around kit with EGT/CHT/O2 meters. When dual and 2-1 pipes on hand would cost about $500 to get the CHT/EGT/O2 meters. Peels got wiped off from twice landing completely upside down w/o me directly under to protect them...

hobot said:

1375 F 10" from exhaust ring is really hot...combustion temp might not get that high...was this on pump gas? Normally asperated? You weren't running lean were you? :wink:

Click to expand...

Peel was mostly fed 91 octane no-lead no-booze pump gas through 34 Miki Carb right out the box no dialing in at all, as only intended to break in then change to the standard wisdoms of power sets ups here.
So almost 1400'F scared me at first till I looked up air cooled aircraft racers to see they got like 1600'F exht temps! Heads got to 425'F when maxing out. Peel was accidental combo that performed better after 80's mph than my poor wimpy 70/hp/365lb/6spd/9000 rpm+ SuVee, which fucked with my head no end at first besides about running out from under me till I got my P!! dragster planting reflexes re-established - but by golly didn't take me long to exploit that power with even better bigger performance jump in tri-linked power handling plus like 70's lbs removed. Weighed about 40-45 lbs more than Ludwig's Twiggy C'do. Peels 2-1 pipes essentially burnt/oxidized chrome off to the Y junction 18" from head, with O2 bung just beyond that 3-4".

I've a set of old rusty 750 headers with O2 bungs and temp needle holes in them if anyone wants to experiment to dial in and observe scope of volts/O2 in wide running ranges then put back nice pipes. i was is/am planning a pass around kit with EGT/CHT/O2 meters. When dual and 2-1 pipes on hand would cost about $500 to get the CHT/EGT/O2 meters. Peels got wiped off from twice landing completely upside down w/o me directly under to protect them...

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What's a SuVee (Suzuki)? What was it? I know we're not supposed to talk about those "other" bikes here but interested.

Not sure if those two into ones would be good choice for me to play with. Don't you need to special tune to those?

I suggest you need to ask what an oxygen sensor actually measures in the exhaust gas - how specific is it and how is it calibrated ? It is probably the situation that different fuels change the accuracy of the results. So if you jet for a certain O2 reading with one fuel, when you use something else and jet to the same O2 reading, the actual mixture is different.
About two into one exhausts. Mine was constructed in a certain way based on experience and judgement. It is easy to get it wrong. If you like I will measure it and post to this forum. It is too loud for a road bike. When I fitted it, I also changed the cam timing to allow for it.

acotrel said:

I suggest you need to ask what an oxygen sensor actually measures in the exhaust gas - how specific is it and how is it calibrated ? It is probably the situation that different fuels change the accuracy of the results. So if you jet for a certain O2 reading with one fuel, when you use something else and jet to the same O2 reading, the actual mixture is different.
About two into one exhausts. Mine was constructed in a certain way based on experience and judgement. It is easy to get it wrong. If you like I will measure it and post to this forum. It is too loud for a road bike.

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Yes your right about the different fuels. In my case would be normal pump gas so only dealing with the inconsistency with that. But you bring up an interesting point...here in the USA, age of fuel plays a factor. Have to use fresh fuel I guess...can of worms :shock:

I suggest you have to find the worst case scenario, and jet for that. If you are racing and permitted to use methanol, you don't have that problem.

dennisgb said:

concours said:

A lean mixture at LESS THAN WOT is not likely to cause catastrophic engine damage because the engine, at only 50% (for example) power output, has a surplus of cooling capacity, and poor drivability will cause the rider to lose his cool long before the engine poops.

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Yes your probably right about this...but for me it would be an uncomfortable situation. Only because I have fried engines with lean buring and it isn't pretty.

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[/quote]
Ugly yes, not from partial throttle...

Dennis SuVee is my '00 'boney' SV650 Suzuki "Intruder". I've both dual pipes and a 2>1 set up for temp and O2. Good O2 meters were pretty expensive back when so never got one.

Note fairing removed and mirrors rolled in for the snow angels splats in the pasture till i got a feel for staying up w/o traction nor counter steering. When power enough to spin rear leaned at hwy speed one must account for gravity pulling the lost traction tire, front or back or both down hill to aim.

Btw what's the deal with the one ring piston?

"Btw what's the deal with the one ring piston?"

Less friction loss, seals well. Used to be (when they were first used) they'd need frequent changing, but now with modern rings/oil/nikasil, yummy long life is achieved. I logged 23,000 hard miles on an 800cc triple, compression was 143lbs across at the end, same as when it had 500 miles... single ring design.

concours said:

dennisgb said:

concours said:

A lean mixture at LESS THAN WOT is not likely to cause catastrophic engine damage because the engine, at only 50% (for example) power output, has a surplus of cooling capacity, and poor drivability will cause the rider to lose his cool long before the engine poops.

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Yes your probably right about this...but for me it would be an uncomfortable situation. Only because I have fried engines with lean buring and it isn't pretty.

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Ugly yes, not from partial throttle...
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That is a piston out of a two stroke, a completely different situation. It is much more critical when you lean off. If you really get one going to remain competitive, you are always in the danger zone and it is extremely important to watch the weather.

acotrel,

I burned a hole in the top of the piston on mine. I think that is the more common result of lean burning.

Hobot,

That's a good bike...the SV. I can't believe your riding it in the snow...

6 mo's after I got my 1st Combat, it was a great runner but leaked everywhere and was pretty worn out so decided to learn motorcycle mechanics with the hand holding of vendors and NOC and Brit Iron bunch. They discussed modern C'do level replacements and the SV650 was the most mentioned and I found a like new 2000 version for $4000 to use while learning all the crapola that can go wrong on a C'do a few beyond anything discussed on this list to boot. i have 3x's more time on SuVee, killed a deer and couple of small goats and broken ribs in big dog so we is blood brothers. I seriously wanted to learn how to max out on a modern so THE Gravel and Snow allowed this w/o track time, which I later found out was childs play compared and whipped ass on the head corner instructor with the low to no traction skills. its pretty equivalent power as a good factory Combat though the Combat has a tad more power if you are hard hearted enough to run it like a racer. Thank goodness I've never had to do anything to the SV dual down draft carbs thought there are a bunch of hop of stuff to make more power but its just a utilitarian econo corner cripple commuter to me so did upgrade both ends suspension and only run non-DOT used race tires, so am able to out ride other corner cripples on it - till HP comes into play then its left in the dust by 600cc inline 4's. Peel was like half again more powerful quick and 15-20 mph higher top end. 3 big dogs took Suvee down again in Nov or I'd be out on the snow again practicing for the looseness Peel turns pavement into such free delights.

dennisgb said:

acotrel,

I burned a hole in the top of the piston on mine. I think that is the more common result of lean burning.

Hobot,

That's a good bike...the SV. I can't believe your riding it in the snow...

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There are plety of indications of too lean before that happens. did you ignore the beads of aluminium on the plugs ? you must have known it was running like pig if it got to that stage, if it is on tune, your motor should not spit or cough at any throttle opening under any load.lt should supply excellent power. If is like that and you change the muffler or get dud fuel, easy to burn a piston

acotrel said:

There are plety of indications of too lean before that happens. did you ignore the beads of aluminium on the plugs ? you must have known it was running like pig if it got to that stage, if it is on tune, your motor should not spit or cough at any throttle opening under any load.lt should supply excellent power. If is like that and you change the muffler or get dud fuel, easy to burn a piston

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It was a drag bike. Burned up during a run after changing carbs...it was in my young and stupid days. It taugh me a lesson that I never forgot tho.

Take a step back and do it again. We've all done rash things and damaged motors. With these things you need to be slow and systematic changing only one thing at a time. Then note the result.

Seeing a telecast of the end of a 12 hr sports car race (Cars !), they mentioned the McLaren had plenty of fuel at the end,
and, not needing to save fuel, had been given the go-ahead for "full rich setting No # 1, for maximum power".

Lean running is fuel saving mode.....

Rohan said:

Seeing a telecast of the end of a 12 hr sports car race (Cars !), they mentioned the McLaren had plenty of fuel at the end,
and, not needing to save fuel, had been given the go-ahead for "full rich setting No # 1, for maximum power".

Lean running is fuel saving mode.....

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That's quite right. But it all depends on where the line is between rich and lean.

There is no extra power to be gained by being 'too' rich... only 'full' rich.

I'd suggest that 'full' rich on an F1 car will not be much below 14.7:1.