Dyno Day at Red Baron (Saturday 29th)

[SARGE]

Good to see someone knows what a scow is.
Bet ya nobody here (except Motu old fart) knows about scows and how they plied their trade on Aucklands upper harbour for many years. You can still find one out and about.. it does tours from the Maritime museum in the Viaduct. It called the Ted Ashby. It wasnt a garbage scow I dont think.. used to bring supplies up to riverhead from Aucland.

i had my wedding reception on that boat .. 30 VERY pissed frinds of the Mrs( i didnt know anyone yet so i spent the night sitting in the rigging with a bottle of scotch..)

[The Stranger:Me]

wank factor.....

Odd that you would find knowledge and accuracy a wank.

Personally I find unsubstantiated claims of my [insert bike] is faster than a Hayabusa 0 to 100 and on the quarter mile a bigger wank.

[SARGE]

Typical lean conditions:
- poor acceleration - feels flat
- Engine doesn't respond when throttle is snapped open - picks up speed as throttle is closed
- Engine runs hot, knocks, pings and overheats (end result- hole in piston)
- Engine surges or "hunts" when cruising at part throttle
- Popping/ spitting through carb when throttle is opened, or popping and spitting through pipe on deceleration with a closed throttle (classic lean pilot circuit symptoms)
- Engine runs better in warm weather, worse in cool
- Performance gets worse when the air filter is removed

Typical Rich Conditions
- Acceleration is flat, uneven
- Engine will "8 stroke" as it loads up and skips combustion cycles
- Throttle needs to be opened continuously to maintain acceleration
- Engine works better when cold
- Black smoke from the tail pipe
- Poor fuel economy
- Engine performance improves when air cleaner is removed
- If the pilot screw is overly rich, idle is rough and the engine won't return to idle without blipping the throttle
- Black sooty plugs, sooty exhaust pipe

Here's some tips, old wives' tales and cute remarks:
- If the bike pulls hard, idles, doesn't smoke, detonate or punch holes through the piston - ride it
- If the bike pulls and the plugs are not blistering white - leave it alone
- If you install a new exhaust system or air filters, go up two sizes on the main right of the bat - then evaluate
- If you encounter mid-range detonation, try raising the needle one clip

Float height (AKA fuel level & how to..)
To get best low end power, set float height so that the engine will accept full throttle in 2nd gear from 2.5k to 3k rpm at minimum. Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.

A. If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm).
This will lower the fuel level, making full throttle / 2k-3k rpm leaner.

B. If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level. Example: change float height from 15mm to 14mm to richen up that area.

REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting. Warning: If the engine is left with the fuel level too high, the engine may foul plugs on the street and will be "soft" and boggy at part throttle operation. Adjust Floats to raise/ lower the Fuel Level.

Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm. Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!

If there are low end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, also check for needle wear and needle jet (part of the emulsion tube). It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round!

Tuning the leanness out

The backfiring indicates air/fuel mixture or pilot jet leaness. I'd start with the idling mixture as it's the easiest and cheapest.

Manufacturers specs are normally one and a half turns out from the slightly seated position - don't force the screw it's got a taper on the screw you're turning as well as in the carb.


Start the engine and get it to working temp. Light a cigarette or whatever
you smoke as you'll be busy from here on. You'll be letting the engine run
for a while so do it outside where there's air circulation or put a fan on
the engine and put the beers within reach.

Adjust the idling speed to the spec or to where you can hear it's running at
a constant speed (the idling speed is adjusted by hand by turning the brass
screw with the spring on it sticking out of the back of the carb).

Now turn the pilot screw out one quarter from the manufacturers spec. If the
engine speed drops, return the screw to where it was and turn it in one
quarter. If the engine speed drops, you're OK (and I'm OK). Drink the beer.
Don't go for a test ride after the beer.

If the engine speed increases as you turn the screw out, keep going until
you reach the point of max RPM. If it takes more than 3 turns for the engine
speed to level off, the pilot jet is too large. Install a leaner one. This
will probably not be your scenario.

If the engine speed increases as you turn the screw in, keep going until it
levels off. If the pilot screw ends up less than half a turn open, the pilot
jet is too small.

Trick : When you've found the peak idle speed, turn the mixture screw in one
quarter turn. If it doesn't change the idle speed leave it there. If it does
drop, return it to the last setting

[Motu]

Good to see someone knows what a scow is.
Bet ya nobody here (except Motu old fart) knows about scows and how they plied their trade on Aucklands upper harbour for many years. You can still find one out and about.. it does tours from the Maritime museum in the Viaduct. It called the Ted Ashby. It wasnt a garbage scow I dont think.. used to bring supplies up to riverhead from Aucland.

Used to watch Subrizky's scows ply the Tamaki Estuary when I was a kid at Bucklands Beach,my grandmother lived on The Parade - we thought they were pirate ships because they had rat lines...never saw a sail on them though....or a Skull and Crossbones.

I put my XLV750 on a dyno before and after my exhaust change to see if they changed the power (no) A run up to the red line in each gear,30 secs max,the bike had done 90,000km and I rode it harder than that everytime I got on it.Have faith in your bike....or don't.

[The Stranger:Me]

dont think i'll be there... BWAHAHAHAHAH

RB's dyno dont measure torque.. only RWHP.. for a ral Dyno... go see the fellas at AMPS.. full on Dynojet system.. tell you how much pressure you got in your tires

All dynos measure torque and use this to calculate the horsepower.
Horsepower=Torque*RPM/5252 thus if any 2 variable are known the other can be calculated.

You may note that on all dyno runs showing both torque and horsepower the lines converge at 5252 RPM.

[SARGE]

All dynos measure torque and use this to calculate the horsepower.
Horsepower=Torque*RPM/5252 thus if any 2 variable are known the other can be calculated.

You may note that on all dyno runs showing both torque and horsepower the lines converge at 5252 RPM.

RB's Dyno DOES NOT display torque and it reads in Ps, not HP

[The Stranger:Me]

RB's Dyno DOES NOT display torque and it reads in Ps, not HP

Not doubting you at all.

However as a conversion factor was posted here a while ago to convert PS to HP, which if I recollect corectly was extreemly close anyway, it is still a simple matter to calculate the torque figures

And my appologies but I assumed that the HP in RWHP that stood for horse power.

[SARGE]

Not doubting you at all.

However as a conversion factor was posted here a while ago to convert PS to HP, which if I recollect corectly was extreemly close anyway, it is still a simple matter to calculate the torque figures

And my appologies but I assumed that the HP in RWHP that stood for horse power.

you need to have RPM figs available to calculate torque from HP.. again .. something RB's dyno does not display


T = HP x 5252

N


T = Torque (LbFt)
HP = Horsepower
N = Speed (rpm)

[The Stranger:Me]

You win!
Yes you do need the RPM figure and if they can't provide this on a chart or grid I wont be attending.

[avgas]

Saph will have to wait for the next one.... got too much on my plate this next month

[SARGE]

You win!
Yes you do need the RPM figure and if they can't provide this on a chart or grid I wont be attending.

i have some old pulls on my FJ laying around ..i'll see if i can scan one somehow and post it .. no RPM grid.. you can call Gio over at RB and ask to see a few also (although he is a bit grumpy lately.)

[Motu]

In the real world of a spring brake dyno with a big dial and clipboard - Horsepower is not measured and does not exist,it is calculated from torque and rpm readings.In our world of computer chips it's all done for us and is printed out in a coloured graph.

You can also get a cheap road dyno - you make a run and download the data into your computer along with your vehicle weight,tyre size and gearing,the results are very comparable to the Dynotune inertia dyno readings.Instead of spinning up a roller of known weight - you spin up your bike or car,and feed in it's specs.Cheap too.

[SARGE]

In the real world of a spring brake dyno with a big dial and clipboard - Horsepower is not measured and does not exist,it is calculated from torque and rpm readings.In our world of computer chips it's all done for us and is printed out in a coloured graph.

You can also get a cheap road dyno - you make a run and download the data into your computer along with your vehicle weight,tyre size and gearing,the results are very comparable to the Dynotune inertia dyno readings.Instead of spinning up a roller of known weight - you spin up your bike or car,and feed in it's specs.Cheap too.

Beltronics makes a basic unit ( http://www.beltronics.com/fx.html ), as does Escort ( http://www.crutchfield.com/S-A9viQf0...23450&I=036GT2 )

[Lou Girardin]

high KM bike + redline for 30 seconds = large pile of scrap metal.

bike should be well warmed up before the pull... not much else you can do.. up to the operator really.. hope its Geoff doing the runs

30 bloody seconds? Were they trying to make it go pop?
All a dyno run needs is a quick squirt up to the limiter, then back off.
I guess there's technicians, then there's butchers.

[R6_kid:Me]

lol, this one really took off. Basically the idea behind it was to be able to say "my {insert bike name} has XXX.XX hp at XXXXXrpm."

I am planning on getting my bike tuned later on in the year at AMPS when i have some dosh spare. After all i am running a dynajet kit so it pays to go to the people with the right equipment to do th setup.