Dangers of email flashes

[Spatt]

I get to see an work on a number of bikes a year for racers and track day guys.    Recently I got in two motors for builds from club racers.  Both stock motors with one ~400 miles on the motor.  Should be a pretty simple task, limited mileage normally means less time for damage to parts and gentlemen was running a simple emailed flash and the other bike was running just a dynojet fuel map uploaded to the ecu via FTECU.  One motor was running VP T4 and the other Sunoco Optima both I would say are definitely a step above your pump 93 for a stock motor. 

The results were pretty awesome.  I have no knowledge of the tune other than after rebuilding I'll start with one of my maps and adjust it for the motor.  I understand it takes time to schedule tuning and but in my opinion its always better if you can to physically get the bike on a dyno and work with a tuner you know.  

Alternatively you might just get a present like these pistons and cylinder.  Curiously the failures always seems on the FZ to be related to cylinder #1.  On the SV's I use 2 wideband sensors for tuning and on the FZ I only monitor at the collector of the two cylinders.  I'll maybe take some time to modify a header to allow me to log both cylinders and see what differences there are in the two.

Either way just be careful out there with your bike and you money is my suggestion.  All this can be fixed but its at the cost of additional parts and time.

[sorkyah]

by email, i assume you mean home tuners sharing their created maps?

[geophb]

Good stuff! Cylinder #1 is on the shifter side, is that the one your referring to? Backwards from what I would think.

If you compare the fueling between cylinders on the stock map there are differences of about 5% more fueling in cylinder 1 (clutch lever side) vs cylinder 2(brake lever side). (also in non critical areas the tune varies up to about 15% but that irrelevant as nobody is doing 12,000 rpm at 0% throttle)

Cylinder 1 failures are most likely because cylinder 1 sees the most heat based on the cooling setup.  If you look at the cooling flow path, cylinder 2 gets hit with freshly cooled coolant right in the exhaust side of the cylinder, then already heated coolant flows to cylinder 1 then out the thermostat.  So, the exhaust side of cylinder 1 is going to see the highest temperatures thus why it fails first and why Yamaha has more fuel to that cylinder. 

I don't think dual widebands is the fix as you probably would not want them equal in afr ratio as mentioned above unless you wanted to see the actual spread. 

Hoping cylinder 1 your talking about is the shifter peg side because otherwise everything i just typed is bogus 

Edited December 26, 2019 by geophb

[HulkHogan]

Are you referring to the mail-in flash services?  I got a mail-in FTECU service and now have no control over it nor any license number.  For the same price, I could have purchased the cable and flash license.  I then purchased the ActivTune and because I don't have the cable found out that I don't have any options to save learned maps, etc.  It really sucks that I didn't know to simply purchase the cables and do it myself.  If my flash is out of whack, I wouldn't know it either.

[paxx]

3 hours ago, geophb said:

Good stuff! Cylinder #1 is on the shifter side, is that the one your referring to? Backwards from what I would think.

If you compare the fueling between cylinders on the stock map there are differences of about 5% more fueling in cylinder 1 (clutch lever side) vs cylinder 2(brake lever side). (also in non critical areas the tune varies up to about 15% but that irrelevant as nobody is doing 12,000 rpm at 0% throttle)

Cylinder 1 failures are most likely because cylinder 1 sees the most heat based on the cooling setup.  If you look at the cooling flow path, cylinder 2 gets hit with freshly cooled coolant right in the exhaust side of the cylinder, then already heated coolant flows to cylinder 1 then out the thermostat.  So, the exhaust side of cylinder 1 is going to see the highest temperatures thus why it fails first and why Yamaha has more fuel to that cylinder. 

I don't think dual widebands is the fix as you probably would not want them equal in afr ratio as mentioned above unless you wanted to see the actual spread. 

Hoping cylinder 1 your talking about is the shifter peg side because otherwise everything i just typed is bogus 

Your theory on cylinder one coolant temperature is off. I know it seems to make logical sense but in reality the coolant temperature is about equal throughout the system. I'm not saying cylinder one does not run hotter but if it does it's not related to coolant but some other factor. Perhaps the cylinder tends to run leaner  or maybe there is less surface are due to water jacket differences. 

[geophb]

53 minutes ago, paxx said:

Your theory on cylinder one coolant temperature is off. I know it seems to make logical sense but in reality the coolant temperature is about equal throughout the system. I'm not saying cylinder one does not run hotter but if it does it's not related to coolant but some other factor. Perhaps the cylinder tends to run leaner  or maybe there is less surface are due to water jacket differences. 

Are you saying that the water inlet and outlet on the radiator are about the same temperature? This is simply not the case.  These pictures he posted are not cruising around town with 178deg water temps.  This was most likely full load WOT, where coolant outlet temps from the head are 210+ easily and inlet temps to the head would have to be significantly lower  or coolant temps would rise until failure/meltdown (im talking like 100 deg difference between inlet/outlet of radiator, which obviously depends on the ambient temperature and the efficiency of the heat exchanger.) I have not measured it so i dont have actual numbers.

With casting and manufacturing as good as it is today I would say that flow characteristics through each cylinder and material thickness between cylinders is negligible. 

Also I just want to reiterate that I am not explaining why they failed, I am connecting the dots on why Cylinder 1 typically fails first.  

[twf]

Not coolant issue. It is from knocking. Either wrong fuel for given compression, to lean fuel/air mixture or too much ignition timing advance. Or combination of those.  

[twf]

Head will have same pattern. And it does not have to be only cylinder #1.

here is example of both in same time.

[Spatt]

9 hours ago, twf said:

Not coolant issue. It is from knocking. Either wrong fuel for given compression, to lean fuel/air mixture or too much ignition timing advance. Or combination of those.  

Zoran I agree.  Its always hard to judge these things.  Could be as simple as mixing up fuel cans at the track.  Could be someone pushing timing past MBT, without knowing all the variables hard to say.   

I also agree the last thing I would suspect is a coolant flow issue, these motors were stock so I dont see it taxing the cooling system.

 

[Spatt]

17 hours ago, geophb said:

I don't think dual widebands is the fix as you probably would not want them equal in afr ratio as mentioned above unless you wanted to see the actual spread. 

Hard to see if there is more flow to one cylinder without a way to quantify it.  On most twins Im using 3 widebands, 1 in each headpipe and a sniffer in the muffler.  You could argue its overkill but its the only way to see what fueling looks like at each cylinder in isolation.

[geophb]

3 minutes ago, Spatt said:

Hard to see if there is more flow to one cylinder without a way to quantify it.  On most twins Im using 3 widebands, 1 in each headpipe and a sniffer in the muffler.  You could argue its overkill but its the only way to see what fueling looks like at each cylinder in isolation.

Just curious, If you make your cylinder 1&2 maps identical have you noticed an afr difference between cylinders?

I wonder how many sensors/data input Yamaha uses to build their ecus because they obviously found that one cylinder needs more fuel