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I looked at my graph pics, I have quite a few.I can't find one at less than 100mV and with a fresh O2 sensor my graphs are pretty consistent between 100-800.

Where the graphs go inconsistent is when the O2 sensor heater function fails.A new NTK reads 1.8 Ohms on the two grey heater wires. A dead Bosch was 3.2 Ohms and a dead NTK 4.4 Ohms and both would be inconsistent and for a long while until the exhaust gasses could warm the tip enough and keep it warm for the sensor to do its job.

What I know for sure is that with a good sensor the engine runs and sounds much better when RPMs are brought up to ~3500-4000 in the shop.

So my guess for now? TBs out of balance + O2 sensor going bad!
 

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Discussion Starter #182
Ok

So I will buy a new NTK O2 sensor - Install and we'll confirm if indeed its a O2 sensor problem (Unless MCU is malfunctioning) and eliminate that part.

Other than that - everything has been already tested multiple times and it would indicate wither MCU is bad or TBs out of balance.

Thx and will get back.

Thx Dan
 

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Ok

So I will buy a new NTK O2 sensor - Install and we'll confirm if indeed its a O2 sensor problem (Unless MCU is malfunctioning) and eliminate that part.

Other than that - everything has been already tested multiple times and it would indicate wither MCU is bad or TBs out of balance.

Thx and will get back.

Thx Dan
Based on many years following for any failure of these K1200 Motronic ECU, I would say it is NOT very probable. However nothing is impossible given many electric / testing / manipulations you or the previous owner may have done. If I was in your shoes, swapping the ECU would be the last item on my list when everything else has failed...

As far as the TB being out-of-balances, there is A LOT of evidences based on your screen shots. BUT YOU MUST CHECK YOUR TOOL (any tool for this matter). These gauges / tool can show incorrect value for a given column - either with age or when they have been dropped / damaged.

If you do not have access to another vacuum set to compare, you can use either method:
1) you make a 4-into-1 to plug into a single nipple of any 4 TB to see if all 4 column read the same. Of course if the 4-into-1 setup is not perfect they would let a vacuum difference show up. You confirm with method 2 below.

2) you choose each 4 hoses (one by one) and plug it into same nipple of any TB - just use the easiest to access. Make sure you plug all 3 other TB nipples while you do this check. You do not want to introduce an intake air leak that will mess up the idle RPM.

Once you are sure the tool is right and the columns are in fact reacting the same for a given vacuum value , ONLY THEN can you make conclusion you have EITHER:
A) intake air leaks on 1 or more cylinder / intake causing a TB imbalance
B) 1 or more butterfly is not in sync with the others (letting more or less air in)
C) lower compression on 1 or more cylinder (leaking valve or piston-rings will both cause imbalance in vacuum)

P.S.: you would need a leak-down tester to confirm last item above. A simple compression test does not always help with subtle issue like leaking head gasket or cracked cylinder head. Testing at engine operation temp is also very important - a cold engine test is not worth much.
 

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Discussion Starter #184
OK Sailor

I get it. As you have seen. I've followed your recommendations throughout this long period of testing and diagnosis. Obviously I want to get at the root cause of this problem and move on here!!

I also know what how to perform review, analysis, troubleshooting and problem determination from 37 years working in Information Technology. Don't ask how many hours I've been on calls before I heard "oops" in the background or "IT's Fixed" without any explanation. Or the "Problem Management" aka "Post Incident restoral" work to obtain "Root Cause" and implement "permanent solutions" to Application code, Network routing, firewall, or "packet issues" caused by WAN/Telco issues, Data issues or Server/DBASE failures.

And as you have mentioned numerous times - Human error or "change" related problems being prevalent in "TOO Many" issue. I have confirmed when Changes aren't made the number of problem drops by Oh about 90%. Change Management - a nightmare in itself.

So, I've ordered the NTK 25542 from RockAuto and will install, before replying again.

And see about confirming the nanometer equipment
.
 

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I still prefer my very old (1980ish) Motion Pro mercury column manometers for their large scale.However my buddy has a Carbtune and some dial gauge setup so I used both to
confirm then.Three different tools and they all read the same!

So now and once a year I mount the Motion Pro tool but just as a check up.
 

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Discussion Starter #186
Thx

I did see that this SyncPro I got with my Yamaha needs to be calibrated which I had not done. SO I attempted to follow instructions on backside by placing the 4 hoses to a manifold included and then hose off manifold to TB4? I adjusted all 4 mercury columns to even on the meter. Is that correct?

Attached the 4 hoses again to the 4 TB's and started. 1 2 3 all read low in sight with the 4th column (To TB4 solid blue and way up the column.
 

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Discussion Starter #188
ok

Thx for that info. And I printed out and went through it. Also the instructions with the kit.

It appears that "fluid" is missing from columns 1 2 and 3. With 4 being the only column is proper level of fluid.

Also, oddly, there is supposed to be "restrictors" at the end of each rubber hose and only "you guessed it" only column 4 had a restrictor in it.

I'm ordering more fluid and restrictors (at least 3) which I did not find with the kit.

So I figured I'd just measure each TB using column 4 on the nanometer.

This is what I found

TB1 = about 2 1/2 bars up column
TB2 = 3 bars up column
TB3 = 4 bars up column
TB4 = 4 bars up column

Dan
 

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Discussion Starter #189
Ok

Scratch the previous readings from the SyncPro nanometer

Received the new O2 Sensor and installed.

Took bike for ride to warm up and test results of new O2 sensor. Again bike running ok but still same surging and vibration.

I received the "refill kit" and replaced the lost fluid in the unit.

Then I followed procedure to "calibrate" the unit prior to attaching to the 4 Tb's and measuring.

1st Photo shows nanometer once calibrated from Master TB #3.
2nd Photo shows bike running and "levels' in each column corresponding to TB 1 - 4.

Note: balance shows a "staircase" from 1 - 4 but they are not the far off.

I would not think that would be causing the continued surging and poor running condition??
 

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Each graduation is 2 Cm hg.So you are out by 4 Cm hg between 1 and 4.That's quite a lot.
The balance recommendation for a carburated 4 cylinders motorcycle is usually balanced within 2 Cm hg.Altough most of us could do better.
My K is balanced at 0.5 Cm hg.
 

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Discussion Starter #192
So

Keep thinking something is going on with cyl 1 with sound of engine when running.

so pulled the plugs again and looked at them.

Seems like plug for cyl1 has some "oil shine" on it.

So again set cyl1 to TDC and did a leakdown test.

Homemade leakdown tester shows a initial difference between air intake reading of 5 PSI with cyl gauge of 5 PSI.

Init

In gauge = 40 PSI
Out gauge = 45 PSI

After 10 minutes
In gauge = 40 PSI
Out Gauge =45 PSI

Pulled the oil filler plug and not change - hear air in crankcase

After 30 minutes
In gauge - crypt up to 45 PSI
Out gauge - Crypt up to 54 PSI

even pulled crankcase oil fuller plug with no change.
So gaining pressure in cyl1

Does not appear like a leakdown for valves or cylinder
 

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