Vibration! A cure for bad vibrations, Spark Plug Caps!!

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
If your bike has vibrations in the seat, handle bars or foot pegs, read on as this procedure "may" help reduce some of those harmonic vibrations. If you can remove the spark plug caps, you can check this and correct this condition.

WHAT IS THE CAUSE?:
The the Spark Plug Cap (SPC) threads into the High Tension Lead (HTL) wire core using a brass screw with a conventional clockwise thread. As the wire ages, the insulation around the wires core may relax allowing the copper core wire to move away from the caps brass screw. This loss of connection translates to vibrations across throughout mid to upper RPM's. Remember this is a waste spark ignition and each coil is responsible for 2 spark plugs firing and a poor connection at either plug can alter the timing, energy, or duration of the spark to a cylinder! We feel this as harmonic vibration in the bars and seat. The good news is, its easy to fix!
IMO - unless the wires core is completely broken, it IS NOT responsible for a misfire! That is, the engine will start, idle, and accelerate fine. But the chassis may have harmonic vibration from about 4K on up.

HOW TO CHECK IT AND CORRECT IT:
  • From the left side, remove the two 10 mm bolts holding the radiator and let it settle on the hoses. Be careful of the lower bracket hitting the radiators CORE! More info here ->See post 6 for more pictures.
  • Remove spark plug cap #4 (right side). PULL ON THE THE CAP BODY, NOT THE WIRE!!!
  • With the cap free in hand, hold the HTL (wire) and gently rotate the CAP ASSEMBLY CLOCKWISE. The cap may turn about a half turn on the wire and **should become snug and resist turning.** If the cap SPINS ON THE WIRE IT NEEDS REPAIRED!
  • REPAIR THE WIRE: If the cap spins with no resistance to rotation, unscrew it by rotating the CAP counter clockwise while holding the wire. Using a pair of sharp side cutting pliers, cleanly cut off 1/4" (6 mm) from the HTL.
  • Using small pick, fan out the copper wire strands into a 360° pattern. Do not bend them repeatedly!
  • FAN OUT WIRES:
  • Push the SPC onto the wire and turn it clockwise until its snug.
  • Add a ZIPTIRE to the boot! Because the wires are strained once fitted to the engine, the ZIPTIE will extend the interval before coming loose again.
  • Proceed to next cap and remove it for inspection. I find it easier to leave the caps out until all wires are verified/repaired. Turn the bars and hang them over the radiator.

*** ADDITIONAL TESTING; If you have a DMM (Digital multimeter) and want to test the resistor internal to the SPC, see section below for additional testing before installing the cap onto the wire.

SPC INSTALLATION INTO VALVE COVER:
  • Starting on the left side of the engine, insert SPC #1. You should feel and hear the lock on the cap engage the spark plugs conductor. The dust seal should simultaneously seat on the valve cover. If the SPC pops back up any amount after seating it, remove the SPC and move the dust seal up the body towards the HTC.
  • Firmly Seat the SPC onto the plug.
  • Firmly Seat the dust seal onto the the valve cover. Confirm it seals 360 degrees.
  • Proceed to next SPC.

ADDITIONAL TESTING:
The SPC is composed of several parts which should be verified by testing and visual inspection during spark plug replacement or if they are suspect of causing a misfire or vibration. Because these connections are subject to high voltage (15,000+ volts) a bad connections can burn and arc damaging components.
With an ohm meter set to K ohms, insert the test leads into each end of the cap. It should measure 10K ohms. Internal to the cap is a resistor, spring, plug lock, and self threading cable connector. If any of these component have corrosion, arcing, or burning, they should be replaced. Also, the FSM does not list a limit. Mine all measured 10.7 ~ 10.8K ohms.
The resistor spark plugs are supposed to measure 5.0K ohms. My used CR9EK's measured ~ 4.0K ohms each.

COMPONENTS:
On top of my meter you see the spring, ceramic resistor, locking insert (locks Cap to Plug), and the end of the cap body.


Spark Plug Cap (SPC) Drawing:


Actual components internal to cap:
Note: use a flat head screw driver to remove the locking insert.



SPECULATION/ROOT CAUSE:
In this photo the wires spiral wound core was pushed off to one side and the this cap spun freely with no resistance to turning. I cannot prove it, but if you read about inductance and capacitance you see were a tiny change can change the timing of how a coil charges and discharges. It may be milliseconds/microseconds, but it correlates to all if the cylinders not being fired at the same time and this induces the vibration we feel.

HOW WAS THIS DISCOVERED:
I found that the spark plug wire to cap had gotten loose as described here. Although it didn't create a misfire or make the bike run bad (it ran great), it did make a harmonic vibration across all RPMs which rules out throttle body sync. This vibration was increasing so I went for ONE CHANGE and that was to remove the four plug caps from the head and inspect how the high tension lead was seated to the caps. I DID NOT TOUCH ANYTHING ELSE, JUST THE SPC/s & HTS's.

That's when I found the HTL was no longer tight in the SPC. At first I thought this condition added resistance to the junction and it may very well do that. However, the spark plug and the cap assembly account for 13 to 16,000 ohms of resistance THUS IT IS VERY UNLIKELY that a copper wire against a brass screw has high resistance. i.e. more than 10 ohms total. It is MORE likely there is capacitance altering the coils saturation time (charge rate). Remember this is a waste spark system and one coil is responsible for two cylinders. The capacitance may actually alter when the spark arrives thus inducing harmonic vibrations to the firing as it out of time ever so slightly.

PS - I found that one wire being loose can cause a noticeable vibration!! In the last event, cap #4 (spun freely w/out resistance). Before that it was #2 about 2000 miles ago.

SPARK PLUGS:
Check the gap on your plugs and do not Exceed the Recommended gap. If using conventional carbon plugs (CR9EK side fire or CR9E End Fire) the gap should be set to less than the maximum as it opens as it wears. See picture below.

Spec: 0.024–0.028 in (0.6–0.7 mm)

**********************************
PRECIOUS METAL PLUGS AND GAPING:
Before installing spark plugs, the gap must be checked as the plug has many other applications (not just the FZ6 engine) which means the gap MAY NOT BE SUITABLE for this vehicle!
If the gap is too large it can be the cause of the poor acceleration upon re-wetting the intake.
There is a right way and wrong way to verify the correct the plugs gap. Yes, the wrong way could damage a precious metal plug. Using the proper tools for the job reduces the risk of damage.

Regarding application:
NGK Spark Plugs USA

How to Gap a Plug (precious metal specific):
NGK Spark Plugs USA

Bottom line: the plugs must be gaped to meet the requirements of the engine they are installed in.
Spec: 0.024–0.028 in (0.6–0.7 mm)


**********************************
SPARK PLUG TORQUE SPEC:
18 Nm (1.8 m·kg, 13 ft·lb)
**********************************

Used Plugs ~ 13,000 miles and Excessive Gap from Wear:
Note: Plugs gap is opening up as material wears away (2 and 3).




**********************************
THIS DOES NOT FIX: vibrations induced by poor drive chain maintenance, worn sprockets, or kinky chains.
SEE "How to string align your rear wheel!!" for chain and wheel alignment issues: http://www.600riders.com/forum/how-to-s-/40463-how-string-align-your-rear-wheel.html
It is recommended to perform this when changing spark plugs and before performing a Throttle Body Sync.
**********************************

Off Topic but related to ignition testing and from post 33 of this thread. If anyone wants to see the coils unleash on the plug, Place the meter into Diagnostic mode and ground the spark plug bodies.
HOW TO TEST YOU COILS AND ECM:

Our bikes have the option of being placed into a diagnostic mode that will trigger each of the coils to deliver 5 sparks. You can use this to test the coils and look for arc over without the engine actually running so you can HEAR electrical leakage should it exist.

** YOU MUST insert a spark plug. **
** YOU MUST ground the body of the spark plug to the engine block. **
An alligator clip to the plugs body and the other end clamped to a bare metal engine surface should be adequate.

DIAGNOSTIC MODE, Setting the diagnostic mode
1. Turn the main switch to “OFF” and set the engine stop switch to “RUN”.
2. Disconnect the wire harness coupler from the fuel pump (Green Connector).
3. Simultaneously press and hold the “SELECT” and “RESET” buttons, turn the main switch to “ON”, and continue to press the buttons for 8 seconds or more.
4. Press the “SELECT” button to select the diagnostic monitoring mode “dIAG”.
5. After selecting “dIAG”, simultaneously press the “SELECT” and “RESET” buttons for 2 seconds or more to execute the selection.
6. Set the engine stop switch to “OFF”.
7. Select the diagnostic code number that applies to the item that was verified with the fault code number by pressing the “SELECT” and “RESET” buttons ((30 or 31)).
8. Verify the operation of the sensor or actuator.
• Sensor operation
The data representing the operating conditions of the sensor appears on the trip LCD.
• Actuator operation
Set the engine stop switch to “RUN” to operate the actuator.
If the engine stop switch is set to “RUN”, set it to “STOP”, and then set it to “RUN” again.
9. Turn the main switch to “OFF” to cancel the diagnostic mode.

NOTE:
• To decrease the selected diagnostic code number, press the “RESET” button. Press the “RESET” button for 1 second or longer to automatically decrease the diagnostic code numbers.
• To increase the selected diagnostic code number, press the “SELECT” button. Press the “SELECT” button for 1 second or longer to automatically increase the diagnostic code numbers.

Sensor code from operation table:
30: Ignition coil #1, #4
31: Ignition coil #2, #3


See FSM for other sensors which can be tested in diagnostic mode.

2008 FZ6 Coil:
FWIW: Near the Spade is a "+" and "-" embodied in the housing. RED to PLUS SIDE!


**********************************
EDITS:
2014-11-08 Added pictures, Zip-Tire and lower the radiator core
2014-05-27 Added link to String Align Rear Wheel
2014-05-09 Check those precious metal plugs
2014-04-11 Embed post 33
2014-04-11 FIX BROKEN LINKS! errr....
2014-03-31 Fix broken links
2013-09-04 Clarify actions, list order of operation
**********************************
 
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Gelvatron

Junior Member
Elite Member
Just replaced my chain and lubed the swing arm and rear axle I swear it doesn't vibrate at all, if you lived closer I'd say come ride it, I think the chain alignment and wheel alignment are very close and the chain slack is spot on But my hand doesn't got I sleep anymore
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

Just replaced my chain and lubed the swing arm and rear axle I swear it doesn't vibrate at all, if you lived closer I'd say come ride it, I think the chain alignment and wheel alignment are very close and the chain slack is spot on But my hand doesn't got I sleep anymore
Thanks - its just a little ride! :thumbup:

That's how bike normally is; vibration free. So when it makes my butt vibrate something is wrong! This simply fix which was the only thing I touched and made a huge difference returning it to its former SMOOTH SELF!

So anyone having vibration issues that are ENGINE SPEED RELATED (NOT ROAD SPEED), this is by far the first thing I'd be checking. Its so simple yet very dramatic in nature. I may keep an eye out for a better way to terminate the cap to wire.

JJD952
 

norcalwelder

Junior Member
Re: A cure for bad vibrations, spark plug caps!!

I did this yesterday and wow, what a difference! The high tension leads were in those plugs pretty loose and the wires where corroded and most of the strands were broken. I also gapped my plugs. Thanks for the heads up about this!
 

regder

Junior Member
Re: A cure for bad vibrations, spark plug caps!!

Interesting, I've had this sort of vibration on and off for the past few years. Mostly off, but since I've started riding it this year, it hasn't gone away.

Can you do this from the side like the plugs or do you need to remove the battery box/air filter housing?
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

90% is from the right side and no need to lift the tank or pull the air box. The caps are very tight coming out as they are long and hit the frame but they do come out. The other 10% is through the tiny opening in the left side. I highly recommend inspection. As said, if turned clockwise while holding the wire, they should be snug and offer resistance to turning. If they spin freely, unscrew them and correct it. You will be rewarded!

Also - if anyone pulls them out AND HAS AN OHM METER, please measure the resistance of the caps from the conductor at the plug wire to the conductor at the plugs tip. Thanks! Another member who shall remain nameless found two if the four loose, corrected it and again, all the small high frequency vibes went away!

Edit;
From the service manual:
Spark plug cap: Resistance 10.0 kΩ

Also, while the CAPS are disconnected from the high tension lead, MEASURE THE CAPS RESISTANCE!!!! It has components internal to the body which can go bad! i.e. should corrosion or arc over begin, the resistance will go up. Should the resistor burn open (unlikely) but if it does you'll have a weak spark or no spark.
View attachment 48134 View attachment 48135 View attachment 48136
Its worth a look if they don't measure properly!


Remove TWo Bolts and allow Radiator to settle for Access:


Don't let this mount poke into the Radiators core! Blue arrow!


These TWO bolts out and there is plenty of room:
 
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motojoe122

No ride is too far...
Moderator
Elite Member
Re: A cure for bad vibrations, spark plug caps!!

I did this yesterday and wow, what a difference! The high tension leads were in those plugs pretty loose and the wires where corroded and most of the strands were broken. I also gapped my plugs. Thanks for the heads up about this!
I did it the other day too, #3 and 4 caps were loose. Checked the plug gap as well, all were in spec. It made a noticable difference in vibe reduction.
 
Re: A cure for bad vibrations, spark plug caps!!

After seeing this topic last week, and I did the job today. Although #2 and #4 needed to be done, the vibes remain.
This bike has enough vibes to supply two other bikes :cheer:
Still fun to ride tho.
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

After seeing this topic last week, and I did the job today. Although #2 and #4 needed to be done, the vibes remain.
This bike has enough vibes to supply two other bikes :cheer:
Still fun to ride tho.
Can you give us some details? When where, what RPM, At Speed, under load, etc ??? This WILL NOT FIX - drive train vibrations like:
- dry chains / worn chains
- kinky chains / over tight chains
- out round/out of balance tires
- bent wheels

For the most part, if you have ran a couple treatments of injector cleaner, have new plugs, the spark plug caps are tight, air filter is mostly clean, and the valves are adjusted properly; this will help ALL RPM's! If your vibe is MOST prominent below 4000 RPM - Do all of this and then Sync the throttle bodies.

Other items to consider:
- Valve adjustment / compression test
- Bad coils/Bad wires
- Bad spark plug caps. Take them apart from the plugs end and examine the spring.
- Bad Gas
- Engine to the frame bolts are tight BUT the FRAME is stressed (loosen all bolts, blip starter, tighten all bolts).
 
Re: A cure for bad vibrations, spark plug caps!!

Can you give us some details? When where, what RPM, At Speed, under load, etc ??? This WILL NOT FIX - drive train vibrations like:
- dry chains / worn chains
- kinky chains / over tight chains
- out round/out of balance tires
- bent wheels

For the most part, if you have ran a couple treatments of injector cleaner, have new plugs, the spark plug caps are tight, air filter is mostly clean, and the valves are adjusted properly; this will help ALL RPM's! If your vibe is MOST prominent below 4000 RPM - Do all of this and then Sync the throttle bodies.

Other items to consider:
- Valve adjustment / compression test
- Bad coils/Bad wires
- Bad spark plug caps. Take them apart from the plugs end and examine the spring.
- Bad Gas
- Engine to the frame bolts are tight BUT the FRAME is stressed (loosen all bolts, blip starter, tighten all bolts).
Thx for the thoughts on this. The vibes begin at idle, and increase heavily after 6000..
Been through the sync'ing, re-torque, good gas, new plugs, and this coil-wire check.
No joy.
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

Thx for the thoughts on this. The vibes begin at idle, and increase heavily after 6000..
Been through the sync'ing, re-torque, good gas, new plugs, and this coil-wire check.
No joy.
Might be worth it to do a compression test. If they are not equal, proceed to Valve lash check. But you can say "heavily after 6000.." as in not drive train but engine??? i.e. if in neutral it does it doing a static rev?

If valve adjustments are made, you'd have to sync again.
 

Clay350

Junior Member
Re: A cure for bad vibrations, spark plug caps!!

I honestly dont think this can have an affect on vibration. Just don't see it. If one or more cylinders aren't firing it would be very obvious.

My vibration has always been in the 6-8 k range like most fz6. It is not a coincidence that this is vaguely where our engine have a lull in the power band. What im saying is that its completely normal and cant be fixed for this engine. It can only be marginalized by other means such as motor mounts etc....
 
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FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

I honestly dont think this can have an affect on vibration. Just don't see it. If one or more cylinders aren't firing it would be very obvious.

My vibration has always been in the 6-8 k range like most fz6. It is not a coincidence that this is vaguely where our engine have a lull in the power band. What im saying is that its completely normal and cant be fixed for this engine. It can only be marginalized by other means such as motor mounts etc....

Are you saying - added resistance from a compromised connection can not cause an increase in vibration? If that is the intent of the above statement - I'm telling everyone else, that is NOT the case and it DOES MAKE A HUGE DIFFERENCE!!! That is exactly why I changed only one thing and nothing else. I didn't remove the plugs, just the caps.

Also if you read my original post, you see I was not complaining of a complete misfire - but a vibration. Doing this simple action cured high frequency vibe that was present across all RPMs.
 

FloppyRunner

Motorcycle Noooooooooooob
Re: A cure for bad vibrations, spark plug caps!!

If whoever does this next could snap some pictures of the relevant components, that'd be greatly appreciated. I may be able to do it this weekend; if so I'll get some then. Honestly, I'm not entirely sure what we're talking about, but I probably just need to tear into it myself.
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

If whoever does this next could snap some pictures of the relevant components, that'd be greatly appreciated. I may be able to do it this weekend; if so I'll get some then. Honestly, I'm not entirely sure what we're talking about, but I probably just need to tear into it myself.

Scroll up; Joe Read your mind!!! :thumbup: I posted!

As for the wires end; when snugged down; some will come up tight; others will feel like a stripped thread. Fix the ones that feel stripped.
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

New info to share....

from this post: http://www.600riders.com/forum/fz6-performance-mods-section/43406-spark-plug-choice-2.html#post542095

Which has my thoughts. Oh and some from Cliff.

One of the reasons gap could be twice as important on our bike is it uses 2 coils for 4 spark plugs. One coil for #1 and #4 cylinder and one coil for #2 and #3 cylinder. What happens is the coil fires at TDC and the end of the exhaust stroke for each piston that is mechanically at TDC and end of exhaust stroke. In other words pistons #2 and #3 are both in the same position in the cylinder but they are at opposites in firing and exhaust. One being the end of compression and beginning of power. The other cylinder would be the end of exhaust and beginning of the intake. So the coil is firing twice as many times as a coil that is dedicated to one cylinder. Dielectrically there is more stress on the coil pack because the path for it's spark has been increased. It is more likely to create corona (with increased gap) internally and break down internally or when there is an insulation problem it may more readily take that path and not produce a strong or weak spark where we want it. The coils are looking a 2 plugs... Be careful setting the Iridiums!
Set your gap to factory specs! :)

What it really lacks by design is saturation time. At 14,000 RPM that doesn't leave much time with "waste spark system" so its very likely coil output energy is weak at high RPM. Remember its not just a spark and there is current factor. Hence the reason the gap is so critical.

Just an observation but Yama may have learned something over the years as the 09 does not use the "K" plug with the double ground strap side fire electrode. Also NGK calls for less gap on the CR9E single ground strap plug (conventional plug) 0.028" vs 0.032" on the K version.
POINT; the CR9EK is gapped at 0.032" The spec for our bike is 0.6–0.7 mm (0.024–0.028 in). be sure to correct this before installing your plugs!

EDIT:
I'm curious if the ECM/Coil packs would be OK without the resistor Plug CAP or would this impair them or something like the instrument cluster from the EMI noise emitted either radiant or back into the connecting wires? I might remove the interanl resistor in the cap and see what happens! Why you ask? Because I can feel when the plug wires get loose in the caps. Not to thread derail, but I'm curious if there is anything to be gained by removing the inline resistor to get more energy to the plug?

The Downside:
The resistor cap and plug add 10K and 5K of resistance. This drops the current delivered to the plug. By reducing the current, there is less electrical noise emitted by the ignition system, more heat generated by the resistance and less energy delivered to the plug (think in terms of current here). But its very likely the load in watts goes down with these resistors in place and the ECM or Coils may lack the balls to run without the series resistors. So this could all go horrible wrong and lead to a misfire. You see what I don't know is if the ECU and Coil packs have the energy to run w/out that 10K resistor plug cap?

If this was purely from a noise suppression iussue it seems a better choice would have been a shielded plug wire as the CAP and plug are shielded (EMI wise) by being recessed in the head. I just don't see why they did both? The head is canceling the radiant EMI however there is an exposed wire that's acting like an antenna as its a solid core non-suppression wire tossing out EMI noise everywhere. So it almost seems like they did it for the sake of keeping the energy demand low.

I guess my point is the coil output is so feeble with a mere 0.028" max gap that it needs all the energy it can muster at the plugs gap. Hint most HEI coils fire plugs gapped at 0.50" or better these days so this seems weak!
Thoughts anyone?

Other things of interest:
NGK DENSO BOSCH BRISK SPARK PLUG TEST - YouTube

Some thoughts on Ethonal based fuel.
NGK Spark Plugs USA

Read up on this:
NGK Spark Plugs USA
NGK sparkplugs information and specification

08 and lower
CR9EK // 4548 // OEM Gap = 0.032" // Iriduim # CR9EIX gap 0.032"

09
CR9E // 6263 // OEM Gap = 0.028" // Iriduim # CR9EIX gap 0.028" // single ground wire

While here lets throw Torque Spec:
17.5 Nm (1.75 m·kgf, 12.7 ft·lbf)
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Re: A cure for bad vibrations, spark plug caps!!

Very interesting from an Aviation thread....

Missing picture is is showing the internal resistor which is breaking down and failing. See link below if this peaks your interest.
Excerpt: <<PASTE>>
As you can see in this photo of a two month old Champion RHB32S fine-wire spark plug with only 110 hours in service, there is corrosion on the conductive surfaces. When it was new two months ago, the resistance was normal, about 1500 ohms. But today, this spark plug’s resistance is over 12,000 ohms! That means some of the spark energy isn’t passing through to the electrodes. This spark plug was causing elevated CHT’s in the affected cylinder.
Installing new spark plugs resolved the CHT problem, and stopped the intermittent vibration problems at low rpm.

Note: CHT is Cylinder Head Temperature....

Full link: Spark plugs. Why you should check yours, today! | Platinum Aviation Blog

Excerpt: <<PASTE>>
For the past two years Tempest has been educating the general aviation industry on the importance of checking the resistance of spark plugs. Here are some common myths and misconceptions about spark plugs and resistors:

1. Resistors are used in spark plugs to reduce radio noise.

False - resistors, although they may help with radio noise reduction, are used primarily to reduce the electrode erosion effects caused by capacitance after-fire. This is a known after-firing of the plug caused by the residual energy built up through the harness leads and magnetos.


Granted we are NOT running magnetos so I have some research to do...

Just thought I would share. We are not alone. In this thread there is mention of why those resistors are in there. It's about the field collapsing and reducing the spark plugs life as well as noise suppression.

My POINT: how many of you with vibration issues have a fault in one of these areas, plugs, wires, cap, or power to your coils, coils or ECM, thus causing increased vibrations but minimal drive-ability complaints? IMO - way too many complaints thus something is being overlooked!
 
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motojoe122

No ride is too far...
Moderator
Elite Member
Re: A cure for bad vibrations, spark plug caps!!

Eat your words broooother!!!!! :BLAA: :spank: :spank: haha!
Geez, not sure how I missed this:don'tknow: Yeah, I'll take it with a spooon full of Techron:BLAA: I think I still have some random pics from when I did this, but they are on my phone. Not sure if it will U/L.
 
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