A Case for Fogging

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A Case for Fogging - Venture Riders Forum

 

This post is based on my experience over decades of both getting it right and of course getting things wrong.

Like many of us sometimes I just fall for a piece of sport machinery, often the older the better.

We stand there looking at a forgotten project and we think “how hard can it be”.. A good question but not the right question! How much will this project cost both in time and money may be the better question?

Perhaps you can justify both, or you have already completed a project before, so knowing all too well what it may take in both money and time. My opinion is that it can be very satisfying to inch our way through a project bike, then counting down the days, weeks or months to the first ride. I might add that I have always found the learning curve and interaction of these projects to be stimulating as we inevitably expand our social circle to include interested parties and or forums which often become not just an amazing resource, but lead to interesting and shared experiences!

 

Recently during a discussion with Freebird revolving around an OP’s post on power or lack of while in 5^th gave this post some direction! I have wanted to share my earned experience but found it hard to keep the it limited to just around combustion issues! All the other known issues are covered very well here both in the library and through posting. So, I hope to just brief over the other circuits even though they are critical to performance!

 

First every fix requires a budget; you decide what that budget is or how flexible it can be.

 

A Case for Fogging? For those of us old enough and can still remember, that seasonal engines came with manuals describing the proper procedures for storing during out of season “months” (not years) anything from lawnmowers to outboards, bikes or whatever’s.

What happened to this procedure? The resulting effects of incorrectly storing an engine is loss of output! That means wasted potential horse power, which in turn means lost torque.

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Seems like we all know what torque is these days in large part due to the car manufacturing industry now promoting torque over HP? So I guess there is no need to explain that this all starts off the center of the crank; which is then leveraged through the design components above it.

 

Let’s modernise the old engine for a moment and imagine a check engine light on the dash. I know the gen 2 has such a light but as far as I know it is a basic circuit light only for electronics. Now the OBD 1&2 can or may spit a code and, the check engine light is on suggesting you read the code. But a flashing check engine light should suggest you pull over and check it now.

Common codes, 300, 301 ect we know means the monitor system has logged an incorrect value based usually on crank rotation. Easy enough we have a misfire.

 

Back to real life, we are the logic for our older engines, which means we need an old fashion understanding in troubleshooting! So let’s just keep this in mind.

 

Below are some photos of a V4 resting, notice how the piston isn’t centered.

This is a very low mileage engine, in no means was it in need of opening other than to serve as a reference for another project.

This mirrors what an engine will go through while stored, the V angle and gravity will cause the piston to rest on the spring! Think about it and we’ll get back to it.

 

What else is happening? Well valve springs are also in a compressed partial duty cycle. Some valve seats are exposed and some are seated yet all are exposed to corrosive build up potential.

So is it worth considering during the project? A good question and in my experience we usually manage around this with a prep that I’ll share here. But true to say this may have effect. The valve springs will usually if at all show weakness at the higher RPMs where touring bikes rarely play for long.

 

Next is battery voltage referred to by HV (House) if the bike is new to you, you either have a steady battery Voltage or you need a replacement? For the most part of troubleshooting I’m using a charger on trickle.

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HV at 12.3 - 13 should be expected at the coils when key and kill are in the run position. I can’t stress enough that this needs to be 2^{nd down} from the top of our check list! Troubleshooting the coils as shown in the manual is I think the best way; as we load the system circuits in real time, we see what the combustion cycle experiences! Again being brief here, if the testing gap meets spec – good to go. But you can still go further and monitor consistency, which could point to a week pickup coil or a fault in the control module. Odd misses can be ignition coil not cycling quick enough or, pickup coils. Consistent misses on all 4 isn’t common but the rhythm and visual misses if on all 4 are evident then it’s control module.

 

There are many easy patches to correct HV loss at the ignition coils if cleaning contacts alone won’t correct it.

 

Carbs; seems like everyone can rebuild them after acquiring a kit? Not so but with proper attention to detail and a basic understanding of CV carburetors sure but, you need to be absolutely sure that you have completely gone through every circuit in the castings! Again there is a lot of forum help on this so I’ll brief past.

One note on this is to maintain stock air box and filter. Also and until you know for certain always check and reinstall factory jetting sizes, changing jets on an engine that is not performing to spec is usually an unsuccessful effort.

 

Old gas is bad gas and should be disposed of. An old fuel filter is a waste of carb rebuilds.

 

You should not tune an engine with any gasoline additives mixed in the tank.

Gas is gasoline, it is not fuel till air/fuel ratio makes it so.

 

I buy 3 gallons of cheap dino oil for frequent changes during the procedures and a can of crankcase flush would be beneficial. I start with the first oil/filter change before testing the engine.

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A typical scenario : The seller bought the bike from someone who bought the bike after it hadn’t been used in many years. They spent some money and time getting the bike running and as is often the case, rebuilt the carbs!?

Often we see that they mention “the carbs just need to be synced”? News flash, if you rebuild the carbs properly, they would have been bench synced! The syncing we assume needs doing is matching to the pressures produced in the cylinders! There is a reason why this is more difficult than just acquiring a set of CarbTunes.

So here’s the BIG question: why then would we sync them in a running mode, without first knowing the pressure values within the circuit?

I am going to expand on this a bit: if you are tuning which includes syncing and, after 10 minutes of chasing your tail over the pilot settings??? What question can you ask that can be properly answered without knowing what the compression is?

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Compression is the most basic and obvious first step when working with an older engine, especially if it’s a sport machine!

There are a few steps that should fall in some kind of order to get a usable dry reading.

Battery assessment

Fresh oil and filter would be helpful (the cheap stuff)

Disconnect fuel delivery such as fuel pump

Remove all spark plugs, number them and take your best guess at reading them.

*For the record, you cannot tune with old plugs, you can peak at history though.

Carbs should be removed or at a minimum drained, this effects dry readings

Finally short your coils HT wires

 

With a full HV you should be able to spin the crank fast enough to develop good reading around 5 rotations but keep it going till she maxes out.

 

Up front guys let me say, don’t panic with low results unless they are below 60psi.

 

 

1. Let’s assume the reading are 90, 70, 120 & 179
   

 

The key here is 179, the others are what I would expect with an engine that hasn’t run years. If you just purchased this bike, chances are good that you will end up with close to factory performance potential.

 

 

1. Switching it up we read 170, 95, 185, 190
   

 

This can be more troublesome than the lower readings on these touring V4s which are moderate compression designs made to run off 87 octane. However on the VR1300 the design specs allow for this extra piston pressure!

However cylinder 2 is not contributing enough torque resulting in slowing the next up in the firing order. Because # 2 isn’t producing enough pressure it has the effect of having slowed the expected crank speed. Then next in line for the compression stroke on 3, which is also higher than “standard” pressure thus it requires more energy to complete the compression stroke. This stroke is in fact going to be achieved through the robbing energy out of the crank that was developed by #1 and transferred to the crank shaft via rotational effort, and the cycle repeats!

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This also effects scavenging as it reduces velocity in the exhaust pulse, which means just that you fill the volume with less fresh charge, and, also reduce combustion temperature! You would think you paid the price for #2 lack of pressure with 3 right? But no you pay twice because of the collector!! Wait, are we done paying for #2 not quite. We have ignored another influence; Ignition Advance; holy shoot this is turning into a never ending downer, right? Well advance by nature moves forward charge ignition meaning that we load the piston earlier during compression stroke resulting in earlier building pressure and this to requires more energy from #1 to complete #3compression stroke, YIKES.

So let’s think about it, we have diminished output at the crank end which both scenarios will do. Can this result in less torque over all gears not just 5^th? Yes because we know where torque is developed, crank rotation and torque output is a result of imposed piston pressures. We just tend to notice it more in 5^th and then we assume it’s too tall a gear! Under the above conditions it is.

 

This can creep up on us who have owned these bikes for a long time and, we just start looking towards other solutions which we have read and others have tried.

Yet Puc just demonstrated on his “almost as old as he is” VR1200 can pull onto the HW in 5^th at way to low a speed and rpm’s.

 

That aside I too had the problem with my VR1300 with 5^th and corrected it through balancing my compression which was close to senior 1!

One final note that is relevant to my direction here; Freebird mentioned upgrading coils; this caught my attention: I agree that a faster, stronger and more reliable secondary output is a plus. Why is this a power gain and or why might this be included with 5^th gear problems? Simple really; we know or knew these bikes have power, we refuse to lean towards a lack of power. What we didn’t know was power vacationed away, often unnoticed until 5^th. The stronger spark Freebird alludes to is A gain because of the pressure and shape changes the fuel charge will experience during compression!

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So what causes the higher compression? That’s pretty easy to answer; there are 2 reasons, both are our fault and boil down to, too rich of a combustion charge!

 

3 causes come to mind right away - enricher leaking or improperly set? Sticking with this circuit we do see way to often bikes warming way too long on the enricher/choke. How many times do we fire up the bike off season idling with enricher on?

I start mine let it run for less than 3 minutes on a crack of choke, then shut it off and let it warm through conduction while I ready for the days ride.

Next is the mains, shimmed or worn needles and jets which will cool combustion especially at low RPM. Assuming of course, we are metric riders then this third reason can’t be, as we know these bikes need RPM.

 

Now we break the 2 scenario’s down for correcting. I use now only 2 different products.

Scenario 1 is stuck rings! Rings are strange things when we really know how they are designed to work. Firstly they are springs and they must be able to spring in order to lock compression! Not all designs lock the same way. Next they will and should be able to rotate; this has to do with honing angles and the shock of when the ring releases. Thinking about it we can see why they are sharp edged and need stay sharp! Next is heat transfer, this is very important and why glazing is such a bad consequence of using incorrect chemicals in a cylinder; is also why we DO NOT use ATF for freeing stuck rings!

 

So for both I use Deep Creep. Now there are and I have used other products and had used them for many years as combo formula I learnt very young but, Deep Creep works well for me!

 

For high Compression problems I use 1^st Carb cleaner then Deep Creep, yep that simple!

1^st rule is never put liquid above a piston when or where compression is a potential. This is easily avoided providing we do not reinstall the plugs. Treating stuck rings usually takes 2 days of soaking with Deep Creep. The idea is to fill the combustion chambers to the top allowing to soak overnight. Then engage the trans and jerk the rear wheel, then refill! You will know when after the second refill is gone that she is ready, and you can check with a straw inserted checking to see if it’s dry when removed. Again a couple of jerks on the rear wheel will help break the rings loose.

 

I also fill the intakes at each interval, if you’re up for it, then do the same for the exhaust ports. Truth is I have found that it will creep to the exhaust seats anyways!

After 2 or 3 days while work advances on other parts of the bike I will then blow the cylinders out, being careful to not make a mess; eye protection is a good idea!

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Load your fresh spark plugs, and if the carbs and ignition are ready just add some gas, I have bench tanks so… You are ready to fire it up! I always use a shop

fan on the bike to help maintain temperatures!

I’ll let it run around 1500 rpm ish for about 10 solid minutes with minimum idle adjustments. With your air box on you can and should give it a couple of short snaps, you will notice as the chems burn away the revs will become more crisp keeping snaps below 4000! The deceleration of the rpm really helps get the rings back in shape!

Remember that the oil is contaminated now and shouldn’t be pressed hard or long.

 

For me this is the time to retest the compression for gains.

 

Now scenario 2 is adding the carbon buster and will require that chem to be the first added but, it will need at least 2 refills a day for 2 days then add the Deep Creep. However it is usually necessary to treat each valve both intake and exhaust directly with the chem and a little light wiping with a rag. The reason here is because the deposits that formed as a result of too rich a charge have tendency to stick to the fillets of the valve which will reduce volume in and out as well disturb flow. And so this takes a bit more effort when compared to stuck rings but, is still less effort then tearing it all apart to clean the carbon off!

Eye protection again is a smart idea.

 

Very import note to mention, this procedure will severely contaminate the oil so no testing or running the engine with the oil, you should simply drain it.

After the soaking is completed refill the crankcase, remember the oil filter hasn’t been contaminated yet. Run the engine as above then check compression, note your gains, then decide if you need to soak longer. If you are good to go then this is when I would flush the crankcase following the can directions. And again you need another fill and this time filter as well. Now it’s time to start tuning so long as you are close to spec, we can call it a WIN.

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Ok next comes the debate about reduced engine life after decarbonizing!? Yes this can be and has been a known issue! Again let us think about it for a moment… Carbon is a very fine and relentless abrasive material. Let’s weigh the options. We can do a tear down and honing, then there are the bearing measuring, grinding and more grinding…..

So how do we get away from this? The answer lies in the end results of decarbonizing, and what the results of the next round of testing shows.. The key for me has been simply refreshing the oil and filter 3 times before moving to my final synthetic brand and filter! Now we can’t say for certain that we can capture 100% of the fine carbon but we can get most of it as it will suspend in the oil,,, look at it this way, we don’t have leftover grinding products that got missed so I call it a draw.

 

Let’s not forget that in the case of VR1200s the connecting rods were overloaded in the above scenarios.

 

So that is it, these bikes will just keep running so long as we keep both the compression and opposing sides of the stokes within limits with proper maintenance.

I would like to add a personal thought and it has merit based on my understanding of combustion. Fooling with stochie takes math, a visual and a consequential understanding of combustion cycle after cycle. Fine if you are so inclined, I for one enjoy those conversations. But I have yet to see a touring bike benefit from such experimentation, and let us not kid ourselves as that is exactly what jetting and shimming is; there is always a cost attached to that potential gain! We run touring bikes, reliability, range, predictable, and control mixed with some comfort needs to be the end game. These are heavy bikes, off the line 1/4s mean nothing at the end of the tour.

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All the above could have been avoided by one, adding compression tests to your biyearly schedule and fogging before properly storing our sport machines.

Also using a fuel stabilizer before storing then emptying the carbs, can save you many common carb problems!

 

Below we see the position of the 2 pistons

I have fogged this couple of times over the years but was surprised that even though I haven’t in a very long time I was with minimal press able to move the piston.

 

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[wrscomncents]

All the above could have been avoided by one, adding compression tests to your biyearly schedule and fogging before properly storing our sport machines.

Also using a fuel stabilizer before storing then emptying the carbs, can save you many common carb problems!

 

Below we see the position of the 2 pistons

I have fogged this couple of times over the years but was surprised that even though I haven’t in a very long time I was with minimal press able to move the piston.

 

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Steven, great post. I may try this after the season is over. I bought an older bike (1999) that I believe sat quite a bit. Thanks for the info.

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My pleasure.

 

If I get a call to a project I'm usually gone for months. I take some shortcuts to avoid issues come the next season.

 

Gas stabilizer is added to the tank which also helps the pump. I run the bike carbs dry disconnecting Pump connector left side behind the frame riser tubing. Or use the drain ports on the bowls.

 

Let it cool for a bit and just give a 2 second shot of DeepCreep through the throat of the carbs and leave it set.

 

Always remember to never rotate an engine with fluid above the pistons - while the spark plugs are still in the heads !!!

Usually in a week or so the fluid will have creeped past. What ever extra there may have been is now in the crankcase.

 

So this above is not to solve stuck rings or varnished walls but works towards preventing the problems.

 

When you do attempt it take some readings and share them here. Maybe your experience will give confidence to others.

[cecdoo]

Very interesting write-up have often thought of fogging the bikes, always fogged the Sea-Doos. Might just give them a shot in each carb this year.

 

Thanks, Craig

[uhfradarwill]

I'll know the compression numbers for my 1989 very soon but I'll never "store" this bike or any of my vehicles ever!

I'll go out every week at least and fire them up for some time and ride them if the weather permits.

Storage, phooey lol

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I'll know the compression numbers for my 1989 very soon but I'll never "store" this bike or any of my vehicles ever!

I'll go out every week at least and fire them up for some time and ride them if the weather permits.

Storage, phooey lol

 

With the low mileage your bike has you can expect top marks from the compression test. Even with stuck rings if that be the case, its such an easy fix and worth the effort.

 

An example I didn't mention - for some guys who have low exhaust pipe temperatures on 1 or 2 cylinders and are sure the carb set is in proper working order will first try and tune their way past that. There are times that the pilot circuit is the fault; if not then a stuck ring set is the next likely cause.

 

I also avoided the conversation of actual operating compression so far in this post (load verses no load just like voltage) because it is a much more entailed discussion. But, for relevance sake a quick brief. We test compression then match results to the (standards) posted for that engine, the reason for the posted limits are many but, we can by rule of thumb assume the actual operation pressures as a result, which are quite a bit higher and is why the limits matter.

In general think of this - the closer we are to stoichiometric the more efficient the pressure is - pushing the piston down. So one without the other are simply just 2 benchmarks;;; but locked up together with a well timed ignition then- the path of least resistance is, the rotation of the crank.

 

So this is why we should always start with a compression check before rebuilding the carbs.

 

A leak-down test - now that takes more effort and experience to sort out.

 

Anyways that's how I know it to work.

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Looking for a place to post this Ignition system explanation so here it is.

 

I watch these at higher speed setting on youtube to cut down the viewing time.

 

Keep in mind that TCI and CDI work differently: https://www.sportdevices.com/rpm_readings/CDI_and_TCI.htm#:~:text=CDI%20Ignition%20makes%20the%20spark,using%20a%20SCR%20(Thyristor).&text=This%20type%20of%20ignition%20makes,before%20the%20spark%20is%20done.

 

 

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Well we just had a good discussion on PCV for the 1326 cc. Again we get back to the basics and the need to know how close the engines we run are to the benchmarks provided by the factory. Knowing is key to our tuning and repairs.

Fluid dynamics is not easy: It baffles the mind to realize that a dip, tube splice or blunt edge may represent a performance flaw but such is the case.

CCV (closed crankcase ventilation is by far a safer and cleaner way to go, why it took so long to arrive is well no different then the temptation to reverse it because 1 we have trouble understanding it and 2 we don't trust it I guess.

OCV is easier, makes sense too when we only choose to see one side of the loop. OCV has kill many an engine and any of us that worked on the 60's and 70's American muscle engines have experienced the effects and visuals after removing a valve cover; gritty grime right thru the system. Have you ever had the chance to split a intake manifold? I have for more than just one reason too, the signs we see inside are often depressing to say the least.

In my time of fooling and experimenting with engines crankcase venting has always been somewhat of a pain until I began working on European engines. Those especially the Benze were quite complex and finicky as well. When they mess up the E.M.S begins spitting codes, it can be a bugger to track down. They can also rune the cats and begin blowing blue out the tail pipes. At first it's a WTF moment, where do I start the guess work.

The BMW 4.4 often get valve seals changed because the YIY doesn't even consider the CCV  system as a potential and that works out to be roughly a $2970.00 booboo and that's not considering cats.

All that to say it is an important factor to maintain and understand the CCV on any internal combustion engine.

I found this link by the EPA, it is a bit slow to read because of how the we turn the pages but still a very worth while read IMO, it basically starts on page 7 look for the green arrow to change page. There's a lot to this I hope you'll see my intrigue in combustion and the results of the symphony at play.

For a quick sufferance on the value of this read check out page 11

https://nepis.epa.gov/Exe/ZyNET.exe/91010D2I.txt?ZyActionD=ZyDocument&Client=EPA&Index=1976 Thru 1980&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A\ZYFILES\INDEX DATA\76THRU80\TXT\00000021\91010D2I.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h|-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r85g16/r85g16/x150y150g16/i500&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results page&MaximumPages=1&ZyEntry=11