Blue smoke from my WLA

[David V]

I'm getting some blue smoke from my WLA at the moment.
Not when she's cold but as soon as she gets hot, there's more and more of it. From the exhaust but also from the rear cylinder that leaks around the exhaust pipe.
Could this be piston rings ?
Would a compression test show anything ? I have a compression tester that I've used with my jeep. Not a dedicated bike one.
I've never stripped her head off yet. Maybe I'll have to.

David V

[artificer]

Blue smoke is oil related....usually rings or dusted engine cylinder/s....why not do a dry then wet compression test?

[John W. Rymark]

Hello,

Two things, most importantly blue smoke sure is oil getting into the combustion chamber and out the exhaust. Most likely suspect are the rings. Had a friend at one time who went through new rings of a top end job pretty fast. As I recall there was discussion of an over rich fuel supply (carb) washing down the cylinder walls and creating excessive wear resulting in premature ring wear. On the other side, I've heard of too lean a mixture causing too much heat, over heating which causes premature wear of the rings. Either way, it sounds like the rings going. If you don't use her much, perhaps the rings are just set, not expanding properly. I think I'd try some Marvel Mystery Oil or some automatic transmission fluid squirted down the cylinders and let it set a few days to see if you just need to losen up the rings.

On a separate note, and I don't mean to be rude to this string, but I noticed the note from Artificer. In my recollection an artificer is a model maker. I was a simulator technician in the US Navy. We set up and repaired the digital computer systems, interfacing and consoles of simulators (like aircraft, ships engineering, submarines). If one were to look up our people,..Tradevman or TD it would also say artificer. Model maker?

[artificer]

Rather than explain....this says it all & a bit more....http://en.wikipedia.org/wiki/Artificer

[David V]

Well I finally found the time to do a compression test tonight - only on the rear cylinder as I didn't take the tank off.
Result 4.25. And an over rich plug front and back.
Maybe this weekend I'll take the take off and check out the front too.
This bike has always run better richer. Needle is 3 full turns out and down about 10 clicks.

However this does seem down quite a lot to me. And the bike is not very powerful - well all is relative !

Does that seem like rings to you guys ?

David

[John W. Rymark]

Yes, it seems like the rings. Also, as I recall the guy with the WLA who had to reinstall rings too early had a rich problem (i.e. ran better rich). I believe he finally resolved the having to run rich with a timing adjustment. The last I heard of him he was running an electronic timer. With today's electronic timing installed to look like a regular points unit, how could you go wrong.

Regarding lack of power. Certainly a compression symptom. However, once you get new rings installed and that rich/timing situation sorted out, if you chose to run points (not electronic) then you might consider looking at your WLA operator manual. A bike with manual spark advance isn't just for starting. A manual spark advance requires manipulation, tracking of the throttle and spark advance. A common observation with a manual spark advance is no umpppha up even a slight inclined grade, engine slowing or lugging down, no power. On a manual spark advance the throttle and spark advance are meant to be rotated together. If you don't have a counter wieghts changing the timing in an old jeep, or vacum advance in a later jeep, you aren't in proper timing and lack power as you increase the load on the engine. Well, anyway, please consider.

[1stCAVREG]

Hello,
As everyone has noted, ring failure is the likely culprit for the blue smoke but there several reasons the rings may have failed.
You have not told us how long it has been since the last rebuild. If it is fairly recent, it is possible that one or more rings have been put in upside down (modern rings often have a camphered top outer edge, if upside down, oil will pass into the combustion chamber). Too tight a ring gap can cause a ring to break and score a cylinder. Too loose a ring gap and oil will pass through the gap. Improper ring gap alignment between upper and lower ring will also allow oil to pass into the combustion chamber. Incorrect ring size (example, using a .050 ring on a .040 piston) will not be round (it will be elliptical) and will not seal the cylinder properly, quickly wearing out.

Fuel mixture, too rich will cause premature ring failure by washing the lubrication off the cylinders. It will also allow carbonization of the heads causing poor performance.

Too lean will cause overheating and can eventually burn a hole through the piston.

Only a proper medium mixture will give best all around performance, neither lean nor rich.

Spark plugs, is it possible you have been running a plug too hot for your driving conditions?
Is your carburetor an M-88 with a fixed high speed? If yes, is the needle fully seated and is it running the correct #1 jet? If not, this could be a source of running too rich.

On the M-88 with the fixed needle, the adjustable low speed needle effects only idle operations and light load operations under 35 mph. No impact on the mixture over 35 mph.

Sluggish operation (poor carburetion and bad rings aside): proper timing is a must. Are you doing your timing with or without a test light? If you are not using a test light to establish exactly when the points break, your timing may be off (I say “may be off” because you might accidently properly set the points).

Point gap is a snug .022”. Plug gap is .028”.

Electronic ignition? Personally speaking, a waste of money. They can and will break down. Heat is their enemy and heat is what they get riding inside an H-D breaker housing. Points can be cleaned on the fly to get you home.

If you running the H-D early style points, make sure that the points are tungsten. Some aftermarket makes are cheaping out on the material. Also, with the aftermarkets, the moveable point may have flashing at the pivot point which needs to be trimmed so the point sits properly on the post. Also check that the fiber block is square and square the points as well to get a proper gap. You can also run the 1949-1969 style points (a readily available GM point set) by converting the breaker head to the later points (a friend has a pattern and does this upon request) or by converting to the later 1949-1969 breaker head.

Additionally on your performance and points, look at the points themselves, are they burning cleanly or is there transference of material from one point to the other? Depending on which point is getting the material will indicate if your condenser is too strong or too weak. Regardless, if transference is occurring you will need a new condenser.

Back to the ring failure, it can also be caused by a dirty air cleaner. Further, now that you have blue smoke, you are also likely experiencing “blow-by”. Blow-by is the combustion gasses passing the rings and getting into the lower end. The heat of the blow-by gasses are too intense for the lower end bearings and will lead to a premature failure of your rods and flywheel shaft bearings.

One more possible source of ring failure is a bent rod. When you pull your cylinders, examine the carbon tracks on the sides of your pistons. These tracks will be on the sides with your wrist pin holes since the pistons are cam ground with the wider surfaces front and rear.

A straight rod will have a fairly straight up and down carbon track with slight flaring at the top and bottom. A bent/ twisted rod will have a track running at an angle away from up and down. If you have a bent/twisted rod, you will need to take of that before changing out the rings/pistons or you will be in exactly the same boat you are in sooner then you want to be.

[David V]

I found this bike 2 years ago and she hadn't been running for several years. I find that it was miracle that after cleaning the tanks and totally restoring the carb which was a real mess, she started nearly first kick with a new battery.

I don't know the history of the bike - I bought it from a woman selling her divorced husbands "toys". He wasn't a mechanic - just bought toys to drive and ride and then moved on the another.
It was imported in 1986 from the States to the UK. She didn't know anything about it.
If the bike has been rebuilt at some stage - it was a long time ago. All the wiring is still original like the rest. Some of it in not good shape. I don't think it has ever been "restored" as we think of. Certainly I would think not after she came over in 86. But who knows.
I know the head has been off at some stage because the head with the small hole drilled in it for a radio suppression wire is on the wrong cylinder.
There are oil leaks around some of the head bolts. I have tightened some head bolts that were loose.

The carb is the classic M88 military with new jets and float (cork one although I have a Rubber Ducky to fit sometime) and main nozzle. It has a fixed high speed needle. I will check that it is fully seated. I can also check the jet number. It does not have the extra carb extension to the manifold - it's a type VII WLA.
Frankly since redoing the carb I've not had any problems with it but it has always run rich. I tried replacing the low speed needle with a new one but it wouldn't take it - must like the way the old one sits.

As for timing, I replaced the points with NOS HD ones and rechecked. The old ones were twisted. It's spot on the mark but I've not checked with a timing light. Points show no burning or wear. Point gap is good and plugs are new. Champions - I'll have to check the number. Are there better or worse plugs for these machines ?
I do not want to go electronic. I tried it on my MB and it just didn't feel the same. I like the manual advance/retard.
She starts first kick.

There is no oil in the air filter. I did put some in but it leaked all over the floor - maybe overfilled so I took it all out. Is this a problem ?
And also I run just normal lead-free gas with no additive. Maybe not good either.

Thanks for your pointers.

To complete my tools, I think a timing light is needed and a valve spring compressor maybe.

Cheers

David

[1stCAVREG]

“There are oil leaks around some of the head bolts. I have tightened some head bolts that were loose.”

Replace the head gaskets. Spray the gaskets with aluminium paint for a good seal. Check the head surface for warpage or a burn passage caused by loose head bolts. When tightening, be sure to use a criss-cross pattern and gradually tighten the bolts up to or close to 65 foot-pounds

“It does not have the extra carb extension to the manifold - it's a type VII WLA.”

Carb extension only relieved vapour lock caused by the early short manifold.

“ I tried replacing the low speed needle with a new one but it wouldn't take it - must like the way the old one sits.”

Depends on the aftermarket source. The ones made prior to 2009 had the wrong thread pitch. Colony now makes low speed needles and their thread pitch is correct.

“As for timing, I replaced the points with NOS HD ones and rechecked. The old ones were twisted. It's spot on the mark but I've not checked with a timing light. “

The mark is only for getting your timing into a general area. The timing light needed is really a continuity test lamp. The dash oil signal lamp can be used by swinging the wire from the sending unit over to the point arm and watching the dash light go on and off (ignition on). Also a volt-ohm meter can be used (set to DCV).

“Points show no burning or wear. Point gap is good and plugs are new. Champions - I'll have to check the number. Are there better or worse plugs for these machines?”

Depends on the motor’s age and your riding style, I use D-14 (cold) & D-16 (hot) Champions.

“There is no oil in the air filter. I did put some in but it leaked all over the floor - maybe overfilled so I took it all out. Is this a problem?”

Yes, without oil, the air filter is not cleaning the air properly. Dirt particles which the mesh may be trapping at one point in time can at another point in time come loose and feed into the engine wearing the rings and scratching the bore.

The oil bath air cleaner’s oil cup has a “fill” mark. Above that and it will leak. Also, if the oil bath cup was not properly cared for over the years, it may have gotten a hole in it, allowing it to leak. The gasket also needs periodic renewal.

“And also I run just normal lead-free gas with no additive. Maybe not good either.”

Probably not. Marvel mystery oil seems to be a good top end additive but do not use it on a new top end until after run-in. It can cause the cylinder to glaze, preventing new rings from seating in the bore.

If you have access to low-lead aviation fuel, mixing your regular no-lead with the low-lead will help. 5:1 or even 10:1 (anything helps, the low-lead aviation is usually at least 100 octane)

“To complete my tools, I think a timing light is needed and a valve spring compressor maybe.”

Get a K-D #383.

“Frankly since redoing the carb I've not had any problems with it but it has always run rich.”

It is possible you have an air leak and are over compensating for it by the rich fuel.

1) Be sure the throttle shaft is pulled up before tightening the butterfly screws, otherwise the top spring will be pulling up a shaft that is not bottomed on the body and will cause erosion to both the top of the butterfly and the top of the inside of the carb throat where the butterfly pivots.

2) Look at both the low speed needle and the low speed needle collar, excessive wear at that point will add to the air mixture making it difficult to fine tune.

When tuning, the practice is to turn in the low speed until the motor starts to die and then opening five clicks. However this may produce a too rich mixture. Instead, as the motor starts to die, increase the idle and then dial in the low speed needle a second time.

[David V]

I'm assuming the new Xenon type timing lights with an inductor will work on 6volt systems ?
All are marked for 12 volt.
This Ok ?

http://www.gunson.co.uk/item.aspx?cat=662&item=3442

[David V]

A manual spark advance requires manipulation, tracking of the throttle and spark advance. A common observation with a manual spark advance is no umpppha up even a slight inclined grade, engine slowing or lugging down, no power. On a manual spark advance the throttle and spark advance are meant to be rotated together. If you don't have a counter wieghts changing the timing in an old jeep, or vacum advance in a later jeep, you aren't in proper timing and lack power as you increase the load on the engine. Well, anyway, please consider.

John , I'm not sure I'm using the advance - retard throttle as well I should.
I'm really only using it to start to bike on retard and then I twist to advance and leave it that way.
I live on the top of a hill - apparently I should retard the spark to go up inclines.

Could you explain a bit more in depth because it sounds that I should really set up the idle on retard and then advance with the left throttle at the same time as I accelerate. Each time ?
This sounds complicated.

David

[1stCAVREG]

Dave,
An automotive timing light will not be of any use on the WLA. The light you need is what is provided by a continuity tester. After setting the valves, setting the points to .022”, and bring the timing mark into position for the front cylinder (slightly forward of center), you want to set the timer head to fully advanced at the exact moment the points breaks. This is achieved by a plain test light or a VOM.

With a test light, connect one end to the positive battery terminal and the other to the timer wire terminal post. Take a second wire and run it from the battery’s negative terminal to the timer base. The light will go out exactly at the moment the points open. It is at that exact point that you want to adjust your timer to fully advanced. After setting the timer, using your handlebar spark advance spiral, retard and advance your timer to verify that the light goes out exactly when the timer is fully advanced.

On your second matter that you addressed to John, it is not a matter of constantly retarding and advancing the spark while riding or even on a frequent occasion. It is a matter of rare occurrence. Times to retard the spark is at start up, at a traffic light stop (only to sound cool to those near by), and on a steep inclines but only if the motor is failing to perform as expected and retarding the spark helps motor performance. Riding with the motor retarded is not a good thing as it will lead to cylinder overheating.

When riding my 46UL on the Blue Ridge and through the Smokies, I never found the need to retard my spark while on an incline.