smoke on one side

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Mar 19, 2005
Feel like a dope for asking for help on this...but it is strange.
My left side has started to smoke , but suddenly, one day not there, the next it a red light, and the poor fellow behind me gave me the stink finger for it.
The smoke is whiteish, not black. The plugs appear to indicate oil, but why?
smoke on one side

and overnight? Or do I read the plugs wrong, and it is not oil...could it be that the float needle has gone? It doesn't look like it is too rich though. Could it be suddenly the oil seal on the valve?. Can't think the oil ring went so suddenly. The problem kind of comes and goes, most embarassing when you give it gas from an idle, but the pipe puffs out smoke at an idle too. Most of the nice clouds go away when the motor has reached middle rpm range, and even disappeared for a while on a ride yesterday( I was mistakenly so...happy for a few moments,but it returned at an idle later.
The compression is even on both sides, maybe low (110-15 lbs), but even.
Any neat ideas?
I will pull off the carb and look at the valve seal, which isn't too old, 4-5 months old maybe.
This all started after a good long run, now that I think of it, on the next day, not only did I have a cold, but the bike had a puddle of oil under it that had run out of the bottom of the air filter, not that the oil tank had been too full, but somehow the oil had gotten up there and gone out of the breather into the filter and on the floor. Oil pump works, I'd say, as the oil gets pumped into the tank, but somehow all this strange stuff has happened at once, including a leak/crack in the gas tank...maybe the poor girl just doesn't want to work this summer....thanks for all ideas!
left side smoking

You need to determine if the wetness is gas or oil, smell it. If it's oil something has broken. Intermittent smoking may indicate the oil ring.
What spark plugs are those???made in France. Even the dry one doesn't look very good and the electrode protrusion looks too long. NGK BP7ES or Champion N7YC are specified.
Sounds like a broken piston ring to me, that explains the smoke and also the oil in air filter as the blowby into the crankcases would be a lot more than normal. Could also be an inlet valve seal which has hardened and/or split. But even your right side plug looks to be running rich so once you find the fault your carbs need a tune.
Smells not like much to me, and if it was gas, it's had since yesterday to evaporate, so it wouldn't make my old nose react by now. The stuff is sticky though, I'd truly say oil is the cause.
As to the plugs, I've used these things for now about 5-6 years, Beru UltraX/Crossfires. They are not the cause...they will take a lousy idle and make it noticably better.....4 sparks instead of one, much less chance of the gas not igniting with 4 electrodes. I wouldn't go back to the old fashioned type. These are much better.
smoke on one side

True, the other looks a bit dark(see the size right too, this time!), but after sitting for a half hour running at idle, while I tried to diagnose the smoke on the other side of the'd be a bit dirty too.
I will replace them soon, as they are a couple years old now, but they aren't the problem.
I keep wondering why an oil tank that was not overfull would spew out oil on the floor through the breather pipe/air filter. This was a good cup of oil. I didn't give it much thought as it occured at the same time the leak in the tank did, and the leak let gas drip on the old breather pipe, and swelled it up and it I saw I better replace it and did. All the oil lines got replaced too at the same time. But having a breather line go rotten from gasoline doesn't explain where the oil that somehow was in the breather line came from...could something backup to the point where way too much oil would fill the tank....can't see how. There is a set amount in the oil system and a tank that isn't overfull, isn't likely to become overfull by itself. If so...I will patent it and make a buck....produce my own oil and tell the Shieks go to stick thier heads in the pipeline..
More than likely I will find the oil seal out of place, or...worse case, the rings will need to be replaced......anyone got a comment on the compression? Is 110-115 OK or am I at the bottom end of what I should have.....thanks once again for the help.....
That is unlikely if the compression is the same both sides, however if the oil control ring is the problem you may get over oiling in the cylinder but still keep good compression, the 2 top rings keep compression, the lowest ring is to control oil.

Ignore my previous comment on the plugs, leaving it at tickover will mask the true running colour (but you are still rich at tickover :) )
I will get the adjust on the carbs correct...someday. The one that looks a bit rich...that's the "good" one. The other, where I now have oil smoke coming out...that side has to be adjusted MUCH leaner with the air adjust screw...none of that "1 1/2 turns out" for that needs about three or four turns out to run good at an idle and during the first part of opening the throttle. Like that carb is somehow much richer than the other and the air screw has to compensate for it. Crap concidering the pair of carbs are new, since last fall. Maybe a bad float needle. But that is a gas mixture problem...and we are now dealing with an oil smoke problem, instead...or does this info change the approach? Not that I see how...gas smoke is black, and I have grey/white, and the carb is adjustable, just not near the same adjustment as the other carb.......
I have had the tank off a couple of times too and full with water to clean and then fix the crack in it....but the tank was dried out pretty good before putting it back in service..and a bit of water in the gas won't cause all that much problem, and if so, then in both sides and not one...
New Amals have major quality issues, they have not been made by Amal for some time but by an outfit that bought the tooling along with the SU carb tooling. Trouble is having the tooling is not enough, some knowledge helps too.

One item that is normally missed on Amal concentrics is float height,

for more info download this. ...
Thanks for the info....hadn't seen those pages before......will take a look through. Not that I have too much to learn about those stinkers....if they were properly made, I'd have no problem with that one, but something is wrong with it, not surprising as even with the other one I had to bore out the air hole myself...those jerks in quality control must be on drugs or something. That one works fine now and is easy to adjust...but the other has something plain wrong with it, either the body itself, or could be the float needle...or like you said, the float, something makes it too rich to start out with....before the air needle adjust even gets involved in it. The whole carburation system works differently with those new I have to use the choke, and I never had to before.
Will do the deed later today, carb out and reinspect, remove the valve cover and look at the valve seal, and if nothing else pops up...will have to pull the head and maybe do the rings...been a good 14 years or so anyway...just a bummer of a job, and if once again I don't have to bore to oversize...hard to find the original size rings maybe. All crappy stuff in the middle of the riding season...when I have looked at the stuff, I will give a buzz...but if one of you has a brilliant idea what the reason could be for the sudden oil smoke...please be so kind as to share it before I pull the head off and it turns out to be something dumb I haven't thought of yet....Thanks!
Rings are readily available, they wear out quickly but the bores don't so do not jump to a rebore too quickly. If its within limits and has no scores new rings with 1000 miles on cheap oil will bed them in nicely. I am still on Std bore but 3rd set of rings on an 850.
wouldn't dream of re boring if I don't have to...mine has had new rings a number of times and still at original bore I know the deal. If you don't have to...don't do it.
But.....I thought I had it figured yesterday...god was I happy! Found my sloppy workmanship had blocked off that side of the intake from the air filter, and the air filter is oil the oil soaked type......
smoke on one side

Started the motor. No smoke when it was cold...looked good! To absolutly eliminate the question of it being the air filter or not, I ran it without to test a bit....but the problem came back when the motor was warm...crap! Have slept on it....and you know how some problems get worked out in half sleep? Maybe it worked again this time and I know what is wrong.
Remember all this happened after a long hard ride? I will add here, I did the valves last fall...and got a NOS gasket from a dealer. Keep that in mind and picture what would result if it was just too old and hard and there developed a small leak between the oil passage and the bore during a long hard ride(80-90 mph for an hour and a half).....has the NOS head gasket given up the ghost? That would explain it not blowing smoke when cold, would cover it having good if maybe low compression, would cover why there might have been too much pressure in the oil system and throwing oil out of the breather tube....would explain the "overnight" appearance of the problem.....

What do you think? If I pull the head, I will be doing the rings anyway I think, too. The compression is a bit low...or it it correct? Someone let me know (110-115 lbs).....Thanks!

PS....I thank you also for the tip on the float level. Mine was a good .080 ABOVE the rim of the float the float bowl gasket isn't constantly wet, like it was and it starts without the choke too.....
Hmmm.... Lemme take a guess at this one.

So, what do we know? The smoking occurs at idle after high speed operation - and it goes away after a bit more riding, right? Idle is a high vacuum state, and its occurring right after you've pushed quite a bit of oil around the engine

Unless you found a gobs of oil in the intake manifold, we also know that the oil can only be coming from three places: rings, head gasket or valve stems.

Lets rule out the rings for now. Mostly because we know that bad rings are worst when cold. The head gasket is still possible, but less likely because that tiny oil drain-back hole is so damn far from the cylinders - and separated by a flame ring. I think you'd have more symptoms if it were the gasket. I know you had the head done recently, however I think that's the path for your oil.

First, I'd guess that your oil pressure relief valve is sticking or seized - a common occurance. That, in and of itself, isn't the problem, but - if I'm on the right track - its one third of your issue.

I'm also willing to bet that one or more of the rocker-shafts in your head is rotated so the oil passage is point toward the oil passage in the rocker arm. If that's the case, you're flooding the head with oil faster than it can drain back - but only at high rpms.

Finally, I'd take a look at the valve stem oil seal for the offending intake. Sometimes they don't seat and I've seen them come off and just ride the valve stem. So, with oil pooled up above the top of the guide, your high vacuum idling after a high speed pass will suck oil in around the valve stem, which you then have to burn off for a bit.

Some things I'd check anyway...
Some good ideas and viewpoints...Thanks!
To set the record more did not smoke when cold. When it warmed up/oil circulated, it puffs at an idle but really lets a cloud loose when you rev it a bit like when you drive normally away in first gear. It clouds when you blip the throttle and the smoke clears out after a few moments and it runs pretty clean till you blip the throttle again...all vacuum situations. I think after you drive it a bit about, at a good clip, it doesn't smoke when you stop and check it, until it idles for a minute and then the puffs and clouds start again. I took a look into the intake and both intake valves had about the same amount of moisture on them, no tell tale oil running down one valve or such, no discolouring either. This NOS gasket had a bend in it somewhere, if I'm not mistaken, between the pushrod hole and the bore...I didn't have another one and I just bent it straight and installed it. But that may not be what is at fault.
I would happily check the seal on the valve, but getting that spring off without removing the head could be a trick. I can pressurize the bore through the plug hole, but how to get the spring compressed and the retainers off the valve stem.....does someone have a good idea for a tool to do this? I know on an auto, there is a level/fork thing you can use, but is there something that would be usable on the Norton?
I personally don't think it is the rings...too "overnight" for that, and I tend towards the valve stem seal or the gasket...but it may be that I have to pull the head to check the valve stem seal, and that will anyway mean a new head gasket, and if I'm going that far.....I'll do the rings too most likely...would indeed be nice to have it just be a valve stem seal and avoid all that extra work.
As to it being a turned rocker shaft. I could check if one is turned by removing the small oval plates that hold the shaft in place and looking if the slots have turned, but I think that since both intake valves are located in the same compartment in the head, if there was a flooding of the head, it wouldn't appear as a cloud from just one side. Unless there was something wrong with something on that one side (seal). Same for the pressure relief valve. That's a thing that is relevant to both sides of the motor, and not just one, and we are looking for something that just has to do with one side of the I will rule both those things out as a cause of clouds, but I will at least check the relief valve...good idea.

That leaves, a blown/moved seal, a blown gasket, or rings.

Rings, as you say, will be more of a problem when cold and not when hot, but also, they tend to wear evenly, both being served by the same air filter and oil. I will wait to see if anyone has a trick idea for checking that valve stem seal, if no one does....I will get on the phone to RGM and order the seals, gasket and rings.....unless one of you has a better idea!!!!
If anyone has a sketch of a tool to get to that valve stem seal without pulling the so kind as to insert it into the thread...Thanks!
gasket falls apart?

Been quite a couple weeks since I got the parts to do the ring job, etc. Had 4 machines apart, 2 belonging to other people, naturally impatient people. Neat problems like having to cut new threads pull motors apart and such. Not even my own car was kind to me and blew its timing belt. Now there is no compression in any of the cylinders.... can't see any damage, but must have punched holes in the pistons, or bent valves.... and in all four cylinders? Crazy. So now I have no car and I took the time to get the Norton apart. Neat little problem I found, if I'm correct. The gasket fell apart. The thing was made of three layers, a metal, copper, with what must be graphite on both sides. The graphite decided to separate from the copper and squeeze out of the sides, like a big Mac will if you aren't careful enough. Big Macs will just put tomatoes and sauce on your pants or shirt...this gasket must have opened up a passage for the oil to get into the cylinder. Never seen anything like this before. Gasket was only replaced last fall when I did a valve job.
Anyone seen something like this before?

smoke on one side
smoke on one side

smoke on one side
smoke on one side

Have a fine and safe weekend!!!
The cycle goddess has been having a tiff with me, but I finally got to finding the definate reason the motor was blowing smoke.

After ordering rings and seals and getting as far as breaking one of the new rings when I installed it incorrectly and had to remove it, now I have a new set of rings...another 50 dollars or so. I have finally taken the time to check the valve seals too, and one was riding the valve stem. Problem solved...question answered.

Unless, though, I stop having new problems pop will still be a while till she runs again.
Wondered, last fall, when I did a valve job, why that one nut, front corner, wouldn't quite get feeling like it was tight...felt mushy. Now that I have the rings...I find that my "gut" feeling about that one bolt, had a reason. Pulled itself out of the head, and took all the threads with it. Great. Now I have to find someone here in Schnitzelland that can do a Helicoil for the brit thread.....will start phoning tomorrow. Can't do much though...even if I find someone who will do the Helicoil, at least not this week.......picking up the motor I had to buy, to replace the motor in my car...which blew the timing belt last is wonderful. Ride safe!
I don't smoke in the morning, but my norton sometimes does! (73 Commando) I have great compression, new carbs, etc. The reason for my mosquito abatement from just one cylinder turns out to be wet sumping. If I am diligent about putting the bike away by rotating the crank up to compression, the oil holes in the crank will not seep as bad into the crankcase as if left off compression, and I may get a week or so without much oil ending up in the crankcase. Beyond the week or so, or if I didn't rotate the crank, and it is in the most leakable position, I may end up with oil in the case overnight. (My oil pump is obviously loose, allowing a pretty good flow from the tank to the case) When it has wet sumped enough, and I fire up the bike, one cylinder with obviously not perfect ring seal, allows blow by up to the combustion chamber, and look out mosquitos! This only lasts for for about 3-4 minutes, about the time I normally let it warm up. If I put the crank on compression, and ride every day, it NEVER does this. I am purchasing the anti reverse valve for my oil line, which should solve my problem. I hope this helps, smoke sucks!
quick question....After putting my motor back together, running it in, changing the oil and going for a spin last evening...all was well, until a mile from home on the return route, and the same smoke started blowing out the same side....and I had been sooooooo happy, it ran sooooo well.
Anyone know why the valve seal might have twice come off...and so fast? I'm not sure if it is the valve seal...but it was very sudden again and a real "fog" again behind me...acceleration and deceleration....anyone know a cure, if it is indeed the valve seal again? Seal was brand new..viton type. Thanks!!!
wow that really sucks (no pun intended re oil getting sucked down the guide!)

I read someone's opinion (don't remember where) that the new seals, with the little gripper springs, grip the valve stem better than they do the guide and thus tend to get pulled off. According to this guy, the old seals didn't have the little gripper spring and thus didn't pull themselves off the guide.

Of course that's just something I read on the internet. No idea if it's really true. Maybe someone else could comment on that...

read that somewhere too.....the valve guides I inserted last fall were really old NOS that I had bought years ago...maybe I have mixed seals and guide types....any comments to this, all you tech wizards??? Is this posible? I need another type of valve seal?
Thanks Debbie...maybe we can get on the right track sometime soon with this, what should have been, simple little ring job.....for awhile though, I was indeed in went like a well tuned rocket....everything was perfect
......except that the repair on the tank had opened up half way through the ride.
Nothing works quite so well to remind you it's about time to head on home :lol: :lol: :lol:
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