Right cylinder blue smoke on an R80/7. Oh dear...

Discussion in 'Airheads' started by Blackburn Buccaneer, Feb 27, 2019.

  1. tsADV

    tsADV Been here awhile

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    Not sure how well you know the bike's history. Maybe worth checking the stamped diameter on the pistons - if the barrels have been rebored and oversize pistons fitted, they'll need the matching over size rings. And don't let anyone sell you rings intended for nicasil barrels if you need rings for iron lined ones!
    #21
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  2. nk14zp

    nk14zp Long timer

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    I would make sure no oil is getting in the intake first. Then I would change the oil. Then ride it like I stole it for a week.
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  3. Plaka

    Plaka Brevis illi vita est

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    I was thinking re-do the break in too. But first I would inspect the cylinder wall through the spark plug hole with a Streamlight Reach. And inspect the valve lips while one is at it.
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  4. nk14zp

    nk14zp Long timer

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    Could carbs out of sync cause smoking? Either way I'd check that too.
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  5. Plaka

    Plaka Brevis illi vita est

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    only if both pipes should be smoking and only one is, ie, there is another problem and it will show as oil in the intake tube between the air filter and the carb. Unsynced carbs cause very noticeable vibration.
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  6. B_C_Ries

    B_C_Ries Long timer

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    Out of sync carbs did cause my 1977 R100/7 to smoke on the right side. But my intake valve guides are worn pretty badly. But the smoking did stop after I synced the carbs.
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  7. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

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    Just changed the oil and filter and ran it without the right side intake. Still smokes when hot and when I give it a bit of gas, but not nearly as much and not constantly. Didn't smoke at all when cold, not even when revving a bit.

    Playing with the mixture screw made it smoke out of both sides, but that could just be the cross pipe.

    Right plug looked like it ran rich, not too oily. I adjusted the carbs a bit, runs a lot better now, still some smoke on the right side, but once again, not nearly as much.

    I'll post the pictures in a minute after I return from some errands.
    #27
  8. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

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    Here's the starboard head without the valve cover. I know the gasket is on wrong, fixed it after the pics. :thumb

    [​IMG]

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    Might as well put the 'new' Hagons on there. Old ones were shot.

    [​IMG]

    Regrettably facing the wrong way lol

    [​IMG]
    #28
  9. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

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    Must add that the oil is now 20W50 retro formula. It seams to seal a bit better with this oil.

    Also, there were some metal shavings in the oil filter, but nothing too crazy I'd say. The only concerning thing was maybe two or three larger sharp particles in the whole filter. Not nearly as much of a mess as my Moto Guzzi V50 had that needed a new top end, though.
    #29
  10. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

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    Alrighty, quick update:

    Changing the oil and adjusting the carbs helped quite a lot, it doesn't smoke under acceleration anymore, nor does it smoke under idling with a hot engine. It does puff out some smoke when you give it a thorough twist to a high RPM while standing still, is that a problem for airheads? It's quite common for the other old shit we have riding around in the family, but my R45 doesn't do that at all. Figure we will still pull the heads to have them looked at by a pro come spring, weather's turning sour again and my dad's gonna store it in the garage.


    Also changed the other fluids and the trans oil was abysmal. My god, when was that last changed? Quite a lot of sliver in it and generally terrible oil quality. Also, I definitely didn't pull 800cc out of the trans, more like 600cc. Guess that explains the slight trans whine it had while riding it slowly in first and second gear. The whine is completely gone now and it shifts a lot smoother.


    Thanks for all the excellent tips and help! I'll continue this thread when the weather changes and some funds have been raised. Cheers!
    #30
  11. tsADV

    tsADV Been here awhile

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    Nice pictures, and ditto bike. I also like the wooden shoes in the background!

    A couple of comments; it looks to me like a previous owner has replaced some parts in the valve train - the clue is the 90 deg "square" rocker blocks that hold the intake rocker down - easy to see on the picture above. The standard ones for your bike should be the "rounded corners" version you have on the exhaust side. Take a look at Anton Largiardes website for a concise description of rocker gear used for different airhead model years (someone else may comment on the discolouration of the tip of the intake rocker - heat treatment, but why needed?).

    You mentioned you saw a poor condition gear oil coming out, with quite a lot of sliver in it. If this was glittery metal flakes, it could indicate significant wear of some of the bearings, which may need replacing soon. Continue keeping an eye (and ear) on it, and check for rough movement of the output shaft, which you can rotate by turning the rear wheel.
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  12. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

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    Thanks! You gotta stay true to the stereotype with the clogs yo :evil

    Yeah I was wondering about those rocker tips, why would you use heat treatment on them? No clue. I didn't know the rocker blocks weren't stock like that.

    The trans bearings are indeed starting to go, I first noticed some whining when slowly riding around the neighborhood, but it has subsided significantly since the oil change. There definitely was some flaking on the magnetic plug. Figure we'll get a few more months of gentle riding out of the bearings. The rear main seal or output shaft seal needs to be replaced as well, so when the trans is out I'll take it to a shop for a rebuild, shouldn't be too expensive.
    #32
  13. Piggdekk

    Piggdekk love speed, hate rush

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    I had the same discoloration on my exhaust rockers tips and assumed it was the heat coming from the tip of the valve. Was I wrong?
    luca
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  14. aptbldr

    aptbldr easy rider

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    Pretty sure that is heat-treating to harden the machined face of rocker tip.
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  15. Plaka

    Plaka Brevis illi vita est

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    Rocker cover gaskets are on bass ackwards and looks like some sealant on them, which should not be needed.

    Adding some moly to the tranny may extend the life. No, rebuilds are not cheap. Lubro Moly makes a MoS2 Anti friction additive for gears that is easy to get (like on amazon). a 50 Gram tube goes a long way.
    #35
  16. Cogswell

    Cogswell Trying to live the new normal.

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    You may want to level the carbs a little bit too. From this picture it looks like quite an angle.

    [​IMG]
    #36
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  17. B_C_Ries

    B_C_Ries Long timer

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    some of us angle the carbs on purpose to make the cable path straighter.
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  18. cycleman2

    cycleman2 Long timer

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    That is quite an angle on the carbs, they should be level with the bike sitting level on both wheels. I use a small round level and place it on the carbs. Seeing that the carbs are at that angle I wouldn't be surprised that a lot of your smoking issues could be caused by running too rich. Too rich is a problem with any engine as it tends to wash the cylinder walls.

    Excessive smoke especially on the right side is offen caused by the crank case vent not working properly. Lots of info on how to cure that one. You can check by taking the rubber boot off the intake, and having a look just inside the intake, on the floor of the head before it goes into the valve. Excess oil will collect in this area if the crankcase vent isn't working properly.

    On a bike with unknown real history, records & receipts and such, just about anything could be going on. As you've already done, change all the fluids and ride it for some miles and then if you are still concerned about smoking gear wine etc then maybe look further. In a lot of cases a bike that has sat around alot is not going to run right. Also if you have somebody local that is good with airheads, then check with them. It's been my experience that a lot of problems are caused by the carbs being set up improperly. When these engines are running right, you should need to choke/enrich them to get them to start and then after a short distance you can shut the chokes off. A good clue is that if the bike will start, after sitting overnight, without the assist of the choke/enrichener then it is too rich. It is also perfectly normal for these engines to increase their idle from cold off choke to hot off choke. For me that is always a clue as to how well the carbs are adjusted. You want the steady idle around 1000 rpm when the bike is fully warmed up.

    As a general rule airheads like to run on the lean side, not the rich side. Just not too lean.
    #38
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  19. Jim Day

    Jim Day full manic mechanic

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    Sounds like you are blowing oil out of your breather which then ends up going through the right carb. The question is why? I've just read this one post not the whole thread but it sounds like rings.
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  20. Jim Day

    Jim Day full manic mechanic

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    There you go.
    #40