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Discussion Starter · #1 ·
And for my post #3, I will give this a shot here before taking it over to Technical Discussion. I just bought a high mileage 2002 Honda Shadow Sabre. It has about 56k miles on it, and I bought it knowing that it would probably need a little bit of love.

Anyway, when I ride the bike for about 15-20 minutes, the exhaust starts to smoke. It is pretty minimal when I idle, but when I accelerate or run at speed, it is a bit thicker. I am having a hard time telling if it is white or if it has a blue hue to it since I am colorblind. The friend I bought it from ran it with no-smoke and said that I should try that, and if it doesn't solve it he will be willing to pay for the repairs that need to be done. Does this sound indicative of any specific problem? Maybe head gasket or piston rings? If so, any rough estimates of how much damage we are looking at in the pocket book, and if it would be fine to ride at 65 mph about 100 miles to get it to the nearest shop, or if we should be finding a truck that can get it up there. Thanks in advance.
 

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Tests:
When warm, smell the exhaust for steam/antifreeze odor or oil stench.
A mirror will fog if it is water and water level will drop.
Check to ensure it is not over-filled with oil.
Do a compression check and test for air leak sounds around the valve stems if you pull the covers.

All that said, you description is pointing to valve seals which tend to pass oil on acceleration or deccelaration, depending on which ones are sloppy. Still....it might be rings depending on how it was treated. Knowing which exhaust pipe is passing smoke also helps focus. If valve guides, no harm no foul provided you watch the oil level. It will need to get done and you can ride it provided you are attentive and very confident that there isn't something more serious happening.

If it is valve guides, since the motor comes out anyway, do the rings too is my vote.
 

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Discussion Starter · #7 ·
Alright, I took the bike out for another ride to get it smoking today, and here is what I was able to figure out. It is definitely burning oil, and it is only coming from the rear cylinder. Is there any other troubleshooting that I can do without pulling the engine? If so, is there a guide somewhere? I have done work on my car and my little scooter, but still haven't quite gotten my bike figured out. Thanks.
 

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Alright, I took the bike out for another ride to get it smoking today, and here is what I was able to figure out. It is definitely burning oil, and it is only coming from the rear cylinder. Is there any other troubleshooting that I can do without pulling the engine? If so, is there a guide somewhere? I have done work on my car and my little scooter, but still haven't quite gotten my bike figured out. Thanks.
Some members were nice enough to put some manuals online, check here for yours. General Discussion - Honda Shadow Forums : Shadow Motorcycle Forum

First do a compression check, use the search funtion of this site and you will find a couple discussions on how to do this. A compression check will be the fastest and easiest way to get decent diagnostic information.


you could pull your Exhaust off and check the exhaust valves for fresh wet oil, if it is baked on carbon then pull your carbs and see if there is any sign of oil on the intake valves. This could rule out or confirm the valve guides as the issue but is not a guarranty. But do this after the compression test. You will need to remove these anyways if you have to pull the heads or engine.
 

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Alright, I took the bike out for another ride to get it smoking today, and here is what I was able to figure out. It is definitely burning oil, and it is only coming from the rear cylinder. Is there any other troubleshooting that I can do without pulling the engine? If so, is there a guide somewhere? I have done work on my car and my little scooter, but still haven't quite gotten my bike figured out. Thanks.
If you were asking my opinion...(not saying you are...), and you was asking should you attempt a valve guide/valve cleanup/rings job (again not saying your asking for me 'umble opinion...)

I'd be sayin' this:

Unless you have a nice work space, tools to do it (begged, borrowed, or stolen), and the knowledge and confidence to the job...

Go to a nice reasonable local independant shop and have the work done over the winter break (didn't notice where you're from and whether or not you even have 'winter'...).

Come spring you'll be riding and enjoying your bike, and still have the hair on your head...

:mrgreen:

Seriously, while it's not a HUGE job, it is a BIG job. It's much more fun installing handlebars, seats, saddlebags, sissy bars (ok-"backrests") and the like unless you are a true grease monkey who really enjoys the deeper end of the motorcycle maintenance pool....

just a few bones from someone who's been-there, and done-that.
 

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Discussion Starter · #10 ·
I am confident in my abilities, but lack the knowledge at the moment. If I had a shop manual keeping me in check, and if I dropped the money in the tools as a long term investment, I don't think I would have a major problem. I have done piston rings on a small 49cc 2-stroke, but know that this would be a significant jump up in difficulty. I have the space in my garage to work on it. Being a mechanical engineer, I do have a love for understanding how all my toys work :D

As for the rest, the exhaust is off, and there is definitely fresh oil at the exhaust of the rear cylinder. The front cylinder is fine though. The spark plug was also heavily fouled in the rear. I am still working on procuring a compression tester, but they both seemed to put out a fair push of air. The front felt like it may have had a little more push, but I will wait until I can actually take measurements to determine that for sure.
 

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I am confident in my abilities, but lack the knowledge at the moment. If I had a shop manual keeping me in check, and if I dropped the money in the tools as a long term investment, I don't think I would have a major problem. I have done piston rings on a small 49cc 2-stroke, but know that this would be a significant jump up in difficulty. I have the space in my garage to work on it. Being a mechanical engineer, I do have a love for understanding how all my toys work :D

As for the rest, the exhaust is off, and there is definitely fresh oil at the exhaust of the rear cylinder. The front cylinder is fine though. The spark plug was also heavily fouled in the rear. I am still working on procuring a compression tester, but they both seemed to put out a fair push of air. The front felt like it may have had a little more push, but I will wait until I can actually take measurements to determine that for sure.
Sounds like you're ready to go! :!:

Good luck...and keep us posted...

Lacking a proper garage at the moment, I am quite envious :mad:

:D
 

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Discussion Starter · #12 ·
So I ended up talking to my mechanic before I took the plunge to either have him work on it, or start trying to take it apart myself. By this point I noticed that the smoke was fairly intermittent, and he though this sounded like the rings may have just been gummed up. He suggested putting some ATF in there and riding around a bit since the smoke was the only symptom. I ended up doing this, and the smoke became less and less regular.

Today I decided that I would change the oil since in theory once it was cleaned, fresh oil would be the next step to getting everything running cleanly. In the old oil, I noticed a few metal shavings, bigger than dust. The engine is now smoking even more than it was before.

Does this still sound like it is likely pointing to the piston rings going out?
 

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SkaFreak, it sounds to me your going to need to do a" top end" job. And you'll need to do both cylinders too. Our local Auto Zone will loan tools out check with yours. And keep us posted and good luck.
 

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Discussion Starter · #15 ·
So to revive a dead thread, I still have not gotten my bike into the shop or torn it apart myself. I did however decide to buy a compression tester just to see if I had a leak that would really push me over into tearing the engine down and doing the rings. The time and money are both issues now, so I am being kinda hesitant. That being said, the compression test (done cold) showed 120psi on both the front and back cylinder. Since the compression is the same on both cylinders, is it still probably the rings, or might something else be going on?
 

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Adding (a couple oz's.) oil to cylinder will verify if it's rings (increase in PSI compression test), or valve face's burnt (no increase in PSI compression test).

If it's not rings, it's valve seals. Dry rotted, tore, or missing...letting oil past stem into combustion chamber.

I could be wrong on Sabre, But I bet it's engine removal to get even the head covers off.
 
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