Problem: thick exhause smoke...


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brian
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Location: Clearwater, Florida, USA
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Problem: thick exhause smoke...

Post by brian »

Hello gang, I bow at the throne of kings!

I’ve been member here for quite some time, having bought my first bike, an ’82 in 91, selling it a few years later when times got tough, then bought my second bike, an ’82 in ’01 that I have had since. I knew I wanted a CBX the first time I saw one in the showroom back in 81/82 other than that I am real amateur having only tackled routine maintenance (which is all my bike has needed) in the garage.

I do like riding. Do many 100-300 mile rides locally in Florida. Many times to Daytona, Deals Gap once, 2 years ago drove to Ohio, met 2 brother-in-laws (or is it brothers-in-law) trailered our bikes to Sturgis and rode around that area for 4 days. Did the first few days of the C2C a few years back.

Well to the point: I did a no-no and let the bike sit for 3 months in the garage. I went out today to get it running in preparation for the annual Christmas toy-ride. A bit hard to start, but I had put the battery tender on prior so no real problems other then when it DID start there was lots of smoke from the right exhaust (have standard 6 into 2 pipes). Let it run for awhile, revving it, etc. The smoke lessened but still VERY much there.

What is your diagnosis? Can I tackle the fix in my garage? If not, is it safe to drive to a shop around 10 miles away? The previous owner had installed K&N’s so if a head-gasket, I don’t think I have to tilt the engine. A few years ago my brother and I (mostly my brother) took the carb bank off to inspect the fuel-pump diaphragm, so if along those lines I could tackle it myself with my copy of the shop manual and basic tools. More than that, I might be over my head. Help? Advice? Thanks in advance! PS: I took a video I could post to you-tube if needed.
Brian L - Clearwater, FL USA

EMS
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Re: Problem: thick exhause smoke...

Post by EMS »

Hello Brian:

I take a shot. Usually, letting a bike sit for 3 months should not be that big of a deal. We, here in the "snowbelt", let our bikes sit for some 5 months. O.K., we winterize them, but smoking is not necessarily something you get from NOT winterizing. My uneducated guess would be, you may have bad valve shaft seals. When a bike sits, oil leaks through the bad seals into the combustion chamber and when you start the bike, the oil burns and you see smoke coming out the exhaust. Once it burns off, the smoking stops. That could be a likely reason for the symptoms your bike has. :think:

steve murdoch icoa #5322
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Re: Problem: thick exhause smoke...

Post by steve murdoch icoa #5322 »

My guess would be valve seals like EMS mentioned. What mileage is on the engine?
Just for curiosity, was the smoke a grey/blue colour or was it blacker?
If it has started to clear up a bit with some running i don't think you would have a problem with a 10 mile trip to a shop.
Remember to not let it idle for too long without a large fan blowing on the motor.

brian
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Re: Problem: thick exhause smoke...

Post by brian »

Thanks guys. It is definitely grey/blue and thick when it first started then cleared up a bit after running but was still noticeably there. I'll check the service manual over the next few days, in the meantime are the valve seals a do-it-yourself deal (for a novice with service manual and basic tools)? I'm the third owner of the bike and the original speedo was swapped for a 140 mph version then that broke and I put in another. My "guess" is it has 45K to 50K miles or so.
Brian L - Clearwater, FL USA

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herdygerdy
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Re: Problem: thick exhause smoke...

Post by herdygerdy »

I'm with EMS on this. If it starts and runs happily, albeit smoking its head off out the RH pipe only AND doesn't make any strange noises, I would be inclined to take it for a good long run at a variety of speeds and rpms and not just to the bike shop.

If the shop is an unknown quantity to you, they may be rubbing their hands with glee - and bugger up your bike as well.

But before doing this, check the oil level is at the TOP of the hash marks on the stick, measured on the main stand with the stick completely unthreaded and just sitting in the hole. Yes, you will see the top of the oil level when it is at the correct level.

Do you have small children? Could one of them been left alone in the shed with the bike and decided to " help Daddy work on the bike" by pouring some unknown fluid into the silencer? May be worth pulling header pipes 4 and 6 and having a wee peek down the holes. Any fluid leaking out of the bottom of the collector?

If nothing untoward, even change the oil and filter and take it for a good thrashing, for being so lazy and sitting in the garage.

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Re: Problem: thick exhause smoke...

Post by daves79x »

Brian:

Don't do anything - just run it for a few heat/cool cycles and it will stop smoking. This is not uncommon on bikes that have been sitting a while.

Dave

brian
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Re: Problem: thick exhause smoke...

Post by brian »

Thanks again guys. I trust the mechanic, he'll treat me right, but just the same it is a bit low on oil, only by half a quart or so (probably burnt that much on Sunday!) so I'll top it off tomorrow and work it in over the next few days depending on if I get out of work at a decent hour. Kids are grown so nothing down the exhaust (and I don't think my wife hates me or the CBX that much!). Give me a few days and I'll report back after I top off the oil, let it idle, take it for a spin, etc. The oil pressure light has not come on (other then while starting like normal). Thanks again, and stay tuned... (note to self: stop by the flower shop when I buy the oil just in case....)
Brian L - Clearwater, FL USA

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Re: Problem: thick exhause smoke...

Post by Larry Zimmer »

Just to add to the consensus: common occurrence, Brian. My '82 does it every year after sitting for the Winter. (or, sitting for several weeks between starts.) Also, the likely cause of a bit more oil consumption. Oil top-off much easier (and less taxing) than pulling the head to replace the valve stem seals.
Larry Zimmer
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brian
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Re: Problem: thick exhause smoke...

Post by brian »

Thanks everyone. I finally had some time today (Sunday). Made sure the oil was topped off, started (easy) and let it idle in the driveway. Blue smoke was heavy for the first 5 minutes or so then seemed to lessen. Revving would increase it but for sure it seemed to be clearing up. Felt better taking it out on the road - periodically pulled over to look at the exhaust. After 2-3 miles, nothing! When I felt comfortable, pushed it. Pulled and ran strong. The beast was back (thankfully)! I'll keep an eye out on it and the oil level, and make a note to not let it sit for so long! Thanks again for your advice.
Brian L - Clearwater, FL USA

steve murdoch icoa #5322
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Re: Problem: thick exhause smoke...

Post by steve murdoch icoa #5322 »

Brian, we got a couple inches of snow here today so tell me again the part about going for a ride.
Glad to hear you got things sorted.

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