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Smoking Problem

Posted: Wed Aug 18, 2010 11:26 pm
by bdb
I recently was bitten by the CBX bug, and bought a '79 from the original owner, who bought the bike new in the summer of '78. He rode it until the mid 80's, and it's been parked ever since. I pulled the carbs, which were a mess and gave them a good cleaning with Honda carb cleaner, except somehow I missed the pilot jets, and didn't pull the screws and clean them. I got the carbs back on, changed the oil, put in gas with a fair dose of carb cleaner, and it fired right up. It runs good when cold, with no sign of smoke. As it starts to warm up, it starts to smoke, the more it warms up, the more it smokes, until it is literally fogging in the road behind me. It's not a blue oil smoke, nor a black carbon smoke, it's white. I pulled one plug and it was quite white. At first I figured it was caused by the carb cleaner in the gas, so I drained it, and put in straight gas. No change. Since the bike is not insured, I've only ridden it maybe 2 or 3 miles. Could there be lingering carb cleaner in the carbs that's slowly burninng out? But why would it only smoke when warmed up? Could there be something in the pipes that a good run would clean out? I'm afraid to run it too much for fear of doing damage. The carbs have not been balanced yet, nor cylinders checked the compression, but it seems to have power to spare. There's a bad rattle at idle in the engine when warmed up, but I assume that's the clutch. Any suggestions? Any help would be greatly appreciated.
Brian

Re: Smoking Problem

Posted: Thu Aug 19, 2010 7:19 am
by EMS
Anything left in the carbs causing strange symptoms should long be gone. Smoking only when warmed up could be a sign of bad valve stem seals. Seals like to dry out and deteriorate when a vehicle is parked for an extensive length of time.

Re: Smoking Problem

Posted: Thu Aug 19, 2010 12:52 pm
by steve murdoch icoa #5322
Welcome to the site, Brian.
I agree with EMS that it probably is valve seals. My '79 did the same thing after sitting for 3 years. It had close to 70,000 kms at the time. I got lucky and managed another season of riding...after about 5 minutes of riding the seals would soften up and expand enough to seal.
I have been to Peterborough Cycle Salvage a number of times and have received good info from them. Just a thought if you wanted someone to look at your bike.

Re: Smoking Problem

Posted: Thu Aug 19, 2010 12:58 pm
by steve murdoch icoa #5322
A VERY long shot might be too much engine oil. Maybe too much was added when you changed it.
I have seen bikes prepped for long term storage that have been doused in WD40, including the inside of pipes. A VERY, VERY long shot might be that the previous owner coated the inside of the pipes knowing that it was going to be dormant for a while.

Re: Smoking Problem

Posted: Thu Aug 19, 2010 1:47 pm
by NobleHops
bdb wrote:I recently was bitten by the CBX bug, and bought a '79 from the original owner...

Brian, welcome to the site!

These guys will get you sorted. Got any pics of your bike? :)

Again, welcome!

N.

Re: Smoking Problem

Posted: Thu Aug 19, 2010 11:08 pm
by bdb
Thanks for suggestions. The smoke doesn't look or smell like oil smoke to me, but it could well be. Here's a picture of the bike. The paint it badly faded, look better in the picture than it is. Bike has VIN CB12001413.

Re: Smoking Problem

Posted: Fri Aug 20, 2010 9:16 am
by NobleHops
Other than the faded paint that is a very solid bike! Looks great!

N.

Re: Smoking Problem

Posted: Sat Aug 21, 2010 8:13 am
by daves79x
Brian:
Welcome and nice pickup on the low serial number bike. You have not ridden the bike nearly far enough considering it has been down so long. My experience with CBXs sitting for years has been very good, but the first few miles will not give you a good picture. The exhaust clearly has some 'crap' burning out, but so does the engine. I've found that you need to put the engine through several heat and cool cycles and put a couple hundred miles on it, change the oil and filter again, and clean the sump. Then see where you are. And the rattle at idle when warm is the clutch - very typical of the '79s especially. Keep us posted.

Dave

Re: Smoking Problem

Posted: Tue Aug 31, 2010 12:41 am
by twinegar
It wouldn't be a bad idea with a used bike that you like a lot to stick oil pressure and temp gauges on for at least a little while until you sort this out. I almost seized my 79 in 2008 and had I been able to see the temp I could have babied it home or shut it off. I made it home just the same but it could have gotten ugly. A couple gauges on a bike isn't a bad idea and could save a lot of money as a just in case add on. If I could afford it every one of my bikes would have those gauges.