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fast and nasty carbon fouling

Posted: Wed Apr 01, 2009 9:52 am
by Fargo360
Ughh...I got the itch today and needed to get the bike running even though there is a wicked flood and we just had a blizzard. So I pulled it out and just started it up to make sure its running smooth for when the snow melts. I got it started up but noticed that it seems like one cylinder isn't running. I know there is fuel and air, so that leaves spark or compression. I pull the plug and notice that it is pretty well fouled, put it against the head and crank it...no spark. I pulled it away a little quick and it sparked against the head, but not to the pole. I had an extra plug and tried that, and it sparked fine, so I threw that one in there and fired it up. Ran great. I noticed I had a little exhaust leak so I shut it down and tightened the clamp. I fired it up again and it ran well for a few minutes then seemed a bit off, so I pulled that new plug and was a bit dismayed that it was carbon fouled already. I am under the impression that carbon fouling is resultant from rich mix, poor spark, poor timing, or poor compression. I am pretty sure I don't have a rich mix, so where should I start? Check the timing? Then maybe get new condensors? and finally pull it apart (not really wanting to do this)?

Posted: Wed Apr 01, 2009 10:29 am
by Fargo360
Oh yeah, and I noticed some smoke coming from the breather tube

Posted: Wed Apr 01, 2009 12:07 pm
by Wrider
Could be oil getting past your rings/valve guide seals.
Could be simply jetted too rich on that side.
Could simply be that your spark unit isn't strong enough to ignite the mixture in that cylinder!

I'd check your carbs first, then the spark unit, then the seals, then the rings.

Posted: Wed Apr 01, 2009 4:25 pm
by Fargo360
Well, I know the carbs are good. They both got a carb kit and a very thorough cleaning this winter. As for checking the spark unit, are you talking about the condensor? If I have to go after the seals, I'll probably just change them and do the rings while I'm at it.

Posted: Wed Apr 01, 2009 6:45 pm
by Wrider
Yeah, check your condensor first. :) I've seen it where it sparks but not under the high pressure of the cylinder, causing it to foul quickly. Make sure the spark is up to spec in the manual.

Posted: Thu Apr 02, 2009 12:26 am
by coffee_brake
The nearest thing to a miracle cure for older bikes:

http://www.wgcarbs.com/index.php?option ... &Itemid=26

Folks who take the time to do it, swear by the Coil Mod. It bypasses the old wiring (which, due to its age, is adding to the resistance in the system) so the coils fire like they did when new. Also on this page somewhere are instructions for points bikes.

Posted: Thu Apr 02, 2009 7:45 am
by Tennif Shoe
coffee_brake wrote:The nearest thing to a miracle cure for older bikes:

http://www.wgcarbs.com/index.php?option ... &Itemid=26

Folks who take the time to do it, swear by the Coil Mod. It bypasses the old wiring (which, due to its age, is adding to the resistance in the system) so the coils fire like they did when new. Also on this page somewhere are instructions for points bikes.
very good write up never thought about it :D

Posted: Thu Apr 02, 2009 6:31 pm
by Fargo360
Hmm, it seems to be writen for kawasaki bikes. I wonder if it will work the same on my old Honda?

Posted: Thu Apr 02, 2009 7:49 pm
by Johnj
Yes, it will work on any bike.

Posted: Fri Apr 03, 2009 11:11 am
by Fargo360
Is there anyone who's done this on an old honda?