Ducati Monster Forum

Moto Board => Tech => Topic started by: jrswanson1 on September 20, 2012, 09:46:16 AM

Title: Carbs gumming up
Post by: jrswanson1 on September 20, 2012, 09:46:16 AM
I purchased a carburated vehicle for the first time since 1987.  Is anyone with a carbed motorcycle having issues with the new ethanol gas?  The newest addition to the stable was built in 1983, with four carbs.  The previous owner said he didn't add Sea Foam often enough and now it's not running.  After I get the brakes fixed, I'm going to try to get this thing going.  Just curious if anyone else is having this issue.
Title: Re: Carbs gumming up
Post by: Slide Panda on September 20, 2012, 10:15:31 AM
Folks are having more issues with carbs. But if kept in good order they work just fine - it just takes a bit more to keep good order. Considering they are 29 years old, do you have any notion of when the last time the carbs were pulled and really cleaned? How old are the soft part and jets?
Title: Re: Carbs gumming up
Post by: ducpainter on September 20, 2012, 10:28:38 AM
How long has it been sitting?
Title: Re: Carbs gumming up
Post by: jrswanson1 on September 20, 2012, 10:38:23 AM
This particular bike was sitting for two years out in the open.  The PO stopped riding it because he couldn't get it started and ended up getting another bike.  I think if I saw that sad motorcycle sitting in the lot every day for two years, I'd have covered it at least  :'( .  This bike is almost 30 years old, with 15,000 miles on it.  If I can resurrect it, I'll be happy, and so will the wife, since she'll ride a cruiser, not a sport bike  [laugh]
Title: Re: Carbs gumming up
Post by: ducpainter on September 20, 2012, 10:43:48 AM
Quote from: jrswanson1 on September 20, 2012, 10:38:23 AM
This particular bike was sitting for two years out in the open.  The PO stopped riding it because he couldn't get it started and ended up getting another bike.  I think if I saw that sad motorcycle sitting in the lot every day for two years, I'd have covered it at least  :'( .  This bike is almost 30 years old, with 15,000 miles on it.  If I can resurrect it, I'll be happy, and so will the wife, since she'll ride a cruiser, not a sport bike  [laugh]
It's possible that it had MBTE fuel in it when it was parked.

That stuff, in small quantities, turned into a crystalline mung.

Ethanol fuel will phase separate and become mostly water.

I'm not a big carb parts replacer. Most of the gaskets are rubber, and more like o-rings and are reusable. Jets, other than needle jets, don't really wear all that much but do get dirty/clogged. Float needle and seat assemblies can usually be cleaned.

I'd pull the float bowls and see what was up.
Title: Re: Carbs gumming up
Post by: Bill in OKC on September 20, 2012, 11:20:46 AM
If the bike is 30 years old the carbs need to be rebuilt anyway.  I bought a 1975 GT550 and it had crystallized stuff around the jets and sludge in the bottom of the bowls that had clogged the choke circuit.  Older bikes didn't have much in the way of fuel filters, mine had just a screen in the petcock that had what looked like calcium deposits on it.  An ultrasonic cleaner fixed that - just don't use one to clean the floats [bang].  The bike had stopped running before ethanol had ever hit the streets.