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Discussion Starter #1
It's been 15 years of dreaming and wishing and now my first bike is sitting out in the garage. I'm not taking the New Riders Course for another month+ (first one that's available), so.. there he sits, lol.

It's a 1983 Yamaha Maxim 400 with just 14,000km on it. Seems to be in good shape, but it's running like crap. I've changed the oil/filter, air filter, fuel filter and put in fresh gas. It ran a little better after that, but still not great. Have a friend who said he can clean the carbs for me, so hopefully that'll be the fix. Managed to cause some awful brassy discolouration on the engine yesterday by leaving it to idle for a bit (trying to circulate the new fuel with an engine cleaner additive), which I'm super disappointed about.

Aannyyway.. here's "Max"
 

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Retired twice: Navy and as a govt contractor
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looks good, how long has it been sitting?
 

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Discussion Starter #3
The guy I bought it off of was out on it for a couple short rides last summer.

Seems like there's some fuel in the oil, so I'm thinking it's unlikely a carb cleaning will be my solution.
 

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Nice ride, and a great choice for a starter!!!

Actually, that carb cleaning should be quite helpful. I was reading another thread where a guy asked pretty much the same question. Several people suggested a stuck float valve in the carb.
 

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That's a beautiful bike. Gotta love those old Yams. They are great fun!! I hope you get it fixed soon so you can ride it.
 

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Female Rider
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Maybe, just a little. It's really hard to believe how "few" issues I've had with my old girl. I don't want to give her any ideas but she's been really good to me and brought me home every time. And she is so much fun to ride, plenty of pep if I need it.

I do need to check the brakes this week. They seemed just a little soft the other day when the darn light short cycled & changed. Not sure if it was just from sitting all winter but I hope to clean & polish both bikes tomorrow and will check them then.
 

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Gone.
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Gas in the oil is likely from the carburetor floats sticking or out of adjustment. A competent carburetor cleaning should take care of that, but don't run it anymore until you change the oil.

The running issue could be caused by dirty or clogged carburetor circuits, which will also be cured by a competent cleaning. It could also be caused by something else, but as the bike was sitting for so long a clogged carburetor circuit is highly likely. Another likely cause is an air leak in the intake boots, also likely with an older bike that has been sitting.

If you caused the header pipes to get discolored that generally means the bike was running hot. That can happen when you let it idle too long, but can also be caused by the bike running lean. Which in turn is often associated with dirty carburetors and air leaks.
 

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Discussion Starter #11
Well my buddy just drove off on it.. taking it back to his place to clean the carbs and such.. hopefully it'll be good as new after that!

The discolouration isn't on the pipes, that's the weird part.. it's on the actual engine. It almost looks like maybe someone used some kind of polish or cleaner that discoloured when the engine heated up.
 

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Any chance it might be a plastic film that was applied at the factory when shipping to keep the cases from scratching? I had a 1982 Seca 400 that I sold a year or so ago and the cases were all silver.
 

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Well my buddy just drove off on it.. taking it back to his place to clean the carbs and such.. hopefully it'll be good as new after that!

The discolouration isn't on the pipes, that's the weird part.. it's on the actual engine. It almost looks like maybe someone used some kind of polish or cleaner that discoloured when the engine heated up.
That's a new one on me too.. never seen that before.
 

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Discussion Starter #17
Well good, I'm glad everyone is as confused about it as I am, lol! Maybe I should leave it alone and I'll have something unique and cool :p
 

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Is it on the other side case too? Have you tired Never-Dull on it? Looks like a chemical reaction of some kind. Might also try a sharp pick on the bottom and see if you can scratch it or if there is a film on it. Bottom will never be seen and may even already have some dings on it that may show film. Be worth seeing if you can scratch it and see silver again in that spot. Acetone might help too if it's a plastic film but do that outside or very well ventilated.
 
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