Is it a problem that I see rust in my gas tank? '80 GS550e

[cometa]

After reading some threads where people mentioned checking your gas tank for rust, I happened to notice that I have rust in my gas tank.

How bad is this?
Can I remove it without buying a new gas tank?
What should I do?

BTW... I'm having several other problems (could getting 10-15 mpg have to do with rust?), with the bike, so if this isn't serious I'll probably just ignore it.


Thanks!
-Brian

[earlfor]

Would you consider rust in your food at every meal a serious matter, or would you just ignore it?

Earl

[Nessism]

Your poor gas mileage is most likey a result of rust particles holding your carb float needles off their seats which allows extra gas to flow into the carbs and then out the overflow. You should consider using Kreem or Por 15 to clean up your tank and seal it. Use the search function to learn more about these products.

Good luck.

Ed

[cometa]

thanks!

thanks, gonna search for Kreem & por 15 now!

thanks again

[chuckycheese]

Rust

There is a variety of things that might cause such poor gas mileage although I doubt it's because of rust in your tank (it certainly could be).

You probably need to rebuild your carbs....while you're doing it, either line your gas tank or have it done professionally...it will cost less than $100 and you'll never need to do it again.

I would consider rust in my food to be a serious problem...rust in the gas tank wouldn't raise the same type of concern....8-[ but I would still take care of it.

[Nessism]

Back in 1983 I bought a left over 1982 Yamaha Vision for a good price. On the ride home from the dealership I filled up the tank and noticed rust in there - from storage without gas in the tank. About 15 miles later the bike started to run out of gas which I thought was strange so I switched to reserve. A little while after that the bike ran completely out of gas and stopped running. I walked a couple of miles to get a jug of gas but after restarting the bike I noticed gas flowing out the overflow tubes for the carbs. Managed to get home by playing with the petcock only letting in enough fuel to keep the bike running but not enough to over fill the float bowls. Got home and took the carbs off only to find them filled with rust - which was keeping the float needles from seating.

I don't know if Cometa's bike has the same problem, but I do know that rust CAN cause problems like fuel loss out the overflow tubes leading seemingly to poor mileage.

[chuckycheese]

Yep

Of course, you are correct!

[cometa]

ordered Por-15...

... the Fuel Tank Kit, as recommended by others on the forum. I should get it in about a week and I'll post my experience and out-come. Even if this doesn't fix my gas issues, at least I'll know my fuel tank is in tip-top shape.

P.S. (This should maybe be a new question, but is it possible that this rust could make the bike cut off after warm - when stopped/ideling for more than 5-10 seconds?)

Thanks all!

[nabrams]

As the bike gets warmer, the mixture will get richer. If you're starting off with an ultra-rich mixture because of rust particles holding the float open, then this effect might be what's pushing the mixture over the edge into a non-combustible situation.
By the way there's a fairly straightforward way to guage how bad your rust situation is in the tank. Remove the petcock. If the built-in screen is covered in rust/sludge you'll know it's bad for sure. I've had some very light surface rust in my tank that is not enough to cause any issue.

[cometa]

thanks for the tip, let me make sure i understand your terminology though:
- richer: means the engine is getting more gas than air?

And this is probably obvious, but i need to empty all the gas first, then take off the petcock, right? How do I empty the gas besides just riding till it's empty? Is there a drain somewhere?

Thanks!!

[rustybronco]

the pectcock is the drain, then take it off.

[cometa]

okay...

thanks,
i took off the petcock:
- there was a fair amount of rust buildup at the bottom (where the filter meets the metal)
- there was a little "goo" on the metal also
- the filter itself only had a little rust on it

How good/bad does this sound? Either way, I'm going to clean it since i bought the por-15, but i'd like to know if this is my gas problem.

BTW... the previous owner said he recently rebuilt the carbs

Thanks all for your help

[nabrams]

That is a problem, but it is almost certainly not the only problem.
The previous owner may have done a lousy job "rebuilding" the carbs. Even if he did a great job, they may have rust in them from the tank.
The bottom line: Until you meticulously clean those carbs yourself you're just playing guessing games.
Then there's the whole list of other stuff to verify when you get a used bike - do a search on this forum.
You need to bear in mind that you're dealing with a 25 year old machine. You're going to need to invest between 30 and 60 hours of your time to work out all the kinks.

thanks,
i took off the petcock:
- there was a fair amount of rust buildup at the bottom (where the filter meets the metal)
- there was a little "goo" on the metal also
- the filter itself only had a little rust on it

How good/bad does this sound? Either way, I'm going to clean it since i bought the por-15, but i'd like to know if this is my gas problem.

BTW... the previous owner said he recently rebuilt the carbs

Thanks all for your help

[cometa]

thanks nabrams,
i do believe you are correct...

the petcock seems to be leaking (another post), so i'm going to buy a new petcock, and de-rust, and seal the gas tank.

if/when i'm still getting very bad gas mileage, i'll tackle the carbs i guess. i took a look at the carb cleaning instructions here, and although they look nicely documented with the pics and all, it looks quite complicated and involves a lot of difficult vocabulary (not to mention, it starts off with the carbs out of the engine already - i think).

thanks for your help!