Stale gas

Just bought a '77 KZ650:) It's been sitting with a full tank of gas for about 6-9 months. What do I need to do with it besides empty the tank and put in good gas? Right now, it runs, but really hard to start, and to keep going. Course, that's b4 replacing the old gas.

You should remove the float bowls and drain all the bad gas from them. Refill the tank with some good gas and add some stp injector/carb cleaner fire up the bike and see how it runs as it might pop and buck trying to burn off the expired fuel in the carbs passages. Run it at idle if possible avoid revving it too much as it sat inactive for a while. The oil level should be checked before engine start and it will need changing also.

I would not drive it yet as it might strand you on the road if you went for a "test hop" The condition of the battery needs attention as they will sufate and short out internally. A new battery might be next purchase.

Replace the plugs, Drain the float bowls, Oil the chain with 10W40, check tire pressure, oil level at the oil level window. Charge battery or replace if necessary. Oil you cables. For basic stuff.

Timing check, points set, valve clearance for more advanced stuff

Change the oil and filter before starting it again. The oil may be so old and contaminated that it will damage an otherwise healthy engine. Ed

civilengr3 wrote:

Just bought a '77 KZ650:) It's been sitting with a full tank of gas for about 6-9 months. What do I need to do with it besides empty the tank and put in good gas? Right now, it runs, but really hard to start, and to keep going. Course, that's b4 replacing the old gas.

I would take the tank off. Take the petcock off and clean it (and clean the screen). Rinse the tank thoroughly with clean gas or mineral spirits, then empty out.

take the drain plugs out of the bowls and drain them dry. You can use some carb cleaner sprayed in the top through the fuel line to hose the gunk out. You might want to install the drain screws and fill the bowls from the gas line with some carb cleaner like Seafoam or similar, and let it soak aovernight then flush out.

Install new inline filters after all the cleaning.

Actually if it's been sitting with a full tank for 6-9 months you shouldn't have to do anything. 6-9 months is not long enough for 4 gallons to go stale. The carbs are another story though, if gas has sat in there for 9 months they will need to be disassembled and cleaned. Of course it wouldn't hurt to drain the tank and put in fresh gas. Save the old gas and use it a little at a time mixed with fresh gas. You can tell the cheapskate I am. Petcock is another question, because if you remove the bowl, the rubber seal is ruined and likewise if you remove it from the tank the oring seal will leak most likely, so I leave well enough alone if possible. Of course not a motorcycle, but I let a 1993 Ford E350 van sit 6 long years without starting, and after that length of time it started right up with 6 yr old gas in the tank.

del

Don't worry... the E350 drank the old tank of gas so quick, it didn't have time to do any harm!

wiredgeorge wrote:

Don't worry... the E350 drank the old tank of gas so quick, it didn't have time to do any harm!

Actually it's a 460 and gets 14-15mpg on the highway at 75mph. Not bad for what it is. Can't drive the big diesel trucks anymore, so have to drive the van.

JMKZHI wrote:

RonKZ650 wrote: Save the old gas and use it a little at a time mixed with fresh gas. You can tell the cheapskate I am.

Since fuel costs as much as it does nowadays,
that's not a good cheapskate indicator. hee.
I use old fuel in my lawnmower. JMK.

I have a plastic cup I use to catch the two spoonfulls of gas that comes out when I take out the bowl drain plugs....