What have I gotten myself in for?

[eroellig]

I understood pretty well that a bike that sat for 3 years will need the carbs cleaned up, but I did a compression check yesterday & it looks like I might have a broken ring.

One pipe (from #1 & #2) as been smoking when I fire it up, but I had been thinking it was just a badly misadjusted carb. My compression readings showed otherwise:

#1 135psi
#2 85psi
#3 110psi
#4 130psi

I added 3 squirts of oil into #2 and #3 and got these results:
#2 130psi
#3 130psi

So, how much work & $ do I need to add to my guestimate of making her roadworthy?

Eric

[Pat Kelly]

Is it 'still' smoking after the oil? Maybe just a stuck (not broken) ring and it is now freed-up.
It would be nice if so.

[eroellig]

Yes, it was still smoking.

BTW: What compression readings >SHOULD< I have?

[chevy45412001]

should be

it's not as bad as they should all be within like 10 percent of each other. all bikes will be different at different times in there lives , and wear and tear charicteristics. Ya can't spell worth beans I no.

[Pat Kelly]

A leakdown test will pinpoint the problem area. "search" the forum for the appropriate threads concerning "leakdown test / testers"

[TopCatGr58]

Hey Eroellig,

Like Pat said, could still be a stuck ring, due to sitting for a while!
First, squirt some MM Oil into the top of the pistons, thru the spark plug holes, and let it sit for a few hours, or even a day.
Then, put some MM OIL in the crankcase, and run it for about 10-15 minutes....just idling or slight revving, NO LOAD, don't drive it.

Then, change the oil and filter, and then run it on the road for at least an hour at highway speeds. Needs to get up to normal operating temps for while. This may help to loosen a stuck ring, both oil....more likely with burning smoke, as well as the compression rings....for the lower compression. Could be just a matter of reseating the rings, scrubbing off a mild layer of rust, etc.!?

Then, recheck the compression values after all of this. Then, if it's still very low, then, it does sound like a ring job may be in order, since the oil helped to increase it. Burned valves won't seal enough with oil to increase values.

Regular oversized rings/pistons are NOT available from Yamaha or aftermarket anymore, only the Wiseco Big Bore kits, 1179 or 1196cc, about $400 for a kit, complete with pistons, rings, wristpins, keepers, headgasket. You just need to get the jugs bored, and the other mechanic work, and a head/ring job, from either simple lapping the valves and seats, to getting reground$$, and should replace the valve seals while you're in there.

Good Luck!

[prometheus578]

Leakdown test will give you a percentage of compression loss. You'll also be able to hear where it's going to; out the carbs or the exhaust=valves, into the case =rings. Rings seem to be the main culpret, as the oil test showed.
From sitting, rings could easily just be stuck to the piston and not expanding to the walls of the cylinder. Cylinders #2 and #3 run hotter as they don't have side cooling fins.
I'd try... remove the plugs and crank the engine to try to expel as much of the oil that you placed in there. Messy!
Pour some good carb/carbon cleaner, PB penetrating oil into the cylinders,(might as well do all four) and let them set for a few days. Idea is to let the cleaner seep it's way down around the rings, loosen the carbon or varnish, and free things up.
Crank the engine again without plugs to expel remaining cleaner. Fire it up. It will smoke for a while due to the oil and cleaner that was left in the cylinders, but should clear out in a few minutes. Do not rev the hell out of it. Remember, there might be carb cleaner now in the oil. See if that fixes the prob, and then CHANGE THE OIL!

[andreashweiss]

I have some stock xs1100 pistons with rings,pins,connecting rods,valves,cams,cranks all used but came out of running motors when parted out. In case you do not want to spring for the wisco kit.

[eroellig]

Thanks for the suggestions, guys.

T.C. It isn't road ready. The carbs definitely need a good cleaningn and I wouldn't trust the tires, but I'll try harder on the stuck ring theory before getting excited.

Eric

[Winterhawk]

I agree with everyone. I think it's just stuck rings. Squirt some Zep in the cylinder and let it soak a bit. They should free up and work fine after awhile.

[RiskyBusiness]

Here's the internal link to the leak down tester. I really recommend doing this type of test. It tells you WAY more than a simple compression test.

[eroellig]

Originally posted by RiskyBusiness
Here's the internal link to the leak down tester. I really recommend doing this type of test. It tells you WAY more than a simple compression test.

I took a look at the leakdown tester, but there is one thing that seems to be missing. The directions talk about refering to a label to remake the pressure gage but I don't see one anywhere.

Eric

[RiskyBusiness]

yeah you can make one yourself but it is not needed. The idea is really straight forward. If you set your regulator at 100% at 100 PSI then that is the maximum reading. Down to 90 PSI (AKA 10% leak down) is pretty good. From 90-80 (10-20% leak) would be yellow: not too bad but not really strong. Below 80 (>20% leak down) is red because that cylinder has something bad going on.

If you want to do leak down testing with the regulator set at something lower than 100 PSI for max then you will have to do the math yourself and a label would be nice. If you start at 100 PSI, however, no real need for a label.

Hope that helps.