Engine has about 43K miles on it and is burning oil. Options?

[Loukiii]

So my 86 FJ1200 is burning a little oil. I talked to my mechanic and he said that eventually the cylinders start wearing and they need to be bored out and the rings replaced etc. which he said could cost more than the bike. Thing is, I DONT WANT ANOTHER BIKE. lol I waited 35 years to get this one.
So aside from just ride it and keep filling it up with oil,(it goes through several tanks of gas before I even notice the level go down and I check it before and after every ride) what are my options?

[FJmonkey]

Ride it and keep checking the oil like you do now, Kookaloo.

[jono]

I bought this bike as a donor for my 3xw as lot of parts are the same  its done just over 100000 km and I just started stripping out the motor. The clutch plates still measure in spec thickness wise the lugs are slightly hammered but i think that's human error
the valve seats and valves look pretty good there is slight pitting on the  part of the stem exposed in the ports on some of them maybe because the oil slowly washed away with moisture from condensation as it lay on its side in the PO's backyard for 15 years but the guides still feel good and the bores are good with absolutely no lip, so Yamaha obviously us very good metal in there engines and if yours is using oil you might find its just in need of new rings and a hone and the a proper running in process of the new rings, which I believe is very important to the way a motor lasts, my 3xw has done somewhere between 100000 and 200000 km and doesn't use any oil

jono

[f4fwildcat]

I changed from 10w40 to 20w50 and it made a significant difference. My startups normally had a lot of smoke but once changing to 20w50 that went away significantly. Also there was a lot less oil mist on the inside of the airbox and I didn't need to top up the oil halfway through oil change interval. The best thing is it quietened the engine chain slap significantly and this is on an FJ with I think 64,000 miles on it. Otherwise your only options really are too pull the engine and try a new set of rings and a hone as suggested.

[Loukiii]

I was looking into the honing and new piston rings and a mechanic told me that I would probably not be able to find new piston rings and I wouldnt be able to order them even until after the cylinders were machined because they wouldn't know what size I would need. Is that the truth or was he mistaken?

[Waiex191]

I was looking into the honing and new piston rings and a mechanic told me that I would probably not be able to find new piston rings and I wouldnt be able to order them even until after the cylinders were machined because they wouldn't know what size I would need. Is that the truth or was he mistaken?

That sounds wrong.  They should bore to fit the new piston, if needed.  I'd find another mechanic, or send it to RPM.

[Pat Conlon]

RPM has .020 oversize rings for just this purpose.
http://rpmracingca.com/proddetail.asp?prod=Engine%3A4PU-11605-01

Your mechanic is correct. You won't  know if a simple cylinder hone/ring job or a more expensive cylinder bore is necessary until measurements are done.

[Waiex191]

Your mechanic is correct. You won't  know if a simple cylinder hone/ring job or a more expensive cylinder bore is necessary until measurements are done.

If you read what Lou wrote, it says they would machine the cylinders first (not measure) and then look for rings.

Dumb question - every engine I've had bored to oversize required new pistons.  Can you put in a .020 oversize ring in a standard piston?  Wouldn't you want to keep the piston clearance the same as you bored it out?

[Pat Conlon]

Oh, ok Bryan, I see what you're saying....no one would bore before taking measurements....would they?
Maybe the measurements are fine and they don't need the new bore?
If they do need a new bore, what size for the new bore?

Unless you're a fan of piston slap, the .020 rings must match new .020 pistons and the new bore.

The $$$ question:
Can Loukiii get away with a simple cylinder wall hone/ring job (std.size) or does he need a cylinder bore and all new pistons and rings?
FYI, yes, standard size Yamaha piston rings are available:  
https://andrewsmotorsports.mybigcommerce.com/engine-product-yamaha-fj-fj1200-std-yamaha-piston-rings-set-of-4-4pu-11603-00-00-4pu116030000/

Should you use them?
Don't know....It all Depends on the TDC and BDC cylinder diameter measurements.

I see no listings at RPM for new oversize pistons but Curt Andrews has them in different sizes:
https://andrewsmotorsports.mybigcommerce.com/wiseco-piston-kit-yamaha-fj-complete-kit-k1195-motorcycle-series-11476m77241/

Unless the odometer rolled over (very possible) 43k miles is kinda low mileage for an FJ to burn oil, just maybe, new standard rings and a hone is all that's needed?

Question for Loukiii...are you sure it's the rings and not valve seals?
Does the bike smoke on start up?
Sometimes valve seals dry out and harden, thus leak, only to get refreshed to a 2nd life once the bike is ridden.

Monkey Mark's advice, ride her, get some miles on her and see if the condition improves.

Find out more about your condition
Disconnect and cap off your vacuum advance, pop in some fresh plugs, go for a ride, then read your plugs.
Find out which cylinder(s) are burning oil.
Do a warm WFO compression test, find out which cylinders are low, then squirt some oil in those cylinders, retake the test and see if the compression numbers improve...if they do, that's a good indication that it's your rings.

Like I said, 43k is low for burning oil.....perhaps it's a leaky valve seal, or two?

See what your compression test shows.

[krusty]

So my 86 FJ1200 is burning a little oil. I talked to my mechanic and he said that eventually the cylinders start wearing and they need to be bored out and the rings replaced etc. which he said could cost more than the bike. Thing is, I DONT WANT ANOTHER BIKE. lol I waited 35 years to get this one.
So aside from just ride it and keep filling it up with oil,(it goes through several tanks of gas before I even notice the level go down and I check it before and after every ride) what are my options?

Have you done a compression test? If not do one and go from there. I'm surprised no one has mentioned this unless I missed it.
BTW does the oil level light come on when oil is low. How many miles from topping up down to low level warning?
Are you sure it's only done 43K and not been around the clock once or twice? 43k would be just about run in by then.

[Loukiii]

Question for Loukiii...are you sure it's the rings and not valve seals? No idea. Just going by what the mechanic told me.
Does the bike smoke on start up? I have never noticed any smoke when the bike starts or when it is running.  The first thing I did when I bought the bike was take it to a mechanic and had the oil changed and had him check it over. He told me my carbs were out of synch and that is why it backfires sometimes on decelleration unless I engage the clutch. But I could ride it with no issues until I decide to get the carbs synched. However it seems the bike is not backfiring as much as it was lol After riding the bike a couple times after that I noticed my oil light came on while I was making a turn and went out when I straightened up again.  When I got him I checked the oii and it was a little low so I topped it up about halfway up the window. I called the mechanic and that is when he said "if it is burning oil then this is what you might need to do etc."

The oil light came on again one other time and I turned around and went home but the light went out and when I checked the oil it looked fine.  But perhaps I am just paranoid lol I dont like the idea of being stranded or blowing up an engine

[Loukiii]

So my 86 FJ1200 is burning a little oil. I talked to my mechanic and he said that eventually the cylinders start wearing and they need to be bored out and the rings replaced etc. which he said could cost more than the bike. Thing is, I DONT WANT ANOTHER BIKE. lol I waited 35 years to get this one.
So aside from just ride it and keep filling it up with oil,(it goes through several tanks of gas before I even notice the level go down and I check it before and after every ride) what are my options?

Have you done a compression test? If not do one and go from there. I'm surprised no one has mentioned this unless I missed it.
BTW does the oil level light come on when oil is low. How many miles from topping up down to low level warning?
Are you sure it's only done 43K and not been around the clock once or twice? 43k would be just about run in by then.



I am monitoring that closely now waiting for it to get low again. I didnt really pay attention the first time.

[Pat Conlon]

The FJ's oil level sensor in the crankcase can be fussy. We call the red oil light the kookaloo light. It tends to come on under heavy acceleration, hence, the kookaloo zone.

Unless my oil level is at the top line in the window, the oil light will blink. This blinking red light freaked me out at first until I realized what it was....oil level, not oil pressure.
Check it before each ride and you're golden. You're down there anyway checking your tire pressures.

[FJmonkey]

While you are down there, check the lower fame bolts as well.

[ribbert]

All this talk of pistons, rings, rebore, in what order and so on is jumping the gun a bit, what your mechanic told you (about wear and rings etc) was theoretical, not the result of tests to your specific bike.

Even if it was third time round the clock, it would still be unusual for an FJ to be burning oil because of worn rings, cylinders etc. I know of one personally with 270km that doesn't use excessive oil and there are many other bikes here with these sort of mileages and more, way more.

As Krusty mentioned, over what sort of mileage have you observed this, that is, is it an established pattern or the finding of one or two observations?

The sight glass is at the outermost part of the crankcase and as such is very susceptible to being level, a couple of degrees off dead vertical will throw the reading way off.

An engine burning enough oil to cause noticeable consumption will normally show visible smoking from the exhaust.

Even if the oil level is within the limits (minimum being the bottom of the glass) there are circumstances that make the low level light come on, such as taking off up hill and rapid acceleration in low gears, more so when the oil is really hot and the lower it gets, the easier it comes on (because it's a level light).

So, first thing, establish the consumption over a reasonable distance, say 1000 miles, to rule out things like measuring anomalies. If you are going to check oil level on the centre stand, do it in the same place. Personally, I kneel next to the RHS of the bike and bring it up vertical off the side stand, this way I can feel the exact balance point and it eliminates uneven ground throwing off the reading, also, I don't have a centre stand , but even when I did, I still checked it this way.
If checking the oil cold after being on the side stand, have the bike vertical for a minute or so before checking as cold oil is slower to react.


According to my mechanic.

Noel