oil consumption

I have a '88 VFR that consumes oil. The curent oil is Castrol 10W 40 , the question is if it wold help to change to a heavier weight oil? I did aproximatly 3500 km and it consumed 2l of oil.
The bike had a rough life at the previous owner and has aproximately 80.000 km.

 

That is quite a bit of oil. Never hurts to try a heavier oil.

 

I think I will try a 20W 50 or a Repsol 15W 50, hope this will reduce the consumption.

 

That's about 1 qt per 1000 miles, pretty high. Almost VW territory.

 

I know. I considered to rebuild or change the engine but if I can reduce the consumption with a simple oil change it would be great.

 

Do a compression test, and see how bad the situation is. If you are burning that much oil, don't waste money on expensive synthetics or high end oils. First number viscosity a cold temps, 50W might help. Any leaks or are exhaust pipes black & oily?.

 

It doesn't have any leaks, the exhaust pipes have a bit of black dust at the end but them are not oily. I will do a compression test soon.

 

Any consistent blue smoke? Blue smoke on startup? it's either rings or valve guides. No after market snake oil remedies with wet clutch.

 

Is the case breather tube open, not plugged? Is your catch container full of oil?

 

on startup their is no blue smoke, I let a friend of mine to ride it to see if their is blue smoke and it smokes a little in high rpm. The case breather tube is plugged.

 

I'm no mechanic but that is one hell of a lot of oil going missing withoug evidence of leaks or excessive burning. I have never needed to add oil other than oil changes, but I bet, if I kept that close of an eye on it, I would not have even come close to needing that much oil over the life of my bike, which is somewhere near 186,500 km (116.500 miles). Something is wrong. If that kind of oil is being burned, I would think you would smell it. Will be interesting to hear what you learn of this

 

This weekend I will do a compression test and hopefully I will know what to do next . The bike was almoust free when I bought it, I hope I can reduce the consumption without opening the engine or changing it.

 

Plugged breather will make any motor consume oil, crank pressure has to go somewhere and it is pushing oil up past the rings,and trying to force its way out of any join or gasket, surprised it isn't doing that already, get it unplugged, it was put there for a reason

 

It will be burning it. I had the same problem with a GS1000 years ago. No real visible signs of burning but that's what will be happening. If you see smoke at high RPM it will be the wear in the bores. If you get smoke on the overrun it will be guides. Thicker oil will help but not much in my experience. If you can, get someone to follow you to see if they can detect when it smokes badly if at all. Smelling for it is a good suggestion too. My GS1000 didn't smoke much but it drank oil like a Wankel Rotary.

 

There's part of your problem. With the pistons pumping up/down they will build pressure inside the case. It has to be relieved or you will push oil up past the rings on intake and exhaust stroke. The rings seal themselves on the compression stroke from top side pressure. They don't have the same sealing power from bottom side pressure. Depending on the condition of the engine depends how much oil gets by the rings.


Put that relief pressure tube in a catch can or open to environment. Be careful just hanging it down by the swing arm/rear tire.

 

I did a compression test today.The compressin on piston #1 & #3 is 13,5 , on piston #2 & #4 is over 17

 

The rings in 1/3 could be gummed up from carbon deposits (burnt oil) because it's getting in behind the rings and caking from inside pressures. You might have a 50/50 chance of that. Using a Marvel Mystery Oil additive for a few hundred miles might help. NO kerosine! If the motor wasn't at least medium hot and the throttle held open your compression readings don't mean much. It could also be deposits on the valve seats/face and they are not sealing 100% or close.

Since you're seeing a little blue smoke at higher rpms it points to the rings. Don't worry about the compression right now. Get the case breather open and ride it and see. Stick 500 miles on it. Check the oil before then after. That will give you an idea if that's part of the reason for the oil consumption.

 

i forgot to hold the throttle open when i did the readings X_X , tomorow i will do the readings in the corect way

 

And don't omit the units of your compression test next time.:smile-new:

 

My english on tehnical words is a little bit rusty ( i'm from Romania). I understood that I need to get some additive (Marvel Mystery Oil, don't think we have this in Romania, I will look for something similar) and to unplug the breathe tube from the air case. Is that right?