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250L uses oil, but does not smoke?

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After long hard rides, over 60mph for sustained periods of time, my bike gradually uses oil. It does not smoke, and I am definately checking the oil correctly. On top of this, it does not seem to do it on short, mellow rides.

The crankcase breather goes into some sort of canister on this bike, and then on tube goes into the airbox and one vents to the ground. There is always a small drop of oil on the end of this tube. Could it be dripping out of there, or being pulled through the airbox? What is the vent like on an R model? Can I just plug the hole in the airbox and run a small filter as my crankcase vent?

BTW, it uses about 1/2 qt per 200 miles

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it is probably burning the oil, although small amounts that are not noticed. at high revs these motors are known for blow by. there is not a whole lot you can do, just keep oil in it.

the canister is a charcoal canister to adsorb crankcase gases/fumes. just like the charcoal canister in the fuel system of your automobile.

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Would taller gearing help? I have a 13 tooth on the front now, but I also have a 14 and a 15 I can swap in. I was hoping on doing some touring with this bike this fall, but I can't see lugging around oil with me!

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I think I have a similar issue. My bike is a 96 XR250R, and I find that it too uses oil, but never smokes. In another thread I mentioned that the area around where the crankcase breather tube ends (beside the airbox) is all covered in an oil-dust paste. This may be one path to oil loss.

In any case, it isn't serious, it's just annoying that I have to add a bit of oil between oil changes.

I suspect that, as you mentioned, this happens most when I ride on the highway. My gearing is 13/48, and the RPMs are quite high at 95 km/h.

When I next change my chain and sprockets I will probably go with taller gearing.

d.

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XRs are known to blow some oil out the breather when run hard at high revs. However, if you notice it getting worse with time, then the problem is blow by. This happened on my XR600. After a while it was loosing a lot of oil out the breather. When I took it apart the problem was worn out rings. You measure the rings by taking them off the piston and putting one in the bore. Use the piston to get it square in the bore. Then measure the gap between the ends of the rings. The spec is small like .020 or so. Mine was so large that I didn't even measure it. I laughed instead. It must have been .125 or more. The piston and bore were within spec, so all I did was get new rings and give it a good hone job. When I put it back together, there was a good boost in power and no more oil out the breather.

To summarize, some blow by at high revs is normal. If you notice it getting more and more, then it's rings.

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Great tip, thanks.

I've been thinking about it and I'm not sure I have ever cleaned that area, so it is probably historic grunge and not something sudden.

Cheers!

d.

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according my mechanic here, who happens to be very experienced fixing with RFVC engines, says that the 250 RFVC consumes aproximately about 1 tablespoon of oil every 130 km. he couldnt explain why the engine does that.

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Well, my bike is using a LOT more than that, so I must need rings soon. How hard is a ring job on these bikes? Do you have to remove the engine from the bike? Can you just disconnect the cam chain and pull the jug off?

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On my old XL's -even with fresh rings, valve seals etc, I get a drip out of the vent tube. Even when new in 1973 my XL250 would do that. sometimes more, and especially after a sustained ride at 50MPH or better. To this day for what it si worth the 1974 XL350 I have like to leave a 50 cent coin spot after a ride. However....

My new XR250R and 650L emit nothing from the vent tube, ever - no matter how hard I ride it.

My reccommendation for a top end job, disassemble as much as you can in the frame (letting the frame hold the engine for you while you break loose stubborn bolts) once done - remove engine from frame and work it on a bench, easier on your back that stooping over the bike and easier to work on. Doing a top ne djob is EZ get a manual and follow the steps.

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