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My XR is smoking...


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Hi All,

This is my first post. I have a 1997 Honda XR600R. Recently it started to smoke (blue-ish white). I checked the oil and it was practically empty so I added oil. It continues to smoke though. It smokes when it's warmed up and when I'm accelerating (no smoke at idle). It sounds and feels fine, but the smoke is concerning me. Oh and when I changed the oil, there was kind of a grey swirl (metal particles maybe?)

I'm wondering what the verdict is. Is my piston and cylinder just fried and needing replacement? Could it be a valve guide or seal? I believe the engine has never been torn apart, and considering the year, I'm sure it has tons of hours on it.

Any help is much appreciated.

Thanks all!

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It sounds more like worn rings. Valve seals tend to only smoke at startup. Since the bike is a big bore, it still has a lot of power even though the rings are leaking. It's unlikely that you risk much by continuing riding, but keep an close eye on that oil level and check it every ride. Eventually when the blow by gets large in volume it will start to carry oil out the crankcase breather. That was my signal to open up the engine. I found transmission issues so my $$$ went to that. I measured the piston and bore to find that they were both within spec. It was really only the rings that were worn, so I honed and put in new rings. Got three more years of riding on that piston and bore.

The gray swirls are tiny metal particles in the oil. A little is pretty much normal. A lot is not and indicates the oil may have been in there too long. You might want to change the oil after not too many hours as not all the oil gets drained. Be sure to check the frame oil strainer as well.

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I checked the oil and it was practically empty so I added oil. It continues to smoke though. It smokes when it's warmed up and when I'm accelerating (no smoke at idle). It sounds and feels fine, but the smoke is concerning me.

How long have you had the bike? Did you bring the engine up to operating temp before checking the oil level?

Smoking most or all of the time is usually indicative of worn rings.

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Time to take the top end apart, if you're doing that then rebuilding the head should be on the list, 9 times out of 10 you can get away with just new guides and seals. Its worth checking the Vv spring lengths and then new seals.

As for the piston and bore, you may get away with new rings but budget for a rebore and piston.

I've been though this cycle a few times now with various bike and I just get a light porting job on the head and new high lift cam when i go in for a top end strip.

If you're going into the motor then make sure you do it right and do it once, never think "I should have done..." just bite the bullet and do it.

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