Smokey smoke problem.....

Hey, new to the forum, lets see if you guys have the answers I'm looking for. I have an XR650L with about 10,000 experienced rider miles on it, mostly dirt. XR's only exhaust, mild jetting changes, otherwise stock. The bike runs great, makes great power but smokes like crazy on cold start up, stops after about 30 seconds. I've taken it apart once, thinking it was the valve guide seals, it wasn't. It's apart again now and there isn't any obvious source for the oil to be getting into the combustion chamber. Head gasket looked good, minor leak on the base gasket. I'm thinking it might be a cracked head, but wouldn't that cause the engine to lose compression and therefore power? It runs strong once the smoke stops. Starts warm with the shortest touch on the starter button. It's embarrassing and I need to fix it. Anybody heard of this? Thanks for the info, I'll be checking this forum often.

XrlTim (xrtim was already taken but it's been in my email name for years:ride: )

Hey, Welcome to Thumpertalk, xrltim....

Have you done a leak down test..Not valve stem seals, or a loose valve guide....possibly rings..


I haven't done that, there is some minor scuffing on the lower part of the bore. I was going to have it measured and be sure it's within spec, or get it bored and go with a bigger piston. I'm not dissatisfied with the displacement though so I'd only go as far as needed. I had a vavle job done just for GP the last time it was apart about 3k ago. New guides were put in at that time.

Yep, Sounds like rings then..That scuffing is not good....:worthy:


My 600r does the same thing & my buds 400r. but not all the time. I'm livin with the embarrassment. OIY

My 600r does it also, last winter I replaced the rings, had the cylinder honed, replaced the valve seals, had them re-seated. It was good for about 1 month, now it smokes just like it used to, only on start up.

What mesquitos?

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