| Author | Message | ||
     Djkaplan |
I have an oil leak at the base of the rear cylinder on my 40,000 mile M2. I'd like to replace the base gaskets, but other than the leak, there is nothing... NOTHING wrong otherwise with my top end. The rings are sealing, the valve guides don't leak, the rocker boxes aren't leaking... everything is perfect. Even the oil consumption is near zero (no exaggeration). I haven't done a leakdown test, but the engine doesn't show any signs of losing compression. With 40k on the clock on any other bike, I would at least crosshatch the cylinders and install new rings if I had the top end off, but I'm not sure I want to mess with a good thing on the M2. Would it be prudent to just reuse the old rings if I currently don't have a problem or is this a big no-no? | ||
| Cyclonecharlie |
I don't know of anything that will seal it for long.(not even Yamabond) So if you pull it down, check clearances and taper.I would still run a quick hone and put on a new set of rings.Your talking forty thousand miles, there's got to be wear there.  Charlie | ||
| Bluzm2 |
DJ, Are you going to do both cylinders or just the rear? If just the rear, if you are careful, you can pull the jug without removing the piston from the bore. That way you don't upset anything. Sometimes the wristpin is a bit difficult to pull without a puller. This makes doing it with the cylinder on a bit difficult. If you are doing both jugs, may as well check for taper and do a crosshatch as Charlie mentioned above. Since you have the ehads off, may as well replace the valve seals too. Doesn't take long and they come with the top end kit. Brad | ||
| 01m2 |
I just had the same problem with the rear base gasket at 17k miles. But mine was using oil big time...350 miles to a quart. The valve seals were hard as rocks, the guides were within spec, I had a valve job done as there was some pitting on the valves and seats. The cylinders and pistons looked great. Needed to devise a puller to remove the wrist pins. Did a re-honed with ball type hone and checked the ring end gap they were near new spec. Reused the old rings. So far all is well. | ||
| Yo_barry |
I had a leaky base gasket on my 99 Sportster at about 60K miles. Pulled the head, cylinder, and piston to replace the base gasket. I could still see the crosshatch on the cylinder walls. Just did a little cleanup on the head and piston, and reassembled with the original rings. It's been good for the last 25k miles. |
