Cam cover warped?

I'm starting to think the cam cover on my '11 Roadster must be warped, and I was wondering if anyone has had theirs successfully resurfaced by a machine shop (~$20), or if I should spring for a new one ($230)?

The cam cover gasket first started leaking a few months ago @4k miles, so I replaced it. I was very careful, followed Nev Lush's tips, and tightened the cover progressively using a torque wrench. Now with 10k miles, the gasket has again bulged from the same spot and started leaking. The first time was with the stock crankcase breather setup while the 2nd time is with a RamAir breather, so I'm pretty sure excessive crankcase pressure is not the culprit. I didn't check the cam cover gasket surface for trueness the last time I had it off, but I'm starting to think it must be slightly warped.

I saw a few other members (@08nzrocket, @mr hunt) have had similar problems. I'd be interested to know if a new cam cover solved the problem for good, or better yet, if I can just have the local machine shop run my original cover through a belt sander to straighten it out.

Here's where the gasket failed on both occasions:

When mine did this ( once only so far ) a member on here whos name eludes me said lay the cover flat on a mirror to test trueness. When you changed it the first time did you go back and check the stud tensions after a few thousand miles operation ? Mine is due for a re-torque as ive done close to 5000 klm

I checked the two bolts next to the problem area, and they were tight both times, so I don't think that's the problem. Yeah, I'll be wiser once I take the cover off again and check it on a glass surface. I just hate commuting with the cage while waiting for parts for the Rocket, so I'm trying to decide if I should just order a new cover in advance, or if it would be possible to resurface the original one.

My dealer had my cover milled even though it came back 100% true after the first blow out...he has absolutely no explanation as to why it went twice on my bike.

...on the plus side, it leaks bugger all oil really so apart from a more regular clean to keep oil from dripping I kept riding til it was fixed.

I took the cover off today, and here's the failed spot:



In general, the whole gasket surface on the cam cover looked pretty uneven, mostly because Triumph has powder coated the part after the gasket surface was machined. I could find gaps up to 0.80 mm with a feeler gauge:



I took the cover to the local machine shop for resurfacing, but unfortunately they didn't have a belt sander, and the setup time for milling in a CNC machine would make it cost prohibitive. I wanted to get the bike back together today, so plan B was a piece of glass and some valve grinding paste:



The gasket surface turned out pretty good, so I went ahead and re-installed the cover with a thin smear of black RTV silicone in the problem spot for a peace of mind. I guess I'll find out in the next 4-5k miles if it holds up.

Now one interesting thing I found on other forums is that Triumph has come up with an updated version of the cam cover bolt seals for the Bonneville, which is notorious for leaks. The original Bonneville part (T12603309) is the same as Rocket's, so I think the updated part (T1260337) should work as well. According to the Bonneville guys, these rubber seals / washers are critical for transferring the bolt clamp load to the cover. I'll try the new Bonneville bolt seals the next time I have the cover off (hopefully for a scheduled valve check this time).

Excellent idea !