Well I started diving into a used 2008 R6 race bike I recently bought to start prep for next season. When checking valve clearances, I noticed this intake camshaft cap bolt for cylinder 1 was loose and was surprised to see all of the threads stripped out of the cylinder head. Has anyone had any luck with using helicoils for the camshaft cap bolted connections or recommend a different option that will hold up for race use? On a side note, I have seen two R6 cylinder heads now that had burned up intake cam journals for cylinder 1 and the cap was at least 1/16in off the head. Not sure if these bolts are prone to becoming loose and cause this or is an unrelated coincidence and burned up journals are a result of contamination plugging up the oiling hole for cylinder 1 and starving the journal of oil. Any help or input is appreciated.
Happens all too often. You can use heli coils, (red or green Loctite) but you need to stay after the bolts pretty often to make sure they haven't pulled out. You can't use time serts because of the locating shoulder requirements in the head. If you don't enjoy working on it, probably better to get new head.
Thanks for your response. I enjoy working on bikes and engines as much as racing, but still have more to learn about the weak points of the R6 engine. I'm planning on tearing this one down to get a better understanding of its condition. Hopefully its worth adding a heli coil and some high-temp red loctite 266. It's good to know these bolts are problematic. I'll add this as something to check on a few times per season.
Length of that bolt seems a bit short. Rule of thumb for ferrous engagement is 1.5 X bolt diameter. Probably over torqued. You won’t strip out a Helicoil if done correctly
I'd fix it with a helicoil. Conveniently you can use the cap as a guide to make sure the drill and tap go in straight.
Had the same thing on my bike, pretty sure I caused it though. The bolt in question was a 6 mm and I used a 1/4 grade 8 bolt of the same length to replace it. Slightly larger but still fit through the camshaft journal. Been over 5 years and no issue. Good luck.
