I knew I was long overdue for a valve clearance check since I've never had the valves checked and I acquired this bike at a little over 12k miles. This means I've put 38k miles on it without checking the valves or changing the spark plugs even. For the last month I've noticed that the bike has developed consistent stumble and hesitation throughout the rev range. The first symptoms started about 6-8 months ago that were very slight and only at certain rpms. As it progressively got worse I knew the spark plugs were shot and the valves were likely in need of adjustment. So I waited for a 3 day weekend, knowing that a specific dealership would be open on Sundays and Mondays thus allowing me to obtain shims if needed during the weekend and have the bike buttoned up in time for commute duties at the start of the 4 day work week.
as a guide in addition to the book (I like visual references as I'm a visual person when I haven't done something before), I checked my valves at 40.5k miles. This is the first time the bike has had a valve clearance check.
Much to my surprise, every single one of the valves were within spec! I didn't think that could be right considering it was the first valve check AND the fact that I ride her hard (redline on multiple days, multiple track days, etc) so I double checked. Yup, ALL are within spec. Amazing.
Here is what I have:
#1 intake: .005, .005
#1 exhaust: .009, .009
#2 intake: .006, .006
#2 exhaust: .009, .009
#3 intake: .006, .006
#3 exhaust: .009, .009
#4 intake: .005, .005
#4 exhaust: .009, .009
#2 and #3 cylinders on the intake side were right in the ballpark. #1 and #4 are on the tight side of the range but still in spec. Interestingly, all of the exhaust valves for all cylinders are on the tight side of the range but still within spec.
Considering this is the very first valve check and its at 40.5k miles, good enough for me!
I'll bet the next time I check (8-16k miles), I'll need to make some adjustments for most of the valves, so a HotCam kit will likely be a useful investment.
I kept reading about people saying how the #3 spark plug was such a pain so I thought I would experiment and take out all the plugs before removing the valve cover. Once I got the stuff I needed out of the way for the valve cover removal, removing the #3 plug was a breeze with the OEM spark plug tool. I was pleasantly surprised by this.
Now, I'm pretty sure this is the second set of plugs the 919 has seen, so they likely have 32k miles on them. Man do they look wore out! Pictures don't even really do them justice. Interestingly, the #3 plug looks the best by far, not having any burn marks on the insulation compared to the other 3. Picture has them 1-4 from left to right.
All 4 spark plugs
Close up shot
Removing the valve cover was also not that bad. I didn't drain the coolant, propped the fuel tank up, unbolted the #1 ignition coil and moved it out of the way, and then I was set to go.
Getting the valve cover back on however, will be interesting. I'll have to report on that later today. Since everything is within spec, I don't have to go to the dealership
But I need to drive a ways to pick up the spark plugs I needed, no sweat.
Also changed the oil. I played with the oil a bit while in the northwet and switched from the Rotella T 15w-40 to the T6. I noticed the T6 5w-40 was not performing well here in the hot heat after 2 oil changes. So I did some research and found that the 5w-40 tends to break down a lot quicker than 15w-40 in extremes. Being a motorcycle and being in the high heat of the desert, I decided to venture away from the T6 and look for a 15w-40 synthetic. I couldn't find any 15w-40 anywhere that was synthetic. I happened upon a gallon jug of Royal Purple 10w-40 synthetic for $35 and thought I'd give it a try. Nope, it actually felt worse than the T6 and felt as if it sheared a lot quicker than the T6, and that was during the cold months! What a disappointment. This time I decided to go back to the tried and tested Rotella T 15w-40 for $15 and see how that performs in the upcoming heat.