|09-25-2012, 06:39 AM||#1|
Joined: Oct 2007
Location: Having a coffee on some mountain top
Cam timing - a bizarre issue
My bike is a 2003 950 S with Akra's and a pair of 41mm FCR's.
Following a cam timing issue with a friend's '07 990, I decided that it was time to check mine, maybe I'm a tooth off or something...
The mechanic who installed the cams on my friend's 990 rotated the crank only 75 degrees CCW to set the front cylinder timing instead of 1 revolution and 75 degrees. His bike started and idled fine (with a different sound though), but acted as if he only had one cylinder. Like a big XR650...
Anyways, my bike always felt like it had more. It sounds totally different that any 990 (a much more metallic and "hollow" sound with less bass). I always had cold starting issues (both with the stock CV's and the FCR's). And mid-range was never as good as any 990, with or without the FCR's. With short(ish) 16-45 gearing, it would lay you on your back in 1st gear, but have real difficulty to lift the front is 3rd. Top speed was around 210km/h. Oh, and gas mileage was horrible...!
So, I ripped it apart today and found a very interesting surprise. This is where you guys come in...:
I don't have a spark plug socket (got lost) so I rotated the crank CCW and found the first locking hole in the crank. At this point, the rear cam lobes were pointing towards each other and their marks ("+") are perfectly aligned with the valve cover surface. Without measuring if the rear cylinder is at TDC (the plug is still in place), I can only assume that the crank locking hole is the boss in this situation. I then released the crank locking pin (used a metal rod) and rotated it just 75 degrees CCW. At this point I locked the crank again just to see the the front cylinder cams were perfectly aligned...
Adding another 360 degrees CCW to the crank and locking it where the manual says is the front cylinder cam adjusting position, the front cams are way way way off.
My (long-ish) questions are as follows:
1. If the plugs fire every time the piston is at TDC, is it true that I can adjust either the rear cams or the front? What I mean is, when the crank is locked in the rear cylinder TDC and the cams are fine, I can rotate 435 degrees CCW and adjust the front ---- OR ---- from the position where the front cylinder is at TDC (crank is locked) and the cam marks are aligned, I can go 285 degrees CCW and lock the crank to adjust the rear cams?
2. HOW FOR THE LOVE OF EVERYTHING V-TWIN, could my bike be running pretty well (not perfect) for 4 years with timing that far off???
Any help will be appreciated here...
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