So, I’ve been battling for the last few weeks trying to solve a ticking issue my Raptor developed towards the end of last year. It’s been getting louder and it was getting to the point it was embarrassing to ride!
The tick was coming from the left hand side on the rear cylinder and was quite difficult to pin point it’s exact location. Even using the screw driver trick!
On reading many threads and watching too much YouTube these are the things I tried!
- Removing, cleaning, and Advancing the auto cam chain tensioner manually.
- Measuring and adjusting the valve clearances.
- Tightening and checking all exhaust gaskets including pair gasket(didn’t sound like a leak but I was running out of ideas).
- Checking play and movement of the starter sprag.
- Checking clearance or evidence fouling of the stator
- Checking clearance or evidence of fouling of the crank position sensor.
There was one thing that I couldn’t see anyone mention. Scissor gears on the anti backlash mechanism of the cams. The mechanism on the inlet cam wasn’t moving as freely as I liked so thought I’d investigate. These are supposed to be unserviceable but with a circlip holding everything together I was up for a small challenge.
On removing the circlip there is a spring washer and a shim covering the floating gear and springs. I removed all of these to find out surface rust has built up on the cam preventing the anti backlash gear from moving freely. The springs couldn’t even overcome the force required to move the gear back into position.
So I cleaned up the surfaces with wire wool, cleaned everything meticulously with brake cleaner before covering all components in 10-40 oil and resembling. I performed the same on the exhaust cam and reassembled the bike. On first run the tick has gone!
So the ticking has gone but now it’s highlighted that the same noise has started on the front cylinder. Good job I know what to do
I might get some photos together when I do the front to try and help anyone in future.
Hope this gives some help to those who have tick they can’t seem to locate, I’m not saying it will cure your tick but it does it gives you one more place to look!
[TL;DR]
If you have an annoying tick you can’t figure it out, and have tried everything suggested in the forums, try looking at the anti backlash mechanism on the end of the cam. This can become stiff and may require a strip down, clean, and relube.
