Cam chain replacement is not a difficult job to do on the T300s because the cam chain runs off of one end of the crank. Until the Kawasaki GPZ900R came along, it was typical practice is to drive the cams from the centre of the crank so changing the cam drive chain was a fiddle to say the least and typically was done with a split link. Having a cam chain that runs in a tunnel on the end of the crank means it is possible to use a stronger, endless chain - and avoid the risk of dropping bits of split link into the engine. Much better.
|View of the cam cover (aka cylinder head cover)|
protruding either side of the main spine frame tube.
The cam cover is retained by 10 mushroom-headed
Allen bolts, four are out of sight in this photo and
need care with a good Allen key to remove them
|Wonderful T300 Green profile cams exposed,|
cam chain emerging from its tunnel on the
right-hand side of the engine.
Doing the last bit of the job on the side stand will stop engine oil running out. I was doing this along with an oil change anyway so losing oil was neither here nor there in my case. It also makes the job easier because this way the cam timing marks are tilted up for you to see.
|Arrow mark on cam sprocket shown parallel |
with gasket surface for cam cover.
Next, remove the cam chain tensioner from the rear of the cam chain tunnel, and the steel arch that serves as a top guide for the chain. This sits between the two cam sprockets (not in these photos I'm afraid). Then gradually release the bearing caps on each camshaft. Do two turns on each bolt, working in rotation around all ten bolts as you go.
I use a good single hex 10mm socket on a 1/4" drive ratchet handle. Do this for the inlet camshaft first, lift off all the bearing caps and keeping them in a clean, safe place, then pull the camshaft up with one hand and unloop the cam chain from its sprocket with the other. Repeat for the exhaust cam, putting a bar through the chain to make it easier to remove later on.
|The ignition rotor must be removed |
by releasing an Allen bolt that retains
a large nut, and refitted with thread
lock and to the correct torque
after the new chain has been fitted.
|Feeding the cam chain down the cam tunnel and|
guiding it out, away from its drive sprocket.
Reassembly is, as they say, the reverse of the dismantling process. There is a trick with the tension though, and in settling the green cams in a way that keeps the timing correct. I'm out of time myself now, so more about these tricks next time.
|Comparing wear in the old (top) and replacement (bottom)|
cam chains by showing how much more lateral movement
is possible with the worn chain than with the new.
The new chain, coupled with new engine oil, has made the top end noticeably quieter and the engine feels taught too (not forgetting the carb and air filter clean). I used Shell Ultra 4T fully synthetic 10w40 oil this time. Any fresh oil is impressive, I've found, by smoothing out gear changes. I've ridden about 200 miles on it so far and it feels great. But then, it is Summer and I love my bike.