Here I'm doing a maintenance task that I was really not looking forward to.
I found a guide on the web and it turns out you don't have to remove the tensioner. You can remove the spring and release the ratchet that prevents the plunger retracting.
|Tensioner spring & bolt|
I'm starting with the front cylinder. I've removed the cams, buckets
and shims. Note duster to prevent anything falling into the engine. |
The shims have their size marked on them but this
has been mostly worn off. I use a micrometer to measure them.
calculation sheet. (dimensions in 1/100 mm) Here I work out what shim
to fit to get the correct clearance. The valves that are in spec but
near the lower limit will get a shim one size (0.05mm smaller) this will
bring them into the middle of the range. I'm do this because it will
hopefully mean that they are less likely to go out of spec in the
I'm swapping all four shims but only have to buy two since the two from the exhaust valves can be used on the inlet valves.
this point you might expect me to do the rear cylinder. But its checked
with the crankshaft in a different position and I'm loath to turn the
engine with the cams out. I'll wait until I've got & fitted the new
shims before working on the rear. This makes the job slower but I think
I got a pair of new shims and installed them. The existing shims from the exhaust valves went into the inlets and I put things back together. I checked the clearance and they're all now in spec.
The rear cylinder is a repeat of the front cylinder. This time the tensioner bolt is hidden behind the frame. I removed the footrest hangers and I can get to the bolt by feel.
As with the front, two of the clearances were tight and two were on the low end of the spec range. Again I decided to put in shims two sizes smaller (0.10mm) into the valves out of spec and one size smaller (0.05mm) in those on the bottom end of the range to get them in the middle of the range.
A tip I got from a Youtube video was to zip tie the cam
chain to the can sprockets to keep the timing from going out.
Again I ended up with a set of valves with in-spec clearances. I now put everything back together and I'm good to go.
|I sprayed the radiator before re-fitting|
The bike is all back together and running fine. The next check is in 15,000 miles or about 3 years of riding. Experience tells me that once set the clearances are likely to stay in spec. The job was a bit of work but not as bad as I had feared.