Q. I have a mint Kawasaki ZZR600 E1 which I am happily racking the miles up on. I do my own servicing and the valve clearances are coming up to be checked and reset.
My Haynes manual has flagged up its difficulty with a four-spanner rating, so I wondered if you have got any tips to get me through this?
James Williams, Hartwell
A. Before you start you need a good micrometer or vernier gauge and good feeler gauges. Once you’ve fought your way under the cam cover, make a note of the clearances between the buckets and cams. Sketch out a table for each cylinder’s inlet and exhaust valves.
To know what size shims you’ll need if any are out of adjustment, you need to do this calculation. A = (B-C) + D, where A=new shim size, B=recorded valve clearance, C=specified valve clearance, D=old shim thickness.
If you can’t get it exact, get the intakes as near to optimum as possible, the same goes for the exhausts, but if you can’t get them spot-on, err towards loose, as slightly loose exhausts won’t hurt (due to expansion caused by heat).
If they are too tight the valves are kept open and the bike will run like a bag of nails, as well as wrecking the valves and seats.
To get any new shims sitting pretty, get an old 0.50mm feeler guage and bend 2cm up at 40-60 degree angle, put a little dab of moly grease on the end and it will hold the shim perfectly for dropping in the bucket.
To get them out use the same telescopic magnet you used to lift the buckets. Finally, round up a mate for this as it’s so much easier with two people at several stages of the strip and rebuild.