Will Barber finishes this amazing machine!
Will Barber continues the journey of taking a rough and ready rare Kawasaki from strip-down to restoration.
Last month I introduced you all to this Kawasaki Z1-R TC, owned by Chris Kitchen. He asked me to get this bike sorted, so let’s crack on to completion! Following on from sorting the fuel tap, it was time to get on with the front end of the bike. There was lots to do and the handlebar fairing was removed for access to the various components. Basically here I needed to sort two new Uk-spec indicators, brake cable, front brake light switch, bleed the brakes, sort a ‘pull’ throttle cable, H4 headlamp bulb, check all the instruments and tidy up some paintwork. The front braking system on the Z1-R and TC models are unique in the fact that although the calipers are hydraulically controlled, the master cylinder which sits below the top yolk is operated via a standard ‘Bowden’ cable from a conventional brake lever on the right-hand bar. This in turn pulls the actuation lever on the master cylinder which then hydraulically operates the brake calipers. This was to keep clean lines at the front of the bike without accommodating the chunky master cylinder on the bars. The braking system needed a thorough going over, with a change of fluid, replacing the kinked/stretched lever-to-master cylinder cable, fitting Ferodo brake pads and sorting the brake light switch. After using my Mityvac vacuum brake bleeding kit I got a good solid feel on the lever. The rear brake needed similar treatment to the front. Electrically, there were a few issues, such as corroded terminals and damaged block connectors which were identified and replaced. The rear brake light switch had its pin turned upside down so the brake light was on constantly, hence the last owner simply disconnected it! The bullets were also badly corroded and had already been replaced with bits of incorrect coloured wire, simply twisted together and wrapped in tape. Fifteen minutes’ work saw the brake light switch back to full functionality with new wires and bullets soldered on. I also took the opportunity to add a double female bullet socket in readiness for a positive supply for a new Dyna 2000 ignition system. Other issues included corroded terminals in the fuel gauge connector block from the main harness and the odd terminal block held together with cable ties! These connector blocks are literally not available anywhere! However, after putting up a post on the forum, a fellow Z1-OC member kindly donated the two female terminal blocks I need. With the ignition lights going off when the bars are turned, I sorted this by checking all the connections and cleaning them, also sorting the bent and corroded pins which caused the flickering. I used the Dyna 2000 system to replace the conventional points and condenser system, including the Dyna 2000 ignition control module, Dyna 3-Ohm
mini coils and Taylor silicone leads with integrated plug caps: these ensure longevity of the engine and give the rider peace of mind that the engine will not self-destruct! I fitted the unit just behind the battery with a U-bracket and foam. I set up the system including the boost retard switch, which means that at 4psi of boost, a circuit is completed, sending a signal to the retard function on the Dyna 2000 control module. Along with the leads I fitted one stage ‘hotter’ plugs, hence the replacement of NGK B8ES with NGK B9ES spark plugs. Time for a test ride: I gently rode the bike but it wasn’t behaving, coughing and spluttering under even the slightest of load. After just a few hundred yards it got so bad that I had to limp home and try and suss out what was going on. It felt so rich but I’d even fitted a smaller primary jet so this called for further investigation! There was nothing wrong with the carb, the ignition system was checked, plugs changed, so – having had a chat with owner Chris – we decided I should take off the cylinder head and have a look. I found that the cylinder head had obviously had work done on it due to the fact that we were almost out of the service limit of valve clearance; down to just 2.20mm shims in some cases and while the head was off I suggested it be sent over to SEP in Derby for remedial work. Before I removed the cylinder head, I had to determine what compression ratio we had, but I didn’t yet know the cylinder capacity. I could work this out after I’d removed the head. I brought No.1 piston to TDC and measured how much oil it took to fill the combustion chamber up to the spark plug hole. I got 38cc, which I made a note of! Removing the cylinder head, I immediately spotted problems. The copper one-piece head gasket was clearly leaking thanks to a poorly fitted camchain tunnel O-ring. Also some of the cam-chain tensioner wheel dampers were badly fitted and
crumbling and the cylinder bores were so glazed that the cylinder block had to be removed for inspection. Measuring the bores gave me 1075cc capacity and some maths showed we had a compression ratio of 8.1:1 – bang on for turbo use with forged flat top pistons! Checking the rings/bores/pistons I noticed that the top ring on all four pistons had been fitted upsidedown, this had led to premature wear of the bores and ‘fuel wash’. The fuel mixture had been allowed force its way under the top piston ring and push it outwards, leaving a horrendous wear lip on the edge of each ring and stopping any sealing: there was our rich running then! The only saviour was that the actual pistons were good. In addition to these problems, the cylinder had been honed out too much and I could easily get a 0.1mm feeler gauge down between the piston and cylinder bore! So, time to source a new cylinder block to suit the 72mm MTC pistons, replace the standard cylinder studs with APE high-tensile ones, replace the rings, cam-chain wheel damper rubbers, sort Viton stem seals, new exhaust port seals and get new gaskets. Lots more work was done, and while the cylinder was off for repair I cleaned, prepared and refinished the ATP plenum chamber in gloss black. The cylinder block came back from Engine Tekniks and was also painted satin black to match the original finish. The cylinder block, from a donor Z1000A1, was bored and honed to suit the 75mm MTC pistons and ran a piston to bore clearance of 3 thou. With the motor finally back together after much work, the TC finally fired up. After a second thorough warm-up, the engine oil and oil filter element were then replaced as all the oil was contaminated with fuel from the previous fuel washing issue. I was still not happy with the way the engine was running: it still seemed to be over-fuelling, so I decided to pull the turbo from the bike and thoroughly strip and check everything over and it was then that I found some bad news: the turbine spindle was heavily scored and way beyond service. With a full turbo rebuild now required, I could hopefully rectify the issue of the oil feed being in the wrong port, but where on earth was I going to find spares for the ultra-rare turbo? I used my network of contacts from when I used to drag race. I hooked up with Jason Flather, a true turbo enthusiast. He has a garage full of turbos and is only 40 miles away, so after a few calls we arranged to let him cast his eye over the damaged parts. He confirmed my worst fears: the main bearing and turbine impeller shaft were shot. He also found that the spring loaded carbon seal was stuck in the compressed position, and this would allow copious amounts of fuel do be drawn into the oil cavity and the turbine (exhaust) side: that explained a lot. Jason found another 370 F40, but this one had the later and improved two-piece die-cast centre bearing section, a different turbine housing and a different compressor housing. He worked his magic and soon had the turbo stripped and inspected, conformation that this one had an ‘as new’ turbine impeller and main bearing fitted. What a star Jason is! Thanks mate! After a few more issues (crankcase breather needed modifying again) the Z1R-TC was finally sorted. She finally runs and idles much better than before, though I did recommend that Chris books his bike in with Ben at RTR Motorcycles dyno tuning to get the thing fully sorted – with Allens Performance (Mikuni carb specialist & spares) right next door, it couldn’t go to a better place for fine tuning! It was a pleasure to work on another genuine TC (this is my third) though this one was a bit more demanding than the others. When one of these rare bikes is purchased as a non-runner, it’s only inevitable that you’re going to be faced with more problems than you care for!