KAWASAKI Z1000A
Our Ralph’s beloved Z1000A1 has a few issues with a slippery clutch – how is he going to sort it?
Ralph Ferrand swops out the clutch on his Zed
My 1977 Kawasaki Z1000A1 might not be my most valuable, oldest or even tidiest bike, but out of my collection she is undoubtedly my favourite.
I know, unlike children, you’re not supposed to have a favourite Kawasaki, but this bike has always been closest to my heart and always will be. She is what I would describe as mostly original. She has a four-into-one Harris pipe, a non-original paint set and some super YSS adjustable shocks that make the ride so much nicer. She has no bits of modern bikes and has undrilled, original disc brakes, which are so thick and heavy they will doubtless last forever. The frame is the original rubber item (ha!), but almost all the fasteners have been ditched in favour of stainless steel. The bolts, in the main, were sourced from Screwfix and the raised lettering was machined off in the lathe and then polished to look like chrome. A rivet counter could spend hours picking holes in her, but I don’t care. She looks like a proper Zed and rides like a proper Zed and that’s good enough for me. She’d bored out to 1045cc with a higher than standard compression ratio, because Wiseco pistons were cheaper than stockers at the time. She had been re-bored by the previous owner, but burned considerably more oil than an H2!
When I stripped the engine down the Wiseco pistons were in perfect shape as they hadn’t really been touching the sides of the bores. All those years ago a second-hand block didn’t carry the massive price tag they do now, so I bought another set of barrels and had them re-bored properly. I also had a new set of valve guides fitted while I was about it.
I fitted a new 530 final drive chain and sprockets (you’ll hear about that soon, too), but when I gave her the berries on the test ride, the clutch was slipping a small amount above 6000 revs. It’s probably been like it for ages as I rarely take her over 5000 revs, given that if I have a need for speed, I tend to take Rex out (that’s a ZRX1200R by the way...).
I did a bit of wildly optimistic clutch adjusting before ordering up a new set of friction plates and springs, which to be fair weren’t horridly expensive.
Once the parts arrived the first job was to bath the friction plates in clean engine oil and leave them soaking overnight. One can change the clutch on a big Zed without dropping the engine oil, providing that the bike is lent over a bit. Most Zeds have buggered side-stands in my experience and so just being on the side-stand is enough lean.
When I restored mine, however, I sorted out the side-stand and machined a new precision bolt out of hex 316 stainless steel so the Ole Gurl is a rarity amongst Zeds in that she doesn’t lie at a jaunty angle on the stand. To gain a bit of extra lean, with the help of the ever-enthusiastic current Mrs. Ferrand, we rolled the front wheel on to some blocks of scrap timber. At this angle the oil level was well
below the bottom of the clutch cover.
I whizzed all the M6 cap screws out with my trusty 3/8-inch drive impact driver from the cover. It’s so much quicker than a ratchet. I gave the bottom of the cover a gentle tap with a plastic-faced hammer to break the gasket seal and I was able to pull the cover away. Most of the gasket remained attached to the crankcase and pulled away fairly easily. There were the odd bits that stuck like the proverbial to a blanket, which had to be scraped off with a nice sharp wood chisel. I cannot stress too much that when scraping gasket material the highest level of care must be used, because if one removes any aluminium it will forever leak like a Morris Marina’s sun-roof. With the cover off and degreased, I took the opportunity to polish it on the buffing machine, which will do a day’s worth of rubbing with Autosol in just minutes.
I removed the five M6 bolts that hold the clutch together with the impact wrench, as this obviates the necessity to hold the clutch tightly whilst trying to crack the bolts off. As I removed the springs, I found that they were fairly badly corroded and as such had probably lost a significant amount of their original tension, which wouldn’t have helped the clutch grip. To dismantle a multi-plate clutch a 90° pick tool is an absolute must. As I pulled each plate out, I came to realise that I had really had the best years from them, as indeed had the previous owners. They may well have been originals for all I know. The steel plates were surprisingly rusty for a bike that is as cossetted as this one usually is, though she’s had a few soakings visiting far-flung rallies, I suppose. It was only surface rust and was easily removed with a bench
grinder with wire-wheel fitted. Had I not already decided to change springs and friction plates, I could have measured the length of the springs and thickness of plates to determine whether they were within tolerance; the measurements are supplied by Mr. Kawasaki in his oily tome. Visually, I could see that both were ready for the scrap pile. The pattern parts were both from British manufacturer EBC and the springs boasted that they had more tension than the stock Kawasaki items. With the slightly breathed on engine, it is quite likely that it is chucking out a few more horses than it did when first it left Japan, so heavier clutch springs will be an asset.
Wearing my super-strong workshop gloves I picked out the first friction plate from its oily bath, located its pegs in the fingers of the outer clutch basket and pushed it in as far as it would go. Next, I located a steel plate on to the spline of the inner clutch drum and pushed it in to meet the friction plate. I continued to feed in alternately friction and steel plates until the last friction plate was in. Lastly the aluminium alloy pressure plate went back in, followed by the five clutch springs and the five M6 bolts with washers. Whilst the bolts shouldn’t undo, given they have the tension of the springs under them, I never leave stuff to chance and gave them a healthy dose of anaerobic thread lock and seal before torqueing them to 7ft/lb with my Laser digital torque wrench.
I painted both mating surfaces with Wellseal, let it flash off for 10 minutes, fitted the new gasket, the cover, and all the cap screws and torqued them all down to the prescribed figure. I popped around to the other side of the bike and removed the tear-shaped cover over the clutch actuator. I released the lock nut on the adjuster and used a screwdriver to wind in the centre screw until it just touched the clutch push rod, backed it off a fraction of a turn and then tightened up the lock nut. I replaced the cover and re-adjusted the clutch cable: job done.
As it was such a lovely day, I donned my brain bucket and leathers and headed for the Mendip Hills where I had a truly wonderful ride on the best bike in the world. Sadly, it turned out to be the last for some time. As I write this all my Kawasakis are pawing at the roller shutter door begging to be allowed out for a run in the spring sunshine, but sadly us bikers are in lockdown. Mind you, knowing how long editor Bertie holds on to my words and pics, it could well be that we’ve been given the all-clear by the time this august tome hits your oily mitts! Let’s hope so!