Monday, 11 July 2016

Hacking: CZ250 twins

CZ250 twin, 4000 miles. good condition, £140. That was the advert that introduced me to CZs. I'm on my third one now and reckon ! know them pretty well. That first one was a beauty - smart, fast and reliable. it would cruise in the mid-seventies, overtake in the mid-eighties and drop down hills in the low nineties.

For a year it took me all over the country to rallies and camping holidays, two-up and loaded with gear and did everything I asked of it without complaint. That bike came to a sad end, however, when some drunken revellers put a match to it in the lay-by where I‘d left it whilst doing a night trunk run as a drivers mate. The fire brigade were called but presumably went the long way around as it was burnt out by the time they arrived.

The petrol pipes had been pulled off and the petrol ignited at ground level, assisted by a coating of 2-stroke oil they'd found in the top box after smashing it open. Everything that wasn't metal perished. l pushed home what was left of the bike, the last mile downhill so I sat on the thing as final gesture of defiance.

Word of this calamity got around and a friend of a friend had a friend who’s friend had a CZ twin which he never used and which I could have for £100. This second one was almost identical in appearance and performance. I would ride around hoping that the bastards who had ignited the first bike would turn up.

Mind you, the second bike (four years and 5000 miles old) didn't have the guts of the first, seizing up when I tried to cruise along a motorway at 75mph. Fortunately, the road was straight and dry, she slid in a perfectly straight line, giving me time to pull in the clutch and pull safely onto the hard shoulder. By the time we (my son was on the pillion) had rolled and smoked a couple of fags, and exchanged pleasantries with two or three bikers who stopped to offer assistance, the engine had cooled sufficiently to fire up and complete the rest of the journey (about 30 miles).

An investigation showed both pistons distorted, the rings trapped solidly in their grooves. Tapping out the first gudgeon pin released a torrent of needle rollers, most falling straight into the crankcase! Loads of rags were stuffed into the crankcase for the second one. Fishing the needles out of the engine was a fairly simple job using assorted pieces of wood and a magnet. The pistons from my burnt out machine were used in the second bike. There is only one way of easily and efficiently fitting pistons with small-ends consisting of individual rollers, but I don‘t know what it is - I had to buy a pair of roller cages from a CZ shop (about a fiver each) and have used these ever since. With these, everything went together quickly and the bike was ready to roll again...

It rolled about six feet and came to a sudden halt with a frightening noise of breaking metal. Another investigation revealed that I had not retrieved all the roller needles and the ones left behind had been thrown up by the rotation of the crank and done unpleasant things to the pistons. I now had needles, bits of pistons and circlips in my crankcase.

At this point, I must warn all CZ owners to expect needle rollers to spray all over the place when removing pistons - and to count 28 per cylinder to make sure they've got them all. Should any of these or any foreign bodies - find their way into the crank, the only sure way of clearing it out is to flush it (the CZ shop recommend using petrol but I found thick oil more effective), turn the engine upside down and turn it over several times: then leave it for a few hours to let the oil drain out.

Anyway, there I was through folly and lack of foresight with a well knackered engine. Whilst contemplating my next move, one of my kids rushed home waving a local rag with an ad for - wait for it - a CZ250 twin, 3500 miles, £35! I figured this had to be a wreck, but the engine couldn‘t be in a worse state than mine - so it might be worth having a look at. The next bit reads like a fairy story but i know it was true 'cos I was there. He'd bought a brand new CZ250, ridden it for 3500 miles, put it in the back of his garage for 12 years covered up (during which time he'd kept the battery fully charged), then decided to get rid of it as he needed the garage space. I went, i looked and i bought. With the battery installed it started after three kicks and I was able to ride it home.

After a quick visual examination, I emptied the tank of its stale petrol/ oil mixture and wiped the bike over to remove cobwebs. Half an hour later I’d acquired a test certificate. I had already decided that this vehicle was to take over as number one machine - 15000 miles and four years later it’s still that.

It was a cute, old fashioned looking bike, even by CZ standards. Painted in two-tone green (the only one I've seen like it) and with a long square headlight shell which housed the ignition switch and winker relay, it looks a lot older than its R registration suggests. Its performance isn't a patch on the other two twins, even though its specification is identical.

lt'll just about top 70mph on the level and seldom graduates from the slow lane on motorways. But I love it! It’s reliable and comfortable, economical and easy to ride. What it lacks in » open road performance it makes up for in bottom end nippiness.

It's the easiest bike on the road for home maintenance (save when you remove the pistons). Decoking is easy as the heads and barrels come off without moving the single carb which bolts direct to the crankcase.

Two screws undo the side case for access to the points, ignition timing is a fag paper job. The single carb doesn't need touching, though it does no harm to dismantle it from time to time. It's very easy to forget to check or change the gearbox oil, so I just forget it. The stop light switch has the amusing habit of letting in water and jamming on, the light then drains the battery - but it can be dismantled. Another item worth checking on the newer models is the switch box (ignition and lighting) remove it and make sure the various cables are well connected, cut off frayed ends and reconnect if necessary, then tighten down all the screws to ensure good contact and screw it back firmly in place. All the other maintenance operations are very much self evident and straightforward.

The bike is very adaptable, living on the cheap I bought a Roadrunner from a friend for a couple of quid, it worked well despite being much larger than the recommended size. The rubber grommet from the headlight of a GP100 sliced in two makes two perfect seals for the joint where the down-pipes slide into the silencers.

I know CZs don't enjoy a good reputation - but I cant understand why? They’re not fast and they're not racy looking. But they are solid, hold the road well, parts are really cheap, repairs require very little time and few tools - and they never get stolen.

We read somewhere that these machines are OK if one is blind, deaf and have no money - do you know where I can get a white stick cheap?

Terry Donovan

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