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I know a lot of people blame wear on carburettors, but who else has a genuinely well working original carburettor with 50,0000 miles on it?
I take it you meant 50,000 and not 500,000 !
Please Sir – me. Yes, there’s always one.
Honda 400/4, 55,000miles no issues.
Three Honda CX 500’s, all did over 100,000 miles each, no issues.
BMW R80/7, 211,000 miles, periodically replaced the rubber diaphragms on the Bing’s (3 times in all).
Moto Guzzi V50III, 308,000 miles, replaced the needles once. Dellorto.
(Plenty of other issues, but was my favourite bike to ride).However, the Amal carbs on the BSA’s used to wear their slides and well under 50,000 miles. Don’t the C15 had done 40,000 when part ex’d, and the A10 – whilst a nice engine – was often with the head off. Single carb on the A10.
Do singles have something to do with it? Shouldn’t do, as all the high mileage bikes above had one carb per pot.
I can’t add anything to this discourse, but thank the OP for an interesting read. I have a small book by Rob Carrick & John Wood entitled ‘Villiers Singles Improvements Handbook’ and the technicalities of tuning two strokes is a very complex subject. Pretty irrelevant to MZ discussion, but a great little book. The only tuning I ever did to my first bike, a Francis Barnett Plover, was put put petroil in the tank! Later had a 9E in a DOT trials, but did nothing to that engine.
I would plump for the centre of the gudgeon pin, but the key element is surely the proximity to the cylinder head and the gap remaining between the two which will ultimately determine the compression ratio. But perhaps that is an answer to an unasked question?!
Unrelated directly, but we have had issues with household LED bulbs where they have been used as replacements to standard incandescent.
They have a tendency to flash occasionally when switched off. The rate varies from room to room. One room 34 seconds, another about 80 secs. Just a sudden flash. Contacted Western Power (distributors) and after the engineer checked all was as it should be with the line installation, said that it could be caused by a tiny feedback through the Earthing system that charged the internal capacitor of the individual bulb which then discharged in one flash. Not the sort of thing you want in a bedroom!
So, sensitive indeed, and in a different application.
If it’s not worn and need replacing – leave it in there. At least it won’t fall out and cost you time searching the floor.
I have no knowledge of your particular generator Neil, but I would start to look at the brushes in the generator. If they are worn down to the point of barely touching the commutator – or not at all – that may give the symptoms you describe.
Derek
That’s fine if you are an ‘average’ sized person – average to the nation of manfacture that is, though the smaller framed orientals have made their machines fit all – there comes a point when some personalisation can be beneficial to comfort and desires. Some changes will require cutting and/or welding.
Reed valves. Buy a Yamaha. Leave as designed with regard to the MZ. Two strokes can be tuned, but you steal from Peter to pay Paul, same goes for any engine tuning for more power, there inevitable will be a price.
Welcome to the club Ian, can’t help much more than that.
Had a similar thing with the Honda CX500.
No problem starting if used every day (always closed the taps), but if left a week (or more) would fail to start – unless – drain the carb bowls, then close drain cocks, taps on to refill – started easy.That’s as maybe Matt, but try retarding the timing just a little. The running backwards (a way of reversing in some single cylinder hot bulb diesel two strokes) is due to the timing being advanced enough to promote sending the piston down the ‘wrong’ way. Back it off a bit and see what happens.
Digression:
The Swedish Bolinder hot bulb engine (single pot about six litres in capacity, often called semi-diesels) with no reversing gearbox, could achieve reverse by allowing the engine to almost stall, then operating a separate oil lever to fire just before the piston reached it normal (running forward) firing point. This would then fire, and send the piston back down the bore reversing the direction of the propellor. If missed, lots of blue air and a crash!
Cycle magazine of February 1978 has a five page article on two stroke pre-mixes. I have it as a pdf, but don’t know how to ‘share’ same here. They test 15:1; 20:1; 30:1, and speak of 50:1.
Their ultimate sentence is, quote: –
“Less, in the context of pre-mix lubrication concentration isn’t more; it’s less. Just as logic always insisted.”I have a family member who ran a Husqvarna 360 chain saw for twenty odd years on forestry work on the most frugal of mixes. He even used used car oil to lube the chain. I had the job of servicing his saw when it died, and found the cage of the main ball bearings disintegrated, the small parts finding their way above the piston where before being ejected through the exhaust port, had hammered the piston top so much that instead of being flat topped, it was dished! New bearings and piston later, it lived to see many more days of work.
