My east german MZ ETZ 250 – anno 1983.
Two stroke, single cylinder with 21 HP.
As promised, a new video of Kims Gilera:
Kim has been riding his beautiful Gilera 50 Touring for some years. The old 4-speed engine was a bit oil thirsty, so we planned an engine overhaul. But Kim had a surprise for me, a rare 5-speed engine imported from Italy.
The engine was in an impressive condition, the left crankshaft bearing had rust damage, we changed all bearings, gaskets and seals. The engine is like new, drives and shifts like a dream.
Short video of Kims first ride, i hope to make a better onboard video someday.
More pictures from the restoration are found in the gallery below, remember to check for image comments.
Batte has a nice Puch Grand Prix 3 speed, but the 4 speed fever has spread to him too. We found a nice X50-4 engine in Austria. It had some chain damage to the engine case, our buddy Nikolaj welded it. The engine had been stored for many years, with old oil and a bit of moisture. Most bearings and the crankshaft where damaged due to rust. We changed everything with new parts.
The cylinder had some rust damage too, we’ve found a oversize piston for it. Right now we are waiting for the rebore. We also changed the exhaust timing a bit, it was very low for our taste. The new engine timings are ~99° transfer ports and ~147° exhaust port.
Per is back again with a new moped. He came in for a quick tune-up but stayed for an engine rebuild. The moped was sold as completely restored, but it didn’t run well at all. No power and after several hundred meters a top speed of 25 km/h.
When we checked the ignition, we found that the crankshaft had several mm axial play:
The engine had to be split, luckily that’s a quick job on a Ciao. Someone had ground the crankshaft down to easier slide into the bearings. We ordered a new one, and a few performance parts.
We removed the restriction from the inlet and drilled the carburettor up to 10 mm. We mounted a DR 38,4 mm cylinder, Mazzucchelli race crank and a Giannelli exhaust. Rides very nice with lots of power. Per is running a short gear ratio, so it climbs hills effortlessly.
A few build pics: