About Tomos

March 11, 2010

Myrons showroom 2011 south wall, with 1976 Tomos Automatic hanging, the first US-model Tomos. 2011 Streetmate and 2010 Revival-TS succeeding it by 35 years. The new models way outperform the older ones, in acceleration, speed, braking, handling, lights, comfort, safety, reliability. It’s many mopeders dream to have a 35 year old bike with the performance and reliability of a brand new one. Click to enlarge.





Shaun’s 2005 Tomos Streetmate piston and cylinder at 13,500 miles. The exhaust side of the piston shows many vertical lines, but the exhaust side of the piston rings shows no vertical lines. The rings are free in the ring grooves, not gummed and sticking, and functioning very close to new. The piston has no black carbon buildup, thanks to using Champion two cycle oil. The underside of the piston and the bottom of the cylinder are dripping wet with green oil, from the oil injection. Click to zoom in.





A new Tomos A55 cylinder with a new piston ring has a 0.005″ ring gap. The cylinder is thick, solid aluminum with a nickasil plated cylinder wall. The nickasil is extremely hard, and has a very high melting point. So it stays smooth and fresh for much longer than a cast iron sleeve would. The big cooling fins give it better performance (the fuel and air is denser when it’s cooler) and longer life (less thermal expansion and contraction) by radiating more heat. The thick aluminum with precision locating sleeves keep the cylinder perfectly centered and aligned, even in extremely hot conditions. Click to see closer.




Shaun’s 13,500 mile cylinder with a new ring has a 0.007″ ring gap. The cylinder wall has very little wear, as evidenced by the small ring gap, the lack of vertical lines on the hot exhaust side, the lack of a top lip (where the top ring stops), and the reflections that show the mirror smooth surface. This cylinder will be good for another 13,500 miles. That’s a lot for a 50cc bike.







Shaun’s A55 cylinder with 13,500 miles, and upper ring with 13,500 miles, with a ring gap of 0.025″. Although the ring gap has become much wider, the bike still runs strong, within 1/2 mile per hour of it’s original speed, thanks to the smooth cylinder wall, ring surface, and lack of vertical lines. Comparing these three pictures shows that most of the wear was on the 13,500 mile rings and not the cylinder. That’s pretty amazing.






Above, Shaun’s instruments right after the rings were measured, photographed, and then replaced, at 13,540 miles. The indicated speed is 38mph, true speed is 36mph, cylinder head temperature is a cool 278 degrees farenheit, after running long and hard. Most kitted bikes run at 350 degrees or more, much hotter.






 Take of tour of Koper, Slovenia and visit Tomos:

Welcome to Slovenia! One of Europe’s best kept secrets is a little country next to Italy and once part of Yugoslavia. TOMOS stands for varna (factory) tornih (two-wheelers) koles Sezana (Slovenian town near Venice, Italy).  Like most moped makers, Tomos was born from the ashes of World War II. From 1955 to the 1970’s Tomos made Puch-compatible mopeds, under license. In 1973 the A3 two-speed engine came out and a new frame, all designed by Tomos. They’ve had robotic welding since the 1970’s. In 1992 the A35 two-speed engine came out, with stronger wider gears, better crankshaft design, and a much improved cylinder that made plenty of torque to climb hills good. After many more years of refinement, from 2002 to 2007 the A55 two-speed engine came out, with super high efficiency to burn every last droplet of gasoline to meet the 2006-later EPA air pollution standards for small street motorcycles.

Below are some of the many 50cc motorcycles and mopeds that Tomos has produced. The factory continues to modernize at it’s original location in Koper, Slovenia to meet new market demands. Their devotion, proud heritage, and history are evident in the products they produce. They appreciate your consideration of Tomos for your transportation needs.