The seventies were the peak years in the short history of the two-stroke. At the end of that period, in 1979, Yamaha introduced the ultimate two-stroke street fighter: the Yamaha RD 350 LC (1979-1983).
That was the successor to Yamaha's air-cooled two-stroke. In the meantime, such a Yamaha RD 350 LC has already become a real cult bike. Good, original copies are becoming scarce and are increasing in price. Many LCs have run on circuits. That has usually made them suffer a hard life in which all kinds of things were unscrewed (and thrown away) before the start. Due to tight bends and sliding parts, the exhausts were also referred to as 'wear parts'. But pay close attention to old pain when purchasing an LC.
Technically speaking, such a Yamaha RD 350 LC is well put together
If things go wrong, it is in the well-known two-stroke ways: jamming or holes in the pistons. Replacement of parts 'above the belt' is still the solution there. And oh yes: check out why it went wrong. Crankshaft problems were of a different order until recently. The crankshaft cannot be overhauled and must be replaced in case of trouble. There Yamaha saw the parts very purely as a revenue model. The connecting rods and big end bearings can still be replaced. In the meantime, there are a few specialists who can give such a crankshaft a second life.
The LC is often seen as a road racing machine in plain clothes
He is not. The character of the engine is too civilized for it. The Yamaha RD 350 LC is much more the optical crystallization of what a fast two-stroke should look like than a hyper-nervous racehorse. It is a fierce and fast toy that can also be used for driving. Below 5500 rpm, the RD 350 LC is a pleasantly driving motorcycle. Above that, the exhaust noise hardens and the block pops from 6000 rpm in its powerband. 3000 rpm later the fire under the fries goes out again and you have to switch to get the fire back in. Driving like this is motorcycling 1.0 with hair on the teeth. The only ounce of decadence that remains in the heat of battle is that the LC has self-deactivating flashing lights.
Good quality two-stroke oil is needed to keep things running
And it is necessary to always have half a liter - or less - on board. Petrol stations are real 'land marks' for LC drivers. When the gas was pulled on the Yamaha RD 350 LC, the contents of the tank went fast. In that driving style on winding, secondary roads, an LC is a thorn in the fur for much more modern, heavier and 'faster' motorcycles. In the Ardennes or Vosges, around 350 can literally leave the rider of a 1000 cc four-cylinder in his blue smoke screen.
The update - with a whole new power valve set-up - in 1982 was a much better machine, but it lacked the charm of The Original.
The Yamaha RD350 LC: liquid-cooled two-stroke twin, 347 cc, 47 hp at 8500 rpm, 2 x 26 mm Mikuni, six gears, steel cradle frame, front fork ø 32 mm, rear monoshock, wheels 300 × 18/350 × 18, Brakes V / A: 270 mm disc, 180 mm drum, weight 143 kg, top speed approx. 180 km / h.
Also read:
- Yamaha RD350 LC YPVS
- Yamaha RD350
- The Honda CB450 S. From class bike to classic
- Two strokes: Power from the exhaust
- More stories about classic engines
Can still remember in the early 90's a father and son also had some of these machines in our street. Beautiful to see them on the road, but as soon as they were there you couldn't see them anymore because of the smoke.
Have the slightly younger equivalent, the Aprilia RS250, Reggiani Replica, first series.
It is always nagging people who are driving behind you, because the fully synthetic mixing oil can indeed sometimes be smelled well.
But whining past it is often disappointing.
Around 60 hp is not expected from a 250, especially if the training bike (around here) was a GN250. . . . .
Consumption is indeed solid.
Advantage: driving quietly does not save huge fuel, so why would you 😉
Dear Niels,
Nice bike your Aprilia, try Castrol Power RS 2T, once at temperature no more clouds and clean combustion, mine without oil pump 1:50 ratio, mssch. your oil pump is too rich!
With normal touring 4 to 5 L / 100km and with speed 7 to 8 L / 100km, so you see!
I'm currently burning Putoline Scented full synthetic
Pretty much the same as the Castrol, but from Putoline.
That "Scented" refers to a kind of additive, which gives the oil a kind of "strawberry smell", and after burning it smells a bit like chewing gum.
But indeed, a good full synthetic oil is recommended.
And make sure it's not "semi-synth" or semi-full synth" or anything.
True to life representation, owns one (YPVS) beautifully restored, without oil pump, expansion exhausts and HPI ignition, it drives incredibly well, can tour with it and occasionally let the copains smell a breeze, they look very surprised. after haha… viva the eighties, really nice bike !!!
Two-stroke has more because of fewer parts. The KISS principle applies completely to this (Keep It Simple, Stupid 😜).
Recently watched a video of a contemporary 2-stroke engine, called Suter. Weighs about the same as this 350. But then with about 200 horses. Is for track use. Very interesting.
KTM also has / had a 2-stroke crosser with a newly developed engine, even with a Euro standard sticker on it.
And of course interesting to look at a Swede who develops a 50cc 2-stroke engine that has to do about 26 (!!!) ponies.
A two-stroke is simple in terms of construction, but absolutely not in terms of design! It is a very clever piece of engineering to precisely determine the shape and position of the ports with which the cylinder gets its optimal flushing and filling, and then there is the exhaust system, which has to provide back pressure exactly in time, such as with an expansion pipe or with compensation channels between the different exhaust bends. It seems simple, but it is not.
Although the lack of a distribution, camshaft, valves and oil pump is of course nice and changing head gaskets a piece of cake.
And the zundapp for almost 100 years
Well, the history of the two-stroke was not really that short.
This generation of Japanese two-stroke with great performance. After all, our European two-strokes were built as an economically advantageous workhorse: the DKWs, Jawas, MZs and our own Spartas were old men's bicycles.
Yamaha's great secret was in the reed valves, which allowed full boost pressure to be utilized, so the moment the piston started its working stroke, the intake valves closed and the crankcase pressure built up, which, with the release of the flush ports, efficiently built up the cylinder. filled and expelled the exhaust fumes. With a regular Schnürle patent two-stroke, there was always a coil loss, with this Yamaha almost nothing, although this two-stroke was not as simple as traditional. Suzuki also worked hard at the time in the two-stroke area, such as with the recovery of the lubricating oil (although that did not work very well) and water cooling (the famous GT750 “Water Buffalo”).
Impressive performance. A Jawa 350 Oilmaster had a top speed of 125 km / h. That just for comparison.
I have been able to supply many All Speed exhausts for these beautiful motorcycles.
A local townsman has such a Japanese bomb ..
His hobby? Modern Fireblades and R1s are the snot in front of the eyes, which works quite well ...
It is clear that this requires vigorous stirring in the gearbox, but the desperation in the eyes of a four-stroke row-rocket driver at the next traffic light speaks volumes.