Is it a Yetman Honda or Honda MT125R
Two bikes offered for sale here confused me. I started writing while looking at a full fairing bike labeled as a Yetman Framed Honda and I wondered why the exhaust poking out from under the fairing was so thick? I then started to write something up on the MT125R listed by the same seller. I thought that there was to much going on above the intake and exhaust to be a 2 Stroke.
After talking it over with my co-horts and digging into the RareSportsBikesForSale archives, we have come to the conclusion that the seller swapped pictures, so I will hopefully correct this for them here at Classic Sports Bikes For Sale.
1966 Yetman Honda 305
Who hasn’t borrowed stuff from work? An envelope here, some paper there, low carbon cold-drawn steel tubing. This is how Yetman frames seem to have started. David Yetman recounts his history at TZ350.net and tells of having wrecked his CB77 was unable to buy a new frame. He decided to use his day job with Autodynamics, Inc, builder of Formula Vee race cars, to solve his problems.
This excellent example has a highly modified Honda 305cc engine, engine was enlarged to 350cc with a race cam, larger carburetors, and high compression pistons. The transmission has been “X” -ed which was a common technique at the time to get closer gear ratios without having to spend the money on a 5 speed transmission.
David took his race car chassis experience and developed his frame with all its structural members triangulated either in compression or tension. This, with the engine incorporated as a structural member, allowed the overall strength to increase and weight to decrees. The perfect recipe for a winning race bike. Yetman continued to make frames for road racing and later drag racing. Yetman frames have been designed for engines offered by Honda, Ducati, Triumph and Harley Davidson.
The bike included many Honda CYB factory race parts such as the fork triple clamp and the megaphone exhaust pipes. Other special features are the alloy rims, fiberglass tank and seat, Koni adjustable shock absorbers, and the Ceriani road race forks.
Mike wrote about another MT125R for RSBFS and gives some great background. The seller jumps right in to tell us about the bike.
The Honda MT125R was produced for the U.S. market in the years 1977–1978. It was a production Grand Prix motorcycle racing road racer designed for closed-course competition road racing. The MT125R was produced by Honda Racing Service Center (RSC) and made available to the general public through the American Honda Motorcycle dealer network.
Recycling many parts from Honda’s own dual-sport Elsinore, they were able win on the road with small changes. Adding a larger 34mm Mikumi and moving the whole carburater closer to the engine shortened the intake track and moved the power peak higher in the rpm range. The porting configuration and timing are the same, but a change in the exhaust pipe raises and narrows the power band. A first hand account written for Cycle World, tells of the difficulty in getting the bike moving, but once “on the pipe” the six speeds keep the bike in the power band.
Engine – 123cc 2-stroke air-cooled single cylinder, 6-speed, power 26HP
Chassis – fiberglass tank, fairing, fender and seat cowl
Other – tachometer, mechanical front disk brake, and rear cable operated drum brake
We always like lots of pictures to get the best idea of the condition of the bike. The only pictures provide for both bikes show nice bikes, but when ever buying from a distance, call the vendor and if you are able to, send someone you know and trust to take a look. Especially if the seller mixes up the pictures.