Bernies Bike Shed

SPLIT/SINGLES and what they are!


A ‘Cornet’ engine showing the Y shape conrod and 2 pistons also showing the easy access to the crankshaft.

1952Express with Kuchensplit single motor 2

A rare Express Radex with a slit/single motor designed in 1938 by Richard Kuchen and made by Baker and Polling designed by Kuchen Hence the name BP-K the motor was not reliable rear piston suffered from  seizing and was drop after a year by Express.



1952Express with Kuchensplit single motor


Triumph ?TWN cornet engine

inside the Cornet engine with the one Y shape conrod.The image top lefthand corner is of a prototype 250cc engine which double up 2 x 125 engines looks good but power output was similiar to the standar 250 BDG engine,so it was only a prototype.


This is a PUCH 175 SVS engine showing the configuration of the Puch split single system

Puch and 'Cornet

Puch ‘s split/single system (showing the 250 SGS crank) and bottom picture showing the’Cornet, barrel and head.


A unique racing car from the 30’s a Monaco-Trossi 8 barrels= 16 cylinders =16 pistons plus 2 superchargers = 260 BHP and a two/stroke! what must it sound like??also note the spark plugs protrude beyond the engine cowling.

Monaco Trossi

early version with no engine cowling.


Nice drawing showing the 8 barrels = 16 cylinders not 32 as said above! also it had 2 superchargers power out put was 260 BHP but the balance ratio was 75% front and 25% rear resulting in hugh understeer!!


The Italian make ISO made a split/single in the fifties called the Isomoto(very similar in design to Puch 125SV) they also made a Isetta  bubblecar useing a 246cc split/single engine .later Iso went on to make high powered V8 engine luxury sports cars in the sixties.

iso 125 split single

Often confused with the Puch engine!! this is the snit view of the Iso 125 engine (motorcycle above) the puch has a primary chain! not a gear drive to the clutch.


A Puch crankshaft from a 1942 125T A Y shaped conrod but in a fore and aft configuration.also note the rear ie the one to the right small-end has a slight rectangle shape,so the piston can slide back and forth!!!


Blog at

%d bloggers like this: