Ancient & Modern: Old karts get a second chance

CRW_6461-1Many thanks to Steve Chapman and all at Whilton  Mill KC for inviting the Historic & Classic KC to their Brazilian Cup Meeting on the 29/30th April. Whilton Mill is perfect for the old karts with its mixture of flowing corners, gradients and fast straights.

I had invited Alan Button to come along and do some laps in my 1967
Barlotti Imp with a freshly rebuilt Komet K77. Alan last drove a kart over forty years ago but was soon circulating quickly and reliably, much to my relief. He ver y much enjoyed the experience and is now looking for a kart of his own.

One very welcome new face to the historic karting scene is Robbie Ashton. Robbie had restored the Barlotti Imp that he raced in the sixties and I loaned him a quick Parilla S13 to use for the event. Robbie did not take long to settle back into the groove and we had much fun chasing each other around the circuit.

Another new face at historic events is Peter Freeman who came along to watch accompanied by his long time mechanic and pusher. Peter now has a kart and engine in restoration and hopes to be ready for Shenington in June.
Event regular Brian Malin brought along a ver y original Barlotti Continental with BM F100 JB engine.

A bit of tinkering in the pits had the machine ready to run but unfortunately Brian lost the chain out on the circuit cutting short his fun. Another regular, Peter Brinkworth was present and did sterling ser vice with his pocket of spare plugs to help restart a couple of oiled-up engines. Thanks Peter.

Wyatt Stanley arrived with the interesting front engined Del-Kart but suffered mechanical gremlins on Sunday.Classic racers Jeff Gray and Steve Goodman both circulated with good speed,Jeff unfortunately experiencing some mechanical failures on Saturday, necessitating an overnight engine change enabling him to run on Sunday.

Ian Pittaway had a newly restored Class IV Blow with Villiers 197 engine, driven in period style by Alan Button’s son. Ex-British Class 1 team member Chris Arnold attended on Sunday as a spectator. Chris is preparing some lovely, period ‘70s karts and will hopefully be driving at the Shenington event.

100cc Engine Restoration (Part 5)
This month we will take a look at some of the parts previously removed from the engine. One of the most important components on a 100cc engine is the carburettor. These can usually be divided into two types, both widely used in the sixties and seventies.

Type 1: Dell’Orto MB22A and MB24A.
Type 2: Tillotson Diaphragm type

The Dell’Orto carburettors were widely used in the early to mid-sixties and are generally ver y reliable and suitable for use today. They have an integral float bowl and require a fuel pump if a floor mounted tank is being used. The fuel pump is also usually a Dell’Orto item and is operated by pulses from the crankcase. Don’t forget that when using a fuel pump you will need a fuel return line back to the tank to return the excess flow from the pump. I also use a fixed restrictor in the return line to avoid star vation of the float bowl.

A range of main jets will be required for this type of carb and these are readily available from Dell’Orto dealers. Jet sizes required will be 130 to 125 for running-in and 120 to 110 for racing, dependent on weather conditions. Stripping and rebuilding of this type of carb is ver y straightfor ward, just make sure that ever ything is clean before you put it back together.

I am a big fan of the Dell’Orto carburettor and have used them on early Komet and Parilla engines for several years with no problems.Karting magazine has published many relevant articles relating to Dell’Ortos over the years and the technical among you may find the following articles interesting:

December 1966 issue: Basic preparation of the Italian rotar y valve engines by Roger and John Mills.

April 1971 issue: The preparation of Italian rotar y valve engines for reliability by Paul Fletcher.

Next Month: Strip and rebuild of the
Tillotson carburettor.
Jon Pearce

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