DPE Statement Regarding Comer Carburettor

statement from DPE

Dear Comer Users,

We have been made aware of a situation regarding Comer Carburettor choke shafts and butterflies that we must pass onto all Comer users.

As you may know, the Comer carburettor has a small pin that is designed to prevent the choke shaft butterfly from going over the 90 degree/ fully open position. However, as the Comer carb is a mass produced cast item, the position of this pin can vary slightly, meaning that the choke butterfly can open more on some carbs, than on others. When we became aware of this issue, we checked 8 brand new carburettors and discovered that all 8 carburettors varied slightly in this respect.

To achieve a ”fully open” choke butterfly, some people have bent the butterfly slightly, in other cases, they have bent the stop pin either on purpose or it has become bent by accident. In many cases, people have not bothered about it at all, as the potential performance gain would be miniscule, however where there is a variation, it is true to say there is also the perception of a difference in performance.

As the opening of the choke butterfly can and does vary due to production issues, it would seem to be commonsense to allow for some degree of variation, however at a recent major race event in South Australia, these components were rigorously inspected and a midget driver disqualified. Later at a Tribunal the Midget driver was found guilty of using a non compliant engine due to the use of a product that was “not as supplied by the manufacturer”. The AKA tribunal effectively said: “We don’t care how it came to be bent, it was bent and is therefore illegal.”

So please be aware these components are now being closely scrutinized by some stewards and if the choke butterfly is not 100% flat or the stop pin is bent, regardless of how or why, the stewards may deem it to be illegal.

The Comer carburettor is made by Tillotson, and being a mass produced item, a fix for this from their end is very unlikely. Even if they did fix it tomorrow, there are hundreds, probably thousands of these carburettors already in the Australian Karting environment, not to mention the many thousands of similar carbs in use in other countries around the world.

So what are we going to do?
We have forwarded to the AKA, a solution that we feel is in the best interest of the karter and will not cost one cent, however like many issues raised with the AKA, we cannot put a time frame on when or whether this will ever happen. In the meantime, please be aware that if you bend the choke butterfly or have one that has been bent, or even if it opens more due to normal wear and tear of the stop pin, or the stop pin is bent, you do risk being deemed “non complaint”, so we strongly suggest you examine these components carefully prior to any race events to ensure you are compliant with this current interpretation.

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