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Fuel and Race Classes.


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Moderators note: This thread developed into a thread about fuel used in competition rather than Speed Week down under so I have tried to split off the relevant post and put them here.

P.S. I may have failed miserably as I can no longer find some of the posts I tried to move.
Big Ed.

Us old limey road racers get completly lost here .....

APS-PBF? (I could Hazzard a guess on the PBF I have been one often)
MPH? I know that one its a good magazine


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I thought it was ambitious for Stuart to think of hitting 200 MPH with a 600cc single. It looks a lot more likely now.

This is really "in the weeds", but a minor clarification on the "fuel" and "Gas" distinction. Gas, or petrol is whatever they sell at the venue. It is usually racing gas available in a few different octanes. They pump it in your empty tank and seal the tank with tape and a signature. Fuel is anything: gas, nitro, benzine, scotch, etc. I run in the gas class with a sealed tank, then I rip the seal off and run in the fuel class. It is a little counter intuitive. The gas is highly regulated. Fuel has no restrictions.


Bill Thomas

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In the UK, 70s and 80s, We ran Petrol which was "available at the Pumps "!! Which was fine at first = 100 octane, Then late 70s they started lowering the octane and taking the lead out, I was running 12 to one pistons, I used the same bike on the road at the same time, Things started to go Bang !! I found out later that a lot of the other racers were useing "Pump Petrol" Which they bought from an Airfield !! One bloke with a Norvin used Methanol,!! But the Stain on the side of the Tank gave him away ! I thought it went well ! Cheers Bill.

greg brillus

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Hi there Bill, Has methanol been used much for road racing in the UK over the years, or has it not been allowed...? We can use either petrol based fuels including avgas or methanol in our class of classic racing bikes which is called period 3.....from 1946 to 1962. The twin road racer I am building will be based on a 1949 HRD and running 12.5:1 pistons on methanol. Cheers......Greg.

Bill Thomas

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Morning Greg, Vibrac could tell you more than me, But in the road class I used to run in it was called Pump petrol, I think the others were bending the rules !! Getting it from an Airfield ! The Vintage class I think is allowed Methanol, The bloke with the Norvin was taken to one side and told to change it. But because I road my bike on the road as well I had to use normal petrol. I loved those 12s They made my bike fly on 100 octane ie Avgas Wich you could buy at a normal petrol station, Till the late 70s. I think I ran about 24 to 26 deg's advance on a modified D dist'. When I built my L/ning rep' it was 1980 so I could only run 9 to 1 pistons, Guess who used his L/ning on the road also !! I am going to Hell !! Yours will Fly ! Good Luck, Bill.


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As far as I understand from when i was racing in the 70's,Methanol was not allowed in road racing..In the depths of my faulty memory i remember an almost standard looking Scott starting at the back of the grid at Brands in a 750cc race.It ran on Methanol and it certainly moved up through the field,passing quite a lot bikes..It may have been placed but as was stated at the start of the race it could not appear in the results..John


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The 2014 Auto Cyle Union handbook states:
"14.6 Fuel.
1. Unless otherwise specified in the Supplementary Regulations for any series or championship,
leaded petrol mixtures up to 102 RON, will be permitted, provided that the Customs and
Excise or Inland Revenue dues have been paid. Power boosters, octane boosters and the like are
2. The use of E85 Bio-ethanol pump fuel is permitted. No concessions to individual Class
Technical Regulations are permitted to allow the use of Bio-ethanol fuel. The word Bio Fuel
must be clearly displayed on the fuel tank.
3. Competitors must ensure that a minimum of 2 litres remain in the tank at the end of the race,
for the purpose of any fuel testing that may be required.
4. Any competitor found in contravention of these regulations or who fails to provide a fuel
sample will have his Road Race Licence suspended for a minimum period of 6 months of the
Road Race Season (March – October) and will be liable for all costs involved in the testing. The
competitor will be disqualified from the results and will lose any Championship points awarded
for that class.
Note: For information leaded petrol mixtures up to 102 RON are typified by mixtures of 50% Avgas
and 50% pump petrol."

British Historic Racing - VMCC Ltd. run vintage race meeting under ACU regulations and have the following supplementary regulations relating to fuel:
"Any commercially available pump fuel (unleaded, leaded, super unleaded or lead replacement up to Avgas 100LL specification or Diesel) may be used. The addition of any lead replacement additive approved by the Federation of British Historic Vehicle Clubs is permitted. Methanol may be used in any class of machine." (I think that regarding methanol it means any class of machine pre- 1973,)


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We used methanol in the comet for 2 seasons still have a 1/4 drum to be honest it was a lot of Hassel draining wearing gloves blistering paint work for not a lot of gain in our racing with the cool running vin may be great for an iorn barrel vello bu5 not for me
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