Hitchcocks Forum

Is E85 fuel ok for the Methonal Amal carb conversion , what do I need to know as Australia is doing a grand experiment , the pump is only 8 mins from home and I have our hosts full race 612 engine , carb converted but what oil do I use ? Castrol R or synthetic ? what should my ignition timing be 30 or 32 degrees and what spark plug bp9es or bp8es , clean fuel is good fuel , sick of sticky sooty exhaust ports sugar cane is not food and we have lots of it .

"R" produces a lot of sticky carbon deposits so regular de-cokes are essential. Smells bloody marvelous though and in an Enfield that is probably in pieces fairly often anyway...

I was always led to believe that Castrol R doesn't mix with normal mineral oils and would congeal into a glue type substance blocking oil ways etc.A full strip down and clean may be wise before converting. It also has a very short operating life and is designed only for very regular changes.

Not quite sure what you mean about the carb question. Is it a carburettor which is already set up to run on methanol (methyl alcohol), which is used as a fuel for speedway bikes? If so, the jetting will be different from a petrol set-up, usually a lot richer. Make sure you are using one of the Amal alcohol-resistant carb floats and alcohol resistant fuel hose. I think E85 has about 10% ethanol, enough to attack the older style Mk1 floats, fuel lines and some makes of tank sealant. A.

FUll race 612, alloy barrel, high compression, asking questions on this forum? DONT DO IT!


But if you really need to, start by increase main jet size 1% for each 1% ethanol/methanol. Advance the ignition timing in 2 degree increments degrees to start. Fit a Detonation sensor/EGT gauge.


As for Oil? Check with your local 'preferred brand' supplier; what can they supply/recommend, but a Group 111 or synthetic will be preferred as the motor will be running hotter?

I have the Full Methonal kit as shown in the catalog bar 1 filter I forgot to order , the engine has not been run since the full race rebuild , no stone has been left unturned inc 612 race crank , it seems synthetic oil is the best bet , it's carb is a Amal MK2 concentric and even the fuel tap is for alcohol , E85 only has 15% petrol , as far as I know the engine will run cooler but at 10:1 comp ratio it should cancel out temp wise there are 7 parts to convert the carb to alcohol , I'll ask our hosts on the ignition timing .

I forgot to mention I worked for JCA motorcycles which ran a speedway team with a Jawa bike with a Weslake engine , Metonal or Ethonal is a bit caustic so I will add valve saver upper cylinderlubricant as well ,I'll get the full fuel specs from Caltex who call it Eflex fuel , I have phoned them and will get them to post me the data in case the additives have already been added , this is the fuel that the Australian V8 super cars run on .

To run an engine on 'R' you have to build it on 'R'. If your engine has been built on mineral oil, the die is cast.



If you like the smell, drop a spoonful, or two, into your petrol tank each time you fill up.

For the record: E10 is 10% Ethanol. E85 is 85% Ethanol

When I was only 20 I ran a Yamaha RD200 on Castrol R and the piston rings gummed up and the blow past pressure broke the piston up ..big misstake , R is only good for engines that are striped down after each race , nice smell but no good for road going bikes , my new 612 crank is very strong with a massive big end on needle rollers with a forged conrod , pretty hard to break and oil supply is supplied with the big bore pump and a UK spindle with a neoprene worm , super strong cam followers and all alloy push rods , Samrat rockers and full race valves and springs so the red line might be 6,000 rpm , speedway bikes use synthetic oil as it mixes with Methonal /Ethonal pretty well , with a forged Accralite piston getting the right timing is critical but with BP9ES plugs at 10:1 comp ratio I just dont know what colour they should be with the full Methonal conversion kit , I feel confident that I'm doing the right thing , I used to own a Honda/cosworth production racer CB77R that was very fast and this what gave me ideas about port shapes and this Enfield engine is the pinical of my knowledge . I intend to plod around most of the time and the bike itself is a standard 1995 export so not to get the cops on my back .