AJS & Matchless Owners Club

mjf65 wrote: ↑Fri Aug 20, 2021 9:19 pm
As a novice to AJS ownership but old enough to have used 4 star (five star had been phased out when I started riding) what star (octane) rating were our bikes originally designed to run? Would I be right in saying super unleaded being higher octane will burn quicker and could this be a problem? I've been using Shell standard unleaded for the last 2000 mikes(two years) and fingers crossed all seems well.

You don't say which bike you have, but in general terms.............
I don't know what the exact octane rating was in the 40's and 50's although the wartime 'Pool' petrol was pretty/very low octane. It seems that most of us have no issues using the same carb jetting and more or less the same ignition timing (7/16" or 1/2" BTDC) as in the original manuals for our relatively low compression (about 6.5:1) 'cooking' singles. I guess the higher compression models, e.g. Twins and 'CS' and 'CSR' (at around 7.5:1) wouldn't be too happy on low octane fuel.
I believe that the addition of ethanol weakens the mixture but my '54 G3LS (6.5:1) has run fine on the original Owners Manual settings.

This is what the Owners Manual says for the 1954 singles:

From the FBHVC:

In the mid 1930s Research Octane Numbers (RON) were around 70 which allowed compression ratios to increase to about 5.5:1. Many 1950s vehicles, for example, probably require no more than 80 RON petrol, if such a product were available, yet will run well on 95 or 97+ RON petrol. Furthermore, most pre-war cars were designed to tolerate even lower octane fuels, yet will also run well on today’s 95 or 97 RON petrol. Octane requirement should therefore be seen as a minimum requirement to ensure the correct operation of the engine.


The full article is here:

https://www.fbhvc.co.uk/fuels

the only prob I've had is if you dont drain the carbs if not using the bike continually,the old super seemed never a prob,would go stale of course,have had to replace carbs with the new gear,but drain the things now,no probs

dave16mct wrote: ↑Tue Aug 10, 2021 8:06 pm Is it a light bulb?
Dave

Sorry Dave, I've been otherwise occupied. You know I'd never use a Lucas bulb. It's this. Lucas Oil Safeguard Ethanol Fuel Conditioner.

I don't normally get too wound up over the ethanol thing but I do use fuel stabilizers when the bikes hibernate over winter. This stuff appeared to be an attractive alternative to my recent 29 quid jerry can filling experience! It looks like there are two variants of this - both sufficient for 80 gallons of petrol, but at a fiver difference in price. One is catalogued as 40576, the other as 10576. The cheaper 40576 doesn't appear on Lucas' own pages and the bottles appear identical. Anyone uncovered the difference?
As an aside I filled up my oil-head BMW with the super unleaded the other day and the occasional stutter at tickover that had disappeared after I last stopped using the super returned. Perhaps it prefers slumming it with the cheap stuff

Steve

REF " Being a cynic when it comes to anything at all being put out by the Gov, "

There was a stockpile of fuel going 'off' from the covid lockdown. which needed shifting into people tanks to go off !

The quickest way to do this was to start a panic.

We have had the covid food and fuel lockdowns next is money lockdown for the poor.

kind regards to all

I'm not sure that Boris would have willingly added yet another headache to his several other challenges.
However I did hear a fuel company spokesman say that for taxation/compatibility reasons they would not be mixing E10 with E5 in the same retail filling station tanks so I guess that they wanted every litre of E5 cleared through their storage and distribution chain and the retail tanks. This meant that instead of just topping them up the tanks with E5 had to become completely empty before they would deliver any E10. I imagine this has now been achieved but it caused the ongoing 'shortage' panic.
Besides, if you had a mix of E5 and E10 would you have to change the pump labelling to 'E Seven and a Half' to satisfy Trading Standards?

SPRIDDLER wrote: ↑Sat Oct 02, 2021 11:34 am I did hear a fuel company spokesman say that for taxation/compatibility reasons they would not be mixing E10 with E5 in the same retail filling station tanks

Hi

Where's the compatibility issue? We're all going to be putting E10 into systems that used to manage E5, (and in many cases other standards).

More bluff and bluster from the producers and government

We need smilies, for sarcasm, cynicism and disgust

Regards Mick

i filled up with E10 yesterday for the return trip form this weekends rally 155 miles no problems so far bike ran just fine.

You can use ethanol E10 without any problems. However, it’s not the burning of the fuel that causes the problem, just the hydroscopic quality of ethanol. If left in your tank, water is absorbed, separates and apparently then encourages a bacterial growth which turns the water into a highly corrosive liquid that wreaks the inside of your tank and carb components. Never a problem if you are constantly filling up with fresh E10, but problems start when the petrol is left for some time. Reduce the problem by using E5 with stabilisers, but when the riding season finishes, I always drain the tank and carb. With any modern fuels, always add some lead replacement (Redex) to protect the valve seats.

Chappers looking at your profile you record your background as a "retired arms dealer really" perhaps you could explain your knowledge base on the E5/E10 issue. Thanks