East Coaster MPG

[Motorcyclist Colin]

My wife and I recently went to a Vincent meeting (Where the EC was much admired, incidentally) on the bike. We were obviously two up, but our combined weight would not exceed 16 stones.. The round trip was a little over 100 miles or so. The outward journey was mostly Motorways M20 and M2 with a bit of dual carriage way. We were cruising at around 60mph most of the way. The return journey did a little on motorways but, mostly on a fairly quiet A20. Bike was running beautifully . This is my first ever Villiers Twin engined bike (but probably about my two hundred and something plus bike!) and again we were cruising at 50/60 mph maybe with the odd burst a bit more.The bike made it clear to me that it likes to rev, and will not tolerate slogging.
I did not make an accurate measurement of MPG but I fairly estimate we managed somewhere around 40/45 mpg. Is this about par for the course please? Seems a wee bit thirsty., as the throttle was not very wide open most of the time
Running 34 psi rear and 32 psi front for this trip. Little to no wind either way. On this trip running on E5 and 25/1 mineral mix, never any signs of nipping up or struggling
Overall though, what a great little bike.

[John Pattinson]

Sounds about right with those speeds and 2 up.

[John Wakefield]

I have just been out on a 85 mile club run today and my EC averaged just over 60 mpg, the figure quoted in the road test was 68 mpg average. Mind you I was travelling between 30 and 50 mph solo on B and C roads. You say you were cruising at 50/60 mph I assume this is from the Smiths speedo, well known for being up to 10 mph fast (as on my bike) 60 mph is a bit on the limit for 4T engined bike 2 up. My readings are from a calibrated digital speedo. Tyre pressures according to Service Notes should be Solo 19 psi FRONT and 20 psi REAR for a rider weighing 140 lbs if rider exceeds 140 lbs add the following: FRONT 1 psi for ever 28 lbs increase in weight over 140 lbs REAR 1 psi for every 14 lb increase. If additional load is carried in the form of a pillion passenger or luggage, the actual load bearing upon each tyre should be determined and the pressure increased in accordance with the load and pressure shown in Tyre Manual supplied. I dont have the tyre manual.

[Motorcyclist Colin]

Thank you the "Johns"
I will fit a calibrated bike computer for a speedo check, as 10mph fast at 50mph (ie reading 60mph) is pretty inaccurate. Turning to tyre pressures (John W) I assume the pressures quoted from the Tyre Manual are for 1950 or 1960 tyres. If so, modern tyres, have much "softer", for want of a better word, side walls, and thus, I run modern tyres at higher pressures than "old spec" tyres.On reflection perhaps 34/32 psi was a little high. Iwas experimenting to a degree, with pressures to see what I could get by way of performance,for road holding, speed and economy. I'll get the tyre manufacturers views on their modern tyre pressures when run on old bikes. (should have done that first!)
Road holding was pretty fair as far as I could feel/see, although the bike was not being pushed hard in that area..
Any views, gentlemen ,on revving verses slogging , or indeed cruising speeds,for this engine ? Thanks again for all input.

[John Wakefield]

See how the speeds pan out when you get a calibrated speedo fitted, I think you will find the engine is happiest at around 45-50 mph real speed. The Motor Cycle Mechanics road test of the East Coaster, gave a somewhat optimistic top speed of 80 mph but I think that was a speedo reading, I have never come across a road test by Motor Cycle or Motorcycling who used calibrated speedo's and stop watch timing for acceleration tests. Other 4T engine bikes the Royal Enfield Turbo Twin and Francis Barnett Cruiser 91 only managed just over 70 mph. Re tyres I run mine at around 23 psi front and 25 psi rear

[Bazt2sport]

That's interesting gentlemen.
Could I ask what people are using in way of modern tyres on their roadsters ?
I'm still a long way from turning a wheel but the information would be appreciated.
Thanks.

[John Wakefield]

I am using Heidenau K34 2.75 x 19 front and 3.25 x 18 rear. They perform ok

[Bazt2sport]

Thanks again John.

[Motorcyclist Colin]

I have modern Avon Speedmaster on front and Avon SM on rear. Standard sizes, but as mentioned above I have been experimenting with pressures. Modern Tyres have much softer (ie flexible) sidewalls and benefit from greater pressures than tyres from 1950s/60s . Thus get info from the manufacturers or (knowledgable) suppliers about pressures. Usually old manual recommendations are much too low.
In my (inexpert) view try pressures that suit you in terms of handling and comfort etc as modern tyres will "assist", for want of a better word, the suspension, and can provide good grip with lower rolling resistance. NB I am NOT a tyre expert these are my views only, and your local Copper, or Insurers may well have different opinions!!!

[John Wakefield]

You say you have an Avon Speedmaster on the front, so this will be 300 x 19 the original size specified by Greeves was 275 x 19 but Avon have not done that size for some years. Not sure about the Avon SM rear as this is only available in 350 x 19 400 x 18 and 325 x 17 sizes, it should be 325 x 18 on the Greeves, so is yours an old stock one? Frankly the ribbed pattern Speedmaster is an old design and does not give as much grip or wear as more modern tyres & the 300 size only just clears the fork loop. Like wise the Avon SM. I find the handling with the Heidenau K34 much better.