MPG?

[rjg30091982]

Hi all,I've asked before but just curious again about MPG, my commander will do 140 miles tops before reserve which means with 23 litres of fuel that's roughly 31-32 MPG, my IP2 will do a little more about 145 to the reserve. My commando again only manages 30 MPG?The only thing I own that is good on fuel is my Kawasaki ER5 which does 60MPG, even my diesel mondeo only manages 42mpg around town.All my driving is generally around town but to work I'm 500 metres each side of a 5 mile A road so work and back should be better!I know what your thinking heavy twist grip but on the rare occasion I've kept the revs under 4500 for a whole tank I've got maybe 10 miles more from a tank.Both bikes have always been like this including both commandos!Why do I never get good MPG? I religiously reset the tacho on eve fill up for every vehicle I own to keep an eye on the economy.............What do you get from a tank?Russ

[Anthony Duffield]

On a recent 300 + mile trip (Commander) I managed 50 MPG, this was a mixture of country roads and dual carriageway. I do not trust my fuel gauge, if I top the tank right up to the top and at quarter on the gauge re-fill it takes no more than 10 to 11 litres, I believe the tank capacity to be 22 litres?I am still getting to know the bike and think I have a handle now on the fuel consumption, oil is next on my list.Tony

[rjg30091982]

50 is unbelievable! I can't get close to that at all!I reckon I could do better mpg with a Volvo T5!!!!On those 11 litres tony how many miles do you get? If your doing 50mpg you should be getting 100 odd miles Russ

[vontripper]

hi, my commander I get 155 mpg on full tank , when I fill up put bike on centre stand and fill to the top [Waite a bit to let it settle] GOD told me to do that R. N. 155 MPH that's when I start looking for garage ,can do a bit moor but I don't like stopping and turning on reserve.I only take commander out for long runs and that's on a motorway when I can. I am a bit of a throttle jockey Andover Norton sell kits for S U carbs now, it mite be your carbs need a bit of loving care RG VON

[rjg30091982]

Hi gripper carbs are new 3 years ago.Either I am hopeless at maths (more likely than not) or your doing 31 to the gallon as well!155 miles divided by 22 litres = 7 miles to the litre x 4.5 (litres to gallon) and you get 31 MPG exactly the same as mine as I fill it to the top on side stand which equates to your extra 15 milesOf course I hold my hands up to being useless at maths!!Russ

[Steve Gee]

My maths are not up to much either so I just use this site, http://www.mpg-calculator.co.uk/ 155 miles and 22 Litres comes out as 32.03 MPG

[rjg30091982]

That's what I thought!I read plenty of mpg figures that never make sense and 50mpg from a rotary seems high considering mine is so low and one is untouched the other has had a full rebuild!

[JohnOR]

Hi AllWhen commuting daily years ago I kept a fuel log on a spreadsheet as a running total to give an accurate mpg as variations on one tank could give false figures. this method also predicted when the full tank would become empty. It clearly showed when I either followed a friend on an old AJS350 50mpg or when the side plates were "begining" to fail 35mpg. Around 43 to 45 (or 10M/L if you want strange units) was normal. This was the same for both the Commander and the Interpol. The difference being pre moly coating the commander coped with London traffic better.This is from memory I will see if the data still existsJohn

[Richard Negus]

I looked back in my 'little black book' of Scottish trips on the white/red Commander and then the Classic.2009 home to Tebay services 153 miles, 15.6 litres to refill, 90% motorway 80'ish. Total for the weekend 1150 miles, 100.4 litres = 52 mpg.2010 total 1529, but no fuel figures.2010 total 1145 miles, 99.2 litres = 52.4 mpg.2011 total 1655 miles, no fuel figures but spent £221.76 on fuel.2012 440 miles, broken air-cooled engine.2013 total 1398 miles, 149.7 litres = 41.03 mpgOn both bikes, I bodged out the little vent hole in the filler neck to allow me to fill to the brim - but, having refuelled, don't then leave it on the side stand or all that expensive fluid leaks out onto the concrete.Overall gearing is different; Commander runs 18:42 and the Classic 17:43, which I make to be 8% lower.Even with a small screen, the air-cooled needs more throttle than the Commander to maintain a good speed and it is definitely more tiring to ride.

[David Rodgers]

I did a trip through France and Spain last October and was getting about 10 miles per litre i.e. Putting in 13 litres after 130 miles etc. This equates to 45mpg and was on my newly built Classic (thanks Richard). When joined by a smaller bike and travelling much steadier the figure got up to about 48/49mpg. Conversely when riding much faster it dropped to 41/42mpg. I think that between 40 and 50mpg from an air cooled wankel from 1985 is perfectly acceptable. It's about the same as my T160 Trident.CheersDave

[Joe]

Hello Russ, My Commander, your sister bike, will do 168 miles before switching onto reserve. I can push it a little further but I too don't like stopping to change over to reserve at the side of the road because my daily commute of 40 miles each way is mostly on 70 mph A roads. My bike has covered 189,000 miles, I'm 1.68 M and 77 kilos, short and fat...... I have Krauser rear end without too much inside the boxes and I always stick to the speed limit. I also have the aluminium fuel tank which I'm told holds more fuel than the steel one which I fill only when on the centre stand. I have run out of fuel in the past probably 4 to 6 times in exactly the same place which demonstrates my riding must be consistently bad, on these occasions I had to coast into the same pikey drive every time. I perfected switching over in seconds so I could get away before my wheels were knicked. I've often wondered how the Police accepted a bike where you have to strip it to operate the fuel tap reserve, not the best idea. May be worth checking your brakes aren't binding, an area where Commanders suffer and will affect fuel consumption. After a ride, with a damp rag or your finger if your brave enough touch each of your brake disks, if they sizzle investigate further and put some cream on your burns if you chose the latter option. You can even use an anfrared thermometer. My disks are never hot. Regards, Joe.

[gripper]

I work on 42 MPG on my IP2. Doesn't seem to vary much whatever you do to it. My old Commander was pretty slippery but that's the benefit of a full fairing.

[Anthony Duffield]

All,Last weekend I met the Tay Valley Norton Owners Club members in Comrie at a cafe called Tullybannocher.Leaving Aberdeen I topped up at Portlethen, turned off the A90 at Arbroath onto the A94 then Via Perth the A85 to Comrie. Having met the lads and lasses and had a nice cup of tea and piece of cake at the cafe I left and stopped at Crieff and topped right up to the neck of the tank.From leaving Creiff I took the A822 a small twisty turny road, once on the A9 I kept up a steady 70MPH engine speed around 4100RPM, it rained steadily all the way up the A9.Next stop was Keith where I refilled again to the top of the tank, I paid for 11 litres, Ive just put the two locations into Google Maps, it is 139 miles, I will leave you to do the maths.The reason I filled up in Keith was because the fuel gauge was on quarter, which I am fairly sure now is reading low, I think I could have got home to Oldmeldrum near Aberdeen without filling up at Keith but did not want to risk it.Tony

[rjg30091982]

Thanks all,I haven't used my commander for 2 weeks and it's empty of fuel so I'm going to top it up this weekend and do another test, I'll tax my IP2 and do the same as well and report back in a couple of weeksI guarantee my commander which hit reserve 5 miles ago will take £30 of fuel which is about 23 litres!CheersRuss

[Dell Boy]

About 10 to the litre on all my rotarys. In town much, much less.Derek F.

[johnbirchjar]

45 miles to the gallon from the Classic fitted with a 3/4 fairing.(I know this 'cos I did the "Full to the brim, to reserve, to empty tank." test,on a mixture of highways) my Bora deisel do's about the same as your Mondao around town but 50 on a run,and I would think 50 to the gallon from a Commander is a bit unlikely,J.B.

[rjg30091982]

Well I haven't dug the commander out of the garage but have refuelled my mondeo and KawasakiKawasaki ER5 70.02 mpgMondeo TDCI 42.29 mpgBoth on similar roads!Will check commander in next couple of days

[rjg30091982]

Well filled up the commander145 miles 18 litres works out to be 36 mpg!36!!!!!!!!Why is mine so bad when I can get 70mpg out of my Kawasaki?It's been rebuilt recently, new carbs and new ignition unit?Richard? Any ideas?Do I need to remove the police light as clearly it's causing drag!!!!!!

[Richard Negus]

[quote="rjg30091982"] Richard? Any ideas? /quote]Have a look at the choke cable where it fits into the l/h handlebar switch - is it seated correctly, with some slack in the cable?

[rjg30091982]

I think it's ok I will check next week!It is ticking over at 2000rpm at the moment adjusted at the carb end of the cable because before it would always cut out at lights at 800-900 and I played with it for a while and it was 1000rpm but after putting it all back together it's now 2000rpm!Had to change the CDI also recently which we spoke about but prior to this it has always done the same mileage never anything different always 130-140 then hit reserve.Going to try a completely boring tank of fuel under 4000rpm to see if this changes anything

[Richard Negus]

It is ticking over at 2000rpm at the moment adjusted at the carb end of the cable because before it would always cut out at lights at 800-900 and I played with it for a while and it was 1000rpm but after putting it all back together it's now 2000rpm!

What? There is no adjuster at the carb end of the throttle cable - and it should always have some slack in it with the grip closed. That way, the butterflies are closed when the grip is closed and idle speed is adjusted by the idle air screws on each carburettor outlet casting.

[rjg30091982]

Probably explained this wrong!On the right hand side of the engine where the throttle goes to the linkage there is an adjuster there. There was no adjustment at the throttle end. I think from memory this was made worse or better which ever way you look at it by the new CDI unit. It ran better after the new CDI was fitted but kept cutting out at lights as the revs were two low.

[Anthony Duffield]

I would think 50 to the gallon from a Commander is a bit unlikely,J.B.See attached fuel receipts.06/04/14 13:26 filled up at Crieff Garage unfortunately no record of amount of fuel06/04/14 16:24 filled up at Shell Keith 11.82 litresTrip on my speedo was 145.1 miles, on Google Maps the route I took is suggested to be 138 miles. Just under 3 hours you will have to take my word that I did not put any fuel in on the way to Keith.11.82 litres 2.6 Imp gallons @ 145.1 miles 55.8 miles/gallon. @138 miles 53.0 miles/gallonThis is my final word on the subject Tony

[rjg30091982]

I'm going to do a tank of fuel under 4000rpm and see what I get,Normally I ride progressively but never fast or throttle the bike to death.If this returns 50mpg under 4000rpm I'll be happy the bike is ok but there is no way I can ride that slow daily!!!

[Interpol2471]

36mpg sounds good to me I think I can get around mid 20's if I try hard enough my car only averages 20mpg as well but its one hell of a trip to work....

[rjg30091982]

So finally I've done 125 miles on the commander all religiously under 4000rpm (boring) all along the A38 from home to work which is 70% dual carriage way and it did it on 13.84 litres which is 41 mpg! A mild improvement but still no where near 50-55 like others claim!Russ

[Interpol2471]

I now use Aspen alkylate petrol in all of my bikes so maybe it seems more important to me now at £18 a gallon but no ethanol and no worries when you leave it standing.

[gripper]

The reason you can get 60MPG out of your Kawasaki is that it is a modern lean burn engine with four valves per cylinder, digital fuel injection that probably cuts the fuel off on the over-run, and it probably weighs half of what the Norton does. Try pumping your tyres up to 40 psi.

[rjg30091982]

Hi gripper Yes your right about the Kawasaki but I just don't know how everyone else gets 45-55 mpg from a rotary when I did a full tank less than 4000 rpm and still only managed 41???If everyone else did 41 I'd be happy as the rotary is igniting more than a twin in any case but the fact others getting much better just annoys me!!!Still looking at trading in my ER5 for monkey bike at 130 mpg!!!

[rjg30091982]

Just did a full days ride A roads of Devon Plymouth to bideford and back scenic route average 40-60 MPH.Using my IP2 Bike managed 43mpg. 157 miles on 16.84 litres of fuel.Russ