1200 Slater Mirage Fuel Consumption

gvhbiker

gvhbiker

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Lymm, Cheshire, UK
Hi
Just curious, what fuel consumption/tank range can I expect from my 1978 Slaters 1200 Mirage?
If I'm gentle I'm getting early to mid thirties miles per UK gallon, but I didn't buy it to be gentle!!!! if I'm not I get mid 20's, is this normal?
Seems to be running perfectly with standard jets & plugs look spot on.
Thanks
Geoff
 
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My `78 Mirage would return 28-32 mp(uk)g and it didn`t seem to make much difference how I rode,the result was always pretty much the same.
Just pussy-footing around still returned low thirties.
Although it left the factory spec`d-up as a Mirage it was fitted with 65 pilots as per standard 1200T,not 55`s as should have been,wonder maybe if this was to make it easier to set up for low speed manners just in case Massimo decided to give it a run around the test track,or just an oversight.
I swapped the 65`s for 58`s (RS didn`t have 55`s in stock at the time),but then he did so it ended up with 55`s in an effort to improve things.
I`m no carb expert but I guessed the pilots are always running in the background so thought every little thing might help.
Turned the accelerator pumps down to almost off..
This improved things to the extent that it now returned around 40 mpg at a pinch.
Always seemed to run a little on the rich side no matter what I did.
Strange really but that`s just the way they seem to be,I expect those who have fitted Mikunis or whatever to replace the Dells have experienced an improvement,that`s if you cover enough mileage to justify the outlay.
 
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I reckon it`s those 80 mm slugs that are the culprits,as soon as the cc starts to nudge 1116 then mpg takes a nosedive!.
Always used to start off up the M4 at Almondsbury with 4 gallons on board to see Alan Bell for spares when he was at Hayes thinking right,I should be able to do this in one hit,but always went onto reserve near Maidenhead and had to dive off the M4 in search of fuel.
That was cruising at around the 5500 rpm mark.
Martin Christie of Motor Cycle tested a SF with 30 mm VHB`s around 1972 ,and got over 60 mpg ,and that included speed testing at MIRA,,they re-checked and still got the same figures.
 
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No comparison between twins and 1200s (or triples in gen) for fuel economy. I rarely rode my SF gently and recall 20k/L as normal, didn't vary much at speed. That was from std and then to hi-comp SFC 5/C cam, ported head, which didn't alter it much; no accelerator pumps.

km/L is how we used to measure fuel econ once we stopped using Imperial gallons in Oz, then the L/100km came along and I struggle a bit with that. So I guess that's about 50-55mpg.

Sorry, only experience with 1200s was racing one - refilled every hour in a 4-hour proddy race from memory. Only commenting because Lawrence quoted same figures for his twin and Jota.
 
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Vince said:
What do you mean convert, everything but MPG and PSI is metric in my life, those two stayed Imperial for me.
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Here in the UK we`ve sort of gone metric,but not quite.Petrol is sold in litres,but beer is still sold in pints and mpg is still measured in miles per gallons (by most people).
Measurement is now metric,but road signs still in miles.
My weight is 95 kg which sounds alright but when converted into real money is nearly 15 st (Jesus...how did that happen?)
Older people need to do mental gymnastics to convert metric into something they can relate to,or at least go to the calculator page,young kids will just accept it in the future as normal,although road signs in miles may still have them scratching their heads.
I would still be interested to know how a Mikuni/Keihin or whatever equiped Triple compares to standard,I guess an improvement in mpg is the reason behind it?
 
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gvhbiker said:
Hi
Just curious, what fuel consumption/tank range can I expect from my 1978 Slaters 1200 Mirage?
If I'm gentle I'm getting early to mid thirties miles per UK gallon, but I didn't buy it to be gentle!!!! if I'm not I get mid 20's, is this normal?
Seems to be running perfectly with standard jets & plugs look spot on.
Thanks
Geoff
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Hi Goeff they love fuel just keep feeding her.
My well tuned dellorto fed old mighty flying Kangaroo 1200 struggled to get 180kms out of a tank with the engine spinning around 5000-6000. :)
 
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my 1200TS does 50MPG easilly and spirited riding drops it to 40/43 or so, it is standard stock flat top 8:.9:1 pistons, RGS head A11 cams and Jolta pipes, almost nothing inside the carbs is stock, (PHF32 ex RGS) it has done 14+ dyno runs around four years ago, (very tedious but worth it. Oh yes and she runs as well, it took Nickdav7 about 5 miles to catch me a few weeks ago on his very fast Jota, cant rememnber the speed he saw, but he said it was the fastest ever in his 15 year oiwnership, and at that top speed was a bit "flighty" I was getting the same handling feeling, I was only about 6 MPH down on him, I didn't have time to look at the clocks, but the throttle wire was guitar string tight and she was singing.and loving every moment of it, don't do that very often!
was a lot of fun

CLEM
 
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Bloody hell, guys - some insane variation in your triple fuel consumption figures!! Something must have been pretty wrong with the original setup to see those sorts of improvement just with some carb adjustment! Either that or some of them came stock with totally shite setup and others didn't???
 
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Cape added a bunch of hi-tech add-ons to his Ingatech Ignition, TPS and a 3D ignition map. My 3c gets approx 50ish MPG with Miks and pretty accurate jetting.
 
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Vince said:
Cape added a bunch of hi-tech add-ons
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I wouldn’t say high-tech, but I did make some changes. When I bought the bike it had had the original btz-ignition (Bosch boxes) and the fuel consumption was 35-40mpg(uk). After swapping to Ignitech and building the map/tps-setup the change on fuel consumption was kind of a side effect and a surprise. The main goal with the setup was to get a more tune able advance map and thus a better handling ignition-carburetor-engine-ride combination. Well, the consumption is what it is and I’m happy with it. I’ve been keeping records for the past 25000km and the average is 55mpg(uk). The carbs are still the old lumpy Dell’Ortos with stock(ish) jetting, just well balanced.

Ciao,
Sami
 
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