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Fuel Comsumption

PostPosted: Fri May 22, 2020 5:36 pm
by 68Sxandy
Hi guys,

I did a check this morning on how far I could go on a full tank of fuel, I am running an SX 186 mugello, with a 28mm open mouth dellorto and a JL3 pipe.
I managed a slightly worrying 52 miles before reserve !!!!!

How does this seem to you guys, do I need to try a smaller carb or just get it dyno'd and set up better.

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 5:45 pm
by MickYork
Depends a bit where your reserve is set ? not all taps/reserves are set the same.

Estimating you've used 5L out of a 7L tank your getting 10 miles per litre, not too bad but could do better, but you need to know the exact amount of fuel you used.

Your riding style, average speed, type of road (twisty/hilly), weather (head wind/tail wind), etc, are all factors that will effect your MPG and what can distort one man's MPG to another man's.

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 5:51 pm
by 68Sxandy
Hi Mick,

All good and valid points.

6 years ago Al at Diablo set it up on his dyno, albeit then I had a VW reverse cone exhaust - now a JL3. It ran fine and don't remember fuel consumption being too bad, haven't used it much for 2 years but seems heavy on fuel and boggy in the bottom end.

Test today was very windy, mixed roads with some flat out and some town riding, as for me I am a svelte 16st . :D

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 5:52 pm
by 68Sxandy
I also thought the standard tank held 8.1 L ?

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 5:53 pm
by missing lynx
I have basically the same set up as you and am averaging about 12 mile per ltr but if you were out this morning riding against the high wind you mpl will be drastically reduced

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 5:55 pm
by 68Sxandy
Maybe I should go on a diet and stop worrying .

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 6:20 pm
by MickYork
68Sxandy wrote:Maybe I should go on a diet and stop worrying .


Nah...…..just stop worrying, fuels cheap at the moment :P

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 6:38 pm
by missing lynx
MickYork wrote:
68Sxandy wrote:Maybe I should go on a diet and stop worrying .


Nah...…..just stop worrying, fuels cheap at the moment :P

Or get a bigger tank!!

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 6:47 pm
by Tony Hart
I’ve got a Mugello 186 with a 26mm carb and a 42mm Ancillotti and get 8 miles to the litre! Struggled to get off Tan Hill one year so got a bigger tank and learnt to live with it. It’s done about 14k, relatively trouble free miles, with a couple of new sets of rings so no inclination to mess with it.

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 9:13 pm
by citydaz
Ive got a mugello 186, 28 mil carb and and a JLS3 exhaust, and i also get about 10 miles per litre.
Fitting a larger mid-range tank has helped ease petrol anxiety.
Ive recently lost 9kg in weight so that should improve both performance and range!!

Re: Fuel Comsumption

PostPosted: Fri May 22, 2020 9:41 pm
by MK Monty
Fill up again to see what it takes, then do your sums again, I cut about 30mm of the tube inside the strainer on the tap as my reserve had about 60 miles on it.

Re: Fuel Comsumption

PostPosted: Sat May 23, 2020 12:19 pm
by Hat
Sounds about right, the windy weather will definitely play a part. I’m on the same kit, 30mm delly with breathesweet and franspeed supertourer and get about the same. 50ish miles to reserve and another 30 until empty

Re: Fuel Comsumption

PostPosted: Sun May 24, 2020 9:20 am
by 68Sxandy
Thanks for the replies guys, I am taking it in to see Al at Diablo next week, he remembers dyno'ing last time and having checked his records he says it was set up massively rich due to the poor exhaust.
Hopefully he will sort it again.

Re: Fuel Comsumption

PostPosted: Mon May 25, 2020 10:37 pm
by rossclark
A lot of the fast flow taps have a very long reserve tube.