F1 thirst

[kanonkopdrinker]

Here's a question posed by a Swiss member, currently working on a F1 (owned by a French chap ….)

This bike, when full, will go onto reserve at just 50 miles!

It still has the Mikuni carbs.

Any ideas where he should start looking to explain this great thirst?

All suggestions welcome ….

Merci beaucoup, as they dites …

David

[fogrider]

But how much fuel goes in after the 50 miles ? If its' 2 gallons or less, I would be looking at how the reserve system is set up.

[johnbirchjar]

Sounds like possibly "O" rings?or the floats jamming up? (Unless there is a massive leak somewhere twix the tank and the manifold,)otherwise the bike is running so rich I'm surprised runs at all ,and the bad news is all that fuel sloshing about in the chambers will wash the oil away with catastrophic(and expensive) results ,J.B.

[kanonkopdrinker]

I am told 14 ltrs can be squeezed into the tank after 50 miles.

That sounds thirsty to me.

DC

[fogrider]

Yep, that's around 16 MPG !
Sadly, no-one is telepathic, without the bike or any facts about what was done to it last, what (if any ) mods have been done, the sort of use etc it gets
and who maintains it, one can only guess.
Clogged air filters, high fuel levels, sticking choke system, dragging brakes, soft tyres etc etc etc are typical culprits.
Surely he knows a mechanic over there who can look for the obvious ?

[johnbirchjar]

Re: maintenance,even without the "myths""of our rotories,even basic maintenance should eliminate most of the prob;s of the previous post,J.B.

[Wayne]

Normal riding I get about 90 to 100 miles to reserve. However on the track I have got it down lo less than this. It all depends on the right hand.

I get considerably better mpg on the sport around 45mpg.

The oil consumption matched the mpg on the F1 heavy on the throttle oil consumption goes up.


Regards wayne

[Wayne]

Normal f1 riding I get about 90 to 100 miles to reserve. However on the track I have got it down lo less than this. It all depends on the right hand.

I get considerably better mpg on the sport around 45mpg.

The oil consumption matched the mpg on the F1 heavy on the throttle oil consumption goes up.


Regards wayne

[johnbirchjar]

Hi Wayne,your F1 seems a bit thirsty,(14 ltrs is a tad over 3 gals,roughly 30 miles to the gallon )how come the Sport is that much more economical? 45 to the gallon is Commander(on a good day )and about the norm for IP2's and Classic's,J.B.

[fogrider]

I can concur with Wayne, my F1 Sport is also pretty good on fuel considering the reputation rotaries have. I don't go loony anymore but it certainly does a good 40 mpg.
The reason ? F1 sports don't have the Mikunis of the F1, they have SU's, can't beat'em. !

Just my opinion, had cars with SU's from 1965. ( Mark 5 Jag )

So, do Commanders clear 40mpg too ?

[fogrider]

Bit of an overlap with JB's post, so Commanders do clear 40mpg on SU's.
I have to wonder if the issue with F1's is that the Mikunis are in a poor location, in enclosed bodywork that became known for overheating. Perhaps in a hotter climate (where in France is the bike ?) there is a need for bigger throttle openings to make it shift ?

[wust588]

My money is on a stuck choke. Unless he rides everywhere at 140 mph.

Could be sticking/ worn float needles. Historically, the F1's were always more thirsty than the Sport's.

Certainly, the bike would benefit from a carb strip...…..