Misc: Everything Else Mikuni Fuel Pipe Routing

[b'knighted]

I found this to be a major problem on my big Comet. Reserve would not push fuel past the airlock that forms where the pipe is at its highest above the carb. living in the sticks I may well be 20 miles from a fuel station during the day and 50 - 60 miles at night. Keeping things topped up is not so easy. Last nights detour for car fuel found that even the pay at the pump supermarket stations now close at about 10pm.
My current plan is to fit a tee piece at the high point with a capillary tube bleeding the air to above tank level at the steering head. Just another little job to complete before the bike is finished.

 

[Bill Thomas]

When I first saw Vibrac's Bike, I said I was worried about airlocks,
But other people said they were running like that, It just looked wrong to me.

 

[Michael Vane-Hunt]

I have run my twin with the Mikuni front fuel line as in the picture I posted. I have big bore petcocks. I do not use a reserve type petcock. I leave the right hand petcock closed. I run with only the left petcock open. I can and have gone up many of the passes in BC. I have gone up the Beartooth in Montanna. I ride as fast as I can go mostly in 4th gear 70-75 MPH one up fully loaded. I am heavy. I have run out of fuel several times, ask Glen Breakes, and gone onto the left tap to squeeze out a few more miles each time. I have never had any of the problems mentioned about running the fuel line up and over the top of the carb. Same arrangement on the Comet. I guess I am lucky as I have been riding thus for 20 years. John McDougal set up the carb configuration and Vincent-wise he made very few mistakes.

 

[Michael Vane-Hunt]

PS. On the Egli for sale that Graham posted. It looks to me like the front fuel line runs up and over the top of the carb.

 

[Dave61]

Dave , If you look under "Auctions ", Graham has just put some photos of an Egli 1330,
If you blow up one of the photos, Looks good to me.
Maybe ? if you got some right angle fittings that are from the tank and ground the nut off.
Surry Cycles do them.
If the cone is too big , Where the nut was ,Grind a bit off the outer edge ?.
So short bit of pipe , Then the angle ???.
Just a thought. Cheers Bill.

Thanks Bill,
That makes me feel better about my setup, definitely coming back over the top of the carb.
Just going to tidy up what I`ve got & keep an eye on the clear fuel filters.
Cheers
Dave

 

[Monkeypants]

I have run my twin with the Mikuni front fuel line as in the picture I posted. I have big bore petcocks. I do not use a reserve type petcock. I leave the right hand petcock closed. I run with only the left petcock open. I can and have gone up many of the passes in BC. I have gone up the Beartooth in Montanna. I ride as fast as I can go mostly in 4th gear 70-75 MPH one up fully loaded. I am heavy. I have run out of fuel several times, ask Glen Breakes, and gone onto the left tap to squeeze out a few more miles each time. I have never had any of the problems mentioned about running the fuel line up and over the top of the carb. Same arrangement on the Comet. I guess I am lucky as I have been riding thus for 20 years. John McDougal set up the carb configuration and Vincent-wise he made very few mistakes.

Michael needs to modify the line so that the tubing runs up over the handlebars and back down. I think this would improve his gas mileage quite a bit.

Glen

 

[Michael Vane-Hunt]

I always take the advice of those with superior knowledge. I will do as you suggest, should I remove the front sparkplug?

 

[Monkeypants]

Please don't, that's where we've been attaching the tow rope.
All kidding aside, Michael's bike runs great, even if a bit thirsty for fuel sometimes.

Glen

 

[Bill Thomas]

I found this to be a major problem on my big Comet. Reserve would not push fuel past the airlock that forms where the pipe is at its highest above the carb. living in the sticks I may well be 20 miles from a fuel station during the day and 50 - 60 miles at night. Keeping things topped up is not so easy. Last nights detour for car fuel found that even the pay at the pump supermarket stations now close at about 10pm.
My current plan is to fit a tee piece at the high point with a capillary tube bleeding the air to above tank level at the steering head. Just another little job to complete before the bike is finished.

I put on another thread that there are some petrol taps that have huge reserve pipes sticking up,
And that on Vin's, I fit taps with No reserve, Because we have the other side ?,
So as Ian says this would make it worse with these Carb's ?.
It would mean going on reserve with half a tank left ??, = No point ??.

 

[Michael Vane-Hunt]

Yes. No reserve tap. Run left open, right closed. Right tap when opend will give about 10 or 15 miles on my bike. I aim to fill up every 100 miles or so but in USA midwest back roads this can be difficult.