Manual Petcock

[Wess]

I am debating whether to get the onc murph carries may I please have your input. As always I appreciate your wisdom! Respectfully Yours! Wess Heavner COG #8010 CDA #0239

 

[smithr]

Oh do I have something to say. GOOD LUCK. I have rebuilt petcocks(3) all with good luck for a year or two. I installed the manual conversion to the stock petcock from Murph. I am now on NO petcock with electric valve system. I feel I can safely say that we still do not have a good solution to help prevent hydro lock. In my three concours I have had every know petcock failure. There are three or more of them. The manual conversion to petcock (or any manual) I would forget to turn off even after a year of retraining. If you leave it on while you run in for lunch it is no protection. Plus it failed by leaking gas out of the face of the petcock into my hand one day while going to off. The electric valve conversion is nice but you have to install it very careful or you have problems. The valve from Murph(have to ask for it) only flows about a gallon in 7 minutes. That is very close to not being fast enough. I also took it apart and I can see the inner seal of the valve failing someday. So far the only idiot proof hydro lock protection for the bike is to never fill it with gas. ---------------------------------- I will answer any question. It is up to you to figure out if I should have.

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[Brett0769]

This must be a stupid question, but how can a gallon in 7 minutes not be fast enough? That would be going into reserve in 42 minutes! I don't know what kind of speed you're riding at, but unless you're doing 300mph, 1 gallon/7 minutes should be fine I'm thinkin'.

 

[smithr]

I know it calculates to be plenty. I know one thing though. I have had either a flow rate or vapor lock issue since i installed it. It happens rarely but this was the last one.... Been riding all day at 70+mph speeds. It is now about 88 degrees out and it may be the first time the gas tank is down to 3/4 empty. It looses power so I let off the gas and cost to the side 350 miles from home. The engine never dies and as soon as the bowls have time to refill I continue on at 60- mph. No issues after filling tank. Next day I test it again and even after letting the tank get down to >3/4 empty and temperatures over 90f it never gave me a problem again. This is the third strange issue I have had. 7min/gal may be fine but I know I do not have kinked lines when the get hot because I have tested and looked for this several times now. It is either vapor lock some how or the flow rate is reducing when it gets hot. ---------------------------------- I will answer any question. It is up to you to figure out if I should have.

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[magnum1b]

I have had the Manual Conversion on my 86 since I got it three years ago. I had it hydroloc about a year after I converted it so I got another kit from Murph and also the solenoid valve. I then had fuel starvation problems crop up. When I took the solenoid valve off I had no further fuel starvation problems. It usually occurred when I was down about four gallons, ie: still had 3.5 gallons in the tank. I sent the valve back to Murph for credit as I am convinced it was causal in the starvation events.

 

[2linby]

My experience has been this. I've replaced my petcock once in 119,000 + miles. I decided the replacement cost wasn't prohibitively expensive in comparisson to the potential of a leaking rebuilt or forgetting to turn off a manual petcock. As far as the potential of fuel starvation I've had a ton of experience with this when I decided to add a auxillary fuel tank and plumbing in an auxillary fuel line. Given the propensity of the Concours towards fuel starvation you have to have a direct routing of the lines as any retriction will manifest in fuel starvation issues. What Jack experienced is typical of any change in the fuel line condition. With a full tank you have enough head pressure with 7.5 gallons of fuel weight but as soon as the weight drops below the point inwhich the pressure no longer overcomes the restriction then you have issues. And this is nothing that you want to find out about especially during a rush hour commute home in the HOV lane at 65 MPH heading south on Hwy 167 from Renton, WA to Auburn, WA! So the short of this is: My advice is to replace the petcok with a stock petcok and leave it like that. AKA "2linby" That's 2-lin-by folks! Northwest Area Director COG #5539 AMA #927779 IBA #15034 TEAM OREGON MC Instructor http://community.webshots.com/user/2linby http://tinyurl.com/njas8 (IBA BunBurner Gold Trip) http://tinyurl.com/lwelx (Alaska trip)

 

[oldsawfiler]

My experience: I bought the bike in Feb. and road it 5 months and 5000 miles with no problems. Then in late July. It started "running out of gas" with 2.5+ left in the tank. The first time I thought it was a fluke. The very next tank it happened again. Posted here and talked to local mechs. Came to the conclusion that it was a bad pickup in the tank or the petcock itself. Ordered new petcock and fuel line from Murph. When I went to install the petcock saw that the PO had installed a very small inline fillter. I installed the new petcock even though I could see nothing defective in the old one and left the original line but shortened it line by 1 inch. Walla! 7000 miles since with no more early out on the fuel. I believe that the fuel line was just long enough to cause it to pinch off the flow when the head pressure dropped and the air temp rose to the point that the line became flexible enough to kink. Make shure that the fuel line is just long enough to reach with out any unnesesary bend in it. 1990 Aint she a pretty Tomato (the bike ofcourse) wedshots albums http://community.webshots.com/user/sawfiler64/albums/most-recent