Question for RAY, or anyone chime in....

[motoman]

Did a 575 mile ride this past weekend. The Venturer is factory stock with the exception of 112.5 mains from the 110 stock ones.(Incredible performance with 115's, but decided on a happy medium between performance and economy). Have stock airbox with a Uni-Filter, original stock pipes, and 4" taller than stock windshield(gotta look through it anyways, may as well have the whole barn door). Had some 20 gusting to 40mph head and slighty cross-winds............averaged 36.5mpg@70mph. The latter part of ride it acted like it does when running low on fuel.......then came back to normal with a half of tank. 40 miles later, did it again, dropping cyls., so I switched to reserve and it picked right back up. Would you suspect weak diaphrams in petcocks, which would'nt make a lot of sense, as I presume they still have to unseat, even on reserve........or a problem with the screen stands on petcocks? Tank still had 2 gallons in it when I filled up back home.......took 4.6gal. I turned petcocks back on ON with tank full, and seems to be fine for now. Any input would be of help. Thanks all!

[TopCatGr58]

Hey Motoman,

You did say RESERVE, not prime, so the weak vacuum valve doesn't sound right. Sounds either like you said, the filter tower screens may be cruded up, or even the gas cap vent?? But the reserve is even lower down on the screens, they usually crud up from the bottom, so that almost doesn't make sense either??

Could be just a crudded up petcock? JAT?
T.C.

[dale_1]

ponder?

Slowing to swap to reserve might put less demand on the system letting the (collapsing fuel line) (stopped up cap vent) (slightly restricted fuel flow into bowls) and then refueling at first possibility to start the sequence over again.......

Theres my shot in the dark.....

It Could Happen!

[motoman]

fuel starving?

Thanks T.C and dale_1..........I presume cap vent is in the tower lid?............fuel lines are new as I replaced them last year and cris-crossed them adding a couple in-line conicial filters. Lines are long enough to remove tank, flip around backwards, hook up fuel lines on Prime when syncing carbs. Also took petcocks apart, cleaned, stretched spring just ever so little as diaphram wasn't seating good, fine emory and polished seats, dialectic grease on Orings and gasket sealing portion of diaphrams. Using my petcocks in a replacement tank that that came spotless clean with no rust at car wash, cause paint and grafics were nice, it has been working well for several months now. So what happened the other day just kinda has me baffled for the moment. Tank is full now, and I do notice that a 'roll-on' from 50-60mph is a little more precise and better when petcocks are in RESERVE as opposed to ON. This is the Standard with dual diaphrams.

[DiverRay]

I would change the float level by 1 mm. If you had just a little more fuel in the bowl, you probably would NOT have any more problems. It's a real PITA, but worth the trouble to get it "just right", have it running well, and still get good MPG.

[mason79]

i had the same problem, but at precisely at the reserve level, giving the impression the petciocks were the culprit, but in hindsight, i think with the partial clogged vent cap the fuel greater than reserve level was able to overcome the vacuum in the tank and the weight of the gas at below reserve level was insefficient, starving out the bowls.

i don't know if any persistant blockage allowing gas to flow to true empty would impair the performance of the engine via lean condition.
i took the bits and pieces apart on the cap and sdid my clean thing, be careful with the rubber seal mine was brittle and tore a little.
we'll it was top cats insight on an old thread that yet again bailed me out, and the bike is running like a top.

[TopCatGr58]

Hey Motoman,

The tank vent is in the gas cap itself, a very little washer with a very little hole in it, can get gummed and clogged, and NO VENTing action! You have to take the gas cap apart to get to it inside the cap!
T.C.

[motoman]

Well........what Mason and Ray said was kinda where I was headed........nice to have some input though. Ray, you either done some searching of some of my old posts, or got lucky!...........I'll give ya the benifit of the doubt though.........and yea. my float levels are just shy of an inch, I think 31/32" if I remember right, which I thought would do well at this altitude of 5,000ft..................most everything I ride goes more up than down from that. That is a suspect since I am running 112mains and should theoretically be able to run 107.5 mains. When I bought it new, it always puked a bit of black under hard accelleration, and it lived at 6,500ft. elev. then. At that time it did have stock jetting which was 110's across the board(there was no 'splitting hairs' with the 115's for 2 and 3 when this one came across the pond I guess). Thanks again for all the input............and carbs aren't really a PITA, as I can pull back airbox, remove carb bank, change mains and back on running in just under 45min................re-syncing, another 30min. getting them dead even across the mercury.

[dale_1]

new seal

Originally posted by mason79

i took the bits and pieces apart on the cap and did my clean thing, be careful with the rubber seal mine was brittle and tore a little.

If you need to (you probably already did, but just in case) replace the rubber seal for the gas cap you can use a Peerless Faucet Repair Kit or a slip joint washer Danco stock number 36649B 1 1/2" diameter.

you can get it:

Here

here,

or even here