thesolidman1 Posted October 6, 2013 Report Share Posted October 6, 2013 Hi, I was just having a problem with gas pouring out the overflow on my '13. I found a very very small piece of aluminum in the cavity where the needle goes in the seat. It was hindering the movement of the needle. I got lucky finding it, it was the size of a small grain of sand. No problem now. I would reccomend a fuel filter also. Quote Link to comment Share on other sites More sharing options...
xeriotti Posted October 6, 2013 Author Report Share Posted October 6, 2013 ABOUT THE BIKE: Gave it less level, Problem solved, it runs almost vertical now.... BUT I want to leave something clear. about "Bending the tang" and how it affects the force in which the needle is pressed against the seat.... (Even when 0007 clearly affirmed it NEVER would ) Here we go... LEVERAGE, WILL NEVER CHANGE...If we reffer to the leverage itself as an isolated mechanism, asuming were talking about a second class lever, where the FULCRUM is the float axle, The LOAD is the needle pushing against the seat and the EFFORT is the floating hability of the float, that in fact... FLOATS in gasoline pushing up the needle... The described above is a fact. but theres one variable that affects the real world function of this mechanism. and thats how deep into the fuel is the float. That stablishes how much FORCE is the needle aplying to the SEAT....and if there is enough to actually SEAL TIGHT before it floods....Made a graphic to ilustrate... Quote Link to comment Share on other sites More sharing options...
dadof2 Posted October 6, 2013 Report Share Posted October 6, 2013 A couple of useful checks can be carried out 1) get a spare float bowl fixing bolt, drill it and fit a manometer tube to check the actual fuel level in the carb 2) Set the float height correctly and with the carb upside down fit a length of clear tube to the carb fuel inlet. Fill the pipe until the head above the valve is equivalent to a full tank of fuel to see if the valve leaks. Quote Link to comment Share on other sites More sharing options...
dan williams Posted October 7, 2013 Report Share Posted October 7, 2013 Unlike the Mikuni with its machined brass valve seat and Viton tipped needle the Keihin looks like just a steel needle on a machined surface in the carb body. One of the reasons I call the Keihin primitive. I'm a little suspicious of the seal this provides. The seal isn't a force issue either. The conical shape allows for the most opening with the smallest movement but again without a flexible sealing surface more pressure buys you nothing if there is dirt or a surface imperfection on either of the mating parts. 1 Quote Link to comment Share on other sites More sharing options...
billyt Posted October 7, 2013 Report Share Posted October 7, 2013 Mmmmmm. Kids and carbs............... 1 Quote Link to comment Share on other sites More sharing options...
0007 Posted October 8, 2013 Report Share Posted October 8, 2013 LOL, I give Clearly 30 some years of working in the industry and 15 years of working for a major manufacturer have led me astray Sometimes I refer to the times I have seen people cure the symptom and feel the have cured the cause simply cuz the symptom has gone away 1 Quote Link to comment Share on other sites More sharing options...
shyted Posted October 8, 2013 Report Share Posted October 8, 2013 (edited) 0007 and Danwilliams quotes are bang on. You cant infinately push something closed if it's as far closed as it can be . Think there's another problem there myself. Italian Quallity Control could be better as a good friend of mine just found out with his 1 year old Ducati 1198. Had running problems at low speed from new.Back to the dealers countless times on warrenty.Went to bike recentlyand no start.Battery charge down to 11.9 V .Turned out to be the regulator.£20 quid fix and countless software updates from the dealer without a real reason to have them. Find the problem to get a fix for the longterm. How annoying that must be with a new bike though ! Edited October 8, 2013 by shyted Quote Link to comment Share on other sites More sharing options...
billyt Posted October 9, 2013 Report Share Posted October 9, 2013 (edited) Not sure about the Keihin carb, But on the Mikuni the spring under the Viton tipped fuel shut off plunger is there to take care of the very issue Xerittio, Dan, 007 speak of. There are also two separate adjustments on the tangs. One for travel and one for fuel level. This is the same adjustments regardless of make. Edited October 9, 2013 by billyt Quote Link to comment Share on other sites More sharing options...
dan williams Posted October 9, 2013 Report Share Posted October 9, 2013 (edited) I'm inclined to think the spring under the needle on the Mikuni is partially to absorb energy and keep cumulative impacts from self adjusting the float level tab for you. Edited October 9, 2013 by dan williams Quote Link to comment Share on other sites More sharing options...
xeriotti Posted October 10, 2013 Author Report Share Posted October 10, 2013 I'm inclined to think the spring under the needle on the Mikuni is partially to absorb energy and keep cumulative impacts from self adjusting the float level tab for you. Thats correct nut again, spring tension is not linear un its full compression range.... Quote Link to comment Share on other sites More sharing options...
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