yamste Posted September 5, 2011 Share Posted September 5, 2011 Hi all' just done a carb rebuild on my 1986 FJ 1200 . New needle jets and needle seat o rings together with a full clean and float check. Ive replaced the petcock diaphram and thought i had done the job to stop the fuel leaking out the overflows but its still leaking out one overflow which is confusing me ...surely the diaphram should be stopping any flow to the carbs if the bikes not running seemingly working of the vacuum effect and the new o rings should also be stopping any fuel getting past . Only thing i thought is seats not sealing properly by some dirt from the tank but i fitted an inline fuel filter to stop this happening. Any ideas folks ...had the carbs off 15 times or more Link to comment Share on other sites More sharing options...
Moderator Airhead Posted September 6, 2011 Moderator Share Posted September 6, 2011 Hi all' just done a carb rebuild on my 1986 FJ 1200 . New needle jets and needle seat o rings together with a full clean and float check. Ive replaced the petcock diaphram and thought i had done the job to stop the fuel leaking out the overflows but its still leaking out one overflow which is confusing me ...surely the diaphram should be stopping any flow to the carbs if the bikes not running seemingly working of the vacuum effect and the new o rings should also be stopping any fuel getting past . Only thing i thought is seats not sealing properly by some dirt from the tank but i fitted an inline fuel filter to stop this happening. Any ideas folks ...had the carbs off 15 times or more 15 times duhh thats frustrating. I would think you need to sort out that vacuum tap first, is there any way you can pull off the fuel to carbs pipe to test it for leaking? alas I have no experience of working with these things. as for the carb it must be either crud in the needle valve leaking float (give it a shake) wear on the needle valve a n other? Can I give you a tip..mention the bike model in the topic title when asking for help...much more chance of getting other owners to read it I'll do it for you ...Paul Link to comment Share on other sites More sharing options...
yamste Posted September 7, 2011 Author Share Posted September 7, 2011 Ok thanks paul New needle valves were put in , i have pulled the carbs again and re adjusted the float heights....i did a mock up fuel pipe to the carbs while the tank was off and no leaks, re installed the tank and the carbs flood from from one overflow . A new diaphram was put in the petcock also . All very confusing although im getting use to taking the carbs off and stripped in 5 min There is what looks like an electronic fuel switch on the back of the petcock used for reserve and on via a switch on the side panel , wonder if this is causing a fuel vacuum issue if its not functioning properly.............? Link to comment Share on other sites More sharing options...
Preload Posted September 8, 2011 Share Posted September 8, 2011 So its either a 1TX or 3CV the electric reserve switch can go faulty try disconnecting it, both these models have a fuel pump and it shouldn't really pass any fuel when the ignition is off? Yours isnt a 36Y (1100) with a 1200 motor by any chance as these were gravity fed? Link to comment Share on other sites More sharing options...
yamste Posted September 8, 2011 Author Share Posted September 8, 2011 Hi, yes sorry its a 1TX . Cant see any fuel pump so must be gravity fed . Might be the electric fuel switch is at fault as i cant hear anything switching or moving when the switch is enabled . How would i be able to check to see if it is a 36Y . Cheers Link to comment Share on other sites More sharing options...
Preload Posted September 8, 2011 Share Posted September 8, 2011 The fuel pump is on the right hand side behind the side panel. Im fairly sure when Yamaha bored the lump to 1200 that's when they fitted the pump?? The frame number should start 1TX or 36Y what does the engine number say? Link to comment Share on other sites More sharing options...
yamste Posted September 8, 2011 Author Share Posted September 8, 2011 Just checked the frame number and it is a 1TX . Cant see any fuel pump though . I have taken the thrust pin out of the electric reserve on off fuel switch and disconnected the power to it also . Re installed the tank with fuel in and no leaks so far, i will leave overnight and fill in what happens ....taken the precaution or routing the overflow pipes into a jar just in case it floods overnight. Link to comment Share on other sites More sharing options...
Preload Posted September 9, 2011 Share Posted September 9, 2011 Okay Yamste, It must have been the 3CV they started gutting the pump on.. Link to comment Share on other sites More sharing options...
yamste Posted September 9, 2011 Author Share Posted September 9, 2011 Ok , so the bike was left overnight and for the first time there is no fuel leakage.....routing the fuel infeed pipe has become an issue cos i have fitted an inline filter but because of the tight fitting airbox theres hardly any room for the filter to sit without squashing the pipes around it. Think im going to just run for a while till im sure no more dirt is getting through then remove the filter ...noted that the fuel tap has a filter as well so that should stop nearly all particles getting through .The tank has been cleaned and flushed too. Hope i can ride it now instead of re building it Link to comment Share on other sites More sharing options...
yamste Posted September 9, 2011 Author Share Posted September 9, 2011 Update....i have taken the bike for a test ride seeing as there were no fuel leaks , the bike seems ok and pulls instantly off any throttle response . Could have been the electric on/reserve switch that was the source of the problem as now its disconnected . Hope this helps anyone with similar issues even if you have no FJ . Link to comment Share on other sites More sharing options...
Preload Posted September 10, 2011 Share Posted September 10, 2011 At lest its not leaking money anymore. Also remember your tank range will be less as the last 2-3ltrs will not be accessible. Link to comment Share on other sites More sharing options...
yamste Posted September 10, 2011 Author Share Posted September 10, 2011 Ok preload.....there is a fuel warning light on the dash but that seems a bit iffy at the mo although having the petrol tank cleaned and flushed should have sorted that, maybe the float in the tank is sticking ...wont know untill its full to the top . I am toying with the idea of fitting an old style on off fuel tap if i can find a similar fitment . Link to comment Share on other sites More sharing options...
Preload Posted September 19, 2011 Share Posted September 19, 2011 Been away Yamste, the fuel tap is not very accessible where its sited, you could try an inline tap. Link to comment Share on other sites More sharing options...
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