The vacuum advance is off the side of the carb and is correct , the breather was connected to this pipe on the carb I assume this should got to the air filter actuator here There is only one port on this Then the two breathers tee’d together and fitted here That would leave a pipe off the back of the air filter with nowhere to go Sent from my iPhone using Tapatalk
no Question that the breather connected to the carb is wrong and is sucking fuel in - even worse now I’ve sorted the kink out. I can block this off for now and tee the breathers together and I think I’ll be good to go - it would just be nice to know where the other bits go
Look on the top of the air filter. There should be two connections sticking up from the thermostatic vacuum switch in the air box. One of these should be connected to the round actuator on the snout. The other should be connected to that port on the back of the carb. Purpose is to deflect the warm air pickup flap downwards when the engine’s cold, and when the thermo valve detects warm air in the airbox after the engine’s warmed up, moves the flap up by vacuum power to pick up air from the long snout inside the engine compartment. If nothing was previously connected to that rear port on carb, that would’ve upset the mixture.
That rear port is where the left hand breather was connected all the time , not something I’ve just done, like I say that breather had a joint and the flexible pipe was kinked - the auction from that port was partially blocked so wouldn’t have affected mixture too much ..BUT.. I think it was sucking fuel through every now and again causing my original rough running at missing from time to time when the fuel was filled up - disappearing when the level dropped . I’ve pretty much proved that by unkinking the pipe , coupled with the fuel tank being full it’s sucking fuel in like no tomorrow hence the really poor running now . I’ll replace the gasket tomorrow , blank that port off for now , tee the breathers into one and into the carb and then sort the warm air actuator after because somethings not right with how you describe it and what’s there mate - that actuator definately only had one outlet
The rear port on the carb is manifold vacuum, so it would’ve been sucking on the breather all the time. The thermo switch has two little spigots sticking up, with a metal clip on it, on top of the airbox. Sounds like yours isn’t connected.
@snotty is getting you there..... The breather pipes 1 from each side air vent/bulb should meet in the centre above the engine door and a t piece joins this to the air filter box...the braided hose pipe you have goes to a connector that you can't see to well further up the airbox..if you feel it should have 2 connector points here and a hose from here connects to your white narrowed point on the carb.
I agree - bit of work to do round the air box once I’ve done the rest . Fairly confident we’ve nailed the long running poor running issue ... if not I’ll drain half the tank off and carry on regardless . Thanks for everyone’s help
This must be one of the best variations of random pipework so far. It even includes a beautiful feedback system that whenever the engine is running at best efficiency, it dumps some extra petrol in to make sure it slows down a bit until it stops sucking as hard. But if you can get through the massive flat spot its alright flat out.
Ha ha , I can’t beleive I hadn’t noticed it before Mike , or anyone else that’s had their head in the engine bay... like I say it ran fine when the tank was only half full ish so I had no real cause for concern, although it niggled that there was obviously a problem somewhere. Anyway thanks to the late bay massive I think I’ve sorted it - fixed the kink in the breather - put a tee in the pipes and into the air filter , blanked the vacuum pipe on carb , rebuilt carb and been for a test drive - all seems absolutely Bob on .. happy as Larry
