Fuel tap/diaphragm

[corkdragon]

Hi all - a bit of background so ye know what's this about.....
Am starting to think my CB is showing the effects of her being left sitting for over 2 years before I got her! Latest problem I have been having is when I go above 80 km/hr she starts to struggle - power drops and most times she will cut out. In the beginning it was rare she got to point of cutting out so I put it down to restrictor kicking in. But more and more, she would lose power (like someone threw an anchor behind me), slowing down and cutting out - most times while still going 70km/hr+ around a corner/down the road - leaving me to pull in clutch and try get to side of road without getting into an accident.
I got her checked out few times - "she's fine" I was told. One mechanic put it down to a dent in one of the header pipes. I eventually got one mechanic to listen and check it - turns out the diaphragm had disconnected from the fuel tap and was partially blocking fuel going down into carbs hence the power loss/cut. So, he fixed it but wasn't sure she'd hold.
Fast forward 3 weeks and she's showing signs of the before again - coughing, power loss - not quite to cutting out (dropping a gear and reducing throttle helps keep her going) but no doubt will do again soon. So thing is - anyone know if there is any side effects from this - as in lasting damage to be had? I can source a replacement part but not sure when I can afford to get/fit it. I have a weekend of biking planned for next week (approx 1300km I aim to be cover - so if anyone is around Donegal/derry/belfast give me a wave!).
Any tips/advice I would greatly appreciate it!
a rather confused/frustrated biker from Cork

[Superjack44]

Have you checked for the tank breather pipe for a blockage.
Try this, run the bike until you can hear/feel the bike struggling then open the fuel cap if you hear an inrush of air then the tank breather pipe is probably blocked, the breather pipe can be found under the tank its the smaller bore of the two rubber pipes that connect to the two pipes at the rear of the tank.
Disconnect the small rubber pipe and ensure you can blow through it if you cant its blocked clear it.
If you can blow through the rubber pipe then try and blow back into the tank (this is what was blocked on mine) I pushed a piece of broken bicycle boden cable through it when it met the obstruction I twisted and pushed at the same time until it finally cleared the obstruction.
This pipe must be clear so the tank can breathe if it cant breathe then the petrol flow will be restricted causing symptons you describe.

[corkdragon]

cheers thanks - will do on next day off. will hopefully be a simple fix :) Can't take anymore bad news

[whiskers79]

I took the vacuum diaphragm out of my petrol tap, the damn things are a PITA, and I'm used to turning the petrol on and off myself anyway.