Having lots of fun lately, barely made it back from Bepton in Sussex due to engine on the B11 cutting out. I had to remove some water from the fuel prior to the trip due to the cap drain blocking (again). Last time this happened the fuel filter blocked shortly afterwards and this had happened again. Thinks…why should a small amount of water in the fuel block the filter? Discussing it with a fellow ex water treatment mate, who had been an engineer on merchant vessels, revelation came. Any water separating out and lying in the tank will start to breed bacteria, even in petrol or oil, this explains the jelly like gunge found on the pump inlet filter. The tank and pump were emptied and cleaned with some chlorine tablets to delay any recurrence, tank flushed with fresh fuel, filter changed and the bike now starts and runs fine. Have sectioned the old filter and it looks like the back end of a sewer pit in there. Now I only have to sort out why the 30A fuse, on the charging side by the battery, is trying to cook itself!
Cheers, Gerry.
The filler overflow drain blocking is difficult because the exit under the tank follows a convoluted route from the tank and the diameter is so narrow. I never had the courage to shove a drill up it because of the windy path and concerns of penerating the tank .What’s the best way to fix it? I thought a bit of water in the tank might just evaporate? be so dilulted it wouldnt be a probelm?
Use a inner cable from a bicycle brake cable use part of the outer cover to allow to rotate. One end in a slow battery drill other end into overflow. Work the cable into overflow being careful as you go. Will clear it …
Might find thick goo or lime scale have both in mine…wits2014-06-15 00:56:44
Sounds good but does this rely on the block being in the 1st inch or so. I found pokeing wire in either end after 3 inches of wire inserted you hit a solid block like the path does a sharp turn. Hence the assumption the design engineer put narrow tight turns in the path from the filler to the exit. Can a bicycle cable inner negociate those turns?
Yes the cable will go all the way through, rotate cable in same direction as twist in cable. Allow cable to rotate as slow as possible in drill and slowly use a pinch/push allow cable to rotate between finger thumb method. Maybe a little lubricant sprayed into either end may help.
Once through rotated cable oposite direction helps to clear tube…
Worked for me usual t&c’s … 
If you wanted to clear the tank vent doesm that have to be done from underneath?. It is the other breather tube on the underside but not sure where the top is inside the tank near the top?
The 3 times I have done it , has been from underneath. One goes into tank other will be blocked or if lucky you will see hole under the lock ing cap
The breather goes from the hole beside the filler opening to a 120 degree (ish) elbow, then through the tank via a clear pipe to another similar elbow, thence to a metal nipple mounted on the centre hollow of the tank. Blockages usually appear at this nipple, it is worth running a 3mm drill through the nipple but no more than 10mm in.
Cheers, Gerry.
how do u change the fuel filter. I can see the ufi filter at Guzzibits can be bought with 2 new clamps. Can the clamps be crimped with snout nosed pliers. How do u access the filter it’s in the tank?
Hi Nelgra, the sequence for changing the filter is:
Syphon any fuel from tank, remove side and front panels below the tank, disconnect breather and drain pipes from T piece below left rear of tank, disconnect 3-wire connector from pump. Unbolt and lift rear of tank, it can be blocked up with a piece of wood. Turn on ignition and turn engine over for a few seconds to depressurise the fuel line, would be best to disconnect battery negative after this. Compress grey ring on connector while pushing on pipe, this can be an awkward operation, impossible if line not depressurised. Once connector is released, raise rear of tank and remove backwards, front trim will tend to catch and must be carefully manouvered. Upend tank onto a soft surface to avoid scratching, the pump is held by 6 x 7mm bolts, 2 of which hold the drain and breather pipes, with these undone, the pump can be lifted and wiggled out. The filter is held by crimped clips which must be levered open or carefully cut and discarded. Suppliers of filters usually do suitable small round edged jubilee clips to replace these. Ensure filter is installed in the right direction, (note, UFI filters have an arrow on the side pointing the WRONG way, go by the IN and OUT stamped on the ends). While you are there, worth checking the inside of the tank for debris and also cleaning the nipples on the breather and drain lines, make sure the right length pipes go back on the nipples. Replacement is a reverse sequence except for reconnecting battery last, also worth putting a thin smear of silicon grease on the pump flange. Also note, it is not unknown for the plastic tanks to expand so the fixing bolt hole does not line up, this requires some judicious levering to get it back in line. Hope this helps.
Cheers, Gerry. Duffo2014-06-16 15:13:46
Great write up. Gotta to do it now.
Here’s some pics of the Breva 750 procedure, which may assist:
Breva 750 fuel filter replacement
Guy’s, I just want to say a big thank you for all the above advise and info . I have just had to unblock the drain tube on my Nevada, what a pig of a job. As a keen cyclist myself, I always keep spare’s for my cycles including spare innner and outer gear and brake cables - I found the brake cable inners too thick to negotiate the bends in the tubes so used a length gear cable instead. I needed 400mm of cable to go all the way through the tank tube!
Glad to be of assistance
Blimey no wonder the hoses can have problems, why can't the filter be outside the tank.