Posted by seabreeze on February 9, 2008, 7:17 am
Hi. My xv535 wouldn't start the other week. It was taking a little
while for the front cylinder to fire the last few times I started it.
Rear cylinder was fine.
I've taken off the carbs and cleaned the jets, checked the float
needle valve is working, and generally it all seems ok. Couldn't get
into the diaphram part because my torx key wouldn't fit the special
screw. I'm not sure I really know what the problem is.
Fuel supply seems ok, and the plug was firing fine. Any ideas
appreciated before I give up and start calling mechanics.
Also intending to check the tappets while the carbs are out.
Posted by . on February 9, 2008, 9:00 am
> Hi. My xv535 wouldn't start the other week. It was taking a little
> while for the front cylinder to fire the last few times I started it.
> Rear cylinder was fine.
If you pull the spark plug lead loose and start the engine with the
plug cap just sitting on the threaded end of the spark plug, and then
hold the cap 1/4 of an inch away from the plug and the engine starts
firing on that cylinder, it means the idle mixture is too lean on that
cylinder.
Posted by The Older Gentleman on February 10, 2008, 11:20 am
> Thanks for the response. The reason I suspect fuel/carb is that I took
> the plug out, resting it against the side of the cylinder and it was
> firing fine. The breakdown people I called also put a plug tester on
> the ht lead and it was fine according to that. There was no smell of
> fuel coming from that cylinder with the plug out, after having been
> trying to start it - hence the reasoning that it might be something to
> do with the carb as fuel was definitely coming up the line leading the
> the carbs as evidenced by removing the end of the fuel line and
> turning the engine over.
OK, right, that sounds like a decent enough ignition check, so it
probably is a carb issue.
>
> What's really annoying is that to check the float height, I have to
> put the carbs back, then fill with fuel, and if incorrect, get them
> out again and adjust the float tang - and it isn't easy to get the
> bloody things out in the first place!
I doubt it's a float height problem, mind. They don't suddenly bend
themselves into a position where they block the flow. A scrap of dirt
blocking the movement, maybe. Or a blocked in-line fuel filter to that
partiicular carb, if fitted.
--
BMW K1100LT Ducati 750SS Honda CB400F & SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
chateau dot murray at idnet dot com
Posted by seabreeze on February 10, 2008, 12:11 pm
On 10 Feb, 16:20, totallydeadmail...@yahoo.co.uk (The Older Gentleman)
wrote:
> > Thanks for the response. The reason I suspect fuel/carb is that I took
> > the plug out, resting it against the side of the cylinder and it was
> > firing fine. The breakdown people I called also put a plug tester on
> > the ht lead and it was fine according to that. There was no smell of
> > fuel coming from that cylinder with the plug out, after having been
> > trying to start it - hence the reasoning that it might be something to
> > do with the carb as fuel was definitely coming up the line leading the
> > the carbs as evidenced by removing the end of the fuel line and
> > turning the engine over.
> OK, right, that sounds like a decent enough ignition check, so it
> probably is a carb issue.
> > What's really annoying is that to check the float height, I have to
> > put the carbs back, then fill with fuel, and if incorrect, get them
> > out again and adjust the float tang - and it isn't easy to get the
> > bloody things out in the first place!
> I doubt it's a float height problem, mind. They don't suddenly bend
> themselves into a position where they block the flow. A scrap of dirt
> blocking the movement, maybe. Or a blocked in-line fuel filter to that
> partiicular carb, if fitted.
> --
> BMW K1100LT Ducati 750SS Honda CB400F & SL125
> GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
> BOF#30 WUSS#5 The bells, the bells.....
> chateau dot murray at idnet dot com
Have checked the operation of the float needle valve on the carb of
the cylinder that wasn't firing and that seems to be fine, nothing
blocking the fuel line feed in (it's a shared feed with just a simple
tube connecting both carbs), it opens and closes ok. Cleaned it with
carb cleaner, checked the jets I could get to (as I don't have the
torx tool to get into the daiphragm side of the carb) and cleaned them
with carb cleaner. The fuel filter is further back towards the tank.
The guy who came from the breakdown company, thought it might be a
fuel shut-off valve. At the front of the carb near the bottom there is
a small device with two electrical wires leading away from it, which
is what he thought this was. I can't find it in either the haynes or
clymer manuals I have (though they are rather old versions), but it
seems some kind of carb heater device was fitted to some models of
this bike. Rather than unscrew it to check I would need to confirm
this first. Can't seem why there would be a shut off device on this
but not on earlier models of the bike. It's also on the 'wrong' side
of the carb, as the fuel feeds in on the opposite side.
Posted by The Older Gentleman on February 10, 2008, 12:39 pm
> The guy who came from the breakdown company, thought it might be a
> fuel shut-off valve. At the front of the carb near the bottom there is
> a small device with two electrical wires leading away from it, which
> is what he thought this was. I can't find it in either the haynes or
> clymer manuals I have (though they are rather old versions), but it
> seems some kind of carb heater device was fitted to some models of
> this bike. Rather than unscrew it to check I would need to confirm
> this first. Can't seem why there would be a shut off device on this
> but not on earlier models of the bike. It's also on the 'wrong' side
> of the carb, as the fuel feeds in on the opposite side.
Could be a carb heater, yes....
Sudden thought.....
It hasn't got one of those dreadful Yamaha electric reserve switches,
has it? They always give trouble. Silly question, but the fuel tank *is*
full, right?
--
BMW K1100LT Ducati 750SS Honda CB400F & SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
chateau dot murray at idnet dot com
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> while for the front cylinder to fire the last few times I started it.
> Rear cylinder was fine.