On Sun, 9 May 2021 13:13:10 -0700, The Real Bev wrote:
> The previous ham-fisted owner of my Ducati somehow managed to make the
> round part of the Dellorto where the cables come in oval.
If you're talking about the cap:
I really wonder how this could ever happen. This is cast metal after all.
It's quite simple to ovalize the hoses though:
e. g. if you route them off the cap in an awkward direction and then the
gas tank rubs/presses against it. Can happen with the PHM40 in my KTM 620,
too. The tank was made out of HDPE (polyethylene plastic) by a company
contracted by KTM who originally produced watering cans. What could
possibly go wrong?
Well, the mounting flange for the fuel tap for example. All serious bikes
have a metal plate with threads cast in there so the surface does not bend
and warp. Not the KTM. Consequentially, the rubber O-rings don't see a
flat surface after a while and the whole POS starts to leak. You would be
tempted and just tighten the wood screws a little bit more, but that is
the moment you rip out the threads from the two blind holes cast into the
I then drilled out the entire thing, cut an aluminum plate with threads and
through holes for the fuel sieves to fit from the inside of the tank and
sealed everything with nitrile O-rings, aluminum screws (mind the
electrochemical series!) and copper washers. Worked like a charm. Still
works like a charm.
KTM, however, also managed to spoil the quality of the potentially single
japanese part on the bike, the fuel tap itself. This has some rotary slide
valve inside (plastic as well) that wears into the cast metal outside.
While you can always stop leakages to the outside with new o-rings, that
thing never shuts off completely: No use draining the carb if you put the
bike away for winter, because the bowl will fill ever so slowly anyway.
Which is bad for the float needle, that tends to jam open from time to
Yeah, and before you say "Just leave the damn carb drain bolt open and
route the hose into some container!"...: The particular PHM40 model KTM
chose doesn't have this. Check out:
There's just this big SW21 central screw that keeps it all together.
So your best option is to pull the fuel hose and plug it.
> I looked at some of the Dellorto websites. WTF happened to the
> apolstrophe? And apparently they don't make the one I used any more.
> Hey, it was a 1960...
You could probably fit a very similar one. Question is: Why would you use a
Dellorto if there's much better stuff from Mikuni? The TMR...
... might be a bit big and also on the expensive side, but quality wise,
it's top notch.