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PHBH Pilot Jet pitch size

PostPosted: Fri Oct 01, 2021 12:23 pm
by martyn dwane
Anyone know what pitch a M5 Pilot jet is for the PHBH range, I know it`s M5 size but it`s not M5 x.8 (standard Pitch) and looks to be finer tham .75

Re: PHBH Pilot Jet pitch size

PostPosted: Fri Oct 01, 2021 5:10 pm
by Warkton Tornado No.1
The pitch looks like 0.5 mm, but that was just a quick check. i think there is only one 'standard' fine M5 thread in any case: M5 x 0.5

Re: PHBH Pilot Jet pitch size

PostPosted: Sat Oct 02, 2021 9:18 am
by martyn dwane
Thanks WT, any chance of checking before i buy a set of Taps?

Re: PHBH Pilot Jet pitch size

PostPosted: Sat Oct 02, 2021 11:38 am
by Storkfoot
Image

That’s a 55 pilot straight out of a PHBH30 and it is m5 x 0.8.

Re: PHBH Pilot Jet pitch size

PostPosted: Sat Oct 02, 2021 11:41 am
by martyn dwane
Thanks Storkfoot.
I already have metric coarse taps and dies.

Re: PHBH Pilot Jet pitch size

PostPosted: Sat Oct 02, 2021 12:15 pm
by Warkton Tornado No.1
:oops:

I haven't had the chance to check, but the jet I grabbed from the bench was possibly not a Dell'orto which explains any confusion.....I hope :roll:

However, I will check later today, to be sure.

Re: PHBH Pilot Jet pitch size

PostPosted: Mon Oct 04, 2021 11:19 am
by martyn dwane
im in a quandary now. just read this on Eurocarbs ebay page.

These are all genuine DellOrto jets flow tested at the factory.

Beware of cheaper jets without the “INC” diamond logo which may not be the correct size.

Thread size M5 x 0.75mm

Used as idle jet on many Dellorto carburettors and main jet on SHA, VHB CS & CD and many early Dellorto carburettors.

Re: PHBH Pilot Jet pitch size

PostPosted: Mon Oct 04, 2021 11:55 am
by Storkfoot
I did spend several minutes comparing the .75 to the .8. Neither seemed an absolutely exact match but the .8 seemed very, very close. That said, it could well be .75 as they are a minuscule amount apart.

Maybe another opinion from someone with exceptional eyesight :geek: :geek:

It is, of course, highly likely that Eurocarb are a more informed source than me :)

Re: PHBH Pilot Jet pitch size

PostPosted: Thu Oct 07, 2021 11:07 pm
by Warkton Tornado No.1
I apologise for not being able to confirm the pitch of the M5 jets that Dell'Orto produce, but I cannot find my metric thread gauges, only my Imperial set.

There is an 'M5 x 0.75' though the difference in pitch (0.05 mm) or two thou" is so minute that I would be tempted to use the widely available M5 x 0.8 if it were just a matter of cleaning up an existing hole, particularly as it is likely only the start of the hole will need any correction. If that is the case, a tapered tap - not plug - would tidy up the hole enough to allow jets to be re-inserted.

Re: PHBH Pilot Jet pitch size

PostPosted: Fri Oct 15, 2021 1:41 pm
by martyn dwane
thanks all.