[Roadsters] screw thread size for hitachi carbs

[keith0alan at aol.com]

Hello all,

    As far as I know all 1600 carbs are 5x.75 pre ISO French standard metric.
I have never found anyone making them. Early 2000 carbs are the same. Late
2000 and Z carbs are ISO 5x.8 and are commonly available. There are a couple
of options. There is a number size screw quite close. .75mm threads are 33.8
tpi, .8mm is 31.75 tpi. The .75 hole can be tapped to .8 . You loose some
material but it does work. What I do is take the original screws and lightly
tap the head to push the metal back into place then tap a new phillips bit
into the recess to reform the head. A little fiddly but it works. Carefully
cutting a flat slot with a hack saw is an option but pretty far down the list.
Always take good care of your original screws using a proper fitting screw
driver. Some penetrating oil and a little heat will help loosen them. I will
also grab them with a tiny pair of vice grips. This will mark them up a little
but saves the screwdriver recess.

keith williams


-----Original Message-----
From: ppeters914 <ppeters914 at comcast.net>
To: Datsun Roadster List <datsun-roadsters at autox.team.net>
Sent: Sat, Jul 6, 2013 1:01 am
Subject: Re: [Roadsters] screw thread size for hitachi carbs


Good luck, but.....

The headlight retaining screws on the 411 are 4mm with that odd .75 pitch. I
checked with Tacoma Screw, Maryland Metric, and several others. They don't
exist.

Googling found one reference to an old (WWII?) French rifle part.

Maybe Ztherapy?

Pete
Sent via BlackBerry by AT&T

-----Original Message-----
From: "Gordon Glasgow" <gsglasgow at comcast.net>
Sender: datsun-roadsters-bounces at autox.team.netDate: Fri, 5 Jul 2013 22:02:08
To: 'robert williams'<wilrobasy at hotmail.com>;
<datsun-roadsters at autox.team.net>
Subject: Re: [Roadsters] screw thread size for hitachi carbs

Disclaimer: These are the sizes I measured on my 2000 SU's, but I don't
think the 1600 ones are necessarily different. Oddly, my parts manual lists
the same part number for both the piston pot screws and the float bowl cover
screws on the 2000 SU's (contradicting what I just measured), but different
numbers for those two screws on the 1600.

The screws for the piston pots are 5mm x 0.8 pitch. That's pretty standard.

The screws for the float bowl covers are 5mm x 0.75 pitch, which is
definitely not standard. I believe it's called a French Metric. You might be
able to special-order them through a place like Tacoma Screw Products if the
vendors don't have them.

Gordon Glasgow

-----Original Message-----
From: datsun-roadsters-bounces at autox.team.net
[mailto:datsun-roadsters-bounces at autox.team.net] On Behalf Of robert
williams
Sent: Friday, July 05, 2013 7:37 AM
To: datsun-roadsters at autox.team.net
Subject: [Roadsters] screw thread size for hitachi carbs

Hello List,

The ground up resto is in the home straight so looking to finish up a few
smaller items.
Does anyone know the thread size of the following screws:
4 x phillips head screws that fasten the top of the float bowls on the
hitachi carbs 4x screws for the piston pots on the carbs for an early (1966)
1600 low screen.

I thought they may be 11/32 unf but alas they seem to be a smaller.
The tops of my screws are burred and battered from years of abuse so thought
I would replace them.

regards,

Rob
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