Sq4 MKI timing case breather

Singles, twins and fours.
Gui.dorey
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 114
Joined: Tue Sep 05, 2017 7:42 pm
Contact:

Sq4 MKI timing case breather

Postby Gui.dorey » Sun Sep 01, 2019 5:47 pm

Hello everyone,

Does anybody know the size of the banjo bolt used at the back of the timing case as a breather? is it a 3/8"?
I need to find a new banjo fitting for it.

Thanks in advance,
Gui

peterR
Posts: 24
Joined: Mon Feb 08, 2016 10:58 pm
Contact:

Re: Sq4 MKI timing case breather

Postby peterR » Sun Sep 01, 2019 10:06 pm

Hi they are availible from Draganfly if that helps

Banjo bolt, timing case breather 2107-37

Peter R

Gui.dorey
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 114
Joined: Tue Sep 05, 2017 7:42 pm
Contact:

Re: Sq4 MKI timing case breather

Postby Gui.dorey » Mon Sep 02, 2019 6:04 am

The banjo bolt I have. It’s the fitting and pipe I need replacing, and that they don’t have. But should be a standard fitting, thar’s why I wanted to know the exact dimension.

peterR
Posts: 24
Joined: Mon Feb 08, 2016 10:58 pm
Contact:

Re: Sq4 MKI timing case breather

Postby peterR » Mon Sep 02, 2019 9:10 am

Sorry miss read your post. Its damn hard to pull out once the bike is assembled but it looks like a standard banjo with a length of copper pipe (well atleast mine was) that tucks in close/tight to the crankcase and engine mount and points down towards the ground. For what its worth the part number is 2099-37. If you have a look at Draganfly's sq4 bottom end you can just see a picture of it behind the twin oil lines. So if you have the bolt then you should be able to workout the banjo size and solder in a piece of copper pipe for the tail and bend and fit.

Sorry that the best i can do, i'm flatout seeing it on the bike.

User avatar
simon.holyfield
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3529
Joined: Mon Oct 17, 2011 11:16 pm
Location: Norfolk
Contact:

Re: Sq4 MKI timing case breather

Postby simon.holyfield » Mon Sep 02, 2019 10:10 pm

It's probably a BSP thread. Can you get a caliper on the OD? I think it's 1/4" BSP but I'd check first.
cheers

Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'78 CX500
http://ariel-square-four.blogspot.com

Gui.dorey
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 114
Joined: Tue Sep 05, 2017 7:42 pm
Contact:

Re: Sq4 MKI timing case breather

Postby Gui.dorey » Tue Sep 03, 2019 3:38 pm

It’s definitely larger than 1/4”. I don’t think I can get a caliper in there, though. I believe it’s 3/8” but I wanted to be sure before trying to disassemble it.

User avatar
Bob.Murphy
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 883
Joined: Thu Nov 29, 2012 10:32 pm
Location: Kirkliston, on the West side of Edinburgh.
Contact:

Re: Sq4 MKI timing case breather

Postby Bob.Murphy » Tue Sep 03, 2019 6:49 pm

Could it be the same as the one from my '58 'VH' ??

DSCN9014.JPG


DSCN9015.JPG


The hole in the Banjo Union = 0.524 inches.
Banjo Union Head Diameter = 1.002 inches.
Copper Pipe diameter = 0.300 inches (or thereabouts - its a bit distorted after all this time).
Banjo Bolt Across the flats = 0.711 inches.
Banjo Bolt stem length = 0.857 inches.
Banjo bolt Thread Length = 0.527 inches
Banjo Bolt Thread Diameter = 0.512 inches (Remember its old).
Banjo bolt Thread TPI = 19 TPI. (= 1/4 BSP - 19 x 0.518" major diameter).

(Remember that BSP sizes are a bit odd - they are quoted a lot smaller than they appear !).

Probably not the same at all, but you never know :? .

Bob.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH

User avatar
simon.holyfield
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3529
Joined: Mon Oct 17, 2011 11:16 pm
Location: Norfolk
Contact:

Re: Sq4 MKI timing case breather

Postby simon.holyfield » Tue Sep 03, 2019 8:12 pm

Gui.dorey wrote:It’s definitely larger than 1/4”. I don’t think I can get a caliper in there, though. I believe it’s 3/8” but I wanted to be sure before trying to disassemble it.


I think it's a pipe thread. The 1/4 relates to the size of the pipe it connects, not the OD of the thread.
cheers

Simes

'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'78 CX500
http://ariel-square-four.blogspot.com

Gui.dorey
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 114
Joined: Tue Sep 05, 2017 7:42 pm
Contact:

Re: Sq4 MKI timing case breather

Postby Gui.dorey » Tue Sep 03, 2019 9:20 pm

Bob and Simes,
Thanks. That sounds about right. I used an 8mm pipe to fit inside the banjo bolt inside the timing case when I did the mod to get the breather opening towards the area of the cam sprocket. 8mm is about 0.32” which matches the pipe bob measured.

So I should get a banjo union for a 1/4” bolt, if I understood correctly? Imperial dimensions are a bit confusing sometimes...

JohnnyBeckett
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 312
Joined: Sat Jul 07, 2018 5:39 pm
Contact:

Re: Sq4 MKI timing case breather

Postby JohnnyBeckett » Tue Sep 03, 2019 11:08 pm

a 1/4" b s p is .518 of a inch so it is bigger then a 1/4" bst or unf


Return to “Four stroke”

Who is online

Users browsing this forum: No registered users and 5 guests