Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: JamesH on October 23, 2016, 07:03:15 PM

Title: CB750 Oil Control Orifice (early diecast K0).
Post by: JamesH on October 23, 2016, 07:03:15 PM

Hi guys. I'm on the hunt for some unicorn shit...

Need a pair of oil control orifices / jets for an early 750K0 head. Anyone know of anyone who has there or (long shot) even reproduces these?

Pics below...

(http://uploads.tapatalk-cdn.com/20161023/f43dd5d6a7c200c47b8975f4e8a05118.png)

(http://uploads.tapatalk-cdn.com/20161023/53919b1bc755d75f2bd4c945e393a443.png)

(http://uploads.tapatalk-cdn.com/20161023/1540ac42c5e90eadc2a16c9ff8a87e08.jpg)

(http://uploads.tapatalk-cdn.com/20161023/7ac4be2c3a3d9b355e00b4ea78e50a27.jpg)

(http://uploads.tapatalk-cdn.com/20161023/6023db9a4b2ad11c7a0981218f2426f5.jpg)

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: RGP750 on October 23, 2016, 07:17:36 PM

If You want to risk sending me the two types i'll do some fishing
about having some made.

Title: CB750 Oil Control Orifice (early diecast K0).
Post by: JamesH on October 23, 2016, 07:25:15 PM

Sorry Rich, should have been clearer, it's one type, just photographed from both sides..I'll see if Graham doesn't mind popping the one we have in the post to you...

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: AshimotoK0 on October 23, 2016, 08:42:38 PM

I think you will need to get the holes cut with a micro laser. I get tiny, perfectly circular holes cut in three sizes in the  s/steel foils used on a scanning electron microscope unit we make. One hole is so small you can't see it with the naked eye. I get them made via my mate in Cambridge ... I can get you the details if you wish Rich ..pretty sure someone on the USA forum was planning to have those made too. Must be later K0 ...mine just has a hole ...no removable jet whatsoever. Obviously, this had been debated before on here.

You could also sell that part to fit onto the spout of a dollies watering can  ;D ;D


update see here:

http://forums.sohc4.net/index.php?topic=154725.0

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: Phil k on October 25, 2016, 06:04:05 PM

Is that a 12238-300-300? I have one that I purchased in error a couple of years back. If you still need it.

Phil


Sent from my iPad using Tapatalk

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: JamesH on October 25, 2016, 06:15:00 PM

Hi Phil - could you send me a picture of it. If it looks like this I'll take it...:
(http://uploads.tapatalk-cdn.com/20161025/2160a63a4bd4e1ce5d15b3e2e073d75f.png)

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: Trigger on October 25, 2016, 07:05:36 PM

The part number should be 12238-300-000

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: JamesH on October 26, 2016, 09:10:42 PM

Quote from: Phil k on October 25, 2016, 06:04:05 PM

Is that a 12238-300-300? I have one that I purchased in error a couple of years back. If you still need it.

Phil


Sent from my iPad using Tapatalk

Phil - have sent you a Pm mate..

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: MrDavo on October 28, 2016, 03:32:42 PM

My K1 ones look like that from above, I can't see below to see if they have the watering can holes. How easy is it to get them out, as they don't respond to a gentle tug? Do I need heat?

I wouldn't mind giving them a clean out, I guess I could just clean then in situ by squirting brake cleaner through from above, followed by a blast of air.

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: JamesH on October 28, 2016, 03:47:17 PM

Yeah I'd be very very careful. Graham got mine out with Heat / a magnet but if they're well in there probably best left alone and try to flush them through in-situ...

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: Trigger on October 28, 2016, 05:49:52 PM

They have to come out to be cleaned. This is one of the main problems why the engine has no oil to the top end and the cam shaft snaps.
One way to test what jet are in the K1 is, to run a magnet over the jet. If it is the early type the magnet will pick it up as it is steel, the later ones are alloy ;)

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: MrDavo on October 29, 2016, 04:05:01 PM

My K1's quite a late number, so I wasn't surprised to find the jet isn't magnetic  :( If had been steel in alloy, heat would loosen it, as it is, it won't make a difference.

A blast of brake cleaner and air in a can all came out of the stud tunnel, with no visible crud, and the motor was freshly rebuilt, so I'll settle for that.

Title: Re: CB750 Oil Control Orifice (early diecast K0).
Post by: Trigger on October 31, 2016, 07:02:53 AM

They still have to come out to be cleaned, the alloy type come out very easy.