Author Topic: Missing crankcase spigot (Read 1598 times)

Jonm99 · « **on:** January 03, 2023, 04:16:45 AM »

Hi guys,

Just got my bike back from the mechanic after some repairs, including paint corrections to the engine bay. Long story short, I noticed that the oil hose that from the bottom of the oil tank was not connected to anything (as far as I recall, it is supposed to be connected to the bottom crankcase spigot). Upon further inspection, I realized that the crankcase spigot is missing altogether! Was it broken off or simply removed for the paint job? I don't know... question is, is this a replaceable part? If so, can someone please send me a link to part number (I could not find it on the part fiches...). Attaching a pic of the connection area in question as well as a reference pic of what should be there (taken from this form).

Thanks!
Jonathan

newday777 · « **Reply #1 on:** January 03, 2023, 05:35:17 AM »

I've never seen one missing before nor can I see it on the parts fiche.
I'm not where my motors are so I can't check to see if the nipple on the valve cover is the same size.

Did you ask your mechanic why it's missing and what he's doing about it?

PeWe · « **Reply #2 on:** January 03, 2023, 06:30:27 AM »

Is it still in the hose once connected to it?

BenelliSEI · « **Reply #3 on:** January 03, 2023, 06:36:57 AM »

Is the engine out, or in the bike?

ekpent · « **Reply #4 on:** January 03, 2023, 08:47:42 AM »

Is that a chunk of it I still see in the lodged in the hole ? Maybe got broke off at some time when and if the engine was out of the frame.

PeWe · « **Reply #5 on:** January 03, 2023, 10:02:33 AM »

I have a vague memory that I have seen one sitting loose in a case somewhere. Probably at a friends garage stacked with cases, cylinders , heads and other mostly CB parts.

Thread the hole and fit a pipe in correct size. Loctite thread locker.
It is a chance if not open the case so burrs can be taken care of if falling inside.

Pipe thread is conical. There are hose fittings for it.
Engine type not mentioned.
This should fit a CB750 pre K6. Maybe K6 and later too which has a thicker pipe.

A fitting like this. You need an NPT 1/8 tap
https://www.ebay.co.uk/itm/272173007624?hash=item3f5ec68308:g:-aoAAOxyzi9SdXKe

Don R · « **Reply #6 on:** January 03, 2023, 10:54:42 AM »

Grease the tap and pressurize the engine with the exhaust from a shop vac?

BenelliSEI · « **Reply #7 on:** January 03, 2023, 12:46:15 PM »

Last time I did this (on someone else’s daily ride) I just found one in my fittings bin (looked like PeWe’s photo), that just scraped into the hole. Cleaned every thing really well (brake Kleen), packed the threads with freshly mixed JB Weld (the style that comes as two blocks of “plasticine” like putty) and forced it in there. Let it set, overnight. Still in place, years later.

Don R · « **Reply #8 on:** January 03, 2023, 12:52:26 PM »

Bingo! ^

BenelliSEI · « **Reply #9 on:** January 03, 2023, 01:24:28 PM »

Quote from: Don R on January 03, 2023, 12:52:26 PM

Bingo! ^

Sometimes (not always), the simplest solution is OK.

PeWe · « **Reply #10 on:** January 03, 2023, 10:19:03 PM »

JB Weld is really good!

I bought some packages after I read its shelf life is 25 years or more.

Jonm99 · « **Reply #11 on:** January 04, 2023, 12:24:13 AM »

Thanks guys.

The missing bit is not inside the open end of the hose unfortunately.
Don't think the mechanic has a clue to be honest...
As the engine is already in place and access is limited, I would be concerned with burs getting in the case as a result of tapping, but JB weld sounds like a good idea :-)
I am attaching an image I found of the original (my engine after rehauling it), it looks a bit different (as PeWe mentioned, maybe thicker as it is a later model). In terms of size, it's difficult to get in their with a caliper, but as far as I can tell, it's app. 8mm in diameter (maybe a touch more?) and 18mm or so in depth (measuring from the case inwards).
@PeWe - I have a K7, would the link you sent be for the right size still? Also, how much "extra diameter" do I need to account for the JB weld?
And last but not least, I am assuming that it is not a good idea to ride the bike until I fix this?

Thanks again!
J

BenelliSEI · « **Reply #12 on:** January 04, 2023, 05:39:29 AM »

Size the hole diameter in the case by reaching in with a drill bit. The largest that fits is your I.D. of the hole. The fitting does not to be threaded, even a large,plastic,double barbed unit will do. Visit your local big box home improvement store and check out the plumbing aisle. If you use a male pipe nipple (threads or barbs at both ends) cut off the engine end to match the case thickness + a couple of mm’s. Mix just enough JB to fill all the voids and seal it up nicely.

I would not ride with an open, unfiltered hole in the crankcase. Any oil/ vapour overflow from the tank breather hose, or oil bleeding out of the transmission case will end up on your rear tire.

PeWe · « **Reply #13 on:** January 04, 2023, 06:20:55 AM »

A hose must be fitted and routed correctly.
Oil will otherwise hit the rear tire......

Size more to fit the hose used.
My K6 had 1/2" ID hose between case and oil tank.

My K2 a little slimmer, maybe I use 8-9mm ID hose.

Jonm99 · « **Reply #14 on:** January 08, 2023, 02:07:56 AM »

Thanks again guys. The drill bit sizing was genius :-)

So now I have the exact size I need (indeed 1/8 inch on the engine side and 1/2 inch / 12mm on the hose side). Problem is, this seems to be none standard (largest barb tail for 1/8 npt is 10mm - same as PeWe sent). So...either drill a larger hole (really rather not do that) or find a hose that has a smaller ID on the engine side (10mm) than it does on the oil tank side (12-13mm)? Any other suggestions? I also came across a fitting adapter from 1/4 to 1/8, but than the whole setup starts to get quite big and ugly....

RAFster122s · « **Reply #15 on:** January 08, 2023, 02:51:48 AM »

Since it isn't in a pressure or heavy fluid flow you could use a small section of two hoses. One to fit the hose barb and then the the second hose over the first going to the catch tank/oil tank. A smaller transition to find an external diameter hose to fit inside your 1/2" ID and then size the nipple to fit the ID of the inner hose. Bit of sealant between hose sections after you rough up the outside of that inner section's OD and you have a serviceable solution.

PeWe · « **Reply #16 on:** January 08, 2023, 03:07:39 AM »

+3 for double hoses on crank spigot side.
Thin hose covering spigot to make it 12mm. Clamp will keep them both in place.

Another way is to find a 12mm tube with thread to fit the case. If it has a bulb in its outer end, hose will not glide off that easy.

Jonm99 · « **Reply #17 on:** January 08, 2023, 05:31:46 AM »

Ok - I think I got it now. Found a fitting at the local HW shop that was a little too big on the thread side (2.5mm or so) and a little too small on the hose side, the former was attacked by my angle grinder and the latter resolved with a pipe clamp (image attached). Fits snug on both sides now. Next step: JB Weld it in place and pray. Will report back in a few weeks if it holds (or not).
Big thanks again guys!
J

BenelliSEI · « **Reply #18 on:** January 08, 2023, 05:50:02 AM »

Looks good! Good Luck.

PeWe · « **Reply #19 on:** January 08, 2023, 06:35:05 AM »

Make sure that hose will not get a kink when connected to the oil tank.

Jonm99 · « **Reply #20 on:** January 11, 2023, 02:22:04 AM »

Guys - I feel like a jack**s! As I was installing this new spigot, I figured I would go over the routing of the hoses again... and realized that the spigot is NOT missing. It had a hose connected to it and on the other end to the atmosphere. The oil tank drain had another hose connected to it, also to atmosphere (which is why I though that open end was supposed to be attached to a "missing spigot"). Anyway, so where does that leave us.... with an extra hose and what looks like a (perfectly circular) hole in the crankcase (see pic), and a thread for a future owner of a CB with a missing spigot :-). Anyway, I don't remember if that hole was there originally or not - Does anyone know what that is, if it's supposed to be like that, and if not, what it should be plugged with, if at all?

Thanks again!
Jonathan

newday777 · « **Reply #21 on:** January 11, 2023, 04:43:52 AM »

You are missing the collection box/tank the hoses connect/dump into. It isn't necessary, just run the hoses so oil doesn't hit the back tire.....

BenelliSEI · « **Reply #22 on:** January 11, 2023, 06:04:56 AM »

Quote from: Jonm99 on January 11, 2023, 02:22:04 AM

Guys - I feel like a jack**s! As I was installing this new spigot, I figured I would go over the routing of the hoses again... and realized that the spigot is NOT missing. It had a hose connected to it and on the other end to the atmosphere. The oil tank drain had another hose connected to it, also to atmosphere (which is why I though that open end was supposed to be attached to a "missing spigot"). Anyway, so where does that leave us.... with an extra hose and what looks like a (perfectly circular) hole in the crankcase (see pic), and a thread for a future owner of a CB with a missing spigot :-). Anyway, I don't remember if that hole was there originally or not - Does anyone know what that is, if it's supposed to be like that, and if not, what it should be plugged with, if at all?

Thanks again!
Jonathan

Jonathan..... that hose is not from the oil tank drain. It’s a breather hose from the top, rear of your oil tank? It can just be vented to the atmosphere but recognize that if you over fill thetank, oil will come out of it. As noted, keep it away from your rear tire.

The hole that started this thread. Does it go into the transmission case or does it just lead into a recessed area in the top (it’s to drain that spot of any accumulated water)?

Little_Phil · « **Reply #23 on:** January 11, 2023, 07:27:32 AM »

The "hole" is visible on this pic from CMSNL:
https://www.cmsnl.com/honda-cb750k7-four-1977-usa_model495/crankcase-ass_11000405000/

Jonm99 · « **Reply #24 on:** January 11, 2023, 08:40:33 AM »

@BenelliSEI
My oil tank breather hose comes out from the bottom of the oil tank and is (now) connected to the proper spigot on the crankcase (can be seen to the bottom right of THE hole in the previous image I uploaded).

As for the hole, it's in a recessed area, so if I understand correctly, it's meant to be a vent of some sorts?

@Little_Phil
Indeed! Thanks for that, so I guess that settles that....

Thanks again,
Jonathan

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Author Topic: Missing crankcase spigot (Read 1598 times)