Author Topic: Cleaning oil passages - without removing heads?  (Read 1699 times)

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Offline fxef79

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Cleaning oil passages - without removing heads?
« on: March 12, 2020, 02:08:31 PM »
Is there any way to ensure clean oil passages for top-end oiling without actually removing the heads?  Just to ensure there's nothing blocking them?  This is on a CB750K2.

Offline 69cb750

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Re: Cleaning oil passages - without removing heads?
« Reply #1 on: March 12, 2020, 02:38:25 PM »
Connect an electric oil pump to main galley, check if cam squirters are working.

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #2 on: March 12, 2020, 02:50:35 PM »
On further research I recognize now that the fact the oil "squirters" are there precludes any possibility of using a tool (rifle bore brush, for example) to clean those out from the top end.

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #3 on: March 12, 2020, 02:53:36 PM »
Connect an electric oil pump to main galley, check if cam squirters are working.

Ah, but I don't have an electric oil pump.

Saw someone mention compressed air and feeling for whether it comes out at the top... not sure where I'd introduce the air - perhaps at the side oil gallery port above the points?

Offline 754

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Re: Cleaning oil passages - without removing heads?
« Reply #4 on: March 12, 2020, 04:42:06 PM »
First you got to know , the hole in the restrictor plug us tiny..likearoud 60 thou or 1.5mm. If motor is out or frame is cut, you can remove the whole valve train  to clean and inspect, without disturbing head or base gasket. And it only requires one gasket and 4 pucks.
 In the open section I posted a thread about the oiling , if you look it up you cansee the volume.
« Last Edit: March 12, 2020, 04:45:50 PM by 754 »
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Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #5 on: March 12, 2020, 06:27:46 PM »
First you got to know , the hole in the restrictor plug us tiny..likearoud 60 thou or 1.5mm. If motor is out or frame is cut, you can remove the whole valve train  to clean and inspect, without disturbing head or base gasket. And it only requires one gasket and 4 pucks.
 In the open section I posted a thread about the oiling , if you look it up you cansee the volume.
Custom trike frame so no problem with access. Just wary of pulling the head. Haven’t ever done it. Don’t want to get in over my head. I don’t have the tools for messing with valve train.

If the head is pulled, can the top end oil galleries be cleaned out without going further? (Like having to pull the cylinders?  I definitely don’t feel comfortable getting into pistons and rings.


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Offline 754

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Re: Cleaning oil passages - without removing heads?
« Reply #6 on: March 12, 2020, 06:47:53 PM »
You don't have to pull the head it stays torqued, when you pull the little jets the passages are much bigger . You can blow them out. I run a Qtip down around the top looking for debris.
 Do you have a fat Bob superglue ? Like your username ?
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #7 on: March 12, 2020, 06:53:07 PM »
You don't have to pull the head it stays torqued, when you pull the little jets the passages are much bigger . You can blow them out. I run a Qtip down around the top looking for debris.
 Do you have a fat Bob superglue ? Like your username ?
But I’d have to pull the tappets and cam and towers, right?

Yeah, ‘79 shovelhead. Got it as a basket case and tore it down to bare frame and built it back up. But I farmed out the engine to a local shop. That’s my bike. The CB750 is technically my wife’s.

Offline 754

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Re: Cleaning oil passages - without removing heads?
« Reply #8 on: March 12, 2020, 09:36:52 PM »
Yes , pull all that.  After first time it is pretty quick. Easy to do in 2 evenings if you dick around trying to blow things out..
 Cool old FX you got..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline ekpent

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Re: Cleaning oil passages - without removing heads?
« Reply #9 on: March 13, 2020, 08:11:25 AM »
 Is there a reason to think there is a problem , did the engine eat a cam and towers in the past ?

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #10 on: March 13, 2020, 08:25:49 AM »
Is there a reason to think there is a problem , did the engine eat a cam and towers in the past ?

History on my acquisition of this bike is that the PO bought it, rode it once, had no problems other than a badly slipping clutch.  Took it to a shop, had the clutch replaced, and when he got it back he says he immediately heard lots of noise from the engine - which he interpreted as new noise, and as top end noise.  He says he only ran it for a few minutes and immediately shut it down.  He pulled the valve cover and saw no oil coming to the top.  Arguing ensued between him and the shop... of course they say it was like that that when he brought it to them.  He believed that during re-assembly they swapped the scavenge and return oil lines.  He didn't want to deal with it (had gotten himself into too many different projects at one time), and I got it pretty cheap.  Sure enough, the scavenge and return lines were backwards... 5-minute job to swap them, and I confirmed oil is at least "flowing" to the top.  However I have no idea how MUCH oil should be coming up there... zero experience with CB750 (or any Honda i4, for that matter).  At that point I wasn't willing to give it any significant revving to see just how "aggressive" the flow of oil was.  I dropped the pan and the filter, and found some fine metal in the oil, but no big chunks, and nothing clogging the screen.  But what scares me is that I read all the time on here that you have to be very cautious about those oil galleries that feed the top end getting blocked.  So, what I want to know is how to ensure they're clear, and I have the appropriate amount of oil flow up there without having to get any deeper into the engine than I absolutely have to.  Oh... and I really don't know what to look for to visually determine whether there's cam or tower or tappet/rocker damage, again without actually pulling that apart (at least, any more than pulling the cover).

Beyond that information, the only thing the PO could tell me about operational history on this bike is that when he bought it, it had been "sitting for 3 years".  I have a crapload of paperwork he passed to me from the guy he bought it from, mainly receipts for parts and work... but nothing that would give me a lead on whether he was having any engine problems.

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #11 on: March 13, 2020, 08:48:15 AM »
Cool old FX you got..

Love my shovelhead.  Nothing radical... located nearly all original spec stuff and returned it to what it was supposed to be (PO had been converting it into a full-dresser bike).  About the only mechanicals that differ from stock is later model rear calipers.  Did add some small highway pegs, and I bought a convertible windshield (easy on - easy off) off my mom when she upgraded the windshield on her Dyna.

Offline ekpent

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Re: Cleaning oil passages - without removing heads?
« Reply #12 on: March 13, 2020, 11:28:10 AM »
 If it ran for a period of time with absolutely no oil to the top end and enough to start making some very bad noise I would probably be at least pulling the valve cover off and looking for damage on the cam and bearings.Bad things can happen quickly if dry. If you take off the tappet inspection caps while running you should see oil splashing or if not running may see some ground up aluminum and steel if the top end got torched. If the oil pan was fairly clean that may be a good sign. Is it running right now ?
« Last Edit: March 13, 2020, 11:34:05 AM by ekpent »

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #13 on: March 13, 2020, 11:33:15 AM »
If it ran for a period of time with absolutely no oil to the top end and enough to start making some very bad noise I would probably be at least pulling the valve cover off and looking for damage on the cam and bearings. If you take off the inspection caps while running you should see oil splashing or if not running may see some ground up aluminum and steel if the top end got torched. Is it running right now ?

I have had the cover off - in fact it was already off when I brought it home.  But I frankly don't know what "damage on the cam and bearings" will LOOK like.

I just got it running again a couple nights ago - the first things I did after getting it was go through all the brakes (rebuilt the fronts), electrical checks, drop and clean the pan, drop and clean the filter, adjust tappets, adjust cam chain, changed the advancer to the proper one, static timing, checking carbs, and other "surface" stuff.

Does "splashing" occur at idle, or require higher RPM?  At idle what I saw is "oil flow"... not so much "splashing".  But again, I didn't let it run more than a minute or so.


Offline ekpent

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Re: Cleaning oil passages - without removing heads?
« Reply #14 on: March 13, 2020, 11:46:39 AM »
 Unless someone cleaned it up there would be ground metal sludge laying in the head around the cam towers/cam that was damaged. Taking off the cam caps would get a better look but you may not have damage if you did not see those clues. How does it sound the little bit you have ran it ?

Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #15 on: March 13, 2020, 11:55:58 AM »
Unless someone cleaned it up there would be ground metal sludge laying in the head around the cam towers/cam that was damaged. Taking off the cam caps would get a better look but you may not have damage if you did not see those clues. How does it sound the little bit you have ran it ?

I can't attest for how much the guy might have "cleaned it" when he took off the cover - that was before I got it... I didn't notice any particular large collection of ground up metal in the top end, nor sludge or burned looking oil.

With the caveat that I don't have inline 4 experience, I would say I don't hear anything disturbing from the top end when it's running.  I have solid lifters on my shovelhead, and when sitting on the bike I can hear them louder than noise from the top end of this bike.

In fact, after I swapped the advancers and did the static timing (it's a Dyna S ignition, so no dwell or gaps to deal with), and started it (uh... after sorting out what seemed to be stuck floats), I walked around the bike as it idled, head close to the engine (its up on a lift right now), and I heard more noise from the clutch than I did from the top end.

I know that SOME metal settling in the oil pan is normal... but not how much.  I'd say there was a total of 1/4 to 1/2 teaspoon of fine metal in the oil.  Hard to judge exactly how much without actually filtering it and washing it down.

I kept the oil I drained out, and I'm bringing a magnet home from work today to check how much of those shavings are ferrous vs. aluminum.


Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #16 on: March 13, 2020, 12:02:08 PM »
How necessary is "Tool No. 07050-30001" - Rocker arm shaft remover - when taking down the cam and rockers?  From the picture in the shop manual it just looks like a long punch or drift.



Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #17 on: March 13, 2020, 01:27:21 PM »
See, what I'm hoping is that he just had a loose cam chain, and what he was hearing was cam chain slapping on the case.  That's one of the first things I did was adjust the cam chain tensioner.  So I might not ever hear the noise he heard.

Offline seanbarney41

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Re: Cleaning oil passages - without removing heads?
« Reply #18 on: March 13, 2020, 01:39:44 PM »
I have never needed the rocker arm shaft remover.  I have burned up a camshaft from a plugged oil jet before.  I always tell guys you should get a healthy splash of oil out of the exhaust side inspection covers, but if oil was cold just seeing flow may be ok.  Be sure you check BOTH ends of the engine though, as there are two oil galleys leading up to the oil jets under the two cam towers.  Hell, you could have bad flow if the o rings under the outside ends of the cam towers are missing or damaged.  I have seen cams badly damaged from this.
If it works good, it looks good...

Offline seanbarney41

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Re: Cleaning oil passages - without removing heads?
« Reply #19 on: March 13, 2020, 01:41:40 PM »
See, what I'm hoping is that he just had a loose cam chain, and what he was hearing was cam chain slapping on the case.  That's one of the first things I did was adjust the cam chain tensioner.  So I might not ever hear the noise he heard.
that is possible...these are not whisper quiet engines.  A considerable amount of clatter is healthy and normal.
If it works good, it looks good...

Offline Medyo Bastos

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Re: Cleaning oil passages - without removing heads?
« Reply #20 on: March 13, 2020, 03:50:40 PM »
Syncing carbs quiets chain chatter too!


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Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #21 on: March 13, 2020, 05:45:49 PM »
Syncing carbs quiets chain chatter too!


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My carbs:



Standard sync instructions don’t apply. :)

Offline Medyo Bastos

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Re: Cleaning oil passages - without removing heads?
« Reply #22 on: March 13, 2020, 06:10:57 PM »
Question, are your float bowls level?


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Offline fxef79

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Re: Cleaning oil passages - without removing heads?
« Reply #23 on: March 13, 2020, 06:14:39 PM »
Question, are your float bowls level?


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Pretty darn close. That pic was from above the level of the carbs. This is from about the same level:


Online PeWe

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Re: Cleaning oil passages - without removing heads?
« Reply #24 on: March 13, 2020, 11:29:20 PM »
K2 use early head with old style oil orifices which are PITA to remove. The later version is easier.
I guess that you must remove head to get them out without damage them. I blocked an oil/stud hole with an M10 bolt I had made threads for, filled hole with oil and used a tight drill I smacked to pop out the hard sitting orifice. I described that in a thread.
http://forums.sohc4.net/index.php/topic,175940.msg2051709.html#msg2051709
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967