Author Topic: Paddy - '78 CB750 - Version 3.0 Coming Soon! (Read 84197 times)

theofam · « **Reply #250 on:** March 21, 2012, 12:16:02 pm »

LesterPiglet, other way around. 1 & 2 were bone dry. 3 & 4 were wet. The 1 & 2 injector was impregnated with oil. The 3 & 4 was clean as a whistle. Could be the issue, but, to your point, there may be a plugged channel leaving the case that feeds that uphill tube to the 1 & 2 side of the head. Anyone with ideas on how to check this without splitting the case?

SOHCDigger, I hope you're right that I've found the problem! I read two posts where someone snapped off the points-side shaft when trying to turn over a stubborn motor. I figured I'd go the the 19mm nut on the alternator side. Costs me a couple gaskets, but I figured it was a cost I'd rather absorb than risk messing up the points side. Based on how it's turning, you're right, though. It would have worked fine.

The head and cylinder are off. Pics in the next post. I couldn't leave them on there with that golden color, and I didn't want to sand them on the motor, mask the motor, and paint in place.

Greggo, I've not dropped the oil pan yet. I will, as I want to see if any shavings are in the oil pump's screen. I'm going to take the head back to the guy that did it for me originally. I want him to check it out, but I also figure those valve seals aren't made to withstand that kind of heat. I think they're just rubber or some sort of synthetic material. I've got an extra set, so it can't hurt to replace them.

More pics in a few minutes. Thanks for your help and suggestions!

theofam · « **Reply #251 on:** March 21, 2012, 12:35:54 pm »

I'll take you through a bore-by-bore photo tour of what I've found thus far.

Here's #1. It has the most buildup atop the piston. Is this the start of carbon buildup? It appears to be congealed/burned oil. This makes me wonder if the valve seals failed under such extreme heat and let oil into the combustion chamber. However, that side was very dry, so how could oil on the dry side of a head leak down into the combustion chamber? I suppose it could have come up by the rings. I don't recall any smoke via the tailpipe though. Very confused at this point. Thoughts?

#2. There is an additional pic of the piston's side. It has a minor nick (black spot) that is recessed and doesn't appear to have a raised edge when the finger is run over it. Also, the bore looks like a mirror still. I don't think it's an issue, unless someone speaks up.

#3 looks good.

So does #4.

Something surprising to me was how wet the base gasket (cylinder-to-case) was when I lifted the cylinder. Is this typical?

My main concern is the junk on top of each piston. Wouldn't the beginning of carbon buildup be black? It's possible no one has ever cratered a motor in its first five miles and I've discovered the creation of carbon buildup as a brownish substance. Could I be that lucky?!

theofam · « **Reply #252 on:** March 21, 2012, 05:40:09 pm »

Above I asked why the base gasket is soaked.

Could it be due to the o-rings on the bottom of the cylinder not being the same height all the way around? See how wavy these are? I'm trying to figure out how to get them applied in a uniform manner.

The oil pan definitely had some shavings in it. Not sure how freaked out I should be about this. Is it a split-the-case concern? Or, do I run some oil through it once re-assembled and quickly change that oil before putting on any miles?

I pulled the oil screen. I didn't do it on the initial rebuild, and I found a chunk-o-junk in the screen. Not sure if this had been there awhile or not.

MY MAIN CONCERN: I don't know if the oil injector in the head was the problem. If it wasn't the only thing I can point to is this oil passage coming out of the case. It feeds oil to the 1 & 2 side of the head through an o-ring sealed channel that feeds through the cylinder into the head.

MY MAIN QUESTION: Is there a way to clean out that passage in the case without splitting the case? Can I blow compressed air into it without it popping a seal at the oil pump? Should I prime the oil pump and roll over the motor to see if oil comes out of the passage? Any ideas are welcome!

I've spoken with my media blaster and machinist. Media blasting occurs tomorrow. I'll pick up parts Friday morning and take them to the machinist for a once over and valve seal replacement as well as checking pistons against the bores in case I warped anything. 7-10 day turn around.

PARTS I NEED: I am looking for a 77 or 78K cam as well as a cam tower with caps, rocker shafts and rockers. If anyone wants to part with stuff that's in good-to-great condition, let me know.

Off to E-Bay I go!

brandEn · « **Reply #253 on:** March 21, 2012, 05:52:48 pm »

GREAT pics and documentation. I can't comment on the issues but will offer a suggestion. If I was in your situation I would split the cases just to double check the oil passages but mainly for piece of mind. But thats just me. The way I look at things; say an hour to split the case, an hour or so to clean/inspect, and another hour to reassemble. So an afternoon of time for years of satisfaction on knowing that everything is good to go. I would hate to install the motor on hope. But thats just me and my opinion... Hope that helps.

Retro Rocket · « **Reply #254 on:** March 21, 2012, 07:43:08 pm »

I agree with what Brandon has said, the red residue around the valves looks like fuel residue.....May not be but thats what it looks like to me....

theofam · « **Reply #255 on:** March 21, 2012, 07:48:09 pm »

Retro, I think the red was applied during the valve job. I seem to remember it being there when I picked it up from the machinist.

BrandEn, you're probably right, even though I don't want to admit it! I really don't want to try to remove the gasket/sealant between the cases. I just used gasket remover on the head tonight, and it dissolved my paint. I don't care about that, since I'm repainting it anyhow. But, I just dread having to strip and paint the cases again if the gasket remover spills over the side, which it would.

mrrch · « **Reply #256 on:** March 21, 2012, 07:56:50 pm »

I'm with BrandEn on pulling it apart to check. Was the base gasket wetter on the plugged side? The oil pressure om the plugged side had to go somewhere.

brandEn · « **Reply #257 on:** March 21, 2012, 08:01:37 pm »

I may be wrong but you should be able to get everything off with a scraper/razorblade (on the case halves). If you used Yamabond or similiar it does not harden when it dries.

brandEn · « **Reply #258 on:** March 21, 2012, 08:05:37 pm »

Plus worst case scenerio, ask yourself whats worse. Splitting the cases now and maybe having to touch up some paint or installing the engine without splitting the cases, run into a problem having to pull the motor out again, removing the top end, splitting the cases and having to paint anyway? Sorry, if I sound out of line I am just sharing the way I think and look at things and hopefully, maybe helping you.

theofam · « **Reply #259 on:** March 21, 2012, 09:51:03 pm »

BrandEn, please don't apologize. I value your opinion and thought process.

I used Honda's version of Yamabond. I assumed it hardened. Maybe it wouldn't be that tough to clean up if it stays pliable.

MoMo · « **Reply #260 on:** March 21, 2012, 09:56:36 pm »

I have a head complete minus cam from a 77 CB750K if you need one PM me...Larry

MRieck · « **Reply #261 on:** March 22, 2012, 04:53:44 am »

You have aftermarket cylinder studs.....did you use Loctite on them when you screwed them into the upper case. I have seen the Loctite clog the upper case feed hole (pushes up as the stud is screwed in). You can check oil flow by removing the main galley cap and tap out the galley plug on the alternator side (you already have the cover off). Screw the oil galley cap back in, put a plug in the oil flter feed and blow compressed air into the galley plug hole. Air should easily come through the upper case feeds. You really have to pay attention to the oil feeds especially with the larger OD cylinder studs. The old RC ones were tapered for those 2 oil feeds.

theofam · « **Reply #262 on:** March 22, 2012, 08:55:56 am »

MRieck, THANK YOU! This is my first motor, and I have no other reference point to know whether these studs were original or not. I reused the studs, so I don't know their history in terms of whether or not they were installed with Loctite.

I was reticent to button the motor back up. It just seemed the orifice couldn't be the extent of my issue. I'm not familiar with the oil galley cap. But I presume you mean this on the points side:

And this appears to be the galley plug behind the alternator cover. Hmm. I'm not sure what I have in my shop that will pop out the alternator-side plug. Does it just pop back in to re-seat it?

I truly appreciate you visiting my thread. You've seen so many of these motors, it's great to have the advantage of your eyes and knowledge.

brandEn · « **Reply #263 on:** March 22, 2012, 08:57:52 am »

If you get the right side plug off just use a wooden dowel or similiar to reach thru the motor and pop it out.

theofam · « **Reply #264 on:** March 22, 2012, 09:02:15 am »

DAMNIT! Wanna see the inside of my galley cap?!

I've some work to do.

knowsnothing · « **Reply #265 on:** March 22, 2012, 09:03:36 am »

Is that metal or gunk? Gross to see either way.

theofam · « **Reply #266 on:** March 22, 2012, 09:33:40 am »

The junk in the galley cap is plastic media from having the cases blasted when they were apart. I didn't pull the cap and galley plug to clean out that oil channel before engine reassembly.

I did what MRieck suggested and, with the oil filter holes plugged and the galley cap screwed back on, blew compressed air through the oil channel. A few individual pieces of media (maybe 5-6) came up through the oil channel feeding the 1-2 side of the head. Both oil channels are blowing similar air pressure now, so I feel better buttoning this back up now that I know they're both open. Thanks, MRieck!

cheapride · « **Reply #267 on:** March 22, 2012, 10:02:33 am »

This really sucks man. I am learning from you and really hope my engine runs fine. I too have not done a motor before and am so very nervous to start it up for the first time. Would an inspection under the valve tappet covers after the first start up find this out or would the assembly lube still be covering everything?

theofam · « **Reply #268 on:** March 22, 2012, 10:53:31 am »

cheapride, I'm not sure I'm the guy who should be answering any questions!

One of the fellas posted up above that he opened up the intake-side valve adjusters to ensure there was oil slinging about while the motor was running. Not a bad idea, as I'm not sure how else to ensure oil makes it to the head once the motor is assembled.

I decided to remove the oil supply cylinder studs in case there was more media by the supply holes. Turned out there was. Blurry pic on #2, but you'll see what I mean in the #3 pic:

MRieck, I can see how having studs tapered toward the top would help with oil flow. These studs do not appear to have been installed with Loctite, so I reinstalled them dry. Let me know if that's a bad idea.

Both channels are flowing air nicely. In fact, the #2 stud, which was the starving side, has oil residue climbing the stud when I blow air through the oil galley. I think that's a great sign!

cmonSTART · « **Reply #269 on:** March 22, 2012, 11:49:41 am »

Like I said a while before, sorry to hear about your troubles, but this is turning into a very informative and helpful thread. Thanks for documenting it so well!

MCRider · « **Reply #270 on:** March 22, 2012, 11:55:18 am »

Quote from: cheapride on March 22, 2012, 10:02:33 am

This really sucks man. I am learning from you and really hope my engine runs fine. I too have not done a motor before and am so very nervous to start it up for the first time. Would an inspection under the valve tappet covers after the first start up find this out or would the assembly lube still be covering everything?

The benefit of pulling the tappet caps and watching for oil is that within a few moments there wil be oil everywhere and you can say whew.

The problem is that if you don't see oil within a few moments, you don't really know anything. Maybe a few more moments and you'll get oil. Maybe you'll never get oil and you have to dismount and disssemble. Ony to find out that had you waited another moment you'd have oil. Or had you waited another moment you'd had a boat anchor.

Its a frustrating trick.

cheapride · « **Reply #271 on:** March 22, 2012, 12:16:30 pm »

Quote from: MCRider on March 22, 2012, 11:55:18 am

Quote from: cheapride on March 22, 2012, 10:02:33 am
This really sucks man. I am learning from you and really hope my engine runs fine. I too have not done a motor before and am so very nervous to start it up for the first time. Would an inspection under the valve tappet covers after the first start up find this out or would the assembly lube still be covering everything?
The benefit of pulling the tappet caps and watching for oil is that within a few moments there wil be oil everywhere and you can say whew.

The problem is that if you don't see oil within a few moments, you don't really know anything. Maybe a few more moments and you'll get oil. Maybe you'll never get oil and you have to dismount and disssemble. Ony to find out that had you waited another moment you'd have oil. Or had you waited another moment you'd had a boat anchor.

Its a frustrating trick.

I thought about the media being used. The plastic pieces are nice on the aluminum but can clog up in tiny holes. I used soda and hopefully won't have this problem. I was under the impression that any soda left in the engine will be dissolved by the oil. Is this a correct assumption?

Brent

MCRider · « **Reply #272 on:** March 22, 2012, 12:26:31 pm »

Quote from: cheapride on March 22, 2012, 12:16:30 pm

Quote from: MCRider on March 22, 2012, 11:55:18 am
Quote from: cheapride on March 22, 2012, 10:02:33 am
This really sucks man. I am learning from you and really hope my engine runs fine. I too have not done a motor before and am so very nervous to start it up for the first time. Would an inspection under the valve tappet covers after the first start up find this out or would the assembly lube still be covering everything?
The benefit of pulling the tappet caps and watching for oil is that within a few moments there wil be oil everywhere and you can say whew.

The problem is that if you don't see oil within a few moments, you don't really know anything. Maybe a few more moments and you'll get oil. Maybe you'll never get oil and you have to dismount and disssemble. Ony to find out that had you waited another moment you'd have oil. Or had you waited another moment you'd had a boat anchor.

Its a frustrating trick.
I thought about the media being used. The plastic pieces are nice on the aluminum but can clog up in tiny holes. I used soda and hopefully won't have this problem. I was under the impression that any soda left in the engine will be dissolved by the oil. Is this a correct assumption?

Brent

I've used my soda blaster on many pieces, incl carbs, but not on an engine case. I can attest to the fact it dissolves quickly and completely in water. I would suspect in oil as well.

MCRider · « **Reply #273 on:** March 22, 2012, 12:27:05 pm »

Take a little soda and oil in a Tupperware and see.

theofam · « **Reply #274 on:** March 22, 2012, 06:03:51 pm »

I'd dunk the parts in water to dissolve and neutralize the soda. Blow the parts dry and assemble. If you're already assembled, follow MCRider's lead.

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Author Topic: Paddy - '78 CB750 - Version 3.0 Coming Soon! (Read 84197 times)