Author Topic: 1977 CB750 K7 Resto-mod, Knoxville (Read 97607 times)

enwri · « **Reply #75 on:** July 28, 2014, 06:11:00 PM »

That's a pain in the #$%, It will make a big difference whether it's coming from inside the cylinder or from the rubber plugs under the cam. Pull out the spark plug, or the exhaust header and look in the port, post that result, wet and oily or not, it's the difference between bad news about having to remove the engine, and even worse,,, having to remove the engine. I don't think you're going to be able to avoid it. You could If you get the frame cut kit installed before you try to fix it.
Rubber discs are pretty easy, head gasket or cylinder damage isn't much harder, just a few "cough cough" more dollars..
This has happened many many times, there will be plenty of info here.

edit and afterthought.,

Mine was a bit smoky and had one wet oily cylinder before I pulled it apart, the rings were within tolerances but gummed up, (replaced them, std size, with a light hone.) Head gasket was leaking a little due to I think a long dowel poking up too far, the only other things I replaced in the top end were the valve guide seals, rock hard and broken, gaskets, and O rings, cam chain and tens. No more smoke. No more oily cylinder. . 16000 k's later pulled the motor to fix the leaks from the pucks and re torque the head, ( bit late, but better late than never I suppose, wouldn't have at all if it hadn't leaked)
That's what the photo is, hasn't leaked in the 2000 k's since.

P.S. Think about getting the frame kit, it would make it much much less work..

I'm no Psychic, but I see this in your future...

AintNoEasyWay · « **Reply #76 on:** July 29, 2014, 04:28:40 AM »

Damn! Guess that motor will be coming out. Another forum member is stopping by possibly today to take a look with me in person. I don't have a way to do a compression test, but was thinking I should check compression before pulling the engine. I'll check the exhaust header & port first though, as you advise.

Hopefully I'll be back with an update later this evening. I'm going to repost the problem in the sohc bikes part of the forum to see if I get more ideas. As always, thanks a lot, enwri. You & your bike have been through a lot; hope my bike will be with me for the long haul too.

enwri · « **Reply #77 on:** July 30, 2014, 05:47:30 PM »

cb stains. not the knees, that's dirt.

AintNoEasyWay · « **Reply #78 on:** July 30, 2014, 07:15:51 PM »

Enwri, is this what you were talking about when you told me I'd be able to shine my shoes from my oil leak?

AintNoEasyWay · « **Reply #79 on:** August 02, 2014, 05:42:11 AM »

reposting this from the SOHC bikes part of the forum:

Here's a look at the leak from my exhaust. It also seems like the leak from the engine case is getting worse because now it's leaking at the sides from some of the fins. As far as I can tell, the leak from the engine stops once I'm riding, but I pulled back in the garage & found this residue on my exhaust. Figured I should take a pic & show you guys. I changed my oil yesterday before riding.

I haven't found a motorcycle specific compressor that I can borrow, so I still haven't run any tests. But I've just begun plan to rebuild what I can of the engine despite my budget. Would be great if some of you could point further in the right direction. After reading some threads, here's what I've come up with:

APE studs from z1 enterprises, 77.31
Cometic head gasket from z1, 48.23
Cometic base gasket from z1, 12.52
Rings, (need to check my engine number) but 4into1.com has them for $40 a set
Valve stem seals, not sure the best kind to get?
Cam chain tensioner, roller, & guide set from Dynoman, 99.95
Tsubaki cam chain from z1, 32.51
Cylinder head rubber seals from z1, 3.38 each

Cylinder hone, not sure about prices from local shops or if this would be necessary?

This is assuming the valves are in okay condition & only need to be lapped. Does this seem like a thorough enough list for a top end rebuild?

calj737 · « **Reply #80 on:** August 02, 2014, 06:19:09 AM »

If you open then engine and replace rings, anticipate that a re-bore may be necessary. Depends entirely upon the measurements of your current condition. For head work, many choose to send their projects to Mike Rieck and have a quality job of porting done to wake up the engine.

AintNoEasyWay · « **Reply #81 on:** August 03, 2014, 06:04:20 AM »

Sounds good, calj. I've seen Mike around the forums & might contact him once I get into the engine this week. The engine is ready to be taken out, but I got cut short waiting on someone to help me take it out. I'll have my dad around to help me today, so hopefully we can get it out together.

That said, I still have some updates & a few more photos. I changed the oil Friday night & had just filled the tank last Tuesday. After changing the oil Friday, I rode the bike around the block & noticed it kept hiccuping when I gave it throttle. It died on me twice in the small trip around the neighborhood, but after letting it sit a couple minutes, it started up & held an idle long enough for me to get it back up the street. I opened the tank yesterday & there was barely any fuel left! I must be losing both oil & gas.

Also, when prepping to take out my engine yesterday, I drained all my new oil & it was a thick black, as if it had mixed with gasoline...

The photos below show the trouble areas around my engine. Of course I haven't taken off the head yet, but every exhaust valve appears to have the same weird, white coating over it. I assume because oil hasn't been getting to the valves properly?

What kind of mess have I gotten myself into? Stay tuned. Will be back later today with more updates & photos of inside the engine.

Stev-o · « **Reply #82 on:** August 04, 2014, 06:45:23 AM »

If gas mixed with oil, it would be very thin, not thick.
That white valve shows a very lean cond and needs to be addressed.

AintNoEasyWay · « **Reply #83 on:** August 05, 2014, 05:56:16 AM »

I wonder what's making the bike run so lean? I have a standard air box, all standard jetting, clips on the needles are set one down from top, carbs totally clean. My only non-stock part would be my 4-into-1 exhaust. I tuned the carbs to match my 2nd carb, & everything seemed to be running fine...

Some news: I have everything uninstalled to take the engine out, except the exhaust studs. It looks like the engine will slip right out once I have these removed. I tried some heat & PB blaster, then went for the double nut technique, but they still wouldn't budge. I figured I'd let them sit with PB blaster & see if I have better luck later.

calj737 · « **Reply #84 on:** August 05, 2014, 06:02:21 AM »

I'd encourage you to leave those studs in there... If you snap one off, you'll be hating life.

If you must remove them, use a proper stud puller with some directed heat in the stud. But engine should wriggle free with some effort.

edhaeuser · « **Reply #85 on:** August 05, 2014, 06:06:31 AM »

Quote from: AintNoEasyWay on August 05, 2014, 05:56:16 AM

I wonder what's making the bike run so lean? I have a standard air box, all standard jetting, clips on the needles are set one down from top, carbs totally clean. My only non-stock part would be my 4-into-1 exhaust. I tuned the carbs to match my 2nd carb, & everything seemed to be running fine...

Some news: I have everything uninstalled to take the engine out, except the exhaust studs. It looks the engine will slip right out once I have these removed. I tried some heat & PB blaster, then went for the double nut technique, but they still wouldn't budge. I figured I'd let them sit with PB blaster & see if I have better luck later.

Exhaust studs.....I hate those things. Whatever you do, if you break one off, promise you won't try an easy out. Use reverse drill bits ant drill it out. If you are lucky, the stud may come out with tbe drill bit. If not, you can drill oversize for a helicoil. Heat works good too....(before it is broken especially)

I just spent hours with diamond bit die grinders to grind an easyout from a stud. Compliments of a PO. I went through about 15 bits just to get the easyout removed. Then I could go back to my regular reverse drill technique.

Ed

AintNoEasyWay · « **Reply #86 on:** August 05, 2014, 06:13:21 AM »

Quote from: calj737 on August 05, 2014, 06:02:21 AM

I'd encourage you to leave those studs in there... If you snap one off, you'll be hating life.

If you must remove them, use a proper stud puller with some directed heat in the stud. But engine should wriggle free with some effort.

Interesting. My dad & a friend tried helping yesterday, but there didn't seem to be any way to remove the engine without removing the studs. Tilting the engine forward to lift the engine over the back right side of the frame isn't possible because the studs just lock against the frame & I'm afraid of breaking one of by letting it rest on a stud or having a stud hit the frame too hard. We tried using an engine hoist, but that just lifted the entire bike off the ground & the engine was still "locked" into the frame.

The only thing I haven't tried is laying the bike on its side, which I'm trying to avoid.

AintNoEasyWay · « **Reply #87 on:** August 05, 2014, 06:23:29 AM »

Quote from: edhaeuser on August 05, 2014, 06:06:31 AM

Exhaust studs.....I hate those things. Whatever you do, if you break one off, promise you won't try an easy out.

Haha, thanks, Ed. I promise!

enwri · « **Reply #88 on:** August 05, 2014, 06:36:46 AM »

Now you know what we mean about the frame kit thing. The engine will come out with the studs in but it's a tight fit, every little bit helps though. Especially if you don't want to scratch the frame paintwork. I used a narrow block of wood on a trolley jack between the frame rails, (so it could move sideways with the jack until it hit the rail, let it down and moved it to get another 2 inches of movement out of the jack.) and moved it out inch by inch to another block flush with the rails, swapped the jack to the outside when it was halfway. it only takes a little tilt to clear , used a big screwdriver to lever it sideways bit by bit from around the back of the gearbox, keep it fairly even or it jams in.
Interested to see what's going on in this one. I'm sure valves used to look like that when we still had lead in the fuel, but you've got bigger problems than that at the moment.

calj737 · « **Reply #89 on:** August 05, 2014, 07:26:52 AM »

It's easier to lay it on it's side. Stack some magazines or something on ground on right side to support right side of engine, lay over, lift frame off. Still gotta wriggle it.

Frame kit is the best invention since the SOHC4 but as you please...

enwri · « **Reply #90 on:** August 05, 2014, 07:50:54 AM »

Well maybe valves weren't quite that white, but I was expecting at least one of those ex. valves to be wet and oily. Looks a bit wet up closer to the guide though. ( I'm still hoping for an easy fix with guide seals.)
I keep reading how the 77-78's were jetted really lean for pollution control anyway, that's why they needed accelerator pumps. Just maybe not that lean.

calj737 · « **Reply #91 on:** August 05, 2014, 07:59:42 AM »

Quite possibly that one carb was a bit clogged or float was low.

AintNoEasyWay · « **Reply #92 on:** August 05, 2014, 08:05:24 AM »

Quote from: calj737 on August 05, 2014, 07:59:42 AM

Quite possibly that one carb was a bit clogged or float was low.

As far as I can tell, every exhaust valve has a white coating. I'll post up better photos once I have the engine apart. Maybe all my floats are too low?

enwri · « **Reply #93 on:** August 05, 2014, 08:39:45 AM »

Quote from: enwri on August 05, 2014, 06:36:46 AM

Interested to see what's going on in this one. I'm sure valves used to look like that when we still had lead in the fuel, but you've got bigger problems than that at the moment.

Quote from: enwri on August 05, 2014, 07:50:54 AM

Well maybe valves weren't quite that white, but I was expecting at least one of those ex. valves to be wet and oily. Looks a bit wet up closer to the guide though. ( I'm still hoping for an easy fix with guide seals.)
I keep reading how the 77-78's were jetted really lean for pollution control anyway, that's why they needed accelerator pumps. Just maybe not that lean.

Quote from: AintNoEasyWay on August 05, 2014, 08:05:24 AM

Quote from: calj737 on August 05, 2014, 07:59:42 AM
Quite possibly that one carb was a bit clogged or float was low.

As far as I can tell, every exhaust valve has a white coating. I'll post up better photos once I have the engine apart. Maybe all my floats are too low?

Mine are at 12.5mm, needles need to be set at their leanest to run on light throttle properly. stock airbox mains and 35 pilots with 4 into 1. was going to try 14.5. different fuel maybe?

Sorry, don't mind me, just worked out how to quote myself and others.

AintNoEasyWay · « **Reply #94 on:** August 05, 2014, 10:52:51 AM »

Hey enwri, yep, the only thing different is that I think my needle shims are set one down from the top spacing. I can check again since I've already got my carbs out. But like you say, less concerned about that at the moment. Will make sure it gets solved before everything goes back on the bike though.

AintNoEasyWay · « **Reply #95 on:** August 09, 2014, 03:54:37 PM »

So my engine slid out easily today. Not sure why we were having so much trouble with it before, but it was almost a joke getting it out today. about 3 seconds & it was on the furniture dolly. I've taken out the rocker arms & cam shaft. Can any tell me any tricksfor getting the rocker arms lined up correctly again when I'm putting the engine back together? Looks like it'd be quite the task, but just guessing.

So now I'm left to get the head off. Some of those bolts are in hard to reach spots as far as I can tell. I am letting PB blaster soak on the bolts overnight & I'll be back at it in the morning, with a lot of photos then.

calj737 · « **Reply #96 on:** August 09, 2014, 03:56:36 PM »

Stretch a rubber band around the end of the intake side, over the cover, then over the exhaust side. Keeps them pinned up and out of the way, with bands gaining access thru tappet inspection holes.

AintNoEasyWay · « **Reply #97 on:** August 10, 2014, 04:13:23 PM »

Having a hell of a time getting off the cam holder that's over the #1 & #2 cylinders. After some work, I managed to get the other holder off, but this second one absolutely won't budge. I've put PB blaster all around it & down the screw/bolt holes, but it still refuses to come off. Any advice for what I can do to get this thing off? It's the only thing holding me up!

enwri · « **Reply #98 on:** August 10, 2014, 05:40:40 PM »

If you can find a place to get a block and lever under a rocker shaft just slid out of the holder enough to get under it (keep it within all its bushes), or other edge (not any mating surface) make it something that wont mark the shaft and will only push straight up, as close to the dowels as possible, if it lifts at all make it a fraction of a millimetre at a time and work all the dowels evenly. lift it as straight as possible.
Obviously don't use enough force to break the shaft out of the holder, (probably not much, you might find out.) it's had those rockers trying their best to push it up and out but you're pushing from the wrong side of the bush, loading it unevenly, on only one end of the shaft .( rockers are using two bushes at a time.)
It's also assuming the shafts will slip in towards the centre of the head as well as out. Can't remember if they will.
If anyone posts a preferred safer method, use that instead.

AintNoEasyWay · « **Reply #99 on:** August 12, 2014, 05:33:55 AM »

Still no luck getting this second cam holder off. I really don't no why it's stuck on there. Let it set yesterday after spraying again with PB blaster to no avail. Like you say, enwri, I'd prefer to treat it gently in all cases as I know how important the rocker arms shaft & holes are. Anyone else have ideas for getting this part off so I can finally move on?

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Author Topic: 1977 CB750 K7 Resto-mod, Knoxville (Read 97607 times)