Author Topic: 1977 CB750 K7 Resto-mod, Knoxville (Read 97606 times)

calj737 · « **Reply #100 on:** August 12, 2014, 05:39:34 AM »

Can you run a strap thru the rocker sleeves and use the engine's own weight? Slip the straps over a truss and barely lift the engine by the strap, an inch off the ground is enough to allow them to move. You certainly don't want the engine to break loose and come crashing down. Heavy padding below is also advisable. But just hang it and let gravity be your tool.

Also, some heat directed at the base will potentially unlock what's seized.

AintNoEasyWay · « **Reply #101 on:** August 12, 2014, 06:20:30 AM »

Quote from: calj737 on August 12, 2014, 05:39:34 AM

Can you run a strap thru the rocker sleeves and use the engine's own weight? Slip the straps over a truss and barely lift the engine by the strap, an inch off the ground is enough to allow them to move. You certainly don't want the engine to break loose and come crashing down. Heavy padding below is also advisable. But just hang it and let gravity be your tool.

Also, some heat directed at the base will potentially unlock what's seized.

Sounds great, calj. I'll give that a shot this evening. I'm just trying not to damage the inner part of the cam holder where the rocker arm shafts go.

enwri · « **Reply #102 on:** August 12, 2014, 08:02:09 AM »

Just be aware that if only one dowel lets go it could drop and try to bend the studs and damage the other dowel hole by pulling off at an angle. Keep it close to to the ground if you go that way. It's heavy enough to hurt itself. You will probably still need to lever it unless it just comes loose while lifting it .

AintNoEasyWay · « **Reply #103 on:** August 12, 2014, 04:33:08 PM »

Finally got the other holder free after some gentle mallet work. Everything is in good shape. I've removed all the bolts to the head, but it's stuck too. Sprayed PB around where the head gasket sits, so hopefully this will be less trouble than that damn cam holder!

enwri · « **Reply #104 on:** August 12, 2014, 07:10:33 PM »

Even all the little bolts? also, as soon as you can lift the head, or even before, get those little oil restrictors in the oil holes out, and in a safe place. Don't let them fall out in the grass in the driveway when you're degreasing the head and hosing it off. (Just in case you were thinking of doing that.)

AintNoEasyWay · « **Reply #105 on:** August 13, 2014, 07:25:16 AM »

As far as I can tell, there are no other bolts to loosen. I put up a photo below of the bolts that I removed. I removed all the numbered bolts & all bolts that are marked in red on the pic. Did I miss anything? I'm working in my Dad's garage, thankfully, so I shouldn't lose anything unless I'm just totally careless.

enwri · « **Reply #106 on:** August 13, 2014, 08:25:14 PM »

That looks like plenty of bolts to me, Did you ever find any wet plugs or exhaust ports? or were they all the same.
You might get away with an easy rebuild yet.
could the P.O. have filled the pipe with oil to preserve it and it's starting to blow out?
I don't know how many miles you've done on it, or how many it's done in total.

AintNoEasyWay · « **Reply #107 on:** August 14, 2014, 05:21:53 AM »

Quote from: enwri on August 13, 2014, 08:25:14 PM

That looks like plenty of bolts to me, Did you ever find any wet plugs or exhaust ports? or were they all the same.
You might get away with an easy rebuild yet.
could the P.O. have filled the pipe with oil to preserve it and it's starting to blow out?
I don't know how many miles you've done on it, or how many it's done in total.

Morning enwri (suppose it's evening for you?). The plugs looked fine, but I only removed the outer two, #1 & #4. I'll be sure to remove #2 & #3 when I get home today & report back. Exhaust ports all look normal too except all the build of grime & oil collected around the inner ports, but that's mostly down a bit further on the fins near the ports.

It's possible the PO did some storage prep work & neglected to tell me about this. But that's doubtful given that he had done nothing to preserve the tank, carbs, master cylinder, & front brake, all of which I've had to restore.

enwri · « **Reply #108 on:** August 14, 2014, 05:54:43 AM »

10:30 pm and raining here. In a mates shed, fiddling with it again. No work until Monday for me. Might go up to Palm Cove jetty for a ride later and watch the Japanese tourists fishing. There's some keen ones amongst that lot, guaranteed someone will be hoping for a marlin off the jetty.

Nope... No-one fishing, too wet, too windy.

AintNoEasyWay · « **Reply #109 on:** August 14, 2014, 06:16:33 PM »

Enwri, that sounds like a great time.

I was able to work my engine head off today after letting the gasket soak in more PB blaster & gently tapping a putty knife with a mallet around the gasket. Soaking the base gasket in PB overnight tonight & hoping to remove the cylinders tomorrow.

I also checked all my spark plugs. Spark plugs 1, 2, & 4 all look normal while 3 looks very dark in comparison. See #3 in the photo below. I'm thinking that maybe oil is getting past the rings & onto the #3 spark plug. Would you guys agree?

enwri · « **Reply #110 on:** August 14, 2014, 08:42:52 PM »

There are a few ways to get oil in a cylinder, gasket failure or cracked castings between an oil gallery and a cylinder, the two studs either side of the cam chain tunnel on the intake side, are under pressure and can blow oil out. Return galleries can sometimes get broken into as well, cylinder pressure can blow into the gallery, and pull oil in on the intake stroke. (exhaust coming out the crankcase breathers, oil blowing out everywhere else it can.)
The valve guide seals on the intake valves letting oil pull into the port, the port when running, has a vacuum trying to pull oil through the guide, can also just flow under gravity or capillary action when not running. Exhaust guide seals can leak as well, but usually just by gravity/capillary when stopped. Usually seen as a puff of smoke when starting and then reducing, unless completely failed with badly worn guides.

Or the cylinder, because of rings, either gummed up, worn beyond tolerance or broken, or damage to the cylinder wall or piston.

I'm going to bet on gummed up oil rings, either stuck out and worn off, or glued in and not touching the sides, plus the hard guide seals. (hoping anyway.)

On a separate note, I'm sure you know this, and took due care.
Whilst happy to see hammers and chisels in action on all things I can, I would say, the mating surfaces of finely machined parts is probably one of the rare times I would advise against them.
I doubt that there's any damage done, but little nicks in the sides of studs from being hit, create a failure point, burrs hold things apart, gouges create gaps between things that gasket goo cannot always fill.

AintNoEasyWay · « **Reply #111 on:** August 15, 2014, 12:38:18 PM »

Cool. Thanks, enwri. I have tried to be careful with the putty knife; I don't know of any alternatives given that the parts refuse to move without some serious push. How else can I break the seals? I'm planning on replacing the studs, so any damage done to them won't affect the rebuilt engine, as far as I can think.

enwri · « **Reply #112 on:** August 15, 2014, 05:58:25 PM »

Yeah, you don't get much of a choice on where to push these things apart. It's screwdrivers that do the most damage anyway, hammered into gaps and deforming edges, or levering on bits that break off. Unless you are looking to run it on nitromethane or way over torque them these studs should be okay. Others on here might know why these ones seem inadequate and need replacing.

calj737 · « **Reply #113 on:** August 15, 2014, 07:30:48 PM »

Only if they're eroded... Or damaged and nicked up. I replace mine for peace of mind since I'm rebuilding the whole dang bike. If your budget tight, inspect and re-use if possible.

AintNoEasyWay · « **Reply #114 on:** August 22, 2014, 05:39:26 PM »

So I'm still struggling with the removing the jugs.

The only thing I haven't tried is calj's 4 hour BBQ technique. Calj, if I try this, where should I be setting the flame. Inside the cylinders? How are you getting the flame to catch & stay burning? I didn't have much luck getting it to hold when I shot it into PB blaster coated pistons.

I did order a few things from Z1 Enterprises today though:
- Tsubaki cam chain
- Cam chain tensioner, roller, & guide
- APE HD studs
- Cylinder head rubber seals

I was planning on ordering Composite head & base gaskets from Z1 as well. But wanted to ask first: should I get Composite gaskets & then order the rest of the gasket stuff. Or would it work to buy a Vesrah kit: http://4into1.com/vesrah-complete-gasket-set-vg-157-honda-cb750-1974-1978/ ?

I know it'd be easier to just buy all the gaskets/seals together, but I have read people complaining about the lack of quality in Vesrah kits, while Composite gaskets seem to be a big favorite for many on the forums.

calj737 · « **Reply #115 on:** August 22, 2014, 07:27:50 PM »

I used SeaFoam because Kerosene is hard to come by where I live. I filled the cylinders and lit it up. Just kept adding the fluid whenever it burned off.

AintNoEasyWay · « **Reply #116 on:** August 23, 2014, 10:16:53 AM »

Just tried seafoam burning in the cylinders. No luck. Damn this thing is resilient. Would removing the studs help to take the jugs off? I feel like I've tried just about every trick in the book at this point.

calj737 · « **Reply #117 on:** August 23, 2014, 12:52:49 PM »

I would not attempt to remove the studs until the jugs are off. Twisting them from that height will likely shear them.

I bbq'ed for 4 hours, FYI. May also need to pour heat to dowel areas

enwri · « **Reply #118 on:** August 26, 2014, 11:54:09 AM »

Still no good? the suspense is killing me.
You mentioned earlier that a gap opened up at the back, is it big enough to let you slide old gasket material in around the sides of the cylinders while it's pushed forward? if it is, slide thin flat pieces in as far as you can forwards towards the front corners where the dowels are and then knock the cylinder backwards to pull up on the front while you heat the dowel areas on the cylinders. ( I think it's just the front outside corners only)
Only use fibre gasket material (at least an inch long) and work the block backward and forwards slowly building up thickness.
Hopefully, if it's really stuck the gasket pieces will crush out before damaging any mating surfaces.
Just don't use anything harder than the aluminium castings.
I'd be missing a few fins by now, but would probably have it off.

AintNoEasyWay · « **Reply #119 on:** August 26, 2014, 01:00:38 PM »

Quote from: enwri on August 26, 2014, 11:54:09 AM

Still no good? the suspense is killing me.
You mentioned earlier that a gap opened up at the back, is it big enough to let you slide old gasket material in around the sides of the cylinders while it's pushed forward? if it is, slide thin flat pieces in as far as you can forwards towards the front corners where the dowels are and then knock the cylinder backwards to pull up on the front while you heat the dowel areas on the cylinders. ( I think it's just the front outside corners only)
Only use fibre gasket material (at least an inch long) and work the block backward and forwards slowly building up thickness.
Hopefully, if it's really stuck the gasket pieces will crush out before damaging any mating surfaces.
Just don't use anything harder than the aluminium castings.
I'd be missing a few fins by now, but would probable have it off.

Hey enwri, still nothing. My dad brought home some wood pieces from work yesterday, & we tried hammering (using a mallet) them against the "736cc" piece that sticks out from the front of the jugs. It absolutely did not budge out all. I'm wondering if there's some screw I somehow overlooked.

I found a couple more things to try out. From some other post:

"Turn crankshaft so that two outer pistons are at bottom dead center.

Stuff rope or rags tightly into the cylinders.

Place head on cylinders and fasten only with the short screws that connect the head to the cylinder.

Rotate crankshaft with wrench, cylinders pop off of crankcase."

I may try this. I was using the bolt under the points cover to move the pistons instead of the alternator bolt. Is this a grave mistake? I read today in a really old thread where calj737 had typed in bold not to use this.

Another technique I read about was using 50/50 Acetone/ATF mix because it's much stronger than PB blaster.

I'm going to a vintage bike club this evening & plan on asking some of the guys there what they recommend. Thanks for the tip. I will keep that in mind as a possibility as well.

marsvar · « **Reply #120 on:** August 26, 2014, 01:22:50 PM »

Subscribing to this.

--
Marius

calj737 · « **Reply #121 on:** August 26, 2014, 05:21:41 PM »

Definitely do NOT use the bolt under the points cover. You WILL shear it. Do use the 14mm bolt under the alternator side. Yes, it's smaller, so it's deceiving. But it is a case hardened bolt and is suitable for the torque.

Regarding the rope stuffing, I've seen that trick for pushing the head loose, but fail to understand how it will move the jugs? The jugs are not attached to the case, but the case studs pass through the jugs and the head is clamped to the studs. How then does forcing the head away from the piston force the jugs up? I'd thing this would strip the case studs out of the block? Maybe I don't understand something...
sorry, just re-read what you wrote and understand now.

There should be 2 small "indents" on either end of the jugs where you can force a wooden wedge in to assist with separating the jugs. It's not wide either, about 3/8" wide if I am correct. But you probably need to apply heat (torch) at the gasket area, focusing on huge dowels, to help part the Red Seas. I just went through this with another 550. Used propane and a plastic wedge, and lots of cussing.

SOHC4 Cafe Racer Fan · « **Reply #122 on:** August 26, 2014, 05:47:59 PM »

Quote from: calj737 on August 26, 2014, 05:21:41 PM

Definitely do NOT use the bolt under the points cover. You WILL shear it. Do use the 14mm bolt under the alternator side. Yes, it's smaller, so it's deceiving. But it is a case hardened bolt and is suitable for the torque.

Regarding the rope stuffing, I've seen that trick for pushing the head loose, but fail to understand how it will move the jugs? The jugs are not attached to the case, but the case studs pass through the jugs and the head is clamped to the studs. How then does forcing the head away from the piston force the jugs up? I'd thing this would strip the case studs out of the block? Maybe I don't understand something...

There should be 2 small "indents" on either end of the jugs where you can force a wooden wedge in to assist with separating the jugs. It's not wide either, about 3/8" wide if I am correct. But you probably need to apply heat (torch) at the gasket area, focusing on huge dowels, to help part the Red Seas. I just went through this with another 550. Used propane and a plastic wedge, and lots of cussing.

And copious volumes of beer!

enwri · « **Reply #123 on:** August 26, 2014, 06:25:30 PM »

If you do the rope trick, don't use too much rope, keep it so that it stops pretty close to top dead to push.
It will have much more mechanical advantage than if it is only halfway up the bore. (least advantage/leverage)

I suggested on that other thread, to use a piece of wood bolted across the top to do the same thing, and instantly advised against it, but now someone else has suggested it I'll get on it too.

The head will use two more bolts, more the better, just don't use the studs, you won't push them out.
Don't forget the heat at the dowel bosses. Unless you have an oxygen bottle on your torch you won't be able to damage it.

And like Calj says, Don't use the points end nut, it will shear off easily, alternator or nothing, for this bit at least.

AintNoEasyWay · « **Reply #124 on:** September 16, 2014, 05:25:18 AM »

Well, I've been away for a couple weeks, locked down with school & a short vacation too. The bike hasn't been totally neglected as I have been ordering parts here & there for the engine rebuild. Right now I've bought:
-Tsubaki cam chain
-cam chain guide
-cam chain roller
-APE HD studs
-stainless steel hex bolts for the whole engine
-6 new cam shaft rubber puck seals
-Also had to buy a new drive chain & front & rear sprockets for the bike

Still left on the list: new rings, valve stem seals, cam cover-head-base gaskets (waiting to get my engine honed before I purchase).

I managed to get back in the garage last night to try the "rope trick" with the jugs since I still can't get them off. I removed the alternator cover, stuffed rags down into the 1 & 4 cylinders after turning them to bottom, reattached the head & tried turning the crank again, but the jugs absolutely won't budge. I have no clue, guys.

So, I think I may go ahead & see if a machine shop can remove it for me since I need them to hone my cylinders anyway. Any tips for how to approach these guys? I've never worked with a machine shop before & don't know standard procedure. I assume I need my cylinder miked & honed, at the least. Doesn't appear that I'd need a rebore from the condition of the cylinders, but I'm a novice. I'm sure prices vary, but what should I look for? I live in Knoxville, Tennessee. Would really appreciate any tips before I start calling around!!

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Author Topic: 1977 CB750 K7 Resto-mod, Knoxville (Read 97606 times)