Topic: 1977 CB750 K7 Resto-mod, Knoxville

[Restoration Fan]

Ahh, the more of Dino's Hack a Week vids I watch, the more I really am tempted to take apart the cases & inspect everything. Plus, last night I came back across an old video I'd saved of a bike I liked: https://www.youtube.com/watch?x-yt-cl=85114404&x-yt-ts=1422579428&v=67xmWf7U9IM I really dig the engine paint on this, & think it'd be great to have my cases black like this, helping the polished chrome to stand out.

Lol you know I was just messing with you, right?

Honestly, I'm glad we took the cases apart because we got to learn all about the bike that way.  But in our case, we really had no choice because the kick start mechanism was messed up and to fix it, we had to get in there.

But if you aren't forced to open them and believe you can get away with only a top end rebuild, then I would highly recommend just doing that.  Besides, you have to make sure you have her going by the time I come through Knoxville in the fall so we can take them out for a ride.   

Finally, there's nothing stopping you from painting the cases like you want without taking them all apart.

[AintNoEasyWay]

Haha, I know you were kidding, but I'm reasoning with myself over it because I want to be certain my issues are solved. I'm not sure if I told you, but I had a serious oil/gas mix leak around my head gasket & also coming from my exhaust. My guess now is that the pucks weren't doing their job & oil & gas were getting past the old rings as well. I'm set to solve those problems now, but just hope nothing is looming deeper down in the crankcase.

I'll have to search for threads about painting the case without removing everything. As a newb, I have no idea how I'd cure it that way. It's definitely something I'm interested in though!

[calj737]

Fully degrease the motor. Then prep the surface with some denatured alcohol followed by Acetone. Then prime and paint. To cure it, build yourself a bit of a "hot box". Encase the motor in cardboard, lined with tinfoil. Insert a heat gun or other heat source in a corner, and blow.

You'd be surprised at how hot you can make that interior.  Heat during isn't required for a successful paint job, it's just an added benefit. If you do paint and cure without added heat, just make sure the ambient temperature is above 70* and keep it there. Most modern paints don't require heat to cure, but will harden on their own as long as the temps and prep are properly done.

[AintNoEasyWay]

Calj, that sounds great. Do I need to be concerned though about degreaser getting into the motor?

Also, my cylinder head has already been set up by the machine shop. Is there a particular method I need to use to protect the components in the head while painting/hot boxing? Thanks!

[Restoration Fan]

Haha, I know you were kidding, but I'm reasoning with myself over it because I want to be certain my issues are solved. I'm not sure if I told you, but I had a serious oil/gas mix leak around my head gasket & also coming from my exhaust. My guess now is that the pucks weren't doing their job & oil & gas were getting past the old rings as well. I'm set to solve those problems now, but just hope nothing is looming deeper down in the crankcase.

I didn't know that about the oil leak, but nothing you've mentioned above suggests that you would have to tear into the bottom cases unless there's an oil leak coming from one of the oil seals where something pokes out of the lower cases (stator oil seal, kick starter shaft oil seal, points advancer oil seal, gear shift assembly oil seal are the ones I can think of off the top of my head).  Unless that's happening, then it sounds like you just need a top-end rebuild.  Change the rings.  Put on a new base and head gasket, potentially put on new APE studs if you still have the factory ones, order new pucks to install on the top of the head.  Put a thin bead of HondaBond or ThreeBond on the base gasket, same on the pucks as they're installed, torque everything down and re-install the cam towers and cam shaft.

Other reasons for going in to the bottom would be something with the kick starter (like our problem) or needing to replace bearings, primary chain, cam chain or transmission gears, shift forks etc.  If your bike was shifting properly and the transmission and kick starter were working properly, I wouldn't tear open that bottom unless the mileage is really up there.  In that case, then you might want to tear it open to replace the bearings and chains for longevity.

[AintNoEasyWay]

Hey Ron, I think you're right. May be best to stay out of the case for now, especially since I don't have much money to spend & hopefully warm weather isn't too far off up here in Knox. My bike is at just under 25k, so the top end rebuild should carry me for a while. Once I finish school, I'll have the capacity to do a lot more.

I've got new rings, gaskets, pucks, & APE studs (along with just about everything else recommended: cam chain, tensioner, roller, etc). The Hack a Week vids & Hondaman's book will be great guides for me in the coming weeks. Hondaman actually recommends Permatex form-a-gasket sealer for the pucks, so I'll be using that instead of Hondabond. I'm sure Hondabond would be fine as well.

Speaking of non-hardeneing gasket dressing, I saw Dino putting a thin layer of it around his head gasket in his cylinder install video, which I thought was a great idea.

[calj737]

Calj, that sounds great. Do I need to be concerned though about degreaser getting into the motor?

The only places it should infiltrate would be spark plugs, intake or exhaust ports. Stuff some plastic baggies filled with paper towels into those, and cover with tape. Leave some junk plugs installed.

Also, my cylinder head has already been set up by the machine shop. Is there a particular method I need to use to protect the components in the head while painting/hot boxing? Thanks!

Ha! You're not thinking.... The running temp of the engine is WAY hotter than a hotbox  It's reasonable to ask, but the answer is obvious, right? I'm not laughing at you, I'm laughing with you.

[Restoration Fan]

Speaking of non-hardeneing gasket dressing, I saw Dino putting a thin layer of it around his head gasket in his cylinder install video, which I thought was a great idea.

Just to clarify, he actually didn't.  He put it around his BASE gasket.  That's the one that goes beneath the cylinders.  The head gasket goes on top of the cylinders, between the jugs and the head.  He didn't put any gasket sealant on it and the manual recommends that you don't do that either.  But we also put the non-hardening sealant on our base gasket...painted it on just like Dino did in his HackAWeek video, which turned out to be an effective way to get it on there efficiently without getting all over the place.

[AintNoEasyWay]

Calj, that sounds great. Do I need to be concerned though about degreaser getting into the motor?

The only places it should infiltrate would be spark plugs, intake or exhaust ports. Stuff some plastic baggies filled with paper towels into those, and cover with tape. Leave some junk plugs installed.

Also, my cylinder head has already been set up by the machine shop. Is there a particular method I need to use to protect the components in the head while painting/hot boxing? Thanks!

Ha! You're not thinking.... The running temp of the engine is WAY hotter than a hotbox  It's reasonable to ask, but the answer is obvious, right? I'm not laughing at you, I'm laughing with you.

Excellent. Yea, that makes total sense.

Speaking of non-hardeneing gasket dressing, I saw Dino putting a thin layer of it around his head gasket in his cylinder install video, which I thought was a great idea.

Just to clarify, he actually didn't.  He put it around his BASE gasket.  That's the one that goes beneath the cylinders.  The head gasket goes on top of the cylinders, between the jugs and the head.  He didn't put any gasket sealant on it and the manual recommends that you don't do that either.  But we also put the non-hardening sealant on our base gasket...painted it on just like Dino did in his HackAWeek video, which turned out to be an effective way to get it on there efficiently without getting all over the place.

That's right. Gasket dressing on the BASE gasket. My bad. I was also considering putting Permatex copper on the head gasket, but I know that's a sensitive point of contention for a lot of SOHCers. Will see when I get to that point.

[AintNoEasyWay]

Back from the dead...

Well, time to finally revive this old thread & put it to some good use. Cleaned up my pistons last night with some 50/50 water & ZEP purple. I used a green Scotchbrite to get all the thick grime off the top of the pistons; nothing else was strong enough to get it off. What's safe for me to use to get the last few remaining spots of grime off? Steel wool?

My #3 looks pretty rough on top, but I can't afford to replace it at the moment.

Also found that I probably need to get a new cam chain or split the case halves in order to get the chain on. Will probably opt for the latter, but not 100% on that yet.

I'm going to Harbor Freight this weekend to grab an engine stand & mod it up to hold my 750 engine. Should make cleaning/painting a whole lot easier.

[Restoration Fan]

If you've got to put the cam chain back on, either way, it's easier with the cases split.  Go ahead and go for it!

[AintNoEasyWay]

If you've got to put the cam chain back on, either way, it's easier with the cases split.  Go ahead and go for it!

Ron, I think you're right. I better quit hesitating & dive in or this thing will never be back on the streets again.

Finished up the pistons last night with a good bit of PB blaster & Hondaman's method of using old rings to get all the carbon out of the skirts. Proud of how clean I was able to get them.

But, I'm still having trouble getting all the carbon & grime out of the exhaust ports. My head has already had new exhaust valves & valve stem seals installed, & I don't want to take it back apart. What can I use to get these ports cleaned up?

Will soda blasting work on the ports without damaging anything or is there a less abrasive method I could use? Would I just clean it up the soda with water & acetone? What do you all recommend?

[calj737]

I like your method of soda blasting and clean up with soapy water and acetone afterwards.

[enwri]

A rounded end flat blade scraper for cleaning the exhaust ports of any thick crunchy stuff, keep in mind that any grit or carbon might collect between the valve seat and valve, it's a little wedge shaped gap and may be hard to reach, first time the valve opens when you assemble it, it may drop a little grit in the cylinder. Little bit of carbon probably wouldn't matter but definitely no abrasive carbide type grit. Soda is supposed to dissolve isn't it?
 Best if you can crack that valve open and blow it out when you've finished. How strong are your thumbs?

If it were mine, I'd be leaving the cam chain and be riding it by sunday. Well saturday night really, but I don't like annoying the neighbours too much.
Splitting the cases isn't that difficult usually, but seeing how hard yours seemed to be stuck together, who knows. If it's not been laying around open and still clean inside, there's no need to pull it completely apart and clean every individual part. Just get the mating surfaces and gasket surfaces clean of oil. I wouldn't disturb the bigends either, or pull the mains shells out. Just keep it clean.

I've got a weekends worth of work coming up as well.
Got myself one of these primary things, but this one still has rubber in it.
most of mine was in the oil screen.
Hmmm, those bearings feel ok as well, less hours than mine.

[Restoration Fan]

Nate,
Didn't you remove your cam chain already?  If so, then you're either going to have to:
a) split the cases to reattach that
b) drop the chain down through the hole and use something to snake it around the proper sprocket...an extendable magnet might work.  Since you have your pistons off the push rods, this is infinitely more possible than if they were still connected.

As for cleaning the exhaust, I would definitely use the soda blaster.  You can spend hours trying to clean in there by hand or just minutes using the soda blaster...and the blaster will do a more thorough job.  Just make sure that you completely immerse the head in soapy water afterwards.  I was told that using vinegar is an issue because of the chemical reaction, but vinegar dissolves the soda.

After soda blasting all the pieces of our engine, we discovered that even total immersion in soapy water hadn't gotten rid of all the soda.  So we took a squirt bottle and squirted some vinegar into each possible place where soda might have accumulated.  We let that bubble for about 30 seconds and then we re-immersed the piece in soapy water....cleaned that off and rinsed the part...then hit it with air from the air compressor.  After doing that, we didn't find anymore instances of soda accumulation.  So take that for what it's worth.

[AintNoEasyWay]

If it were mine, I'd be leaving the cam chain and be riding it by sunday. Well saturday night really, but I don't like annoying the neighbours too much.

Enwri, Hondaman recommended I leave the original cam chain in as well. Good luck with your project this weekend!

Nate,
Didn't you remove your cam chain already?  If so, then you're either going to have to:
a) split the cases to reattach that
b) drop the chain down through the hole and use something to snake it around the proper sprocket...an extendable magnet might work.  Since you have your pistons off the push rods, this is infinitely more possible than if they were still connected.

As for cleaning the exhaust, I would definitely use the soda blaster.  You can spend hours trying to clean in there by hand or just minutes using the soda blaster...and the blaster will do a more thorough job.  Just make sure that you completely immerse the head in soapy water afterwards.  I was told that using vinegar is an issue because of the chemical reaction, but vinegar dissolves the soda.

After soda blasting all the pieces of our engine, we discovered that even total immersion in soapy water hadn't gotten rid of all the soda.  So we took a squirt bottle and squirted some vinegar into each possible place where soda might have accumulated.  We let that bubble for about 30 seconds and then we re-immersed the piece in soapy water....cleaned that off and rinsed the part...then hit it with air from the air compressor.  After doing that, we didn't find anymore instances of soda accumulation.  So take that for what it's worth.

The original cam chain is still attached. I have the option of not opening the cases at all, just putting a new guide & roller in & leaving it be.

After you & calj's comments, Ron, I'm thinking I'll soda blast things. I'll purchase & modify the Harbor Freight engine stand tonight & tomorrow morning, then use the cheap method of soda blasting with an air compressor.

If I don't split the cases, what would you guys recommend I do to keep from soda getting down in them? Is this really worth trying to prevent or what method should I use to make sure the soda is cleaned out of the cases after the blast? Thanks guys!

[Restoration Fan]

Nate,
If you're not splitting the cases, the engine stand may be something you can hold off on for a while.  You can always do like we did and just build yourself a wooden box that has a hole in one side for the engine studs to hang down.

As far as the soda blasting, don't worry about the soda getting into the combustion chamber.  I'm assuming you're already going to lap the valves and replace the valve stem seals.  If so, just remove those before you soda blast the exhaust chambers and then, once done with the blasting, just immerse the entire head in the soapy water and clean some more to make sure you get all of the soda out of there.

[AintNoEasyWay]

Nate,
If you're not splitting the cases, the engine stand may be something you can hold off on for a while.  You can always do like we did and just build yourself a wooden box that has a hole in one side for the engine studs to hang down.

As far as the soda blasting, don't worry about the soda getting into the combustion chamber.  I'm assuming you're already going to lap the valves and replace the valve stem seals.  If so, just remove those before you soda blast the exhaust chambers and then, once done with the blasting, just immerse the entire head in the soapy water and clean some more to make sure you get all of the soda out of there.

Thanks, Ron. I'm still considering the engine stand just to help out with cleaning & painting.

I've already had the valves lapped by a machine shop & the valve stem seals replaced there as well. I don't have a spring compression tool to get everything back off, & since it's already been fixed up, I'd prefer to leave as is. I'm just trying to figure out if soda blasting into the ports is ok if I don't plan to remove everything.

As an alternative to soda blast, my girlfriend's dad (a Norton restorer out in Memphis) recommended MEK or lacquer thinner soak in the ports then taking a toothbrush (maybe one with stainless bristles) to the port to get everything cleaned up.

[AintNoEasyWay]

Picked up an HF engine stand last night & I'm back at it early this morning. I still had four studs to remove & hitting three of them with heat worked great. One of the corner studs makes it pretty clear why the jugs refused to come off, check out the photo below.

The last remaining studs won't budge after heat & PB blaster. I'm thinking I need to get an attachment for my ratchet so I can get my stud remover closer to the base of the stud. My stud remover is designed to only be able to attach closer to the top of the stud, if that makes sense. Hopefully an extension to the ratchet will give me the torque I need to get this last stud out. Trying to be extremely careful not to break it off. It is already beginning to bend every which way at the top, as you can see in the photo.

Off to the store now to grab my althread, nuts, washers, etc to get this engine stand goin'.

[Restoration Fan]

Nate,
FYI we bent about 1/3 of the studs we removed and our stud removal tool was one that grips at the top as well.  Just keep hitting it with heat and keep turning it. 

[enwri]

If you blast the head and barrels while it's apart you can wash them properly before assembly, then wait until it's together and the crankcase is sealed by the barrels and the other cases before doing the rest of it . If the head is already done it will be easier to just bag and seal the whole top end rather than trying seal the ports and breather individually . plug them before you wrap it up anyway grit will find a way in somehow, watch out for the starter motor hole, the gearbox breather and any other way in you can see.
Like someone already mentioned, you picked an apt username, by the look of those studs, this thing isn't making it easy for you.

[Restoration Fan]

Oh yeah, I forgot to mention that we used the stud remover to remove them all.  But on the ones that began to bend significantly, we attached vice grips to the bottom of the stud...down very close to the case.  And then we applied torque pressure at the bottom with the vice grips at the same time as we applied pressure at the top with the stud removal tool and ratchet.

[calj737]

...and once it begins bending, you're really close to shearing it! Heat the thing until cherry red then shoot PB into the threads. Then carefully use the stud remover while still smoking hot. Even rap it on the top with a dead low to help jar it loose.

[AintNoEasyWay]

Thanks, guys. Finished everything for the engine stand today. Tomorrow morning I'll try to get that last stud out & start some soda blasting on the head & jugs.

[calj737]

Sounds like you might be replacing some of those studs anyway, if so, go ahead and cut the stuck ones shorter so your tool clamps lower. Less distortion and more torque that way.