Topic: 1977 CB750 K7 Resto-mod, Knoxville

[AintNoEasyWay]

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.

[AintNoEasyWay]

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.

[enwri]

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]

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]

Subscribing to this.

--
Marius

[SOHC4 Cafe Racer Fan]

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]

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]

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!!

[AintNoEasyWay]

Awesome. Thanks, cal.

Forgot to mention I also ordered Hondaman's CB750 book yesterday. Hopefully that'll be a big help getting the engine reassembled & running properly again!

[SOHC4 Cafe Racer Fan]

ANEW,

Not sure if you were planning on a complete engine tear down, but if you do, you should replace the primary chain while you are at it and inspect the primary tensioner, in addition to the transmission components.

[AintNoEasyWay]

ANEW,

Not sure if you were planning on a complete engine tear down, but if you do, you should replace the primary chain while you are at it and inspect the primary tensioner, in addition to the transmission components.

Hey cafe fan, I am pretty limited to a top end fix at the moment given finances. I am hoping this will see me through for a while until I can finish school & start considering a complete rebuild. Thanks for your input though.

By the way, the video you had done was awesome! I've shared it with several of my friends here & they love it too.

[SOHC4 Cafe Racer Fan]

ANEW,

Not sure if you were planning on a complete engine tear down, but if you do, you should replace the primary chain while you are at it and inspect the primary tensioner, in addition to the transmission components.

Hey cafe fan, I am pretty limited to a top end fix at the moment given finances. I am hoping this will see me through for a while until I can finish school & start considering a complete rebuild. Thanks for your input though.

By the way, the video you had done was awesome! I've shared it with several of my friends here & they love it too.

Thanks! Much appreciated.

[AintNoEasyWay]

Still no updates as of today. Tonight I'll be going to a vintage bike club meeting, Time Warp Tuesdays! It's an awesome meet up we have every week here in Knoxville. Maybe some of the guys there can point me in the right direction for a local motorcycle machine shop.

Also my Hondaman book is scheduled to arrive tomorrow, so I'm very excited to start digging into that.

[AintNoEasyWay]

Received Hondaman's book last weekend & have been reading through much of the engine section. I also got a tip yesterday for a local motorcycle machine shop, so I'm going to give them a call today.

What kind of head work do I need to plan on doing? I'm going to call them with the plan to have the cylinders miked & honed. If the miking shows that I need a rebore, I'll work from there. But I'm not sure what's considered the bare minimum for valve/head work on a top end rebuild. Lapping? Reaming? I guess I don't fully understand all these things even after reading through the forums. I'll also plan to have them check the surfaces on each side of the jugs & head to assure they're all even.

[AintNoEasyWay]

You certainly want them to check the springs for their specs, replace if needed. Guides need to be checked for wear, seals, and of course the valves and seats.

Optional work is to have some mild porting/polishing done up in the intake and exhaust ports to aide in flow of gases. Everything else would be specific to your motor's idiosyncrasies.

Exactly the advice I needed. Thanks, calj.

[SOHC4 Cafe Racer Fan]

You certainly want them to check the springs for their specs, replace if needed. Guides need to be checked for wear, seals, and of course the valves and seats.

Optional work is to have some mild porting/polishing done up in the intake and exhaust ports to aide in flow of gases. Everything else would be specific to your motor's idiosyncrasies.

Exactly the advice I needed. Thanks, calj.

Yes. Excellent advice indeed.

[enwri]

Any news on your bits at the shop? I hope you're not losing your enthusiasm about it all, when it's all over and you're riding around, you'll have the knowledge, pride and attachment to it that you only get by going through this stage.
 

[AintNoEasyWay]

Hey enwri, thanks for checking in. I tried contacting the machine shop last week, but the phone just rang & rang. I've been very busy with school, work, life, etc. & the bike has hardly gotten any attention in the past two weeks. Really I've only managed to read through more of Hondaman's book...

Financing the rebuild is also a constant issue. I took the time to calculate all the new parts I still need: gaskets, rings, o-rings, dowels, pins, valve stem seals... over $300 this is a conservative estimate, assuming I don't need new valves, guides, etc, & of course, doesn't include machine shop work. For a guy in my position, it's a lot of money...

BUT, your comment gave me a nice kick in the arse. Reminded me of why I'm doing all this in the first place! Also got me imagining myself back on the road, feeling free. Time to start taking this seriously & digging in the couch for pennies.

[SOHC4 Cafe Racer Fan]

That's when you start looking around the house and garage looking for stuff you don't touch anymore that you can Criagslist.  I've done it before to get new toys!

[AintNoEasyWay]

The local machine shop is able to mic my cylinders for free and will hone them for $12 per cylinder. I am going to check a lot of measurements tonight & will see what other work I'll need them to do. I only have a digital caliper though & an old set of feeler guages; nothing advanced like a 1" & 2" micrometer or bore gauges like Hondaman recommends. I'll do what I can with the tools I have for now.

I plan on testing the valves for leaks tonight as well.

Cafe Racer Fan, you're exactly right. As a college student, I've had several instances where I had to gather old things around the apartment & make a few quick sells on eBay.

[AintNoEasyWay]

No leak from my valves after flipping the head & letting penetrating oil sit in the chambers sit for about 20 minutes. This is a good sign I guess? I still have to take everything apart anyway to clean up the valves, check the guides, replace valve stem seals...

Taking my engine to the machine shop tomorrow! No idea how long things will take, but hopefully I hear back from them after they check measurements & all I need is a hone. Then I can go ahead & order all the remaining engine parts I'll need.

It's getting chilly here in Tennessee. I'm starting to look more at just working on the bike through the winter & having it perfect when spring comes. I'd like to do other things besides redo the top end. I want to replace swing arm bushing, front & back wheel bearings, rear brakes, steering bearings, & put a new front disc brake on the bike.

[AintNoEasyWay]

Forgot to mention, I've started making a little extra side cash by helping a local vintage collector keep all his bikes clean. Here's a CB350F I cleaned up this past Saturday.

[AintNoEasyWay]

What solvent/tools should I use to clean up my engine parts? For example, I'm not sure what to use to clean up my pistons or to remove head/base gasket residues. There is a lot of grime on my pistons, should I soak them in something?

Thanks!

[enwri]

That sounds like a cool way to earn a bit of cash, does he have anything other than Hondas? (not that there's anything wrong with having just hondas) There were some interesting ideas tried out over the years. The valve testing is a good sign as well, see if you can borrow a spring compressor that will fit the 750, not all do. search the threads, can usually make a tool to make the ones that don't fit work, (a piece of pipe cut out a bit so you can reach in with a magnet or something to get the collets out) You can even use a G clamp with your new tool, if you have three or more hands and ninja fingers.
 I know you will anyway, but keep all the bits matched up to go back in the same places.
Then you can check the valve seating surfaces for width, I don't know exactly how wide, someone will, generally should all be very similar. There wil be the guide clearances as well, too small for me to measure, as long as the valves don't wobble too much, also in here somewhere will be a thread about just how much they should or shouldn't. It's not a very high mileage engine is it?  They usually last a long time, (unless you have an F3? I think, something about different angles or something)
Not sure what people use to dissolve the gasket material, but paint scrapers or razor blades are going to be handy, obviously no gouging. soaking the pistons is a good start, the back edge of hacksaw blades are handy, be careful not to enlarge the ring lands if you use a wire brush wheel to clean the tops. the square end of a broken ring will be perfect for cleaning the lands out.

I don't know how people survive in cold places, I've got the flanno and jeans on at anything under 25c (77f).

found this     http://forums.sohc4.net/index.php?topic=137876.msg1556659

[AintNoEasyWay]

That sounds like a cool way to earn a bit of cash, does he have anything other than Hondas? (not that there's anything wrong with having just hondas) There were some interesting ideas tried out over the years. The valve testing is a good sign as well, see if you can borrow a spring compressor that will fit the 750, not all do. search the threads, can usually make a tool to make the ones that don't fit work, (a piece of pipe cut out a bit so you can reach in with a magnet or something to get the collets out) You can even use a G clamp with your new tool, if you have three or more hands and ninja fingers.
 I know you will anyway, but keep all the bits matched up to go back in the same places.
Then you can check the valve seating surfaces for width, I don't know exactly how wide, someone will, generally should all be very similar. There wil be the guide clearances as well, too small for me to measure, as long as the valves don't wobble too much, also in here somewhere will be a thread about just how much they should or shouldn't. It's not a very high mileage engine is it?  They usually last a long time, (unless you have an F3? I think, something about different angles or something)
Not sure what people use to dissolve the gasket material, but paint scrapers or razor blades are going to be handy, obviously no gouging. soaking the pistons is a good start, the back edge of hacksaw blades are handy, be careful not to enlarge the ring lands if you use a wire brush wheel to clean the tops. the square end of a broken ring will be perfect for cleaning the lands out.

I don't know how people survive in cold places, I've got the flanno and jeans on at anything under 25c (77f).

found this     http://forums.sohc4.net/index.php?topic=137876.msg1556659

Hey enwri, glad you're back around. Yes, the collector I've been working for has all types of vintage motorcycles, Matchless, BMW, Norton, Yamaha, a CB750, 550, & 350, an Ariel. He is mostly partial to British bikes.

I bought a spring compressor from Sears, but it's a total POS & I plan to return it this weekend. It is not a motorcycle specific spring compressor, but the design should permit it to work on both cars & bikes. Unfortunately it is very poorly made. I'll have to find another alternative. I may just take my cylinder head over to the machine shop as well. My worry is that they won't, like you say, keep everything in exact order & put it back in its proper place. I want to be absolutely I put everything back properly & don't create any undo wear on parts.

Thanks to Hondaman's manual, I have the proper specs for the valves, & really everything in the engine.