Topic: 1977 CB750 K7 Resto-mod, Knoxville

[Restoration Fan]

If you do soda blast, make sure to clean it thoroughly afterwards.  I personally would use vinegar on it after soda blasting  because the vinegar dissolves the soda.   Then wash it with water and blow it dry thoroughly.  You don't want that soda inside the engine.

[AintNoEasyWay]

Just standard vinegar that I'd buy at the grocery store?

[AintNoEasyWay]

Great. Should I bother taping up the head? Remember the springs, stem seals & valves are all in it already. Or can I just soda blast, vinegar dip, then water dip & air compress dry?

[AintNoEasyWay]

Made it out to the bike shop on Saturday & managed to get my cylinder dowel hole cleaned up. The dowel now fits in it & I should be good to go.

Also just PMed Elan about one of the oil pump super kits.

Didn't get any replies on my last question regarding cleaning the head, so I'll ask again: Should I bother taping up the head? Remember the springs, stem seals & valves are all in it already. Or can I just soda blast, vinegar dip, then water dip & air compress dry?

[Restoration Fan]

Made it out to the bike shop on Saturday & managed to get my cylinder dowel hole cleaned up. The dowel now fits in it & I should be good to go.

Also just PMed Elan about one of the oil pump super kits.

Didn't get any replies on my last question regarding cleaning the head, so I'll ask again: Should I bother taping up the head? Remember the springs, stem seals & valves are all in it already. Or can I just soda blast, vinegar dip, then water dip & air compress dry?

Hmmm....I'm not sure I would soda blast if the stem seals are in there.  I was assuming you had the springs, valve stem guides and valves out of the head if you were going to soda blast it. 

If you are going to blast it with those in there...well, in that case, I'd definitely tape up the top of the head so that the springs and seals won't be affected.  I don't know if vinegar has any negative effect on the rubber of the valve stem guides but I know I wouldn't want pressurized soda hitting them.

[AintNoEasyWay]

Thanks, Ron. Yea, that's why I wasn't sure if it was something I should do or not. I may have to find a workaround. I want to paint the head so I need to have it all cleaned up. Any ideas on how to proceed?

[AintNoEasyWay]

Cool, thanks calj. I'll plan on doing that then.

So the big question remains: to replace the cam chain or not. I've cleaned all my holes out & am ready to install the studs. I imagine it's easiest to install the cam chain, roller, & guide before putting all these studs in. My new cam chain is endless though, & after some replies in SOHC bikes part of the forum, I know there's no way I'm skilled enough to try breaking it & redoing it just so I don't have to break open the cases.

That said, what would you guys do? Just install the new roller & guide & keep the old cam chain?

Or, split the cases just to put in a new chain? If I split the cases, aren't there a couple specific tools I need, for example, one to take the rotor out?

Appreciate your thoughts!

[Restoration Fan]

How many miles are on the current cam chain, Nate?

[AintNoEasyWay]

Just under 25k.

Is this the spanner that works for our years, Ron? http://www.motionpro.com/motorcycle/partno/08-0015/ or perhaps a better question, which extra tools did you purchase in order to deal with the rotor & clutch?

[Restoration Fan]

Just under 25k.

Is this the spanner that works for our years, Ron? http://www.motionpro.com/motorcycle/partno/08-0015/ or perhaps a better question, which extra tools did you purchase in order to deal with the rotor & clutch?

Yep, that's what my clutch tool looks like.

If there's only 25,000 miles on that cam chain and you're only trying to do a top end, then I wouldn't break open the cases just to replace the cam chain personally.  But that's just one idiot's opinion, FYI. 

To pull the rotor assembly, you'll need something else.  I purchased the Motion Pro Flywheel Puller Bolt.  Something like this:
http://www.ebay.com/itm/like/171391547963?lpid=82&chn=ps

[AintNoEasyWay]

Haha. To another idiot.

This project has taken long enough. I hate to cut any corners but I really want to ride this summer. Plus, I'm sure I'll redo the engine in a few years when I have the proper resources & means. I'll wait on getting the extra tools to split the case then. Elan is in the middle of moving, so I won't have my oil pump kit until the beginning of next month. Until then, I just focus on getting the top end put back together properly.

[Restoration Fan]

Yeah, I think that's a decent plan.  Just finish the top end rebuild and get it going so you can ride this summer.  Then, you can always plan to do the lower end rebuild later when it's cold.  And you can do that without having to split the top part as well.  Just flip it upside down and remove the bottom. 

But if you're going to do the bottoms at that point, you can plan on replacing the cam chain, cam chain tensioner pulley, bearings and oil seals.  At that point, you should be fully rebuilt on the engine.  And you might even want to consider doing the frame mod kit at that point as well.

[AintNoEasyWay]

Yea, I can definitely see the benefit of the frame mod kits now!

For the cam chain bottom wheel, the pin that fits through the roller has two components, one that locks into a groove in the roller & another larger metal tube piece. They should both face the right hand side if you're looking out at the exhaust, I think. But why do they have holes? Are these just for oiling?

[Restoration Fan]

That's what I assumed when we put ours back together. 

[AintNoEasyWay]

New studs installed. Accidentally installed one with the short end going into the crankcase & had to gently remove it & reinstall. Made sure my oil holes in the back two holes were clear with compressor. Set up the new cam roller, but realized I'll probably have to redo it in order to get the base gasket on. No big deal.

Waiting for some piston circlips to arrive tonight so I can get the pistons back in.

[AintNoEasyWay]

From BrandEn's Leak Free Top End thread, he states "Now is a good time to remove the four cam tower studs on the head and install the Permatex Thread Sealant to the threads. The holes these are installed are open to atmosphere and can be a source for leaks if not sealed."

So people actually remove the four studs in the head just to put thread sealant on them & then reinstall? Is this something you guys bothered with? Let me know what you think!

[Restoration Fan]

The four studs he's talking about are not the ones that go all the way down through the engine into the lower cases.  I believe he's talking about the 4 bolts that are beneath the "rubber pucks" that hold the head down onto the cylinders.  And yes, you should absolutely put sealant around those before you put the cam towers onto them.

And I wouldn't say to remove the cam towers just to get to that...but if you're already doing a top end rebuild, you should do it while you're doing the reassembly.

[AintNoEasyWay]

Yea, that's what I assumed he meant. Thanks, Ron.

I went to walmart during my lunch break today to pick up some oven cleaner, but all the products they had said it wasn't safe for aluminum. Is it still ok to use it on my head, calj737? Appreciate you response.

I'm going to install my pistons to the rods tonight. I bought a ring compressor a couple months ago (http://www.lislecorp.com/divisions/products/?product=79), but I'm not sure I can use it given that the piston rods are still down in the crankcase & not free to move with the pistons.

Dino used the same type of ring compressor in his video here:

But obviously he shows how to do it with the rods already out. Is there a way to use it when your rods are already connected inside the case?

[AintNoEasyWay]

Just got all four pistons installed on the rods & circlips turned back in place. Any ideas on how to get the jugs back on given that the compressor tool I bought probably won't work since the rods are down in the case?

Has anyone used Hondaman's method of sanding down the inside of metal clamps & compressing that way?

[Restoration Fan]

What do you mean by the rods are down in the case?  If you turn the crank, two of them should rise up at a time to allow you to put the pistons back into the cylinders.

[AintNoEasyWay]

I mean that the rods are attached to the crankshaft. If you see Dino's video that I linked to, he already has the rods off the crankshaft & can use the Lisle ring compressor to fit the rings inside the jugs pretty easily.

In my case, since the rods are still attached to the crankshaft down in the cases, I can't really see a way to use the ring compressor I bought.

[AintNoEasyWay]

Ron, I know you guys used the Honda tools to install your pistons into the jugs, I'm just looking for an alternative method. The other methods I've seen explained all seem to involve having the rods already removed from the crankcase, connected to the pistons. For an example, see the Hack-a-week video on the previous page.

[Restoration Fan]

Nate,
You're not going to be able to use the same technique that Dino used in those videos if your rods are still attached to the crankshaft.

You're going to need to use the same technique we used, even if you don't have access to the Honda tools like we did.

Raise the #2 and #3 cylinders by turning the crank and take a couple of pieces of wood and slip them beneath those 2 pistons.  Then take a hose clamp with enough thickness to cover all 3 rings and tighten it up on each of the 2 pistons.  But leave it loose enough that it can slide down the piston when pressure is applied from above.  GENTLY tap the center of the cylinders down until it barely covers the bottom piston rings on both #2 and #3.  Remove the clamp (you will have to take it completely apart and then re-insert the loose end when you put it on cylinders #4 and #1.

Now, move the blocks out from under 2 and 3 and very gently turn the crank to raise #1 and #4 until they're as close to the cylinders as possible.  Repeat the same process with the clamps for #1 and #4 to get the piston rings in those cylinders but note that you won't be able to put those blocks beneath the pistons for 1 and 4.  That should get your pistons back in the cylinders with the new rings on them and it will only take you between 15 and 30 minutes if you do it right.

Only other thing I'd add is that DON'T bang on the cylinder top to get them down.  If it seems like you're having to smack the jugs to get them to go down, you're probably getting something stuck somewhere and something is wrong.  So stop and evaluate what could be catching....fix that...then proceed.

[AintNoEasyWay]

Awesome. Exactly what I needed, Ron. Also for further reference, some of the guys helped me out in the thread too: http://forums.sohc4.net/index.php/topic,107040.msg1688707.html#msg1688707

Baby steps...

[enwri]

Was wondering how this was going, getting to the good bit now. The four studs in Brandons leak thing, I thought he meant the ones in this photo.
I think in manufacture the stud holes can break through to the underside and weep out underneath, right next to the pucks.
I'd stick with the old chain too, do it next time, when you go for the hot cam and heavier valve springs.