Topic: '78 CB750F - Orange-ish Black

[Davidov]

The springs yes! I ended up not needing the valves. Thank you again!

Cal- They are black oxide, and I did experience that when I used these same bolts on the shifter cover about a year ago. I only found surface rust in the socket recess, which was still diappointing. I just swiped it with scotch brite, and dabbed some grease in there.
I just removed the bolts for the shifter cover during the rebuild, and found no rust anywhere else. So not really concerned.

[Davidov]

PAMCO ignition installation and wiring. It looks like good quality. My only wish is that it came "plug and play" with bullet connectors, but that would make it cost more.

List of shame:
Washers used to make a longer bolt work on breather cover
Missing valve cover cross-point bolts under the breather cover
Of the 4 oil line bolts, 1 was an oddball philips head.
1 different intake valve
Half of the valve springs were installed narrow end UP
List of excessive wear:
Rocker shaft hold-down bolts loose on intake 1-2 towers
2 loose cylinder studs
And of the exhast valve guides were all WAY out of spec

So yes, this rebuild was money well spent!

[Davidov]

I did all the concluding work, the hardest part of the whole rebuild! Friday night (Saturday morning) about 1:55am, I fired it up.

I have heard of oil starvation to the head after a rebuild, so I took every precaution. Oil pump screen was cleaned, new o-rings on the pump dowels, and a new gasket. New oil pan gasket as well, added thread sealant to the oil pan bolts. Pump was primed after that work during the rebuild.

I kicked it over manually(by foot?) several times. I cranked it with the starter at intervals. The oil light never went out, but I was sure there was oil flow. I decided to go for it, and cranked it with spark, and behold it started right up. Oil dummy light went off immediately.

The Pamco ignition and fresh compression make it feel soooo much better while starting. About 3/4 stroke of the kick lever and its running.

Still need to synch the carbs, and give it a few break in runs on my neighborhood "test track". 

I'll post a video soon.

[70CB750]

Nice! 

[Davidov]

Wrapped the exhaust during reassembly. Besides the scavenging advantages and more power  ....I think an aircooled engine can benefit from this. The whole front face of the engine is usually shielded by the exhaust pipes.

[seanbarney41]

PAMCO ignition installation and wiring. It looks like good quality. My only wish is that it came "plug and play" with bullet connectors, but that would make it cost more.

List of shame:
Washers used to make a longer bolt work on breather cover
Missing valve cover cross-point bolts under the breather cover
Of the 4 oil line bolts, 1 was an oddball philips head.
1 different intake valve
Half of the valve springs were installed narrow end UP
List of excessive wear:
Rocker shaft hold-down bolts loose on intake 1-2 towers
2 loose cylinder studs
And of the exhast valve guides were all WAY out of spec

So yes, this rebuild was money well spent!

actually the oil lines each have one oddball bolt stock.  The hardest ones to get at have both hex head and crosshead stock.

[Davidov]

actually the oil lines each have one oddball bolt stock.  The hardest ones to get at have both hex head and crosshead stock.

Huh, I figured that was the case since there were different part numbers. Still, I only had 1. So I made them all match.

[Davidov]

All Balls tapered roller bearing kit installed for steering stem. I installed this kit before on a 69 CL350, and the results were very pleasing.

My 750F had some low speed steering wobble that disappeared after the tapered bearing install!

[Davidov]

The heavy, ugly 630 chain had to go as well. It came new in the package when I bought the bike, so I had no reason to convert it back then.

New DID 530 non-o ring chain with new sprockets installed now.

[SOHC4 Cafe Racer Fan]

That rusty one was a problem waiting to go bad.

[Davidov]

First ride to work in a few months. Didn't miss a beat!
I've logged a little over 200 miles on the rebuild now (slowly but surely).

I did the first oil change at 40 miles. I'll do another one now (over 200), and then wait until 500 to do it again.
After that I think I'll started doing 1000-1500 mile regular intervals.

[MRieck]

That 530 chain conversion is a must. You probably pick up 2 HP right there.

[Davidov]

That 530 chain conversion is a must. You probably pick up 2 HP right there.

And no more "That chain is huge! It looks like it belongs on heavy equipment!" comments. 

[seanbarney41]

That 530 chain conversion is a must. You probably pick up 2 HP right there.

And no more "That chain is huge! It looks like it belongs on heavy equipment!" comments. 

I disagree that the conversion is a must.  Sure you pick up a couple pony's...but they are lost as soon as the 530 wears, gets sloppy, and stiff after 8000 miles or so.  My original 630 is hangin' in there after 26,000 miles!

[MCRider]

That 530 chain conversion is a must. You probably pick up 2 HP right there.

And no more "That chain is huge! It looks like it belongs on heavy equipment!" comments. 

I disagree that the conversion is a must.  Sure you pick up a couple pony's...but they are lost as soon as the 530 wears, gets sloppy, and stiff after 8000 miles or so.  My original 630 is hangin' in there after 26,000 miles!

I suspect modern 530s are as strong or stronger than old OEM 630s. So the xtra hp stays around.

What modern hyper bike has a 630 on it?

[Retro Rocket]

That 530 chain conversion is a must. You probably pick up 2 HP right there.

And no more "That chain is huge! It looks like it belongs on heavy equipment!" comments. 

I disagree that the conversion is a must.  Sure you pick up a couple pony's...but they are lost as soon as the 530 wears, gets sloppy, and stiff after 8000 miles or so.  My original 630 is hangin' in there after 26,000 miles!

I suspect modern 530s are as strong or stronger than old OEM 630s. So the xtra hp stays around.

What modern hyper bike has a 630 on it?

You are correct Ron, all modern hyper bikes have 520 , 525 or 530 chains and they are far lighter and stronger than the old 630, 630's will become obsolete, I'm not exactly sure why they haven't already. If a modern 200+ HP bike can get around with a 520-525-530 and not have the stretch problems, most modern chains are pre stretched anyway, then our bikes won't have any problems at all....

[seanbarney41]

That 530 chain conversion is a must. You probably pick up 2 HP right there.

And no more "That chain is huge! It looks like it belongs on heavy equipment!" comments. 

I disagree that the conversion is a must.  Sure you pick up a couple pony's...but they are lost as soon as the 530 wears, gets sloppy, and stiff after 8000 miles or so.  My original 630 is hangin' in there after 26,000 miles!

I suspect modern 530s are as strong or stronger than old OEM 630s. So the xtra hp stays around.

What modern hyper bike has a 630 on it?

all this I theoretically agree to, but I still have not had a 530 chain last anywhere near as long...and just going by feel alone, I think a chewed up sticky sloppy 530 eats more hp than a smooth running 630

You are correct Ron, all modern hyper bikes have 520 , 525 or 530 chains and they are far lighter and stronger than the old 630, 630's will become obsolete, I'm not exactly sure why they haven't already. If a modern 200+ HP bike can get around with a 520-525-530 and not have the stretch problems, most modern chains are pre stretched anyway, then our bikes won't have any problems at all....

[Retro Rocket]

You need to look at the tensile strength of the chains Sean, thats what is important, not just the size, there are good and bad in all chains...

[Davidov]

The 630 was just a "bigger is better" production change.
530 chains are easier to find. Like many said before, the technology of modern 530 chains has come a long way.

So I agree with it being a worthwhile conversion.

[Davidov]

Ongoing project update:
Taking a trip from DFW to Austin to watch Moto GP on the 750F, so I've been going over everything with a fine tooth comb.

I had a new tire mounted and balanced. So I took the opportunity to replace the rear wheel bearings. Left and Right bearings and the sprocket carrier bearing came in the All Balls kit. I really like their products, I've used the steering bearing kits on 2 bikes now. (including the 750)

The bearings were definitely original type, single sealed.

Shortly after the rebuild I noticed some slight "sweating"/"seeping" from the edge of the valve cover. No big deal, but then the right side by Cyl 4 started trailing along the cyl head while riding. 

I think I'll try the sneak in a http://www.cyclexchange.net/Engine%20Parts%20(Non-Cafe-Gaskets).htm Cycle X "leak proof" gasket without removing the engine. No frame kit either....I'm stubborn, I know.

[Davidov]

The other pictures didn't really show up.

HondaMan found that some valve cover gaskets were thinner than original parts and may cause a leak.
It looks like this Vesrah gasket may be one of the too thin types.

This is after a few minutes of warming it up after an oil change.

Going to have to change it out   

[seanbarney41]

Davidov, my F3 valve cover refuses to seal in exactly the same place, but on both sides.  I have changed the gasket twice, and stuffed Threebond into the gap with the cover loose and then torqued the crap out of it.  This worked for a few thousand miles but the leaks just come back.  I think my cover or cylinder head has warped.

[Davidov]

How bad does your F3 leak, Sean?
Have you looked into the Cycle-X leak free gaskets I posted above?

I prepped the surfaces very well, the cyl head was soda blasted during the machine shop work.
The first few hundred miles it would barely sweat on both sides by cyl 1 and 4.

I'm using a OEM type gasket, if that doesn't work I'll go with the Cycle X gasket.

[seanbarney41]

It's not too bad...just makes a mess is all.  I will be riding other bikes this season.  Time to pull that motor and freshen some stuff anyway.  I will check the flatness of the head, use a different valve cover and look into that CycleX gasket, although I have always had the best luck with Honda OEM gaskets.

[SOHC4 Cafe Racer Fan]

I had the same issue with my Cycle X valve cover. It was warped.