Topic: Senior project for high school - 78 CB750K

[Restoration Fan]

Time to start ordering some of the bits we'll need to start reassembling this puppy.  For gaskets, any opinions on the Vesrah complete set http://4into1.com/vesrah-complete-gasket-set-vg-157-honda-cb750-1974-1978/versus the NE complete set http://4into1.com/ne-brand-complete-gasket-set-honda-cb750-1970-1978/# from 4into1.com?

Other than the fact that one is about double the cost of the other and you usually get what you pay for?

[jrich44]

How much do you guys usually pay for soda blasting?  I just got a quote from a local restoration shop and he said he estimated 5 hours @ $80 per hour.  That seems awfully steep to me.  Am I just way off base on my estimate here?

I was charged $20 to do the engine and all it's side covers. Turned out really well.

[grcamna2]

Time to start ordering some of the bits we'll need to start reassembling this puppy.  For gaskets, any opinions on the Vesrah complete set http://4into1.com/vesrah-complete-gasket-set-vg-157-honda-cb750-1974-1978/versus the NE complete set http://4into1.com/ne-brand-complete-gasket-set-honda-cb750-1970-1978/# from 4into1.com?

Other than the fact that one is about double the cost of the other and you usually get what you pay for?

Go w/ Vesrah,I know it's more $ now but the quality is Way better than Chinese gaskets,you should be able to get a better deal if you check around.The gaskets are oem quality and you'll be glad you bought them for the many years you own the bike. 

[Restoration Fan]

Got the Vesrah gaskets ordered, along with rear chain tensioners, new headlight chrome rim and a few more bits and pieces.

Do you guys usually clean up the existing wiring harness or, if you replace it, which one do you replace it with?  I have found a few that list as replacements but I remember reading in other threads where Hondaman and others mention that the aftermarket replacements are missing a few of the needed wires.

[madmtnmotors]

Do you guys usually clean up the existing wiring harness or, if you replace it, which one do you replace it with?  I have found a few that list as replacements but I remember reading in other threads where Hondaman and others mention that the aftermarket replacements are missing a few of the needed wires.

I have refurbished a few, cleaning or replacing every connector and switch:

http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191

[Restoration Fan]

That's a fantastic write-up.  Thank you for sharing that.

[Restoration Fan]

Ever have one of those 1 step forward, one step back kind of days?
Looking at the speedometer and tachometer, we determined that they were in very good condition under the glass and there was really no need to take them apart to clean them up.  Instead, we only needed to strip the black paint, tape them up and paint the sides.

So, speedometer cleaned and taped....check.


Tach cleans up nicely and lift it up to inspect the final work before we get ready to tape it...


....and I drop it on the edge of it and dent the aluminum face. 

[SOHC4 Cafe Racer Fan]

Arrrghh!!!  We've all been there!

[calj737]

Just a little hint: you don't want to drop them. The edges dent very easily.  Guess we should have told you sooner.

(Sorry, could resist an attempt at levity whilst you toil away in frustration)

[madmtnmotors]

A half or quarter circle wooden block, laid on the glass to push outward, cut to match the inner radius of the gauge face, might be used to press/tap the edge back into shape.

DON'T HIT THE GLASS IF YOU TRY TAPPING IT OUT!

[Restoration Fan]

Well, since it was my stupidity that messed it up, this one is on me to fix.  So I took the tach apart and was able to get the trim ring off without completely messing it up.  But it ain't the best looking piece of trim in the world now. 



After removing the glass and all the other innards, I was able to do a decent job of fixing the dent.  It's not flawless but it passes the eyeball test and looks good enough to me at this point.



Now, there are 2 challenges:  sanding out the minor scratches that occurred while removing that chrome ring that joins the top & bottom pieces.....and figuring out how to fix that chrome ring itself so that it doesn't look like a red-headed step child when it's reassembled.  Of course, reassembly is probably guaranteed to be a bear as well since no good deed goes unpunished. 

[madmtnmotors]

Replacement rings can be had, just not sure of the source. The ones I've seen are actual crimp on rings, not the hawky bolt on covers. Maybe someone can recall a source?

[Restoration Fan]

Replacement rings can be had, just not sure of the source. The ones I've seen are actual crimp on rings, not the hawky bolt on covers. Maybe someone can recall a source?

I actually posted that a link would be welcomed but your "crimp on" keywords helped me to realize how to change my search and find them.  So thank you!!!

http://www.cb750faces.com/cb750faces.nl/en/honda-cb750-k2-k6-f1/14-honda-laverda-crimp-ring-set.html#

[Restoration Fan]

Looking at the link I posted in the post above for the tach crimp rings, it shows that they fit the K0 - K6 but doesn't mention the K8.  Does anyone know if the tachs are the same size on the K8 as they are on the K0's through K6's?

[Stev-o]

Highly doubt they are the same, K0-2 are diff than K3-6 too.

Marcel is a forum member, send him a PM....


http://forums.sohc4.net/index.php?topic=125803.0

[Restoration Fan]

Highly doubt they are the same, K0-2 are diff than K3-6 too.

Marcel is a forum member, send him a PM....


http://forums.sohc4.net/index.php?topic=125803.0

Thanks, Stev-o.  Message sent.

[Restoration Fan]

So do you guys always replace the main bearings when you take the cases apart or do you use the PlastiGauge and test them?

I'm already ordering new piston rings but I'm wondering if I should look into getting new main bearings as well.

Also, in case this helps anyone in the future, I contacted Marcel from cb750faces.com who, as Stev-o pointed out, is a member here.  After showing him a couple of photos of the rear of the tach, his belief is that those crimp rings I linked above will indeed fit the tach from a K8.  I'm going to order them and see; will let you guys know if that turns out to be the case.  He also offered a full refund if they don't fit.  Gotta love great customer service!

[Stoli]

Since the bike has under 20K, I would just check them with the plastigauge. They are probably fine.

[AintNoEasyWay]

What kind of engine work are you planning on doing? Will you rebuild the top end as well?

[Restoration Fan]

What kind of engine work are you planning on doing? Will you rebuild the top end as well?

We checked and measured all the stuff that the manual called to be tested.  So far, everything in the engine is well within acceptable tolerances.  We haven't put it back together and torqued it down to PlastiGauge the bearings yet but we're going to do that. 

As far as the top end, we're lapping the valves and replacing the piston rings.  Also, going to replace the valve seals.

We were supposed to take the engine over to my buddy's today to soda blast it.  Didn't get to since we had to have our 10 year old English Setter (Logan's Rambling Wreck....aka Ramble) put down today.  Since this was Logan's dog, I didn't think he nor I would be in the mood to work on the engine today. 

[dave the welder]

very sorry to hear about your dog had to put down 3 myself over the years.i feel your loss

[Restoration Fan]

Thanks, Dave.  He was a good one.

I also owe a great big thanks to SOHCRon for his epic build thread.
 Reading through it, when I got to the exhaust part (http://forums.sohc4.net/index.php?topic=86697.msg1428283#msg1428283) and he mentions that the copper exhaust gaskets often get crushed into the exhaust ports, I thought to myself, "What copper gaskets?  We didn't find any copper gaskets when we removed the headers."  Well, a few minutes later Santa Claus (aka UPS) arrived with 3 more packages.  One of them contained the Vesrah gasket kit and, lo and behold, there are copper gaskets in there.  So now it becomes a game of Copper Gasket Hide & Seek.

Well, a little check with the flashlight showed little hints of copper inside the exhaust port.  But they were mashed so flat and the carbon was so strong on them that, even after multiple cleanings, they still appeared to be part of the port.  Took a flat screwdriver as he advised and "Voila", these puppies came out.


So, SOHCRon, my hat is off to you.  Not only for your awesome thread and the work you put into that thread for all of us.  But moreso because you saved me much weeping & gnashing of teeth as we got ready to reassemble the exhaust and headers.

[toytuff]

very sorry to hear about your dog had to put down 3 myself over the years.i feel your loss

Agree.

tt

[Restoration Fan]

Took the #4 carburetor bowl off to see how much gunk was in the bowl and was very pleasantly surprised to find mostly dust in there.  Looking at the carb rack did generate a few questions though:

a.  Each of the carb bowls only had 2 of the 3 screws holding the bowl onto the carb.  I'm assuming this means that one of the PO's had likely taken the bowls off before, right?  Also, at least 2 of the screws are not the correct screw because the screw head is some kind of hex head or something that looks pretty stripped.



b.  How long do you normally leave the bowls soaking in Berryman's if they're in pretty good shape?  I forgot to take a photo of the bowl before I put it into the carb dip to soak but it was in good shape and the rubber gasket was even in good shape.  It could possibly be reused but I'm going to order replacement ones just to eliminate one possible source of leaks.  Here's a few shots of the floats though and what looks like dust on them.




c.  After just spraying some carb cleaner on the carb exteriors and hitting them lightly with a few cotton swabs, they look like they'll clean up pretty well.  Is there any advantage to taking the carbs off the rack since it looks like we could clean the exteriors without doing so....i.e., is it customary to soak the entire carb in the Berryman's for some amount of time?

[Stoli]

The stock bowl screws were phillips heads and they tend to get stripped so replacing them with the hex head is common. Check the female threads on the missing screw holes to make sure they aren't stripped. The hex heads tend to hold up pretty well, so if they are stripped, someone must have used the wrong size allen wrench in them.

I'm not a carb expert but I don't soak them in the Berryman's so I can't answer that. I typically disassemble the entire unit, soda blast the outsides and clean the internals with a can of carb cleaner, some small wire for the little holes and an air compressor. Make sure you pull out the slow jet even though the manual says not to. You'll never get it clean if you don't.

They don't look too bad in the pics so you might get away without removing the carb bodies from the rack. At the very least, remove the floats and all the jets and screws and blast the cleaner in every hole you find. Also suggest you take off the accel pump on carb 2 and give it a good cleaning. Fuel tends to settle in the passages and clogs them up over time.

Edit: Also be sure to take the keyhole covers off and blast the barrels with cleaner.