RestoCycle restomods a 1981 Honda CB750F

Hey, what projects are you planning or preparing for? CBX, other motos, workshop, WHATEVAH!
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NobleHops
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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

The engine paint turned out really well, very happy with that. As planned we let the parts cure for several days and baked them for an hour at 200 degrees, and the finish is smooth and consistent and there's been no chipping or flaking or any other bad behavior during routine handling as we prepare to reassemble it.

I did a skosh of machining on the head to clearance the B chain tensioner. The plan was to reassemble this coming Monday, but as I ran through everything I realize I still have some odds and ends to do first. I have a clutch basket kit that will take a few hours to install, plus a minor shifter modification, and I still need to drill and tap the head for the tensioner parts, and shorten and finish the tensioner screw. Nothing too major but in between interruptions that's all a solid day's work I guess.

Did some work on the wiring, installed Procom spark units, and the R/R. Also skinned the solenoid and its fusible link and installed an inline fuse holder with ring terminals there too, so we have banished all the old glass fuses.

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A couple of folks have cautioned me about the longevity of the aftermarket ignitors, so just for fun I took my stock Okis and filled them with JBWeld, as the potting was almost all gone. Let's see THIS leak :-)

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JBWelded in that oil cooler mounting boss, still need to mask and paint it though:

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Rebuilt all the brake calipers with new seals, rubber bits, pads, replated hardware:

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Did have to clearance the left caliper bracket just a skosh in the end, no big thing, although the right one was perfect as it was.

I did however get stuffed on trying to use a cool alloy VF750 torque arm and caliper bracket. It does not line up with the rotor. Not sure what the variable is, perhaps it would work with a different rotor, but I'm shelving that for the moment and will investigate a solution that just uses a different alloy torque arm.

Hope to have a big update in a week or so.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

We worked a lot on the engine and related items this past week, and it's nearly together.

Installed a new set of dampers and screws in the clutch basket. Good kit, good instructions. Clutch basket fingers were in good condition, and frankly so were the fiber plates and springs. Did replace the fibers with new, you know, WHILE WE'RE THERE. Clutch is good to go.

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Drilled and tapped the cam chain tensioner adjustment passages for the 8mm screws, and once those were all tidied up we reassembled the head, using the excellent viton valve stem seals.

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Drilled the primary chain oiler to oil the long cam chain...

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Ground out the shifter arm a skosh:

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Sprayed my head and base gaskets with the Permatex copper sealant:

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Installed new primary shaft dampers sourced from J.R. at CBX-tras:

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Installed the uprated oil pump that was rebuilt and blueprinted, plus an uprated pickup screen and the oil plate for use with the oil cooler and sump.

Replaced the big end and crank bearings, installed the primary chain tensioner, transmission, new engine oil seals:

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And with that done, we put the lower crankcase half on, bolted it all up to finish the sump.

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Flipped 'er over, installed the cylinder studs, and orings, and started on the top end.

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Installed new Honda brushes in the generator cover, tidied up the stator wires and grommet, cleaned up the slip rings and a little bit of rust on the rotor, and checked the rotor resistance at 4.5 ohms, good to go.

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Installed a modified R6 starter clutch, perfect fit and operation. Installed the advancer and ignition rotor.

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Skinned the starter mostly to clean and inspect it, found the brushes good. Cleaned up the commutator and grooves, cleaned out the carbon dust and lubed the bushings at both ends, renewed all the electrical contacts, replaced the seal, gaskets and orings, and put it back together. Bench tested good with a battery, good to go.

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Installed the 900F cams (thanks again Z3R0!) and set the valve clearances on the bench, with a run to the Honda shop to swap some shims.

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Installed the generator rotor, shifter, then the clutch:

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Installed the big-bore 65mm pistons and rings:

[img7]https://photos.smugmug.com/photos/i-LMbQfnG/0/L/i-LMbQfnG-L.jpg[/img]

Installed the ignition pickups and tidied its wires, cleaned and cemented the grommet with Hondabond.

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Coaxed the gasket over the studs and installed the cylinders, then the head, and torqued it down carefully, using reannealed copper crush washers. Installed the starter.

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Installed the AHM style guide and a set of Vince and Hyde cam chain tensioners and guide, along with one of his silent Morse "A" chains, and have a new "B" chain in hand too. Prepared to do battle with installing the cam chain sprocket on Monday morning, then will reinstall the cams and button up the last of the engine, and get ready to put it back in the bike.

And that is where we are at with the engine and the bike for now. Hope to hear it bark next week.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by steve murdoch icoa #5322 »

Nils, is that the clutch rubbers kit from Wout?
Like the looks of that table top engine stand.

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by FalldownPhil »

Great work Nils !!
Phil
When you are up to your ass in alligators it is sometimes difficult
to remember that your objective was to drain the swamp !!

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

Steve, that is indeed Wout's kit. Worked great.

That's a K&L engine stand, Very happy with it. Not terribly cheap at $160 or so, but as I told someone else, at this point if it were stolen, I'd replace it.

Thanks Phil!
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by barryadam »

Great work, Nils. Keep the photo essays coming.
That VHT color on the calipers looks really nice.

So does all of the other work.
Looking forward to the rest of the build.

Barry

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by Gearheadgregg »

Awesome Build Nils, That KZ 900 is awesome too ,As usual your builds are very well done and pictured, Keep up the nice work ! Greg :text-goodpost:

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by Goss »

Post a recent disaster Nils and make us all feel better! :lol:

Great work as always!

Regards

Steve
Onboard http://www.youtube.com/watch?v=EqWSsdKtd64
Bike http://www.youtube.com/watch?v=ofjFhEd3

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

Hey, I can do that.

Here's my engine, back out of the frame, with the head off, after I discovered that the upper cam chain tensioner was WAY too tight, causing unnatural sounds from the engine on startup.
IMG_5388.jpg
I hired a VERY experienced local guy to do most of the building of this engine. When he offered to discount his labor rate to remedy the problem he got 'voted off the island'. Should have just built it myself.

How's that Goss? :-)

N.
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Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by FalldownPhil »

Ouch !!
Is that a C-110 on the rack ?
Phil
When you are up to your ass in alligators it is sometimes difficult
to remember that your objective was to drain the swamp !!

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

FalldownPhil wrote:Ouch !!
Is that a C-110 on the rack ?
Phil
CA200 - 90cc of 1964-era Honda fury.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

NobleHops wrote:Hey, I can do that.

Here's my engine, back out of the frame, with the head off, after I discovered that the upper cam chain tensioner was WAY too tight, causing unnatural sounds from the engine on startup.
IMG_5388.jpg
I hired a VERY experienced local guy to do most of the building of this engine. When he offered to discount his labor rate to remedy the problem he got 'voted off the island'. Should have just built it myself.

How's that Goss? :-)

N.

Oh I left out the best part, that I spend the last two hours attempting to remedy. A little oil spilled out of the valve cover when we were messing with it. He grabbed a can of spray brake cleaner and proceeded to hose down the entire head and cylinders to tidy it up. Who can tell me what happened next? it was NOT me bashing his brains in, as much as I wanted to.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by daves79x »

Wow! Sorry to hear of your troubles with this bike. Do you have the fix for the camchain sorted out? I know very well the fix for brake cleaner sprayed on fresh engine paint!

Dave

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by Goss »

NobleHops wrote:Hey, I can do that.

Here's my engine, back out of the frame, with the head off, after I discovered that the upper cam chain tensioner was WAY too tight, causing unnatural sounds from the engine on startup.
IMG_5388.jpg
I hired a VERY experienced local guy to do most of the building of this engine. When he offered to discount his labor rate to remedy the problem he got 'voted off the island'. Should have just built it myself.

How's that Goss? :-)

N.
I just knew you would rise to the challenge Nils, I just didn't think it would be on this scale! Sorry to hear of your disaster, you get 10/10, well he does and shot himself in the foot too. Not a recommendation.

Once you have put it right your skills will outweigh all of his "experience", you would have thought that he would have spotted the issue on assembly.

Sounds like he needs some customer service training...

Regards

Steve
Onboard http://www.youtube.com/watch?v=EqWSsdKtd64
Bike http://www.youtube.com/watch?v=ofjFhEd3

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Re: RestoCycle restomods a 1981 Honda CB750F

Post by NobleHops »

daves79x wrote:Wow! Sorry to hear of your troubles with this bike. Do you have the fix for the camchain sorted out? I know very well the fix for brake cleaner sprayed on fresh engine paint!

Dave
Yeah, I'm gonna beat his brains in. I cleaned and cleaned and cleaned it yesterday, wiped it with denatured alcohol and resprayed the areas where the paint lifted and later today I will bake it and see if it's as durable as the other with the scientific fingernail test. I really do not want to strip and reprep the entire thing.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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