Topic: 78 750K Back from the dead

[PGF550F]

I posted about this 750 I spotted a couple years ago, I ended up getting it and have been slowly bringing it around.My first bike was a 77 550F. That got me hooked and I found this forum. I have been riding the 550 for a couple years now after rebuilding, repairing and learning a lot with that bike, but I think I have taken it as far as I intend to go with it so I started looking for a 750. I picked up this 78 750k in April 2015 and have slowly been working on it and piecing things together, It has been slow going because my wife and I have 2 kids and run on my income alone so I have to be sure to save ca$h where and when I can.

 I once heard that you can do a project Fast, Right or Cheap… pick 2 because you won’t get all three!  I also don’t get a lot of time to pull wrenches due to work and husband/father duties but I find as much time as I can. I live in Canada so without a heated workspace November-April is pretty much lost due to cold weather. I was able to use the heated shop at work this past winter which really moved things along. Here it is in all its glory, extended front forks, high rise bars, aftermarket straight pipes, chopper seat, lowering blocks, no airbox, no points cover, no side covers, no key (no ignition switch), no headlight bucket, no sidestand… and many other missing or broken parts. It did come complete with several pounds of pasture mud crammed in the exhaust and all over the right side. I guess the guy I got it from pulled it out to the pasture from the barn (with the bike laid over on the right side) using his ATV because the rear brake was locked on. Why are people like that?  Given my education with my last project I am sure this project is within my skillset now (plus who doesn’t like a challenge).

[PGF550F]

First off the motor was seized… Tried for months to free it up, ATF/Acetone down the plug holes, PB blaster, Kroil, ATF/Kerosene, Diesel fuel… I tried them all coupled with rocking the Alternator bolt back and forth, all I did was successfully remove the alternator bolt. I tried rocking the rear wheel in gear and all I got was a sore arm. This made me look for a donor motor and I ended up finding a somewhat? complete 76 750F. It was stored in an old grain bin and after some researching about sprocket flanges/output shafts and drive flange differences between model years I decided to go for it. The motor was free and there are lots of useable parts in good shape because it was stored inside. From the looks of what is left of the wire harness; it was abandoned due to a wiring issue.
Out in the sun for the first time in how long

[PGF550F]

I pulled the motor in my backyard by myself using the “lay the stripped frame on the right side and lift it off” method. Worked awesome. Had the motor/frame separated in literally a couple minutes once I laid it over gently. I didn’t completely strip the frame either, still had a rolling chassis and it was still very manageable.

The motor on the 78 was slightly more challenging to remove but I had practice so it went fairly easy as well. I’ll use it for parts and eventually tear it down to see what’s going on, I suspect rusted rings/bores but honestly I won’t know until I tear into it.  I swapped the 76 motor into the 78 frame and went to work servicing the wire harness before I hooked everything back up. I cleaned up almost all the contacts and changed most of the multi-pin connectors on the harness and the one coming from the alternator. My multi-meter and wire diagram got a workout. I repaired/rebuilt the switches and got everything working properly. I used some of the 76 F parts like the key switch, headlight/signal light mount and some mounting tabs for wires and cables up front.

[PGF550F]

The side stand mount was bent and tore out so I spent some time in the driveway re-welding and straightening and then did some touch up paint afterwards.
I am using a side stand from a 550 because I had an extra one.



The 78 came with a set of carbs that I de-racked and cleaned meticulously. I have cleaned lots of carbs before but this was the first time I had ever separated a multi-rack of carbs so that was a bit intimidating but not too bad once I got into it. I used a toothbrush to scrub everything and carb cleaner and compressed air to clean and check every passage/circuit. I cleaned and re-used all the stock Keihin brass. No aftermarket allowed here.

de-racked

reassembled


I got new Norma brand Torro smooth band clamps off Amazon to replace the beat up, bent and bottomed out stock airbox and insulator clamps and they work and look much better. 9mm wide with rolled edge and they fit just like factory.

The spark advancer needed some attention so I cleaned, re-lubed and used a little paint in the engravings to better see for timing.

I got the motor started up after doing a 3000k service on it (valves, points, plugs, etc.) I was amazed how quickly it started up, I kicked it over until the oil pressure light went out, turned on the kill switch and it fired up on the second kick. Just awesome.  I used my test tank off an old lawnmower for the first few starts because I didn’t want to fill up the tank that I know needs re-painting anyway. Those straight pipes are obnoxiously loud and obviously have no backpressure so I’m going to make a set of baffles and run them and see.

[PGF550F]

Well technically second start  

[PGF550F]

Once it ran I knew I had to address the chain drive/offset issue. The 76 F motor uses a 530 spocket and a 10mm shorter output shaft than the 78 K motor. Since I am using the 78K swingarm and rear hub, I had to switch the rear cush drive out for a shorter (earlier) one. I just so happened to have one from the 76 F rear wheel. Got to love parts bikes! Then I added a 10mm spacer to the axle on the cush side and everything bolted up, lined up and works perfectly. I also still have plenty of chain to tire clearance with a 130 rear tire.

F drive flange with 530 rear sprocket


I had to use a press to remove the rear brake cam as it was solidly seized in the brake panel. Then I replaced the rear brake shoes with new SBS ones. While I had the wheel off, I cleaned up and removed the lowering block mounts from the swingarm and shot some paint on the bare metal. More driveway time


I cleaned and repainted the brake caliper, had to use the grease gun method to remove the piston and pad. That works soo well I don’t think it’s ever worth trying anything else. 1/8 NPT standard grease gun hose threads into the caliper just enough to grab the threads and a couple pumps on the lever and out it comes, nice and controlled.

Not even the master cylinder still connected and pumping brake fluid could budge this thing. 14000 PSI out of the grease gun did the trick.

 I still have to order a new Honda seal and I think I’ll get a phenolic piston from Godffery and ss brake lines from Slingshot when the funds allow.



I cleaned up and rebuilt the forks from the 76 F and wow, they needed it. Fresh seals/oil and got them mounted up… What a different stance now! I think the extended forks were +3” over, and bent, ha. I’m essentially using the entire 76F front end (forks, wheel, fender, brake caliper and mount arm)
Hmm, why dont these seal anymore...

[PGF550F]

I tried my hand at polishing some aluminum engine pieces. Wetsanded with 600-1500 grit and then just did a quick pass with emery compound on a spiral sewn wheel. Looks like a slippery slope, once you polish one piece it makes the next one look soo dingy. Only done a couple parts so far.

[Jimray23]

Wow. Its coming along nicely. Keep up the good work.

--------------------------------------------------
Jim
I really don't see why people ask for advice if their not going to take the advice given.

[Marco83]

keep them coming.

[Stev-o]

Wow, I am really impressed with your skills and progress.  Great job on the carbs, the bike sounds good!  Google beer can baffle, this might be an option for you.   I really like those hose clamps, better than others I've bought on Amazon.  Subscribed....

[RAFster122s]

Congrats on your progress and persistence.  One method some have used to separate rusted pistons to bores is fire, yep, fire after you pull the head.  Provided you can separate it on the frozen motor.  Viking style removal method...marshmellows just don't taste good roasted over petrol fires so save them for your charcoal.

Nice work on everything thus far!   Yes, polishing is a very slippery slope...break out the ice cleats or your Yak-Traxxs

[SOHC4 Cafe Racer Fan]

Nice work.  Now to unseize that motor!

[PGF550F]

Thanks for the encouraging comments folks! I have read about some of the members here setting fire right in the bores after they pull the head, I might have to resort to that when the time comes. For now though the 78 motor will sit(still with diesel soaking in the cylinders) while I get the thing roadworthy. Nice to have a spare motor to build up though if needed.

Some relatively boring wiring photos:
before

 Organizing the mess - You can really see the extended forks in this photo, its a bit over-exaggerated by the perspective though


Nearly perfect points cover from forum member chewbacca5000. Polished up nicely, Thanks man!


Cleaned up the exhaust collars with a CLR dip and decided to paint them because there was some exposed metal

VHT header paint

[PGF550F]

The rear fender and taillight that was on this bike was in pretty bad shape when I got it. I swapped it out for a rear fender and taillight from a 75? 550K model. The mounts line up perfectly at the rear seat hump but the  frame rail mounts are a little further back. I drilled a couple holes through the mounting bracket of the fender and welded nuts to the backside. It certainly looks better than the original bent fender but its also a bit shorter too which I like.
Original 750 fender up top, 550 fender on the bottom.

 

[SOHC4 Cafe Racer Fan]

I like the shorter 550 fender.  In fact, I bobbed mine on my 550. 

[PGF550F]

Ya I like the shorter rear fender and was surprised how easy it matched up. The 550 was really just the 750's "little brother" I think there are a lot of interchangeable parts between the two.
I started on stripping and doing bodywork on the tank. I used a wire wheel on my angle grinder to remove all the old paint(no nasty paint stripper to deal with, just dust instead).

A couple different colors for some reason


Its really cool to see how the original paint was protected under the factory stripes.


I totally could have just shot clear over this. The patina was awesome, the tank is in phenominal shape, just a couple smaller dents and dings and the wire wheel left a nice finish but... Im not building a rat rod so I snapped some photos and forged on.

Primer and guide coat(body fill almost entirely done by this point)



After I block it out again Ill see how close I am to finished and then its on to primer sealer and then color/clear. I’m repainting back to the original -for this tank- Gold (iconic 750 color so when I saw that it was originally gold the decision was easy). I still have to order some new tank stripes.

I cleaned up the surface rust on the bottom before primer/paint


That pretty much catches me up to where I'm at. I have to plan when I am going to spray to make sure the humidity isnt too high. Its been raining like crazy here lately so I'm held up a bit on conditions for paint. The shop at work isnt any better for humidity either.

[Stev-o]

Do you plan on using Spraymax 2000 Clear?

[SOHC4 Cafe Racer Fan]

The 550 was really just the 750's "little brother"

Yes, there are some swappable parts -- most notably the 550 swingarm will give you another inch.

Even more than a little brother, the CB500/550 was a super sport style bike akin to how modern 600cc super sport bikes are to liter superbikes.

[RAFster122s]

Was the orange rust beneath the paint?  Eek!

[PGF550F]

Was the orange rust beneath the paint?  Eek!

The orange you see is how the original gold paint looked under all the previous owners substandard rattle can paint jobs.

I do plan on using the SprayMax clear. I used it on my 550 tank and it worked well, best part is not having to set up and clean my spray gun afterwards... for a small job like this the spraymax is perfectly suited.
550 tank:

after wetsand and buff: 

[Stev-o]

Nice paint work!

[PetesPonies]

Nice job. Having done many car restorations and some bikes, You did a great job with something that really wasn't worth the effort. But you brought it back from the grave. I went and looked at a classic vehicle once that was in such poor shape, I told the seller if he offered to me for free, it wouldn't be worth it  And I specialize in rust repair. Well, he did, he offered it for free and no I didn't take it  LOL  Great job on yours !

[PGF550F]

Nice job. Having done many car restorations and some bikes, You did a great job with something that really wasn't worth the effort. But you brought it back from the grave. I went and looked at a classic vehicle once that was in such poor shape, I told the seller if he offered to me for free, it wouldn't be worth it  And I specialize in rust repair. Well, he did, he offered it for free and no I didn't take it  LOL  Great job on yours !

Ya cheap projects always cost the most in the end You know what they say, one mans trash is another ones treasure. I really appreciate all the positive comments folks.

[PGF550F]

Fack, just spent the last 45 minutes fixing photobucket links! Still been working at putting things back together.  Base coat/clearcoat done on the tank. New rubber gas cap seal. Reinstalled the petcock.


After wet sand and buff:


Don’t want any arguments about how much metallics are in this paint job


Still need a set of tank stripe decals, chrome trim and badge$.

Got some OEM carb to airbox boots and got the airbox installed. Built an aluminum electrics cover. Replaced clutch cable, speedo cable and throttle cables. mounted master cylinder and brake lines. Getting to the smaller things now.


Mocking up tank and seat combo.




Sadly I couldn’t get it 100% road ready this season. Winter is pretty much imminent here now. Only be a couple more weeks before we get snow and it’s routinely below freezing here at night now so I just pushed it into the heated shop at work the other day.
Up next: new Tires and tubes, front brake piston, new plug caps and plugs, seat mount/hinge/latch, exhaust baffles, likely a new chain, install new grips, hopefully save enough to fit in a HM ignition box too. Also plan to check advancer shaft runout and try out my new to me dwell meter and timing light. Been doing everything static up till now.

[PetesPonies]

Paint looks really good, congrats!!! Will you go back and reclear over the decal or leave it alone?