First CT70 Build...humble beginings

[geek777]

Hey Fellas,

Got this 1970 K0 from a friend earlier today at a very reasonable price. Going to use it as a project to do with my twin boys. They seemed pretty excited, so we'll see how things go. One of them wants to do all the research and the other all the work...it's not gonna happen that way, but it was cool to listen to the plan it out

It's pretty rough but the frame seems intact with no cracks but does have some internal rust. We're going to strip it down tomorrow and check all the bolt holes to make sure none of them are stripped out.

Loaded in the van...


No title came with the bike and not sure we'll try to register or title it, but I'll be pulling the vin tag before the respray.



Frame vin code




Unloaded...4 boxes of assorted stuff. 2 motors, one mostly complete, the other of questionable use. Both are 3 speeds I'm told. Neither is likely to be the original. Also came with new piston and rings, hosed head light buckets, and 2 engine guards and bunch of little stuff in rough shape,



Some of the box/bin contents...extra fork uppers, extra swing arm etc..




Couple of extra rusty rims and hubs



I'm still reading up on the some of the great project builds and see I have a lot to learn. Any suggestions or input is welcomed, know many of you have done multiple bikes and I would prefer not to make any bonehead mistakes if they can easily be avoided.

 

[69ST]

Welcome aboard :wave: and congrats. Looks like a good base for a restoration project. This should be an awesome father & sons project on a number of levels.

Looks like a really early black tag K0. Yeah, I know, the collector emphasis is on the earliest models, with silver VIN tags. Still, it's a `69 the intro year for the CT70...and it's among the first to have the later style VIN tag, with the black background and silver writing, still a point of minor distinction.

For starters, use great care when removing the VIN tag, it's in amazingly nice condition. I suggest closely inspecting the frame in the triangle, where the fuel lines, spark plug lead and airbox boot pass through. These early frames are notorious for developing stress cracks in this area, above the upper motor mounts. If you find a couple of short, hairline, cracks (one on each side), don't despair they're easy enough to weld, since you're going to repaint anyway.

Rust usually isn't a big deal. The original paint didn't seal the metal, so surface rust is common and can be widespread. As long as you don't find any rust perforations, it's only a cosmetic issue...that can be solved with scratch filler and block sanding. I would strongly suggest having the frame tins glass bead blasted, using low pressure. It's he only way to remove all traces of rust & old paint from every crevice with virtually no removal of solid metal. From the looks of this bike, in your photos, the frame looks solid and straight. For that matter, the original paint appears amazingly vibrant, for 45-year-old lacquer. I suspect this is of those desirable specimens that looks rougher than it really is.

 

[geek777]

Thanks RacerX.

Gonna get some PB Blaster and soak the heck out of every bolt left on the bike and see what can be easily removed. I'll take some more close up pics of the rust on the insider area of the frame as well as flip it upside down and have a really good look at the engine mount area. I did so quickly when we picked up it yesterday and did see anything, but it's possible I missed something. Was thinking to also go through what I have and see what nuts and bolts are good, start to work on a list of what's missing and see if we have can bolt in the engine and any other good parts...sort of a mockup.

There are no dents or wavy metal areas I've found and no areas of perforation but won't know for certain until it's better cleaned up. Maybe after we inventory what's here and compare to the service manual to see what's missing and have our list, we could then tear it down and get it ready for paint.

I've got a Sears plastic tub/hoper style sandblaster (not the greatest thing really) but suspect glass beading is usually done in a media cabinet? If I recall correctly, glass media is more expensive and generally reused, correct? Is there an alternate type of media that would be ok to use which wouldn't damage the metal? Maybe it's better to just pay somebody to do it?

 

[kirrbby]

Welcome geek777. I think you're on the right track with the PBlaster, and as far as the blasting, call and check some prices. It would be a lot of work and mess without a cabinet. Don't forget all the other painted parts too, might as well get everything together and cleaned up at the same time. As racerx said take special care with the vin tag, I think its riveted and glued on. That should be a great bike to do with your boys. How old are they?

 

[larry9901]

I get my glass bead from trinco. They are in Fraser michigan, but can ship anywhere.
I typically use their trim mix #4. It's about 45 dollars for 50 pounds.
It's 4 parts glass and 1 part 220 aluminum oxide.
Works real well and lasts a long time.

I also use it for my business. I engrave plastic aluminum molds and the blast is used on them to clean once etched.

 

[69ST]

My choice/recommendation of abrasives has nothing to do with the purveyor. Trinco is local...just the other side of town and a good outfit. The blast media should be selected for your specific circumstances. IMO, aluminum oxide is a really bad idea, unless you have a specific need for material that hard & aggressive. It does a terrific job etching glass, not what you want with a cabinet. It also devours blast gun bodies, nozzles & orifices. No argument, the cutting action is fast and it lasts a long time. There's just a lot of collateral damage to consider.

Glass bead is a lot softer (~5.5 vs 9.0 for aluminum oxide) and gentler...on everything with which it comes into contact. Thus, it can actually be cheaper to use, overall. Also, you won't have a profiled surface, with virtually zero removal of solid metal. The tradeoff is slower rust removal.

If you don't have a cabinet and enough compressor to power it, you're facing a nightmare DIY project. For a one-off, it'd be cheapest to farm-out the blasting chores. Just stay away from commercial outfits that are geared toward large-scale items...like salt trucks, dumpsters, railroad car chassis, etc. They'll do the job really cheap, and in mere minutes, but the blasting is far to aggressive...enough to remove a lot of metal, leave you with emery board like surfaces, possibly even cause damage.

I wouldn't want to do any media blasting around my shop outside of a cabinet...too messy. On the other hand, a big cabinet might eat too much real estate for your situation. Thus, if you're a longterm hobbyist who will have need of media blasting in the future a small, benchtop, cabinet might be a good compromise. You'd be able to handle everything yourself, except for big items, like the main frame section...which would be cheap enough to farm-out, occasionally.

 

[geek777]

Thanks Guys.

Appreciate the warm welcome and the advice!

Did little inventory, laid things out, took a few pics and thought I'd share :thumb:

There's a few things we can use, but a lot is missing or unusable.

The more complete of the two engines.





Engine serial...I've no idea if this was original to the bike or what year it came out of.



One of two engine cradles...(or whatever the proper term is)



Second cradle with spark plug guard.



Rear tag bracket. Seems to be in good shape other than rust. Surprised how beefy some of these pieces are.



Second, partial set of forks





Harness and coil. The harness was in better than expected condition. Almost no brittle wires, no missing ends and the connectors themselves aren't dry rot or anything. Almost makes me wonder if the harness isn't out of this bike.



Second engine...less complete, shot of the serial.



Bracket for the coil is toast. Not sure it came off this bike, the frame in the area it mounts isn't this bad.



Second swing arm and wheel. Axle stuck...the arm looks to be in slightly better condition that the one on the bike.



Frame inside





Seat area of frame, inside



Bent fork lowers



New piston and rings included.







The parts came from Vietnam...not sure about the piston or rings...thought maybe the 87 denoted the size??



The boys were determined to test the gas tank for leaks...not sure why this was important, but i went with it





The rough and easy to identify list of missing and needed parts the boys put together



Agree that it would be best to get the parts blasted instead of doing it myself. I'll start calling around soon.

Chased the threads in most of the frames welded on nuts. Understandably, some were worse than others but none appeared to be stripped. Found a broken bolt for the right side lift handle so I'll be drilling and using and easy out on that. Could find the frame bolts for the engine guard, so couldn't chase those threads. Didn't see any cracks in the engine mount area, but want to wire brush things in that area and look more carefully before spending money on blasting the painting the frame.

Think I'm going to look for a hard copy service manual so we have something other than a computer to reference while out in the garage.

Thanks again for the tips and pointers. Much appreciated.

 

[b52bombardier1]

For as much glass bead blasting as you will be doing, you will be money ahead to buy your own large Harbor Freight blasting cabinet. Some things will not fit but many will. I used my cabinet on my recent four wheeler rebuild so I can almost guarantee that you will find future uses for a cabinet.

Rick

Two CT90 and two ST90 bikes

 

[69ST]

I'll have to dig up some detail shots showing a frame that has the stress cracks. They can be tiny and nearly impossible to see, until the frame has been blasted back to virgin metal...if they're present, that is. The surfaces should be blasted prior to welding anyway. No biggie, either way.

So far, the worst thing I've seen is a bent/rusty lower fork leg. Those can be replaced easily & cheaply. Best offhand guess is that both of those engines are readily rebuildable. The engine guard with the square tabs, for the plug guard, is correct for a bike with a 1969 d.o.m. The inside of the frame does look pretty rusty, but it appears to be nothing more than heavy surface rust, nothing worth worrying about. If you're after cosmetic perfection, a little bit of epoxy scratch filler...plus a LOT of elbow grease (a.k.a. block sanding) will do the trick - if you wish to enter this war of attrition.

The CT70 never had the "lift handle", only the non-US-spec ST70 & ST50 Dax models, fitted with centerstands did. Of course, those models didn't have the CT70 engine guard. All CT & ST frames of this era have both the engine guard and "lift handle" bosses. That lift handle is only useful for rocking a bike backward, onto the centerstand. CT70 K0s all had kickstands. Thus, the handle is not only incorrect, it's worse than useless - a non-original part that scars the paint at the mounting points. The better solution, imho, is a new pair of the OEM rubber plugs for those unused threaded bosses. *GROMMET PLUGS HOLES_IN FRAME 12/10A (50B)

 

[geek777]

Ordered some parts today. Gonna go for a mostly stock rebuild. Fork leg rebuild kit, all-balls wheels and fork bearings and seals ordered. Got new brake shoes too. Taking the frame/forks/swing arm for paint on Saturday. Other parts, including headlight bucket and shocks won't likely be here till Monday.

This is the parts list:

1 x Honda Mini Taper Bearing setAll Balls Brand CRF50 XR50 CRF70 XR70 Z50 CT70 (W-22-2002)
1 x All Balls - Wheel Bearing and Seal Kit - CT70 '69-94 - Rear (W-22-51300)
1 x Honda CT70 KO Fork Legs Kit (C227-26-158)
2 x TB Brake Shoe set Z50 CT70 SL70 XL70 XR75 ect (TBW0272)
1 x All Balls - Wheel Bearing and Seal Kit - CT70 '69-94 - Front (W-22-51072)

Now to get the VIN tag off without destroying it

 

[cjpayne]

....Now to get the VIN tag off without destroying it

I bet someone here(b17, hint, hint) knows a trick on how not to do that.

 

[geek777]

Thanks cjpayne. Had contacted bc17a (assuming that's who you mean?), hoping he could do the paint for me but he's unable to do it until July. As such, I'm having a local guy do it, but he won't play with removing the VIN tag.

I'll search on it again..did so the other night, but went down a rabbit hole of a thread I'll be ping Todd if I find I'm struggling.

 

[cjpayne]

IMO, he does such good work, I would wait. Candy colors are tricky and best left to the best. A year from now you'll be looking at your bike and I can see you thinking, "I'm glad I waited". Especially when someone says, "Nice bike,.....who did the paint?"

 

[geek777]

IMO, he does such good work, I would wait. Candy colors are tricky and best left to the best. A year from now you'll be looking at your bike and I can see you thinking, "I'm glad I waited". Especially when someone says, "Nice bike,.....who did the paint?"

I agree, his work looks to be top notch and the price is reasonable. Unfortunately, the bike is for my boys and their birthday is when we hope to have it finished...that's in July. Maybe he can do the next one

 

[cjpayne]

Here's an idea that will save time and money. Since boys will be boys and will most likely aquire some dents, dings, and scratches, you could leave the original paint and/or primer/duplicolor it any color you want. When they get older and want cars............well, you get the idea.

 

[geek777]

More goodies ordered today!!

Seat
Bars
knobs
forks seals
fork boots
steering nut
bridgestone tires
tubes
fenders

Held off on shocks (not knowing how big a deal it was to remove the colored caps to paint) and headlight bucket...wasn't sure if I wanted to spend 75 for bucket and z50 style bulb assembly...want to read up more on both of these items.

Gotta remove the vin tag today and get the frame and forks over to the painter. Gonna try the razor blade method of easing the rivets out before going and buying a dremmel type tool from harbor freight.

Hope to be posting up some pics soon

 

[cjpayne]

Frame Data Plate Honda CB 750 CB750 Four K0 K1 K2 K3 Frame H2 | eBay

Just in case you damage your VIN tag, these guys may be able to help. I've heard or read somewhere that a trophy shop can replicate the VIN number stampings(Don't hold me to that!lol)
Hope to see a build thread or before and after pics. Good luck.

 

[scooter]

To get the vin tag off, I carefully get a center on the brass brad and get a pilot started with the smallest bit you have. No bigger then 1/16. Once you have the pilot use a larger bit and drill off the head. I then slide a piece of fishing string behind the plate to break the glue. A hair dryer helps to soften the glue if you keep breaking the string. Dental floss also works. After the plate is off just tap the remainder of the brads into the frame. I use a piece of a broken bit as a punch.


Sent from my iPhone using Tapatalk

 

[bw75]

A good frame painter can and should remove the tag and reinstall it for you. The same with the shock caps

Out on the 70 doing 72cc...

 

[geek777]

Thanks guys. Went and got a HF dremel like tool, a heat gun and an assorted set of bits for metal work. Figured I'd tape the plate up really well before going after the rivets/pins. The drill bit method sounds reasonable and promising. Will keep you posted.