Thread: New Project: Z50 & CT70

Hello Everyone,

I just joined the forum and this is my first post, so please bear with me for a windy discussion.

Way back in the 1973-74 time frame, my Mom and Dad were gracious enough to buy my sister and I minibikes. A Honda Z50 for me and a Honda CT70 for her. As you can imagine, that was one of the most, if not the most, memorable times in my life. I rode the tar out of the Z50, all the way up until I graduated from college. I probably put 100,000 miles on that minibike,; there is no telling.

For my sister however, the story was a little different. After struggling to learn how to ride her CT70, she gassed it while in neutral one day, nailed first gear, and it flipped her over on her back and the bike landed on her. I'm still laughing about it today, but the sad part is she never rode the CT70 ever again. It sat in Dad's garage ever since. It's only got 574 miles on it total, just from various people riding it over the years. Other than that its nearly new except for aging.

Anyway, that's a little history. I have been storing both bikes for years now and suddenly got the itch to see if I could get them running. So, I started searching the Internet and immediately discovered all the information, parts, websites and this forum related to these two minibike classics. I couldn't believe how prominent these bikes still are and how valued and loved they are; as much as I loved my Z50 growing up. I also was thoroughly impressed by all the rebuilds and restorations. Man, there is some beautiful work out there.

Needless to say, I was instantly hooked and rather than thinking about how I'd like to simply try and get these two mini's running, now I've got the bug and inspiration to try and clean them up some and do at least a minor restoration. I don't think I have the resources to do a full, 100% restoration, although the thought has crossed my mind. Instead I think I would prefer to restore them to the point that they look half way decent and run good, and then ride the tar out of them like I did growing up. I want to avoid putting so much time, effort and money into them that I hesitate to ride them. After all, riding is what I love the most.

I have done considerable research this past week. I have determined that the Z50 is a K4 and the CT70 is a K1. The serial number on the 50 is long gone, unreadable. The SN on the 70 is CT70-2054777.

Here a few pics of my two bikes to show the starting point. I'll probably start tearing the Z50 down first, after all, that was my bike, and see how restoration goes on it. On the 70, I want to see if I can get it running first so I'll just do the basics first to see if it sparks to life (I esimate it hasn't been run in over 30 years). Bringing it back to life will be an awesome thing indeed.

Progress will likely be slow, but I will try and post regularly as I make progress, so please visit again periodically. Thanks and looking forward to hearing from some of you experts out there.

Best regards,
- Noel

Welcome! Lots of good folks here, and many of us were old enough to cut our cycling teeth on original Z50s and CT70s. Both of your scoots are worth having and worth fixing. Just remember, . . . it's not an expensive hobby, . . . it just costs a little bit, then a little bit more, then a little bit more, . . . .

-kevin

Thanks for the welcome Kevin. I'm gettin a little long it the tooth myself.
I here ya, if I spend just a little at a time, it won't seem like so much. And the wife won't find out about it as easy either.

- Noel

Welcome to the club. Great hobby and so many nice people.Especially on this site.

Frank

Welcome!!!

Man I'd be in seventh heaven if I still had my first Z50 and CT70!

You found the right place.Good luck on your restorations and i bet your sister may want the 70 back once you restore it.
welcome aboard !

Welcome back! You guys did the right thing hanging onto those two bikes! Once you get them restored and start riding them again, all the memories will come flooding back.
Some web sites to help find parts are: Home Page Motor City Mini Trails RacerX's site, it's awesome!
DrATV OPERATES HERE
Northeast Vintage Cycle OEM NOS and Reproduction Honda Parts Z50 CT70 Minitrail


Brian

Thanks again everyone for welcoming me to the forum. Definately looking forward to sharing on here.

Will post again soon with some progress.

- Noel

Here is an update on my project. I'm currently rebuilding the carb (35 years old since it's been touched) and cleaning the tank in an effort to get her running. I'm showing a bunch of pics here of the setup I'm using to clean hard parts; it's work, but the results are awesome. (Note: I noticed the max was 3 pics, so I'll break up the pics into a few posts).

I'm using a portable stove top burner, a metal paint can, and diluted radiator cleaner, which I boil. The Zerex super cleaner works great. It's basically a mild acid and it's safe on aluminum. I tie on a length of bailing wire and then submege it in the boiling cleaner and let it soak for about 20 minutes. I then take the parts out and scrub them lightly with a brass bristle brush and the acid solution. Be sure to where gloves if you do this. Then I rince in clear hot water and continue with a light scrubing using a Brillo pad. I use the ones with the soap impregniated in the pad. You can't imagine how well these Brillo pads shine parts up, they are incredible. I don't overdue it, just enough to shine the parts up since after the acid bath and the brass wire brush, they are clean.

The pics show the finished carb bodies and the finished small parts. The carb bodies came out so well that in the light, the reflect the rainbow colors just like brand new cast aluminum. I think you can see this in the pic if you look closely.

I have ordered a carb packing kit from Beatrice to replace all of the soft parts in the carb. I also ordered several other parts to get this baby running (air filter element, spark plug, fuel filter, fuel hose, and vent hose).

The fuel tank came out great also. It was full of goo and rust inside and now it looks new inside. I'll see if I can get a pic of the inside tomorrow.

I used several different cleaners in succession. In all stages, I used a couple handfulls of unpainted aquarium gravel that I pour into the tank to act as a scrubbing abrasive when sloshing the tank around. I started by pouring two handfuls of the gravel into the tank and then adding mineral spirits to do the initial cleaning and degreasing. I put the gas cap on and shake the heck out of this from various angles for about 10 minutes. I poured this out and then proceeded by putting the gravel back in and adding the boiling radiator cleaner. Again shaking for like what seemed forever until my arms hurt. I left the radiator cleaner in overnight.

The next day, I poured this mix out, rinsed with water, and then put the gravel back in and added a half bottle of naval jelly rust remover. I shake this around for 10 minutes and then let sit for about 20 minutes. Then I poured this mixture out and rinsed the tank thoroughly with hot water to remove all the gravel and cleaners. I looked new inside at this stage. I blew the tank out with compressed air to get as much water out and then sprayed about 1/4 can of WD-40 in to remove any remaining water residue. I poured the excess WD-40 out, but left enough in to protect it until I'm ready to put in gas. This sounds like alot of work, but it's really not that bad, and the results were great.

Will post the carb re-assembly next, then on to some basic engine cleaning to get her ready to run.

- Noel

More pics.