Z50R Build in Process

[makotosun]

If you are on Planet Minis, then you may have already seen this, but for those of you who aren't, and have an interest in the smaller bikes . . .



My son turns 6 in about a month and he has been riding a TRX70 for nearly a year, but is still a bit shaky on two wheels. I purchased an old beater Z50R several years ago, before I realized how much I overpaid for it and am now starting on the rebuild for him to learn to ride on.

I tore it down to the frame a week or two ago, and have been painting, cleaning, etc. so I thought I'd start a thread on the build for anyone who cares.

The before pics:

 

[makotosun]

It looks bad, but it actually does run. The tank was full of rust and is probably not salvageable.

Here is the intended recipient during disassembly:



Plans are for a strip down, repair/replace as needed, detail as much as possible, and since my boy wants it to look like my old Yamaha Enduro,



it has to be YELLOW

The bike will get new trailwings, a new chain/sprockets, new front fork internals and rebuild, seat cover, new tank, new handlebars, and except for the tank, a mostly fizzy can paint job. Remember, he is learning to ride on this, so I anticipate another redo in a year or two. It just needs to look reasonably good and run reasonably well. Along those lines, it is probably gonna get a china motor for now since I have one on the shelf. Gonna rebuild the stocker for the next rebuild.

Progress so far:

Some of the paint:



Some detailing:

 

[makotosun]

Some new bars (Fly mini bend shortened by 6" overall):



Keeping the stickers:



And the frame ready for assembly:



Lots more to do of course, but I will keep posting as the build goes along. Final specs will be posted after it is complete.

 

[makotosun]

Lots of work on the bike - painting, repairing, locating stuff I misplaced when I took it apart . . .

The original plastic was pretty scrungy, and of course, the wrong color. I used some of the Krylon Fusion paint to make it right:





I have used this stuff before on some other bike projects, and it is amazingly durable. We shall see if it as strong in the face of a determined 5 year old!

I still have to do the shocks so I made up some struts so I could get the thing back to being a roller. Plus the plastics needed to be test fit.



I located some yellow and black grips at Bent Bike in Seattle - they are vintage with the black being a sort of foam rubbery stuff.



This shot makes it look a lot bigger than it really is:

 

[makotosun]

I mocked up the seat with the new fast fifties seat cover, which made a huge difference in the look, especially with the yellow plastics. I also taped the tank decals on to get an idea what it is gonna look like. I was surprised, but the decals have a small yellow line that runs across it, couldn't have planned that one better if I tried. The tank will be flat black behind the sticker (DP90 epoxy) so it will not look so out of place.





I also got the china motor in the frame and it fits like a glove. There is plenty of space behind the left number plate to install a battery, so my somewhat size challenged son will be able to use electric start until he grows a bit more.



Installed the restored exhaust which started out like this:



I am trying to do this on the cheap, so I welded up the rust spots and repainted it and the shields. I needed to cut off and reweld on some of the guard nuts, as they were completely rusted and broken off.

 

[makotosun]

Next we needed to get all of that Chinese power to the pavement, so a Renthal R1 chain was needed:



Might be overkill, but it should last until I need to redo the bike the next time!



The little warning sticker on the chain guard was in poor shape, and when removed, left a different texture on the plastic, so Renthal came to the rescue . . .



The bolts that look like they might be rusty are actually red zinc plated from Rockford Bolt.

I also got the shocks back together after detailing. I am not sure these will be the final shocks as they seem pretty spent in the damping department. I have a line on some nice takeoffs that may go on if I am not happy with these once I can test it.





Still need to get the tank painted, and do up a wiring harness to make the motor work and run the lights that will be added later.

Gonna be gone for a few days so I won't make much more progress til next week . . .

 

[Fyrman]

That's coming along beautifully. Some excellent use of artistic liscense in the paint scheme! We rebuilt an older Z last year for my little guy but he's already moved on to an '84 CT70 that'll get overhauled this year. I'm too much of a sucker for the good old days to go all abstract with the colours so we'll be sticking with all original. It had crossed my mind to go with a John Deere Theme as my kids are big JD fans, (really, it's the kids! ), but I just didn't have the guts. Tahitian Red it is!!

Keep the pics coming, it looks great!

 

[makotosun]

Made a little more progress on the little yellow mini since my last post.

I obtained some number plate backing vinyl in black, to break up the large yellow side number plates, and tossed some fizzy can black on the bad tank so I could visualize the finished product better.



This vinyl stuff will also help keep the paint on those side panels from getting scratched up, as it seems a lot more abrasion tolerant than the paint.

The bike will also have front/rear lights on it, so we start with an Acerbis LED taillight which comes with a neat flap and build some custom mounts for it. I didn't want to drill the fender, and this actually is more solid, and gives the fender some rubber bumpers to rest on.





This sits just under the rear fender and peeks out to give both running and stop lights for the little enduro wannabe! I haven't wired everything up yet, but the test using a 6 volt battery was pretty visible. The bike is 12 volt, so it should be great!



I re-tried the tank emblems on the newly black painted mockup tank to get a better idea what this whole thing is going to look like:





I still need to get the tank I'll be using painted black (flat or satin) using some good auto paint so it won't run the first time my son spills gas on it. I also need to fab a battery mount (battery is ordered) to fit under the left number plate, and a wiring harness, plus a couple of switches.

I have the ears on order for the headlight, but am still trying to decide what headlight I am gonna use for it. He wants it to be round, so I am on the search for that piece.

More when I get it!

 

[makotosun]

OK - I finally have made some progress.

After I got some expert help from a forum member of PlanetMinis, I was able to move ahead with the electrical system. Still have a few things to sort out, but some progress was made today.

First, since this bike has electric start, it needed a battery on board. The Z has no provision for one, and the standard Z battery box is too small to hold a 5 amp battery which is what the motor called for. I decided to shoot the wad and go for as big a battery as I could fit in there, so I got a 7 amp sealed gel battery. So now I need a mount for it.



Not wanting to do too much to modify the frame - don't ask me why - I fabbed a mount using the existing back mudguard bolt, the rear shock peg and one nut welded to the backbone.



A bit of hammerite black and it disappears in there. Then in goes the battery.



The battery is a PS-1270F2 from Portable Power Systems and was about $20 shipped.



Tight, but it does fit under the side cover.



The CDI, Rectifier and most of the excess wiring is bundled directly behind the battery in the void under the backbone. Protected and a safe distance from the exhaust. I still need to make a sheath or something to camaflage the wires that are still visible.



As you can see I added a key switch from DR ATV in the location of the hole in the fram that holds the top motor mount. Fits perfectly and the pigtail puts all the plugs right where I needed them.

I know my wiring looks like a rat's nest, but hey - it is a budget build and is a learners bike for my kid. So sue me.

 

[makotosun]

I also needed a safe place to mount the 12 volt starter solonoid and it fits perfectly under the tank, directly snugged up to the front mounting bracket.



There is a cover over that one hot terminal, and there is clearance for the tank. I will be putting a bit of rubber somthing stuck to the bottom of the tank to assure there is no possible contact with the tank.

I temporarily wired the taillight into the "on" circuit of the key, but eventually it will be wired through a light switch on the handlebars. Gives you an idea of what it looks like. It will also have a brake switch as the light is a dual voltage LED.





Overall, I am happy with the setup, and now just need to wire up the handlebar controls, and other switches. The bike also needs a headlight setup, and I am toying with a couple of ideas.

The bike is getting a lot closer now that I have spark at the plug, so I can work on getting it started up and tuned. The tank still needs final paint, but that is really the only thing holding me up.

 

[makotosun]

More progress this weekend

Made some more progress on the project this weekend. Still don't know which graphic is going on, but the tank got painted.

To start the project, take one (1) Hooper Imports Cub replacement tank in white, plus a Mountain Dew for energy . . .



sand off all of the bad Chinese paintwork (a couple of small runs) then a good scotchbright to remove any shiny spots,

Add some good quality Automotive two stage Urethane paint:



I went with Corvette Yellow, which proved to be an almost perfect match to the Fusion Plastic paint I used on the rest of the bike. The paint was mixed up with the hardener and a small amount of laquer thinner (reducer) then sprayed through a Harbor Freight detail painting gun (about $15 on sale).

I mounted the tank on a stick so it was easy to manipulate it for spraying, as well as keeping the sticky stuff off myself. (Don't forget a respirator - this stuff is kinda nasty to breathe!)

Looked like this after 6 coats of the paint:





The lighting where we painted plus my cheapo camera did not translate very well.

 

[makotosun]

Today, I got the tank home and was able to get some pics in better light:





You can't see the gloss that well in the pics, but it is amazing.

I test fitted to check for color match:





It looks in the pics like there is a bit of difference in the shading, but it is just the reflections, etc. The plastic paint handles the flash differently than the Urethane. The first pic, where you can compare the tank with the back fender, shows how nicely it all works.

I was able to get a pint of the color, plus 1/2 pint of the hardener, some strainers and stir sticks for under $50. I probably have enough paint left to do at least 3 more tanks this size. the actual cost for materials for this tank, including sandpaper, etc. was under $20 - and this for a gas resistant urethane paint! And that is at retail.

I also painted up the original factory bars (less the fixed mount piece) in the same hammerite black as the frame and will be adding that in the next couple of days - I like the bars I have on there, but it is too much of a reach for the little man. I am also going to add some controls off of a chinese clone so I have all the necessary switches for lights, electric start, etc. I plan on hooking up a left lever to the rear brake.

My original plan for headlight mounts is not working exactly as I had hoped, so I am still working out that little detail, but I should be able to finalize all the wiring, mount up the tank, and get the little enduro started up this week!

 

[bjatwood]

Your son is going to have a blast riding the s@#% out of that baby! :drum:
The results look pretty good also. :6:

BJ

 

[makotosun]

Final Mockup before final assembly

OK - I think I have got everything figured out, just need to run some wires to the handlebars and hook them up, get a fuel line on and it should be ready to rock and roll! I am sure there are a lot of details I am forgetting, but if I get some time this weekend, I could have it on the road!

After all the input I got regarding which graphics to use, in the final analysis, none of it mattered, because my boy looked at all of the options, in person, mocked up, and decided he liked the Fast Fifties stuff the best Since it is his bike, I guess his vote has some weight! At least it isn't a spongebob sticker! (though that would be kind of a neat themed project . . .



A view from the driver's seat . . .



I changed out the tops of the handlebar clamps (and the bars!) and the little nubs that stick towards the center will be the mounting points for a little aluminum dash that I will be mounting a neutral and high beam light on. They are stock for a trx70.

I also need a bar pad - I have a black one, but may go with something more intersting. Gotta migrate the yellow grips from the other bars too.

I got the headlight setup mocked up - still need to final sand and paint the "ears" but it is just about the right size, etc. It is a stock headlight shell from a Z50 and an off road light from DR ATV.



You can see, he really liked the graphics . . . Sure a lot of red for a bike that he wanted to be yellow!

So - what does the whole thing look like together? . . . .

 

[makotosun]

Like This!



I think that is it's best side



And of course, the pipe side, which has been underrepresented in this thread.



I need to hook up a brake light switch to the rear brake, and maybe to the front too. The lever mount I have is off of a ZB50, and it has the little hole to mount a brake light switch in.

All in all, I am pretty pleased, and will get some final closing shots posted as soon as I can get all the bolts tightened, and get it out of the garage for some glamour shots!

 

[makotosun]

This thread has been quiet for some time, although I did finish the bike. I finished the story on Planet Minis, but thought I'd toss up some final photos here.

Closeup of the final handgrip setup:



I added horn at the last minute, so that the horn button on the control pod functioned. If you build one of these for your young kid, the horn is a big hit!



Indicator light dashboard - Green for neutral (good for electric start) and amber for the high beam!



The second ride on the bike (The first was at night, since we got it started at about 11:00, how could I not let him do a lap around the yard with the headlight!)



Got him some real MX boots - seems to make him ride better!

 

[makotosun]

And a still photo of the final product with the proud new owner!



This project has been the most satisfying I have done yet. I am now able to put some attention on my own panda and CT projects without hearing him say, "when are you gonna finish MY bike Dad?". Plus it is way cool to chase him around the yard for an hour with him on his little enduro and me on the CT!

 

[Darthvader]

My favorite shot."Beaming with pride" Thanks for the journey.

And a still photo of the final product with the proud new owner!



This project has been the most satisfying I have done yet. I am now able to put some attention on my own panda and CT projects without hearing him say, "when are you gonna finish MY bike Dad?". Plus it is way cool to chase him around the yard for an hour with him on his little enduro and me on the CT!