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Chapter 12: The ZB50

8K views 55 replies 10 participants last post by  s_10onbagz 
#1 ·
Before the GROM was cool with it's 125cc motor and it's 5 speed trans, there was the ZB50! I never thought I'd own one, frankly, I thought they were kinda lame. Sometimes, opportunities arise and it's hard to say no.

I'm currently working to get this thing shipped from CA to GA. It hasn't run in about 7 years, which is when the owner suddenly passed away. The brother, is selling on his behalf. I ensured him it was going to a good home and it'll get lots of love and pavement time.

The details of the bikes exact conditions are murky, the brother lives in Texas and only recently went to check out the bike (brother also had two Z50M's but those are being kept). I have a few photos to go off. Overall the bike looks to be fairly complete, I'm no expert but I immediately noticed the lack of blinkers and the dents in the tank. I also noticed a key in the ignition which is fantastic! I also caught relatively low mileage of 445 miles, but it seems the bike has been through it's paces.

For those who own or have owned these bikes, what are some thing I should look for to upgrade. I have access to Japan for parts, I'd like to find an exhaust and some no fade Kitaco pads minimum. I have already found a black MONKEY R tank and the MONKEY R tail fender piece. It doesn't bother me if I'll have OEM blinkers but I'll continue to search.

  • Should I try to grab a front wheel with a disc, would it be easy to set up? Do the ZB forks support caliper or do I also need Monkey R/RT fork legs?
  • Motor swaps - 125, 140, 170, 190? I've seen guys do 190's, that might be the goal.
  • What hard to find "rare" JDM parts should I look for? I'm not very familiar with the scene as I am with the Monkey's.
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#5 ·
Gee, I wonder who told him ;)

I suggested you by proximity and expertise and also a gentleman in Colorado named Barry, who specializes in old Z50M's.


I still have this exhaust for sale.
Also have a new in box Daytona 190 motor listed in another classified ad.
Thanks for dropping by to let me know. While I am interested in both, I'm not financially able to commit right now. I've had a lot of big ticket things come up the last two weeks I'm recovering from. It also didn't help my wife decided to take the dog on a prohibited beach and incur a $300 fine! I'll reach out to you in the near future when I'm ready to buy.
 
#6 ·
LOL about your dog getting fined. That is rough.

I would keep the cosmetics more OEM, only because so many of these bikes are missing their rack and tail light. I do love the Monkey R tail light, tank, and seat, but they go together more so than select parts on a zb.

Front brake can be NSR fork legs, caliper, rotor, and even master cylinder on a Monkey R front hub. I ran this setup on a Z50R and loved it. I wish I kept the monkey r front hub. None of the 10" wheels can easily fit a caliper with pistons on the backside of the caliper.

If you are already committing to the Monkey R parts, I would do a nice aluminum swing arm too. maybe some other dressy parts. do you have an APO to ship from in Japan? I am buying parts quite often for my JDM minibike parts addiction.
 
#8 ·
LOL about your dog getting fined. That is rough.

I would keep the cosmetics more OEM, only because so many of these bikes are missing their rack and tail light. I do love the Monkey R tail light, tank, and seat, but they go together more so than select parts on a zb.

Front brake can be NSR fork legs, caliper, rotor, and even master cylinder on a Monkey R front hub. I ran this setup on a Z50R and loved it. I wish I kept the monkey r front hub. None of the 10" wheels can easily fit a caliper with pistons on the backside of the caliper.

If you are already committing to the Monkey R parts, I would do a nice aluminum swing arm too. maybe some other dressy parts. do you have an APO to ship from in Japan? I am buying parts quite often for my JDM minibike parts addiction.
It seems NSR fork legs are more available than Monkey R legs (only see one set). I'll see if I can piece together a front end. I'd like at minimum to have a front disc for the bigger motor and stopping power. Am I looking for a specific Monkey R swingarm or are there other compatible ones? Is anything compatible with the R? This is all new to me.

I get regular shipments from Japan, while I'm not in the country anymore, I still have a close friend who hooks me up. I shop YAJ and Croooober too often. I'm going to be in a tricky place when he leaves and USPS isn't available to me anymore.

The bike looks nice and complete and in good shape! Provided the price is right, I think it will be a perfect bike for you. Will fit nicely with your others and has better ergos over the Baja.

What are you thoughts on the overall look you are going for? Clip-ons and hugger front fender?


Sent from my iPhone using Tapatalk Pro
I have no idea on the look, I'm going to have to do some searching for inspiration. I just can't give into getting a Grom, I have to be U N I Q U E.
 
#7 ·
The bike looks nice and complete and in good shape! Provided the price is right, I think it will be a perfect bike for you. Will fit nicely with your others and has better ergos over the Baja.

What are you thoughts on the overall look you are going for? Clip-ons and hugger front fender?


Sent from my iPhone using Tapatalk Pro
 
#11 ·
I know what I said but dude wants to trade one of my 88cc builds + $350 cash for his 190 5 speed. I'm working on trying to make it happen. Am I going to regret not getting an E-start model? The SSR 170 wasn't great to kick, I have a feeling this one wont be any more fun.

Also, is 190 just too much for this bike? Should I be looking at just a 140? I don't want to build something that isn't enjoyable to ride. I guess worst case if the 190 is too much, I shouldn't have much trouble trading down?

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#12 ·
For swing arm, any DRUM brake ZB50 / Monkey R / Monkey RT is standard so you can run drum or disc. When I bought Brad's ZB50, it came with the G-Craft Triple square tubing swing arm for a ZB50 and it was super nice. Then I had the G-craft bracket to run a brembo crab caliper on the drum brake nub.

I wonder if your buddy would feed my crooober addiction and ship stuff over for me. I'd toss him a few bucks. haha.
 
#13 ·
I found one aftermarket aluminum swingarm so far but it was NIB so it was still pricey. I saw Webike has some options which is nice too but I'm more of a used market price kinda guy.

I think I'm going to try and source a R/RT front end. Might have to piece it together but it seems like the easiest solution for a front disc set up. I know I'm going to have to build the bike around a bigger motor to be safe. The bike shows up together so I'll comb over it, see if I can get the stock motor running for now. If not, I have a nice 88 on the bench.
 
#14 ·
I think the common theme is adding stock monkey r front and rear hugger fenders if you do the monkey r front end. I will approve. The stock motor will run, these engines run with basically no compression as long as the carb is good. Keep in mind you need a perimeter frame intake manifold for whatever engine you use.
 
#15 ·
While ZB50's are incredibly cool bikes, I caution anyone that is over 5'5" on investing huge money to build them into machines they expect to ride for periods of time longer than 45 minutes. About a decade ago, I sunk some money into a ST90(clone)...and the build was impressive. It had a bored and stroked midsize motor making 157cc, custom wide spoked wheels, blah blah...it looked fantastic. At 5'9" i found it to be very uncomfortable for riding any distance or length of time. I was really let out that I had invested so much time and energy into this and didn't like riding it.

So my recommendation might be to first get it running and ride it around and see if you can handle to tightness and smallness of the bike...if you love it, then invest the money. Otherwise, you could end up with a very expensive thing that's just constantly in your way in the garage.
 
#17 ·
While ZB50's are incredibly cool bikes, I caution anyone that is over 5'5" on investing huge money to build them into machines they expect to ride for periods of time longer than 45 minutes. About a decade ago, I sunk some money into a ST90(clone)...and the build was impressive. It had a bored and stroked midsize motor making 157cc, custom wide spoked wheels, blah blah...it looked fantastic. At 5'9" i found it to be very uncomfortable for riding any distance or length of time. I was really let out that I had invested so much time and energy into this and didn't like riding it.

So my recommendation might be to first get it running and ride it around and see if you can handle to tightness and smallness of the bike...if you love it, then invest the money. Otherwise, you could end up with a very expensive thing that's just constantly in your way in the garage.
Lucky for me, I'm 5'5! My riding duration most likely wont exceed 45 minutes. I rode my Baja in stock configuration for hours all over Japan, wasn't great but it was doable. My garage is already full of expensive speed bumps, all these motocompos and can only ride one bike at time!

It seems a 190 is just excessive and the amount of money needed to build a safe bike around it wouldn't be worth it. Maybe I should just turn this 88 into a 108, already has that nice 4 speed bottom end.
 
#16 ·
Fatcaaat, good to see you still post. I remember your big motor builds from years ago. Did you hit any speed bumps? Hitting a very mild speed bump was probably the main reason for selling my built up ZB50. It hurt in all of the worst places.

All in all, the over adjustable rear sets were 100x better than the g-craft fixed rear sets, but I would still prefer traditional pegs (50 stunt).Takegawa low bars were okay, but I agree 100% that these bikes are made for short adults.
 
#19 ·
Andddddddd we're off.. So first thing is first, it's in pretty good overall shape. 445 miles on the clock but you can tell those may have been some hard miles. Immediately started pulling stuff apart because after a few kicks it wouldn't start (not to my surprise, I knew it wasn't running).

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Sorry for the sideways photo. First thing I noticed was the seat is in great shape, no tears, a few dirty spots I can clean up. The suspension is SOFT, can I give it the XR70 treatment? Heavier fork oil, HD springs? Rear shock I'll pull, measure, see whats out there. It's missing the blinkers, not just physically but the wiring with them, luckily they didn't tear all the wiring from the loom or anything. Missing the OEM airbox as well, noticed a stack of washers where the tank mounts. The battery was so dead it wouldn't even take a charge either. Rear fender has a crack that was once epoxied. There is some surface rust along the frame and some blast overspray that I cleaned up already.

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The carb was a mess, some real old gas. My pilot jet gave birth to some solid gas, so that was cool.

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Pulled off the sweet stator cover and quickly noticed that a chain grenaded at some point in here, really tore up the cover and it looks like it damaged the stator plate but it's not that bad? Hard to tell from the photo but it's cracked and a small piece seems to have broken off.

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Ultrasonic cleaned the carb and had a spare Daytona POWER ADVANCE FILTER that happened to fit, so that's cool.

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That's kinda where I left it for the day. Pulled out the headlight and made sure the wiring for blinkers was all there (was), replaced the inline fuel filter, and started to make new wiring for the blinkers. I'm going to go with the ones I ran on my Cub build, I really liked them and they fit the bike well.

Ordered a battery, blinkers / relay, and 10" tubes... I'm still not sure what to grab for tires yet. I bumped another post from over a decade ago to try to gauge some response for best 10" tires for the bike.

Also, I noticed the CDI isn't the same connection as the Z/XR/CRF bikes, does anyone make an aftermarket CDI for these?
 
#22 ·
Tim and I spoke offline and I answered this question - Yes, it's the Chinese 5 pin layout. So those looking for a CDI could use this - TB MX Performance CDI - All Models - Red - TBparts.com or if you have a CDI already, you can just buy the harness TRC CDI Wire Harness Honda to 5 Pin China - TRC-1995 - Electrical - Pit Bike Engine Parts - TBolt USA, LLC.

Yes, nothing escapes your eagle eyes. It seems when the chain grenades it took out the trigger mount on the stator plate, luckily I have spare motors laying around.

In other news, it runs! Albeit like crap. As Tim pointed out, the fact the pulse trigger is probably not mount correctly isn't helping. I also have oil pushing past the plug and it feels like some pretty low compression.

Side note, worst bike to kick over I've ever had. The foot peg is in a terrible spot (owe my shin!) and the exhaust has this weird spring loaded piece on it that my heel hits.

DUMB.
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Booo. Also note the liberal use of HONDABOND seeping from between the head and cylinder..

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#25 · (Edited)
Figured it out after some Googling.

In short; when switching from incandescent to LED, there can be an issue if you can a turn signal indicator in your speedo. It's supposed to act as a ground path but there isn't enough resistance to make it work. So there are two solutions:
  1. Adding a diode Diode for 4-Way Blink Fix
    1. Rectangle Product Handwriting Slope Font
  2. Add load resistors Load Equalizers for LED blinker signals on Motorcycles


So, that's great. My question now becomes, what is the easiest solution given my problem. Based off the above sketch in comparison to my wiring diagram, I have one wiring (+) and one negative going into my gauge cluster turn bulb. This differs from the sketch, so can I add the one diode or will I need to split the wires coming in? Maybe adding just the 2W load resistor will work? But where do I add it? There is no diagram.

I hate wiring.
 
#28 ·
Kirrbby you're right, I miss read the diagram. I'm going the diode route.

I played musical engines last night and salvaged some parts!

I'm guessing when the chain exploded and rocked the ignition cover, it did a number here too. Broke off one of the mounting arms for the pulse trigger off the stator plate, which I thought, "cool, I'll replace that back plate". As you can see this from the photo here, the pulse trigger is trashed as well. This puts in a bit of of a pickle because I need to run THIS particular coil which has lighting outputs on it.
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So I got creative when I saw all the part numbers matched up. It's one wire to replace the trigger. Heated it up and swapped it for one off a spare parts motor. Now, I'm not a doctor but I have an inclination it'll work. This coil is getting tossed onto the Monkey Baja motor with the BBR 88cc super stock setup that I was running before I got my 108. You're thinking, the Baja has lights, why do you need to swap the coil over? Well, the coil from that motor went onto the 108 motor. Yay.. So after swapping some stator plates, soldering some coils, I have everything tidied up.

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It just now hit me that I need to order a clutch lever/perch and cable for this motor, so that'll put me back until mid-next week since it's Friday evening. Also have to figure out what I have left for carbs laying around..
 
#32 · (Edited)
I still owe you this answer... I'll get that figured out today.

Finished up the wiring last night for the blinkers with integrated turn and brake lights. I'm pretty happy with how it came out, I really wish I had some color wiring just to get it that OEM look but I did use recycled wiring and connectors from my Cub build, so at least there is that.

I think my diodes will be here today so I can get them wired in and hopefully solve my blinker issue. I have my motor buttoned up and I'm going to see how it'll fit with the intake/carb set up I have. Expecting my clutch cable and lever today at some point as well.


Update - Can't fit the clutch lever on the stock bars, soo looks like I need to buy a set of bars, great. Intake/carb setup I have fits under the tank and clears the frame. Getting an air filter to fit maybe tricky. Might have to go with a pancake? Maybe one of those smaller K&N cones...

Diodes are delayed. I hate USPS, 3 day used to mean 3 day. I can't believe the authorized the changes to slow down mail hopefully it doesn't last (20 attorneys general file a complaint to block the Postal Service's strategic plan)
 
#33 ·
Okay, I have an update with some photos this time. Got super lucky on this one, turns out my old Baja exhaust fits PERFECT. I had to make a small bracket (which I didn't take a finished photo of yet) to make up for <6 inch gap. I also backed out the exhaust studs to give me enough to thread onto, tossed some loctite on them just to be safe.

Sanded, sanded, and sanded the front and rear fenders. I also fixed a pretty mean crack in the rear that was poorly repaired in the past. I did a pretty solid job, you can't see the crack from the side the matters. Unfortunately the previous repairer went with the theory of "lots of epoxy is always the answer" and the backside is pretty boogered up. The paint obviously isn't perfect but I wet sanded up to 2500 before paint and then before clear. It'll do.

Bought a set of pro taper XR50 BMX bars in black since they closely matched the size of OEM. The throttle cable I have is super long compared to what I need, why can't there be a way to make custom throttle lengths...is there? Clutch cable seems to be the right length.

I also was dead set on fitting a breather tappet on top, so I made that work with absolute minimal clearance. Oh and speaking of clearance, I got an air filter to BARELY clear the frame. Some how my carb/intake/filter combo just worked.

Only issue I ran into was the kicker, you can see it's a pretty wide offset and it still doesn't clear the exhaust. I grabbed my Takegawa knuckled one off my Baja and it JUST touches the rear brake arm. I found this one on TBolt that I'll order, I can't imagine this wont clear (Kick Start Lever Angle CRF Type 14mm shaft - WHS-4030 - Controls - CRF70 and XR70 - Japanese Mini Bike Parts - TBolt USA, LLC)

Still waiting on my diodes, really excited about the change to USPS's mailing times. This is going to get really ridiculous if it doesn't change.

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I shortened up the bracket, rounded the corners and sprayed it please don't rust black.

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