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1980 Z50R Mild Revamp

34K views 191 replies 39 participants last post by  olyelr 
#1 ·
Merry Christmas everyone!



Hello fellas! I am a newbie to this site, as well as mini bikes in general. I raced motorcycles my whole childhood, but I have been out of the scene since around high school (almost 12 years ago!).



My wife purchased a 1980 Z50R for me for Christmas, and I am stoked as a fat kid in a candy store. So far the plan is to get the bike back to decent condition, keeping it SIMPLE and cheap as possible. Nothing major; basically strip it down, replace any worn parts, paint everything that is orange black, get a new seat, new tires, and put it back together.



So what do you all think?!























It seams to run good for being 31 years old. I don't know much about it, but she bought it from a local guy who was the original owner.



I do have one worry though. There is what appears to be a chuck missing from the front side of the motor. Is this a big issues? Heres a pic....

















I will update this thread as I make progress. But, I'm sure it will be a long, drawn out process.



Glad to be a part of the minibike scene!
 
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#134 ·
yes the piranha is a manual clutch - tbolt sells the cable and parts needed ask vince

i've got a 4 speed manual lifan 125 in my 91 Z50 and its TONS of power for a wee lil bike ...... tough to hill climb, but a blast to ride and it freight trains away from my buddies 88 kit and 88 race head kitted bikes. ... i just need more gearing for the speed it wants to pull

if you are trail riding the snowblower tires are nice too
 
#137 ·
Thanks for the info! Yeah, when I do the motor upgrade I will for sure be upgrading the tires. I was thinking those oversized stock looking ones would be ok, but for some reason the thoughts of the snowblower tires keep overpowering them.


Did you end up finalizing the stickers?
Here's a random preview.... :)


Hahahaha, that dosnt look too bad! You must have some serious computer skills to whip that out.

Most of the summer I had just a black background on the plate (with the outer yellow ring showing) and for some reason it just didnt work for me. So I peeled them off and have been running just the yellow. Thats got me thinking though!!!!

I was checking the project you have going on earlier. Good luck with that, looking good so far!

If you ever get that vinyl computer printer/cutter setup, I can be the test mule and you could whip me out some backgrounds for my number plates!!!!

I would say a 125 will do you well. I have a Lifan 125 in my '82R and it is a tight squeeze for the carby to fit. If I had a different manifold it would be fine.
Being that the 125 I have is a zombie engine (was dead for a long time and I brought it back to life some how) it has plenty enough power for a fun bike.
Once you start looking at things like 140 and up it gets into the wheelie on gear change stage and some of the run around fun goes away.

As for that piranha engine the manifold on that looks like it should fit under the tank without you having to raise it. I would stick with the 22mm carby if you are going to use the stock exhaust.
I have a 26mm on my 160 and and high flow exhaust to match.
Thanks for the info Brodie. Yeah, the 140 seemed like it would be just a bit big for a fun everyday cruiser. While it would be fun to RIP IT, I still want to be able to cruise too.

So the stock exhaust would work ok with a new motor? Obviously a high performance one would be better, but if it will run ok with the stocker than I am all for saving some cash.
 
#136 ·
I would say a 125 will do you well. I have a Lifan 125 in my '82R and it is a tight squeeze for the carby to fit. If I had a different manifold it would be fine.
Being that the 125 I have is a zombie engine (was dead for a long time and I brought it back to life some how) it has plenty enough power for a fun bike.
Once you start looking at things like 140 and up it gets into the wheelie on gear change stage and some of the run around fun goes away.

As for that piranha engine the manifold on that looks like it should fit under the tank without you having to raise it. I would stick with the 22mm carby if you are going to use the stock exhaust.
I have a 26mm on my 160 and and high flow exhaust to match.
 
#138 ·
It would run ok with the stock exhaust but the flow will be restricted. That is why the 22mm carby would be better, less intake as the exhaust is restricted. When you take the exhaust out just give it a good clean and see if you can smooth up any areas to help with flow. I am not sure there is anything that can be removed from the muffler to help but someone else might know. Will be interesting to see what you decide. Also I believe you can get semi-auto 125 if you are still after that.
 
#139 ·
Im thinking I should keep it at 125 or less. Probably end up going the 125 route though. I just dont want to be mad that I didnt go with the 140. But I think you have pretty much justified to not go that big for my intended use.

As far as manual or semi, I am still torn. I think a clutch would be bitchin, but at the same time I am pondering about the times I putt around in the yard and woods with my son, where a semi auto would be way better. Hmmmmmmmm. I have a lot of time to think about it. But right now I am thinking clutch. I wonder if the clutches hold up well on these things?
 
#141 ·
I'm a pretty big guy who is used to riding a cr500af and cr250 and I've taken my Z with lifan125 on a couple of two hour long trail rides where it's been ridden pretty aggressively and the clutch and motor have held up fine. There is a good bit of sand around where I've ridden it too and the snowblower tires tracked thru it awesome - they are a little squirrelly on loose gravel however! I've heard of people taking a stock exhaust, cutting it open and making it free flow, even going as far as changing the header and tailpipe to increase flow, bu welding it all back up and paint/powder coat to make it look stock. I think that is awesome personally
 
#147 ·
Thanks for the info!


I just wish i could find the lifan125 complete kit again for the price i paid less than a year ago - it was low enough it might have even been a pricing error on the vendors site, i think it was $230 shipped for the complete kit with carb and ignition...

Yeah, its like another 100 bucks or more now.
 
#142 ·
I just wish i could find the lifan125 complete kit again for the price i paid less than a year ago - it was low enough it might have even been a pricing error on the vendors site, i think it was $230 shipped for the complete kit with carb and ignition...
 
#148 ·
You need the chain guards and muffler guards on it!
And who are you part of, the minibike police?

just read that it is powder coated. Semi or high gloss. You should have gave your motor a quick silver painting. make a world of difference

Im not sure on what type of gloss, I just told them I wanted it glossy not flat. I didnt touch the motor because, well, I really have been planning on a new one so I figured why put the effort into it. I thought it looked pretty good for having over 30 years of wear and tear hahahaha.
 
#145 ·
I put a lifan 125 on my stocker 83 z50r for awhile. The only problems i ran into was the stock throttle cable was not adjustable enough for the carb to open all the way, and since the motor is a bit longer i had to take off the front fender. Im sure you can trim off a little bit of the fender and it would work but i planned on putting the bike back to stock so i just took it off. The motor ran pretty good with the carb that came with it and stock exhaust. Now that i upgraded to the vm26 carb i need a new exhaust. The carb fit under the tank with the intake it came with but you had to take the tank off to put the throttle cable on then put the tank back on.
 
#152 ·
forgot to add -

the throttle would only life the slide 2/3 of the way open on the carb that came with the 125 --- carefully a small bit at a time - I filed off the stop on the plastic cam on the throttle tube which allowed it to twist a little extra until i had it turning perfect amount to lift the slide to the top of its proper travel
 
#154 ·
One of my new Honda stickers on the tank got fubar'd from a small gas spill so I guess I gotta order another one. Whats the trick to help prevent this from happening again, beside not getting gas on it ^_^ Clear coat over the entire tank and stickers? Can you put clear over these stickers?
 
#162 ·
I just went through this...depending on the quality of your decal, clear coating over it will also cause it to smear. The decals I bought from DRATV seem to be printed off a home printer and the quality is not that durable. Clear coating over these decals caused the color to run. Had to sand down the clear and remove the stickers.

Now that the stickers have been placed over the clear, I will have to be very cautious not to spill fuel on them.
 
#155 · (Edited)
Well the Z made it through its first summer of shredding (under my ownership). Im still pist about the Honda sticker on the tank but oh well. She's gonna finish out the year looking like this...


















I still may get some numbers on the plates yet this year. The black background just didnt do it for me so I peeled them off. I shoulda took some pics.


I still have brand new black fenders to install. These are the stock painted ones, and there are a few dings which are allowing the red to show through.
 
#157 ·
Very impressive! You did a great job on this little z. Can't wait to read how the engine mods turn out when you get her finished.

I'm not too sure that is the correct word for this project. But thanks for the kind words! I will surely continue posting updates and progress, but it will probably be quite a while before I start the motor project.
 
#165 ·
125cc is all you need in that frame. 8Hp feels stupid fast when you're that close to the ground, probably want a 15/16 tooth countershaft sprocket to go with your stock rear. If you've got access to a mig, fabbing up your own pipe from a China 125 exhaust is cake. I'm surprised no one has mentioned using an XR75/80 swingarm in place of the stocker yet.

Land vehicle Vehicle Motorcycle Car Motor vehicle
 
#167 ·
125cc is all you need in that frame. 8Hp feels stupid fast when you're that close to the ground, probably want a 15/16 tooth countershaft sprocket to go with your stock rear. If you've got access to a mig, fabbing up your own pipe from a China 125 exhaust is cake. I'm surprised no one has mentioned using an XR75/80 swingarm in place of the stocker yet.
Ive seen a few with the XR70 swingers, but I think that is a little long for what I am after.

What motor are you running in your bike?
 
#169 ·
Jeez all mighty. Its been over a year since I logged in here. Still beating the piss out of the black stallion and she's holding up well if I do say so myself.

As much fun as we have all been having on my stock Z's, for some reason I just can't get the motor upgrade out of my mind. I mean the 3rd gear wide open skidding sliding bumping grinding side by side racing has been a blast no doubt, and will still give ya some serious arm pump if you hang in there long enough. When the two bikes are identical in speed and power, it really doesn't matter how freaking slow they are it still translates into a fun battle. But I think a little more oooomf would add to the effect.

I have never road a mini with anything more than the stock motor so I am in the dark here on what size I should go with. Sure some serious power would be fun, but I want rideable power. I want to be able to use the motor to it's potential while still being able to control the bike. And I am talking romping through the woods and trails, not just dicking around in my yard and pulling wheelies on the way down to get the mail.

And honestly right now I would like to just stick with the stock (heavy duty) suspension I have on the bike now. I always have had plans for a long swinger and real shocks/forks, but it aint gonna happen for a while yet.

Is a 125 all I need? Every time I scour T-Bolt I end up juggling between that or a 140. But the 140 just seems like it would be too much for what I am after. And what brand do you guys suggest? Piranha? Pitster Pro?

I just don't know which way to go with this and am looking for some insight before I get crazy and pull the trigger. I am not overly mechanically inclined yet with small engines so the 88 kit or anything Honda like that is not really what I am after. I just want a simple plug and play deal.

What motor did you use, and were you happy with it?

Thanks fella's!
 
#170 ·
I was in the exact same place not too long ago. All my friends have z's and its so much fun racing them together when they are all stock. Really shows you who's got talent. Then one would get a better motor and it ruined it.

Now, I was all about he stock z until I wanted a street 50. Way too slow. Worried I get run over. I ended up with a TB 88cc kit with race head and carb. Dude, this is an amazing bit of kit. I built it on an XR bottom end with CDI and it rips!!! Done 60mph down hill with the 4 speed trans. It's great fun a probably just the thing your looking for.

I'm a fan of trying to keep the bike as high end and bullet proof as I can. Running the stock Honda crank and cases I feel is a real bonus. Those clone motors always stand out and look weird on a stock looking bike like yours.

What are you looking for in the end though. More torque or more mph? Do you want a 4 speed and manual clutch? I never rode the 88 with a 3 speed but I'm sure it would be amazing. Gear it up a bit as you will have plenty of torque to pull it.

If you want to add crazy power to it, you are going to also have to think about other upgrades. Exhaust, swinger to keep the front down, brakes. All that. The 88 will need a new exhaust but I bought a cheap ass monkey style (runs in the same place as our Rs) and its perfect. Just have to space the right number plate out about a half inch or so. It was 50 bones shipped.
 
#171 ·
Thanks for your insight, Coop.

I would love to be able to keep the bike all Honda for reliability, but right now I don't think it's the right time for that. The motor is completely original to my knowledge so it is due for a rebuild anyway. I keep dreaming about sending the motor out to geezer for a full blown rebuild/upgrade. I just don't want to spend the money at this point in time. Plus, I would really rather wait till I can do the work myself. So I figure I will keep it hidden in a closet and just plan on a full tilt built when I have the know-how and money for it.

Another reason I wanted to go with a Chinese motor is for the trans. One more gear would be a major bonus, and I am really leaning toward a motor with a clutch. What did you do to get a 4 speed on yours? I think I have seen the manual kits for the Honda's, but I thought they kept the 3 speed?

What do I want in the end? Hell I am not really sure yet to be honest. I think I just want a little more power more-so than speed... not crazy power... just more so it is a little more fun for a grown person to ride. Speed wise, the stock motor pinned out in 3rd romping through bumpy two tracks on factory suspension is really about fast enough... it just takes so damn long to get up to speed. And you cant keep the speed up while going up a hill. I guess I'm looking for power?
 
#172 ·
I have a manual clutch125 in my z50r clone with exhaust.
i run 8" wheels & 17 front & 29 rear gearing.
With this gearing it isn't too much engine for the bike but I wanted a little more top end.
Tbolt sells a similar 125 kit for $299 shipped.
I think you cannot go wrong with a 125 engine & they are reliable
 
#173 ·
Yeah, that 125 would be a good pic. Can't beat the price. Team that with a cheap ebay exhaust and your all set.

http://pages.ebay.com/link/?nav=item.view&alt=web&id=190800912082

I bought a 4 speed trans from DrATV and installed it with a ct70 manual clutch I already had. The trans and clutch are totally separate though. You don't need to run one with the other. You can still have an auto with a 4sp if you wished.

Stick with the stock gearing at first and see how it goes. Depends on the ratio of the trans.
 
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