honda z50 1973 minitrail restoration! need tips and guildlines

[Big Will The Junior]

hey guys im new to the forum!i love working in mechanic, i decided to restore this little minibike because it had been in the family for a long time and i want to make to make it licensed so i can ride it in the streets.i am pretty good in my perspective in mechanics and how it works and building it, presicsly 2 stroke because i have a yamaha bws50cc (also known as zuma50 in the united states) and i modified it alot.


For the mini trail i want to restore it but since it will be going to be used in the streets i want it to go faster than the normal 50cc. i thought of buying this kit Kitaco 75cc Big Bore Kit for Z50 - Classic Honda - Pit Bike PartsHonda Trail Bikesor maby even the one with the race head-Honda Trail Bikes my question is for the engine and the whole thing is, is the crankshaft and everything going to touch my new engine? and i really dont know 4 stroke.

i also want to keep the stock pipe because i want the original look, also i dont plan on changing the engine later and i will not use this everyday but i know the aluminium engine will rev more than the cast iron and that it will be less raliable.

i will keep you informed for every step i take i will take.-these are also some new pieces that i am looking forward to buy because that i dont have that piece or because i want a new one becaus it is dirty rusted ect..
- on this site - CHP CLASSIC HONDA PRIVATEER RACING Honda Mini Trails Honda mini bikes and Honda Z50 Honda 50 Honda Minitrail NOS Parts and services Kitaco and Takegawa performance parts.

-z12 30$
-z19k 48.31$
-z150 95$
-z22d 6.75$
-z26 2.25$
-18-100 14$
-205 3.99$
-217 25.95$ x2 chrome! or normal= z129 19.45$-p410mO 7.99$
-p848K 79.95$ rear shock-207 0.68*** x2-203 10$
-z231 39.95$
-z194-12 39.95$
-32 5$
-33k 9.24$-39 2$*****x2-45k
-1 42.53$-light assembly!-- z91- 32.64$- z94 41.85$
-49 49$
-84 16$
-z208 26.99******x2
-z100 2.50$-z207 56.95$
- Honda Trail Bikeshere are some pictures of my mini trail right now, it is all disasembled. - as you can see in the last picture there was a piston ring that was broken in two maby thats why it was going so badly ahaha.

[PlanetMinis.com]

[Big Will The Junior]

GREAT lookss like all the spaces between every paragraph they were not inserted or somthing!also is it possible to add a fourth gear in the tranny? stock theres 3

ahh i just saw the edit button didnt see it before

FIXED

[tmas]

is it possible to add a fourth gear in the tranny? stock theres 3

Yes. The ATC 70 & TRX 70 4 speed transmissions will work but you have to split the cases.
Here is a few pics of my 1973 which I sold.
tmas

1973 Z50A K4

[Big Will The Junior]

Yes. The ATC 70 & TRX 70 4 speed transmissions will work but you have to split the cases.
Here is a few pics of my 1973 which I sold.
tmas

1973 Z50A K4

thanks alot, looks pretty nice, is both sites that i reffered too are good? do you know other sites and can you show me a site were i can get these gears?
also is there any guides to install them and do you feel a good differance?

thanks alot this project is going to be a blast

[Y2daT]

TboltUSA carys a 4speed kit for 150. if your going to split the cases I grab a stroker crank and connecting rod on the piston you can go to 88cc giving you 110cc if combined with the stroker kit. and a (xr70 crf70 ct70) head will give you larger valves. or a tb race head will go even bigger on the valves. You could throw in a high volume oil pump as well and some extra stiff valve springs if you intend to run a mild race or race cam.
.
Just some ideas, there is always more you can do like manual clutch kits
.
and for the bike itself there are lots of 10" and 12" rims to choose from that fit the 50 hubs you already have a xr70 swinger will give you room for the 10's
.
TBoltUSA is a forum member of this site and offer good customer support. I recently bought a GPX140 china motor from them. i got it and noticed my cdi was missing and kick starter was the wrong size. I contacted tbolts support via email and a week later I had a new kicker wireharness and cdi unit free of charge and everything works great now.
Basicly Tbolt fixed what china messed up.

[tmas]

thanks alot, looks pretty nice, is both sites that i reffered too are good? do you know other sites and can you show me a site were i can get these gears?
also is there any guides to install them and do you feel a good differance?

thanks alot this project is going to be a blast

Yes both sites are good.You would have to find the Honda four speed transmission on ebay or off a PM member. The extra gear does make a difference.There are free online manuals and youtube videos that would help you through the installation.
tmas

1985 HONDA ATC70 ATC 70 TRANSMISSION GEARS TRANS SHIFT DRUM FORKS ENGINE MOTOR | eBay

[Big Will The Junior]

thanks alot! i will think about the 4th gear kit does it give much more top speed i want to go around 70-80 km-h. if i were to open the case i dont want to buy another crank shaft because i am already spending alot of money on it, but will the stock one be strong enough to not break? also i need to change my rims, do i really need to change the swinger in the back for a longer one for 10 inch rims? also i am really looking forward to this kit! Honda Trail Bikes my only concern is like i said the the crank shaft if it will be tough enought and if the head is assemble like in the picture so i just have to install the piston on the crank shaft, then put the piston rings ect, because it looks very complex to install the valve and everything in a 4 stroke head.


thanks alot!

EDIT: i found the edit button so now the thread is better its neater on top

[tmas]

The stock crank is ok for the kit you want. Pretty easy install. He is a link to a speed calculator that will help you get to 70-80 km.
tmas

Honda50.com Gear Ratio - Speed Calculator

[Big Will The Junior]

thanks,

but i rather just base it on peoples experiences with their bike, do you think with this kit i will acheive 70-80 km-h?

thank you

[tmas]

thanks,

but i rather just base it on peoples experiences with their bike, do you think with this kit i will acheive 70-80 km-h?

thank you

Yes, but you can also play around with the front and back sprocket sizes to get to 80 km.
tmas

[Big Will The Junior]

ok, and about the stock pipe on the 88cc kit will it be ok? and does it say 88cc on the engine?

thanks

edit: also i saw your mini trail that you sold, the stand that you installed did u have to do modification or it fitted bolt on? the stand on the side

i almost forgot, do i need an http://tboltusa.com/store/trail-bike...ls-p-1380.html high volume oil pump? is it worth it?

[tmas]

ok, and about the stock pipe on the 88cc kit will it be ok? and does it say 88cc on the engine?

thanks

edit: also i saw your mini trail that you sold, the stand that you installed did u have to do modification or it fitted bolt on? the stand on the side

i almost forgot, do i need an Trail Bikes High Volume Oil PumpZ50 K0-81 Models - TB Parts - Z50 K0-78 - TBW0225-6V - TBolt USA, LLC high volume oil pump? is it worth it?

Get a better pipe for more gains. Get the oil pump too. A must. It does not say 88cc on the barrel.
tmas


Honda Trail Bikes

[Big Will The Junior]

ok great, and what about this kit is it comparable to the 88cc big bore? Kitaco 75cc Big Bore Kit for Z50 - Classic Honda - Pit Bike Parts

[tmas]

ok great, and what about this kit is it comparable to the 88cc big bore? Kitaco 75cc Big Bore Kit for Z50 - Classic Honda - Pit Bike Parts

Debatable topic. Both are good. Maybe others will voice their opinion.
tmas

[Big Will The Junior]

ok thanks so it will be vs the 88cc kit with the 20mm carb and the racing head and cam vs that 75cc big bore with stock head and stock carb and stock cam,

becaus the 88cc is very expensive and i need to get the extra oil pump too so people give me your oppinions

[tmas]

Maybe think about getting a cam instead of stock.
tmas

Honda Trail Bikes

[Brodie]

Subscribed, Looks to be an interesting build!