Finally got a Honda z50!

[coolpool]

I was recently in Southern Ontario and was chatting with my old friend about any and all vintage machines which we both enjoy immensely. He mentioned that at one of the places he picks up firewood he seen an older Honda 50 minibike sitting in the corner of one of the barns. Knowing that I wanted one, he talked to the owner and got it for $100.00 with potential transmission issues. I only have one picture but it looks fairly complete and I'm pretty sure I can fix it up for less than $1000.00 even with shipping costs to Alberta which is what they're worth up this way. The hard part is finding the darn things....fixing is easy;)

[shortline10]

Nice score

[knappyfeet]

I love it!

[kiser]

Great find, they are a blast!

[coolpool]

Fast forward almost 1 year and I finally have this beast at home. Physically it's in good condition with a clean tank, intact seat, good tires and decent plastics. All controls still move as it was stored indoors since parked. Wear on the handgrips don't show excessive use either. The bad is it does roll freely but the kicker won't budge the motor. The crankcase was empty when I got it so I filled it and the cylinder completely with ATF and fresh oil and let it sit for a few weeks....no change. I ordered a factory manual and will pull the motor and tear into it and see what surprises await. Kickstand1 mentioned I should look into getting the dents in the tank fixed using the paintless dent removal method. Once it's running I'll definitely do that.

[shortline10]

Nice score , I would pull the flywheel cover and rock the crankshaft back and fourth .

[big specht]

Second that and you can use a stud welding gun to pull out the dents

[coolpool]

I took your advice and pulled the cover. I can freely spin the flywheel back and forth but then I'll hear a click inside and it stops. If I play around with it it goes again until the click then stops. Trans is all the way in neutral up as far as i can feel with the shifter. I don't think it's grabbing any gears as I push down at all. Maybe pull the head and see if the cam chain isn't broken or a valve dropped?

[shortline10]

The older model z50 has a manual timing chain tensioner setup so if it’s not maintained things happen :lol:

[coolpool]

That's what I'm leaning towards. I can feel vacuum when the piston moves slightly so i'll pull the tappet covers and see if anything is moving there. There's definitely something up with the transmission as I can't get it to go in any gear at the moment. We'll get her figured out soon enough. Thanks for all the input folks!

[coolpool]

Update: Appears that two of three bolts came out of the cam gear and the 3rd loosened off and caused some damage. The exhaust valve hit the piston and bent when it was out of time momentarily but didn't seem to hurt the piston at all. Unfortunately I'll need to replace both side covers as the cam was drifting back and forth and damaged both. What I'll do right away is:

- replace both valves, guides and seals
- replace both side covers
- mic the bore and hone as required if in spec
- bore out if above is not in spec
- replace piston/rings

Potential Fixes:
-replace with new stock piston/rings if still in spec
-oversize piston/rings if needed
-replace cam gear
-replace cam due to surface scratches (anyone think it's in too bad of shape?)

I was very surprised how bad the muffler is compared to the rest of the machine. Lots of patching and will need a nut welded on for the side shield to bolt to.

The transmission is still an issue but that will get looked at in good time.

[shortline10]

The cheap way out is to just buy a complete 70cc topend kit . Most are less than 100.00 and it’s a definite power boost .

A kit like this .
https://www.ebay.com/itm/283986629386?hash=item421eec130a:g:vRcAAOSwt4xfQIw 8&amdata=enc%3AAQAHAAAA4MWsmjRENy5wvpj2mxVzwYz%2B2eb QT08kfkm0hQLlEN8%2B%2FhlnRpnG8XFdMjbvy%2Bam1fKGdcn sS%2BEnFNg5ZIFiXn5%2BAM3BZDm2kC%2BgsvmyLd6%2FamNAB k21AxznEKaaEJGVC4zdl%2F%2F9TyRrvFxt0OhH4R6ypPMVcYj wa66mrSyYN%2FX3LgRQ6%2FJteIhUIVNO88AefEvQTamUpuB5H CEEELENaxcacklSKVpwJXYHH1o6QRLjMIAlW4rjcpmFq0BYyWq x8I%2FLit3d%2Br9MExZhU%2Bm4fKR0cEBJUrHpox6nmQXbH6u z%7Ctkp%3ABFBMhuuspIdh

[coolpool]

That's definitely a great option shortline. Curious, will the 70cc kit bolt on directly to the 50cc block? With CDN exchange and shipping it'll be around $200 but still cheaper than OEM I'm thinking.

[shortline10]

Yes it all bolts right in , cylinder will fit in the cases .

You can also go this route and make a rocket ship lol .
I’ve done a few and they get scary fast for a short wheel base .

https://tboltusa.com/store/crf50-z50-xr50-big-bore-engine-kits-c-100_122_124.html

[coolpool]

Yikes....no I'm lucky the mini bike is even allowed at my place after my sons bad motorcycle accident in 2012. Thanks for the ideas though :-)

[coolpool]

Update: The cylinder is still in spec so I honed it a bit and will now start to gather new top end parts. I got a nice surprise when I removed the clutch and main gear to dig into the transmission issue and found it was just stuck between gears and shifts just fine once I rotated the bottom end 360 degrees. I'm guessing I can get this fixed up for less than I thought originally.

[coolpool]

Ordered all parts today including extras like new chain and sprockets and new exhaust guard hardware to replace the badly rusted ones. I did have to go to eBay for an exhaust valve which kind of sucks. Everything else came from PhatMX out of Toronto, ON for around $450. All in this should be back up and running for less than $500.00 which is good for Canadian prices and horrible shipping costs. The most expensive thing was a new OEM kill switch at $134.00!

[coolpool]

A late Christmas present....my parts are here from PhatMX! Just waiting on the exhaust valve from eBay then I should be all set.

[shortline10]

If you purchased a new piston make sure to check the deck height with the stock piston .
There is so much crap out there that aren’t designed for the factory OEM cylinder heads combustion chamber .

[coolpool]

If you purchased a new piston make sure to check the deck height with the stock piston .
There is so much crap out there that aren’t designed for the factory OEM cylinder heads combustion chamber .

I purchased a new 50cc one as my bore checked out OK. Great advice shortline, will do. Thanks! What does ease my mind is the company states to be the largest supplier of mini parts in Canada https://phatmx.com/

Can you shoot me a text, I lost your contact with the change of company phones.

Does anyone have a secret stash of OEM exhaust valves for these things?

[coolpool]

Still picking away. I've had to order a new intake valve, fork boots, rear bearings, and wheel seals front and rear. I didn't like the rust on the rear shock dampers so I made up a simple tool to take them apart and paint everything up preserving it for future generations....this is not a restoration folks, just a dependable rider I hope.

[coolpool]

Lots done since last post. I tore apart the front shocks and cleaned everything up, applied new grease and re-installed new fork boots. I also cleaned and re-greased the steering stem bearings. Brakes front and rear were tore apart and all parts cleaned and lubricated and are now fully functional. I also noticed the steering stop was bent to one side (explains the tank dent on the right) and wore down. I straightened the stop out and filled in the worn areas with weld. I tore into the carb and cleaned it up...got lucky this thing was probably parked completely out of gas so nothing was gummed up. I also tested the coil, cleaned/adjusted the points and confirmed spark. The muffler was in rough shape (as I knew) but didn't realize how bad until I sand blasted it. I added multiple sheet metal patches always chasing thin spots which is why it looks bird turdy. Lots of quick tacking versus a prolonged bead which burnt through easily even with the Mig on #2 heat. It's functional again....just not pretty..... like me. I also welded the side nut on that holds the heat shield in place which was missing from a previous repair. She fired up and idled on the second kick....pretty happy so far. I still need to cut down the new chain and finish bolting on the side cover and chain guards and final test ride. Going to have to wait as there's still a ton of snow on the ground here.

[coolpool]

Just need to order some decals for the side plates and maybe try to deal with the dents in the tank and I'll call it a wrap. It goes into gear great and takes off in first easy enough so I'm hoping the bad transmission idea is false as reported by the PO. I'm thinking I'll put it on a milk crate and slowly run it through the gears in the shop until we lose a lot of snow and I can actually put some strain on it riding.

[kiser]

Looks like it came together nicely, It will make a nice rider again! I hate seeing bikes get parted out so I'm glad you saved another one!

[ironchop]

Wow nice save!

I'm glad you kept the original cylinder.

You can easily fit that in the back of the Jeep, I bet

[coolpool]

I finally got around to actually riding this beast a little. It moves along quite nice I must say. It does shift a bit hard even after performing the clutch disengagement procedure a few times and having fresh oil in it. Discs may be sticking a bit.....I'll ride it for awhile and see if things improve.