Next Rebuild Z50AK1 Silver Tag

hambone

Active Member
Went out and checked some parts I have, found a good std. bore cylinder, is this cylinder compatible with the early Z50 or is it from a later version? Cylinder on top is the one I found, bottom is the original cylinder.
newcyl.JPG
 

Gary

Well-Known Member
Curious if the frame date code matches the tank? Funny to see they have the sprocket mounted backward wonder if they were trying to get a few more miles on it or they didn't know the difference? I have the original front tire to mine unfortunately I am not near it to check it for you.
 

hambone

Active Member
Gary
You are over my head on that one, but here are the numbers on the tank, which sprocket is on backwards, the rear?
tank2.JPG
 

hambone

Active Member
I know what you were asking now, it's really close, the man I bought it from said it was original, at the time I didn't know all the differences, seem to be original down to the bolts, let me know if you spot something funky.

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hambone

Active Member
There is a blue k1 tank on eBay right now that I think has the same date as yours on it.
I looked for it, the one I saw I couldn't read the date, I got lucky on my tank, that's the first thing I looked at when I bought it. Figured I was going to remove the cap and be looking into a rust pit, I was surprised how clean it was, going to evaporust it overnight when times comes.
 

Robert thran

Well-Known Member
Went out and checked some parts I have, found a good std. bore cylinder, is this cylinder compatible with the early Z50 or is it from a later version? Cylinder on top is the one I found, bottom is the original cylinder.View attachment 77757
i think that cylinder would work buts it’s a later cylinder..notice the 49Cm where your original says 49cc..being it’s a numbers matching bike I would personally just buy a 3rd over piston kit and have it bored keeping it all original ..I’m sure 3rd over would clear any rust for a good rebuild..second over might even clear it out? I might have a good bore stock cylinder with the 49cc stamping..I’ll look when I get home..if I do it’s yours for free if you want. A lot of peoples bore bars wouldn’t go down far enough around here to do a 50cc. I only know one guy.
 

hambone

Active Member
i think that cylinder would work buts it’s a later cylinder..notice the 49Cm where your original says 49cc..being it’s a numbers matching bike I would personally just buy a 3rd over piston kit and have it bored keeping it all original ..I’m sure 3rd over would clear any rust for a good rebuild..second over might even clear it out? I might have a good bore stock cylinder with the 49cc stamping..I’ll look when I get home..if I do it’s yours for free if you want. A lot of peoples bore bars wouldn’t go down far enough around here to do a 50cc. I only know one guy.
That would be sweet, I will buy it if you find one, I figure mine could be bored to clear the rust, it would be nice to keep original. I'm in no hurry, got a lot of cleaning to do.
 

kirrbby

Well-Known Member
1969/07/14 ...July 14th

The pics are lacking, on that tank. It looks like it might have been lined to me too...but the seller says it's clean, but might NEED to be lined. Looks pretty nice and near straight tho.
 

hambone

Active Member
Curious if the frame date code matches the tank? Funny to see they have the sprocket mounted backward wonder if they were trying to get a few more miles on it or they didn't know the difference? I have the original front tire to mine unfortunately I am not near it to check it for you.
Gary
You must be a young man with good eyes, :LOL:, Good catch, I looked at that sprocket, yup, it's backwards, learn something everyday. I wonder if that could have happened with a flat tire? sprocket isn't worn too bad, I'm going to throw a chain on it and leave the original sprockets, if they are original?? I also noticed the different size 8's on the bolt heads, that's the only one on both wheels with the big 8.
 

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hambone

Active Member
It was nice to find a clean engine inside when I opened it up. Bought a battery box from Kirb a while back, someone had bent it up to modify it, I have it bent back into place, may touch the lower mounting tabs up.
 

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hambone

Active Member
The clutch cover was that clean when you pulled it off?
I was expecting a good layer of sludge, I see a little right at the drain plug, oil was clean as new, I'm sure not the original oil but someone kept it clean. I didn't see any evidence of the cover ever being removed.
 

hambone

Active Member
Wanted to save the old tires but I quickly gave up on that, both tires were patched, probably explains backwards sprocket, still had the Bridgestone tubes, rims have a little scale inside, headed to the bead blaster. Did I mention these solid rim tires are a PITA?, I used the cut one wire at a time process, they don't want to turn loose until that last wire is cut.
 

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Robert thran

Well-Known Member
Can say I ever have but I have used a piece of an old handle bar to repair a ct70 exhaust pipe where they rust out under the guard insulator .. works great, thicker tube and already chrome,,, welds get mostly hidden under the guard although not for a show bike it’s a good easy repair for a rider..
 
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