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24th June 2017, 07:44 PM
#1
Junior Member
Bringing back a rough J1
G'day all,
Getting back into some Z50 builds after getting side tracked with work and other bike builds.
I picked up a really tired J1 from a mate, had a few bits missing but it seemed salvageable, unfortunately no pics of when I first got it.
I'm starting with the frame, and its got the usual, bent fork plate, missing nuts, broken bolts in threads, fair bit of corrosion, and a stuck rear brake pedal.




First step was the stuck brake pedal, after lots of heat, WD40, hammering, and swearing, I got nowhere except for a few more dings in the frame. Resorted to the grinder and that fixed in a few minutes.

I'm drawing up a new brake pedal shaft, its fairly straightforward, trying to decide on the type of steel, I'm thinking something like a 1030 should be decent enough without any problems welding. Anyone replaced one of these before?
Jake
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24th June 2017, 08:57 PM
#2
Moderator
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24th June 2017, 09:04 PM
#3
Moved to j1 resto section
its engine oil madge ,,,
Your soaking in it ,,!!
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25th June 2017, 08:53 AM
#4

Originally Posted by
Mech_Z50J1
I'm drawing up a new brake pedal shaft, its fairly straightforward, trying to decide on the type of steel, I'm thinking something like a 1030 should be decent enough without any problems welding. Anyone replaced one of these before?
Jake
I'm pretty sure it's just mild steel, they bent fairly easy. :-)
I've tried different materials, plasticine was a bit too soft so I tried a piece of wood dowel, it was easy to shape and drill but burst into flames when I tried welding it on. Steel seemed the best stuff to use so I'd recommend it.
Keep up the good work and also the pictures coming.
If i'm elected PM, I'll build a bridge from Tasmania for Dex to escape over.
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7th August 2017, 10:44 AM
#5
Junior Member
Thanks for the info, knocked up a quick drawing for a new shaft, made the section that goes in the frame a larger diameter as its going to need a bit of cleaning on the frame (I was a bit rough getting at the original shaft):
DSC_3950.jpg
Got the new shaft, seems like it should do the job:
DSC_3952.jpg
The new shaft fits the brake pedal better than off my old J1!
DSC_3953.jpg
Now I need to get onto the frame!
Jake
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9th August 2017, 02:35 PM
#6
Junior Member
Started the frame today, the bent steering stop tab was pretty easy to get rid off with some grinding:
DSC_3989.jpg
DSC_3999.jpg
Just need to make up a new tab from some pipe/tube, unfortunately pipe/tube ID of 46mm (OD of head tube) isn't a common size, I'll just have to go with the closest:
DSC_4005.jpg
The stuck rear lower fend mounting bolt was a bit of a pain, thought I would try a small easy out I had, that only made things worse...snapped off inside the bolt 
Drilling out and punching through the busted easy out:
DSC_3990.jpg
DSC_3991.jpg
Drilled clean:
DSC_4000.jpg
Tapped and good to go:
DSC_4003.jpg
Jake
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2nd September 2017, 07:35 PM
#7
Junior Member
New steering tab:
The head tube is 46mm diameter, I had a few different ideas to make up a new replacement steering tab, but it was eventually made up by turning a 46mm tube up, 4.5mm wall:
DSC_4030.jpg
Then the tab was cut out and filed up:
DSC_4031.jpg
Ready for welding onto the head tube.
Jake
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7th September 2017, 06:49 PM
#8
Junior Member
Rear frame fender nut:
Start with one of these:
DSC_4047.jpg
And after mucking around way too much, you can make one of these:
DSC_4048.jpg
If only I had some 1/2" hex bar...unfortunately a simple M6 nut has a smaller body than what these are...would you be able to tell the difference? Probably not, but I'm just doing it for fun...
DSC_4045.jpg
Ready for welding:
DSC_4046.jpg
Jake
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7th September 2017, 07:16 PM
#9
Great skills mate, something I really envy is the ability to work metal like this.
Rigby "No dude, you're doing it wrong! Righty-tidey, lefty-losey! Not lefty-tidey mess it up because you're a loser!"
ZRX1200S, RGV250 VJ22, Skyteam T-Rex, Z50A K2U '72, Z50J1 '78, Z50R '82, Tonelli Gorilla
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7th September 2017, 08:52 PM
#10
Senior Member
you have great skills , and way too much spare time . I would just buy the nut needed !
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8th September 2017, 04:06 PM
#11
Top way of doing the steering stop
its engine oil madge ,,,
Your soaking in it ,,!!
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19th November 2017, 10:48 AM
#12
Junior Member
Just a quick update, not much progress.
Holding rear nut in place and welding it up:
DSC_4074.jpg
Then smoothing out the welds a bit:
DSC_4082.jpg
DSC_4184.jpg
Tacking the steering stop in place to check the travel range and make sure it clears the tank:
DSC_4080.jpg
DSC_4170.jpg
Then weld it up fully:
DSC_4177.jpg
Welding up the brake pedal shaft and smoothing out the welds:
DSC_4078.jpg
DSC_4180.jpg
That's the frame pretty much ready for blasting and painting.
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19th November 2017, 10:57 AM
#13
Junior Member
Fork outers
Checking out the forks, looks like one of the threads needs a clean, its an M34x1 thread, I'll have to see what I can clean that up with.
DSC_4189.jpg
DSC_4187.jpg
Right hand indicator mounts is missing a wire hold tab, but I've got some replacement wire for that, I only need about 20mm out of the 30m!
DSC_4010.jpg
Otherwise, forks seems pretty decent.
Cheers
Jake
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23rd November 2017, 09:13 PM
#14
Loving the engineering. Done most of this stuff myself. Grab yourself a thread file from a nut and bolt shop or engineering supplies shop. About $35 from memory. Make sure it has the 1mm pitch on it. Good for internal and external threads. Will take a bit to restore threads but a life saver. Good for steering stem thread also. M22 x 1.
74A×3. 78J1. 79R. 82R. 83R. 99R. 74MR50. 75XR75. 98XR70 Crf70. Crf230. Crf450. KLX140.
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9th December 2017, 01:04 PM
#15
Junior Member
Plated bits
Got some plated bits done, in a silver/gold finish and also some chrome:
DSC_4233.jpg
Although the plastic didn't fair too well on the handle bar knobs:
DSC_4235.jpg
I'm going to try and paint these up gloss black, any decent products out there that adhere well to plastic?
Jake
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9th December 2017, 01:44 PM
#16
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10th December 2017, 01:29 PM
#17
Junior Member
Engine
Thought I would take a look at the engine, I was expecting it to be pretty rough from what I could see on the outside:
DSC_4236.jpg
DSC_4237.jpg
Everything seems to be corroded and stuck good, dirt in lots of places, hardly any oil..shes had a hard life.
DSC_4241.jpg
In the end I found some pretty bad news, shift drum stopper separated and mangled up a few things, looks like it may have been over tightened and the spigot on the case itself has failed:
DSC_4261.jpg
DSC_4264.jpg
I've got some spare J1 cases, this one will be stripped for parts, maybe I'll find a good RH case some day...
I doubt I will get a full set of internals, I can already tell there's some bad signs in the crank and trans too...
Jake
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11th February 2018, 09:35 PM
#18
Junior Member
Back to the frame:
The frames pretty much done, although the races looked trashed, so I punched out the old ones to replace with new:
DSC_4293.jpg
I made up a headset bearing press out of 50mm aluminium bar and a 220mm M12 axle:
DSC_4305.jpg
DSC_4306.jpg
DSC_4303.jpg
Greased up the frame, and froze the bearings:
DSC_4348.jpg
New bearing seated:
DSC_4350.jpg
Cheers
Jake
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15th April 2018, 04:49 PM
#19
Junior Member
Back to the forks
Back to the forks, got my hands on a thread file and used the 1.0 mm pitch thread. The filing was pretty easy, the 34mm fork diameter is large compared to an M6x1.0 for example, and the file is guided pretty easy on the thread.
DSC_4494.jpg
Here you can see the stuffed thread, most of it looks like a combination of grease/dirt/corrosion, but some of the thread body has been worn away.
DSC_4483.jpg
It only took about 15 min for each leg, threads look pretty sweet.
DSC_4497.jpg
Most importantly the fork caps go on nice and easy:
DSC_4495.jpg
Cheers
Jake
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15th April 2018, 04:53 PM
#20
This is really great. Well done. I could do with a set of those bearing presses.
Keep up the great work
Life is too short for cheap carbs...
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15th April 2018, 08:02 PM
#21
Junior Member
Making up the wire holders for the indicators...trying to anyways:
DSC_4502.jpg
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15th April 2018, 08:05 PM
#22
Geez, attention to detail much??? Good effort!
Rigby "No dude, you're doing it wrong! Righty-tidey, lefty-losey! Not lefty-tidey mess it up because you're a loser!"
ZRX1200S, RGV250 VJ22, Skyteam T-Rex, Z50A K2U '72, Z50J1 '78, Z50R '82, Tonelli Gorilla
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15th April 2018, 09:32 PM
#23

Originally Posted by
Mech_Z50J1
Making up the wire holders for the indicators...trying to anyways:
DSC_4502.jpg
Great work so far. Need to flatten the end that is welded to the tab otherwise it won't look original... 
I've spent $100 to make a $10 part so makes perfect sense to me
.
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21st April 2018, 04:11 PM
#24
Junior Member
More fork work
flattened the indicator wire holders and cut it to size, doesn't look too bad:
DSC_4504.jpg
DSC_4510.jpg
DSC_4506.jpg
Should pass once painted up.
Jake
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21st April 2018, 04:44 PM
#25
I didnt even know these were missing on my J1 till I saw this thread! Now I am not sure what to do with the wires!!!!
Rigby "No dude, you're doing it wrong! Righty-tidey, lefty-losey! Not lefty-tidey mess it up because you're a loser!"
ZRX1200S, RGV250 VJ22, Skyteam T-Rex, Z50A K2U '72, Z50J1 '78, Z50R '82, Tonelli Gorilla
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21st April 2018, 07:35 PM
#26

Originally Posted by
Mech_Z50J1
I was only stuffing around but great work!!!