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1970 SL100

Yep, we have a lot of John Deere engines like that. At first I thought I was seeing things. Then a long time mechanic explained it to me that they were made that way.
 
I have a good condition SL100 motor in a box in my garage. Been there for 5 years, never really knew what to do with it. Now I know....give it you. I am 90% sure it's an SL100, but it may be an SL125. I'm gonna go check it out right now and post up what I find. Sorry I just found your thread now.

I can give it to someone in Big Bend this weekend who maybe can get it back to you in SA. I'm in Houston.

Peter
 
OK here is the bad news...it's not an SL100 motor. And it has leaked most of it's oil out in the tub thru the cam sprocket cover.
 
...but the good news it all looks to be as I remember it...good working condition, turns over freely, no external damage, should run with carb and electrics. And it is a CB100 motor. Should be a direct bolt in and identical parts swap. I could also bring it to San Antonio on March 11th - 12th when I am visiting my brother.

Peter
 
...but the good news it all looks to be as I remember it...good working condition, turns over freely, no external damage, should run with carb and electrics. And it is a CB100 motor. Should be a direct bolt in and identical parts swap. I could also bring it to San Antonio on March 11th - 12th when I am visiting my brother.

Peter

I'll take it! Thank's Peter. March is good, thanks again.
 
Well, the 16mm rotor puller I ordered from Motion Pro didn't fit, it was too large and they don't list a 14mm one. I looked on e-bay and found one for $8.99 with free shipping and it was here by Saturday.

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Here it is installed, you just turn it and it pulls the rotor off the crank.

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once the rotor was off, you have to take the woodruff key off the crank.

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There's nothing behind the rotor and stator except the cam chain tensioner.

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After the tensioner is out all you have to do is take the case screws out and split the cases.

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That was another exercise of pure joy. Not! More stuck screws. This time I used a big easy out and didn't worry about it breaking or the heads coming off the screws.

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The crankshaft. The left case pulls off and the tranny and kickstart shaft stay in the right half.

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Kickstart

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Transmission.

the left case and cylinder and head are still at the machine shop. they should be back this week. Regardless of what I found out about the cylinder, piston and rings, I'll be able to put the bottom end back together this week.
 
I'm at a bit of a standstill right now. I use Clay's machine shop on South Presa in San Antonio and they do a great job. Its a bit of an old fashioned place as it looks like machine shops I visited with my dad. They have one guy who does the motorcycle work and he's been sick. Hopefully he'll be back next week.

In the mean time I picked up a parts bike with two engines in Ft. Worth today. I needed the frame and handle bars, but I think I can probably build another engine out of the two.
 
I finally got the parts back from the machine shop today. All good news, the piston is reusable and the bore is good and stock size. The exhaust valve seal was replaced and the valves lapped. I'll be painting the cases and rebuilding the bottom end this week. I ordered new standard size rings and some misc parts I need to finish the motor. Hopefully I'll be done in a couple weeks.
 
Yea, this is going to be a new bike, top to bottom. Nice to see so much attention to getting it right.
 
The cases are done.

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I used Eastwood two part urathane engine paint in aluminum. It looks a little darker than the Honda silver, but it looks good! Its good to 650 degrees.

I'm in the process of replacing the bearings now and have one side finished. I heated the cases to 250 degrees and froze the bearings then drove them home with a large diameter socket.

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I'll take the transmission and kick start apart and clean them and reinstall in the new cases.
 
When the engine was apart, I inspected all the internal parts and didn't end up replacing any bearings or gears. The gears looked good and the crank feels good. The crankshaft is a pressed up affair and it's expensive and complicated to disassemble the crank and rebuild it. I'm hoping everything is as good as it looks and feels.

I put the bottom end back together and I have all five gears and neutral so it looks like I'm good to go.

I had to replace the bearings in the crankcase halves since I took them out when I blasted and painted the cases.

I heated them to about 300 degrees and put the bearings in the freezer. Supposedly they will drop right in, but not this time. It took a little pressure to get them to seat. I used a socket the same size as the race and tapped them in with a hammer. You're not supposed to, but what you gonna do? Don't let your wife catch you doing this!

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A little bit about transmissions, at least a late 60's Honda tranny. There are two shafts and a drum. In the picture below the shift drum is on the lower right, the main shaft on the lower left and the countershaft on the upper left. The shaft on the upper right is the kickstart shaft and the shaft in the center aligns the three shfit forks.

The copper colored contacts on top of the shift drum is the neutral switch. When the drum is in the neutral position, this switch makes contact with the neutral switch and provides a ground to turn on the neutral light. On some bikes it also allows you to engage the starter motor.

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The shift drum engages three forks which do the actual shifting by moving one of three three gears up and down the shafts. Different gears are engaged by engaging dogs on one gear into recesses on another.

Here's a good picture of the shift forks engaged in the shift drum.

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Here's a picture of the other end of the shift fork engaged in one of the gears. This is a good picture because you can see the dogs on the top and bottom of the gear engaged by the shift fork and the gear above and below which are engaged for different ratios. 4th on top 5th on the bottom. The transmission is in neutral so no gears are engaged.

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I reinstalled the kickstart, gearshift, and countershaft seals into the cases.

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Then I started by assembling the transmission and kickstart, using assembly grease to prelube the parts and hold some in place.

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The two transmission shafts assembled.

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The kickstart ratchet. This one has the newer kickstart shaft which is the same diameter all the way to where the kickstart lever attaches. The older type necks down at the end and is prone to break.

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Putting the cases back together is surprisingly easy and just a little bit fiddley. All the shafts are different heights inside the cases and have to line up with ball bearings or plain bearings. I found it easier to insert the transmission, kick start and and crankshaft in the left case, then twist the right case to line up the tallest shaft, then the second tallest and so on. You can push the cases most of the way together by hand if everything is lined up. You need a rubber hammer to fully seat the crank bearings in their races.

Back together!

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I used stainless steel allen head button screws to secure the cases.

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Before inserting the screws I coated them with this.

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Next came the stator, as you can see from the picture below, the plastic sheathing is in bad shape as is the connector.

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First I wrote down the color codes of the wires in the connector then snipped it off the wires and removed the hardened plastic sheathing. That's the neutral switch attached to the green and red wire.

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I tinned the ends of the wires getting the new connector.

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Then I installed the new terminal. I crimped and soldered them so they shouldn't come loose.

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I had ohmed out the stator before I started and it tests good. I retested after I put the new conector on.

Its pretty easy to test a stator if you have the manual to tell you where you should have continuity and where you shouldn't.

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On the right side I reinstalled the shift linkage, clutch, oil pump and oil slinger.

First the oil filter.

Two o-rings.

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The oil pump itself.

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The driven gear

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The cover.

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The shift linkage was next. That's the end of the shift drum sticking out there and a small tab that engages the gear shifter.

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I forgot to take the next couple pictures. A shift cam plate goes on next then the stopper which keeps you from going through two gears at once. Then the shift shaft just slips into the case and engages cam which engages that tab to shft the gears. I'm not sure why the shift shaft doesn't move in and out since there is nothing securing it. I guess the shift lever itself keeps it in.

Then the clutch, it just slips on and is held in place by a circlip you can see in the middle. The springs sit on those four shafts and are held in place by four bolts.

The oil slinger.

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This washer goes underneath the nut which holds it on. They don't want you to put this on backwards.

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Tightening up the nut with the special socket.

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The cover goes on next with a new gasket.

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The finished crankcase.

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I've still got to paint the head and install the cam tensioner, piston, rings, and cam and points which I hope to do next week.
 
AARRRRRRRGH

After some delay to do some maintenance on the other bikes I was able to get back to the SL100.


The rings I ordered came in and I was ready to put the to end on the engine. Wait a minute, the wrist pin is really loose in the crank. Lets look at the old piston and pin and see what gives.

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Well, not only is the wrist pin larger, the piston is too! After some measuring and thinking and more measuring it seems like I have a 125 crank and piston in the 100. Unfortunately, the original cylinder was no good and I obtained a 100 cc replacement on e-bay.

And finally some good news, one of the cylinders that came with the engines I got with the Fort Worth frame apparently has been bored out to 125 cc. I'll have to get the cylinder and piston checked by a machine shop and order 125 cc rings so it's a minor setback in the scheme of things.
 
Well crap, I've got four cylinders, three which say 99 CC and one which says 124 CC and three out of the four have the same sleeve diameter.

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Which won't fit in the cases I have.

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This is beginning to piss me off. None of the cylinders will fit the good cases I have. I have to get a piston and rings to fit the crank in the good cases or find an SL100 crank with the right diameter wrist pin to fit the piston I have. Either way, its a crap shoot because I am to the point where I don't know whats what.

More interesting stuff, here's the piston from the 125, Something bounced around in the combusion chamber.


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Here's the piston out of one of the 100cc heads, its got a big ding in the side of the piston.

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oh well...
 
1. Bore out the 100 cc cylinder to fit a 125 cc piston an use one of the pistons I have, I'D still need rings
2. Have the cases bored to accept the 125 cc cylinder
3. Get a 100 cc crank with a 100 cc rod

I chose number 3 and found a good crank and rod. The 100 cc rod has a diameter of 14mm and the 125 rod has a diameter of 15 mm so I had the seller measure the rod. Should e good to go.
 
Nice progress! I really like all the documentation and pics that accompany it. Keep up the excellent work and I look forward to the finished product.
 
I got the parts I needed to put the motor back together as a stock SL100 unit and finally had some time this week to work on it a little.

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This is how I check the ring end gap, slide it into the bore and measure the gap. This one has to be between .006 and .035" so its a pretty big spread.

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I bought a new wrist pin and clips. There wasn't any spec in the manual so I thought better safe than sorry. The new one was exactly the same as the old one though.

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I stuck a penny into the gears to stop the crank from spinning while I worked on it.

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A single is sure easy to work on. I put the rings on the piston and slipped this hose clamp over it. Then, while looking down the bore, I lined up the piston and gently tapped on the cylinder with a rubber mallet. The cylinder sleeve pushed the hose clamp down the piston and the rings slipped into the bore. It only took two taps then I just pushed the cylinder down until all the rings were in the bore and the hose clamp was around the piston skirt.

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This is an oil passage on next to one of the studs.

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The oil runs up the shaft the stud runs thorugh into the head. There is a small o-ring here to seal the shaft between the cylinder and the head. A dowel pin also goes here, but it wasn't instaled when I took the pic.

I was having trouble fitting the cam back into the head so I stopped for tonight, there is very little clearance between the cam and cam journal and if you don't get it lined up just right it binds. I'll give it another try tomorrow night.
 
Man, I can smell the Permatex baking off now. :rider:

:popcorn:




.
 
AARRRGH, part two. The **** cam tensioner won't fit!

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You can see here the adjustment arm won't line up with the mounting hole. The 1970-71 had a one type of cam chain anadjuster and it was replaced with a different type for the 72-73 model year. The cases I bought are for a 1972 model ergo my cam 1970 chain adjuster doesn't fit. If this frickin motor didn't weight 50 lbs I'd throw it down the driveway.

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Here's the two types. The pictures are the same for all models, but the numbers or the newer adjustment mechanism on the right are not on the 1970 fiche. The older adjustment mechanism on the left are. I looked at the 1973 model and the situation is reversed.

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Here is a good picture of the vertical castings in the case that the new type cam tensioner moves up and down between. The other case don't have them. I can't figure out what keeps the rotor from hitting the tensioner, but I'm thinking the stator must hold it flush against the inside of the case. Its not like a cam chan tensioner moves a whole lot.

I checked my spare motor and it has the case I need, but I don't want to split the cases yet another time. Besides, I'd have to blast and paint the other case anyway. Honda doesn't sell all the parts I need for the 1972 cam adjuster, but I found most of them on e-bay. I've ordered the main components and will source the misc hardware from Honda. Another delay.

Here's the cam going in before I figured out what I should have already known.

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The cam goes in here, the head is the bearings, there are two oil passages, one on the journal on each side of the cam. The cam runs on that thin film of oil.

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I found out the problem was my valve tappets weren't loose enough and the cam followers were interfering with the fit. I was too tired the other night and didn't notice it.

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the cam going in.

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The sprocket installed.

and two pictures of the new hardware holding everything together.

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It cost a few extra $$ for new hardware, but it really makes a difference in how the bike looks.
 
I got most of the parts to install the cam tensioner, I'm missing one piece, but it's not critical to the installation, it keeps the cam chain on the lower sprocket if its loose.

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All the parts on the tensioner shaft are here, including the oft missing rubber cap. Notice the rubber o-ring in the middle of the bolt.

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Hook the chain on the crank sprocket.

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Pull the chain tight so it doesn't fall off the lower sprocket.

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Line up the timing mark for TDC on the compression stroke and make sure there is free play in the rockers because both valves are supposed to be closed here.

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There wasn't free play so I spun it again (180 degrees) and this time I got free play in both rockers.

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Then you fiddle with the sprocket to get the chain engaged and it lined up on the cam.

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Once the sprocket is on, the circle at the top of the sprocket should line up with the indentation on top of the head. It didn't at first, so I pulled the sprocket off and moved it over one tooth and then it was on the other side of the mark so that's as close as I can get. You can see its on either side of the mark in the last two pictures. I can adjust for that by moving the points plate.

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The housing goes over the cam sprocket and will hold the points plate.

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This is the cam tensioner bolt in the upper right hand part of the picture.

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The hardware which will hold the tensioner on to the tensioner bolt installed.

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The entire tensioner installed. Notice the difference between it and the older type that was installed when I took the engine apart.
 
Wished I had half your skills. Keep up the report. We all want to see the end result and go for a ride. :-)
 
I finished up the motor this week and can't decide if I want to stick it in the chassis and see if it runs or wait until the frame is blasted and repainted and the forks and shocks are replaced. I'll have to make up my mind soon.

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The points cover was dull and lifeless so I polished it up with a small brass wheel and mothers polish and it looks much better

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A new gasket.

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I'll find a NOS one later, but its not a priority with shocks and fork tubes to buy.

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Same for the alternator cover, it has a gouge in it, looks like from a misadjusted gear shift lever.

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the neutral switch gets a new o-ring.

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It goes here.

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I had to splice a little bit of wire onto the end because its stranded and the end had frayed.

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I used allen head bolts in stainless instead of the hex bolts that it came with.

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I had forgotten that I bought allen head stainless steel screws for the points nd went back and took out the NOS philips screws and replaced them.

Finally I put all the covers back on.

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The finished engine.

I took the forks apart because there was a fork tube on ebay that said it was for an SL 100, but after measuring these tubes I could tell it wasn't.

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Nothing salvagable in side at all, luckily they aren't complex but the parts aren't available from Honda so I'll have to get lucky to find them.

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The front wheel is good, not much rust on the outside or inside, but the back is marginal. I don't know whether to spring for two new rims or just try to find a rear and hope for the best. I hate to go to all the effort to put new spokes in a bad rim.
 
After thinking about the forks, I think most of the internals were missing. Looking at the parts breakdown, I'm going to need to source most of the parts. I have found both sets of fork springs (there are two) and Honda has the hardware, but two pices are going to be difficult to find although there are one of each on ebay right now. Its going to take some time and I need to move this along so I started other things while I think about what I don't have right now.

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The front wheel was good, no rust on the outside and very little on the inside. I removed the spokes and stripped the hub.

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I had a little helper in the shop today, here he is taking the spokes off the hub.

My kids have been a great disappointment to me, five of them and not a one is remotely interested in working with their hands on anything:rofl:. Now that we have grandkids maybe there is hope:mrgreen:.

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The wheel bearings are a interference fit so they are hard to get out, in this case you need something like this bearing puller, although it really works like a bearing pounder.

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Insert the correct size fitting, then engage the bar and

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then you pound it out.

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Then you have to get the bearing off the puller.

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The front hub stripped of bearings and gears.

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This is the speedo gears in the hub.

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The gear is held in by an aluminum bushing which is threaded to take the speedo cable and is held in by a very small set screw. Once the set screw is removed the bushing is pounded out with a small drift.

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And this is how it looks after its cleaned up.


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The front hub has some kind of shiney coating which looks like low luster chrome while the rear hub is painted

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The front hub itself polished right up, but the brake plate had some pretty deep corrosion and after I sanded it out and polished it I realized the underlying aluminum will polish to a mirror like finish while the coating only gets shiney.

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The rear rim is no good so I just stripped the hub.

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After stripping the rear hub all I had left was the rubber cush bushings so I decided to take them out too. My first inclination was to stick a screw in it and pull it out, but that didn't work.

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Next, I drilled out the rubber then grabbed the inner metal sleeve with long nose pliers and pulled them out.

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I ended breaking the long nose pliers on one of them.

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After I got the rubber and metal sleeve out I found out there was an outer metal sleeve that was stuck, all four. I ended up using a cold chisel to split them, mangling them in the process, and disloged them enough to pull them out.

I decided to just strip off the coating on the front hub and paint on the rear hub and applied paint stripper to both. Nothing, nada, the stripper didn't affect either the paint or the metallic coating. I'll just be priming and painting the rear hub and the front brake plate.

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Putting the bearings in takes a press or in this case a hammer and socket.

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Well crap, my balancing stand is too big for the small wheel bearings so I had to figure something out. I have the front wheel axel, but it is too short to fit on the balancing stand. I fabricated a temporary stand out of wood that did the job.

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First I cut the base out of 2X and then made the two arms out of 1X. They had to be exactly the same so the wheel would roll true so I taped them together then cut a vee shape the axel could rest in.

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Cutting to a line is pretty easy for me after years of practice.

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Here's one of my past project, made completely with hand tools. Its made of Cuban Mahogany and curly maple with a little purple heart and ebony.

Notice the white pine drawer pull? All the others are ebony and that one broke and I haven't turned another.

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It got me going and I was able to true the rim within the 2mm tolerance.

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The wheel looks pretty good if I do say so myself.
 
Well, making more progress, I found all the fork internals between Honda and several vintage parts suppliers, now I have to decide if I need to buy new springs. The set I have are corroded because the forks were full of water. I bought a set of NOS shocks from ebay, sill in the box, and dropped the frame and misc bits off at the sand blaster. I've decided to paint all the silver parts with the silver engine paint so the frame, engine, and brake parts match. I also had them blast the rear rim so I can see if it is salvagable.
 
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