Gumpit's Cast Off--1970 CAT 300SS

#21
Here we go and I'm not killing myself this year. This is a 1970 CAT 300SS which was actually a mish-mash of left over parts Muskin had from other models. As always, I've got frame and fork issues: High speed forks, bent handlebars and a ton of booger welds on the frame. I actually have a lot of OG parts including the disc brake, kick stand, NOS CAT wheels and stars. Of course, I need fenders and a clutch cover. However, the star of the show is a genuine 1970 Tecumseh Mini Bike engine that I stole for $25 (my first real mini engine). My hope is to restore to as-built but I'll need to reach out to find fenders and a clutch guard. But if you're willing to loan a set of fenders and a clutch guard, I'll make fiberglass molds of each and keep the molds on hand if folks get desperate. Karen has my order already for the correct seat. Glad to see some regulars in, welcome to the new ones and guys coming back. As always, thanks to OldMiniBikes for supporting and to @manchester1 for moderating!

There is a back story I'll get to along the way....
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Good to see you back Pete !
 
#25
Getting back into the "Schwing" of Things--High Speed Fork Rescue
I had a couple of offers of spare forks which I appreciate but I decided to get my feet wet fixing the bent up originals. I started with the handlebars:
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Click on the above two pics and you'll see how out of whack they were.
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I clamped on a piece of angle iron and heated the left bar with a MAPP torch to twist the bar back into alignment with the right. Everything was level, so on to the forks...which were fun.:rolleyes:

I had to remove the remains of a fender bracket sloppily welded to the tubes (you always know sloppy when there's little penetration and it flies off with a cut off saw).
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Back inside the shop, you can see how whacked these forks were. Note the booger welds at the top tree.
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One fork tube was relatively straight, so I fixed it first to correct the rest of the fork geometry.
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Then I flipped the trees around and removed the top tree from the tubes.
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Same task as before, clamp, heat and twist into alignment.
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Took a bit of finagling and moving around to each tube multiple times, but I eventually got everything square.
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I drilled out the old tube from the top tree.
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I then remounted the top tree and made sure it was square to the lower tree (6 5//8"). This will require the neck being shortened about 1/4" to accommodate the spring and cups.
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And ground to size....
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So about three hours later, this task was done and we now know the bike was metallic red. Boogers to grind off the frame next and then we'll strip the 300SS.
 
#30
Finally, a bit more done. I have to tell you recovering from radiation treatments and prostate seed implants has been an ordeal. I'm more tired than I expected and very glad I picked a fairly simple project. Frame is now stripped after grinding off a bunch of booger welds with little penetration.
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Used oven cleaner to break up the grease...
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First round of stripping is below...
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On the four CAT frames I've done, I'm always impressed at how little rust the frame develops over the years. This one is no different. I'll need to do finish sanding to clean areas the wire wheel couldn't get to, but much easier than the Broncco from last year's build off.
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#33
Forks, handlebars and front spring: Was able to clean up the handlebars today and got the paint off the spring and cups. I wish I could figure out the original color as I discovered the spring was painted the same red I found on the frame....maybe it was. The handlebars are going to need a lot of sanding to get the corrosion off. But we made a start.

Here are the forks finished up:
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Gonna be fun here...
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Spring and cups with still some work to do:
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#34
Engine Tear Down: As I mentioned, this is first "real" mini engine and is a 3.5hp Tecumseh. Over the summer, I had power washed it to get the tons of grease off it. I'm certain it needs a pto side crank seal and there was a bunch of gunk behind shroud extension....so I was anxious to how it looked inside.

I knew I had to fix do something with the coil so I have the part on hand--Note the "repair" to the plug wire!
IMG_1084.jpg I got the side cover off and it was full of sludge and gritty dirt, so I was expecting the worst.
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There's a reason I like big blocks....I can't get my hands where I need them in a small block! Took a while to get the cam and rod caps bolts off.
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Despite all the sludge, the crank journals are in really good shape with no spalling.
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Cam lobes were fine, too.
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After about an hour with liberal use of brake cleaner, I got the crankcase clean. The cylinder bore appears to be sleeved and is in good shape, too. IMG_1090.jpg
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Valves will be pulled tomorrow and we'll see how those look (lots of carbon built up).
 
#38
Valve Removal and Coil Repair: While I've not posted for a bit, I have documented what's been happening.
The valves came out pretty easily. The engine is old enough where it had two keepers per valve (upper and lower retainer).
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The exhaust valve had a ton of carbon on it, but both cleaned up nicely.
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The coil had to be replaced as the spark plug wire had been pieced together.
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So, to disassemble I needed to take stock of what I was up against.
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There's a clip that held the coil in place...next to my thumb
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I drove it off gently with the handle end of the hammer.
IMG_1098.jpg And I made sure I had a pic of the orientation before I reassembled. IMG_1099.jpg

and a little clean up, IMG_1101.jpg and reassembly IMG_1102.jpg ....still need to get new points.
 
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#40
It ain't done. I'm going to ask Karen to move it to projects as I did get a lot done as you'll see. Life interfered....again and I did not have time to post as I got things done, but it's all documented. Like all of us, COVID changed my world and, as a university professor, my classes had to go online taking 30-40 hours a week of time just to prepare. We also lost my mother in law and brother in law while my dad was diagnosed with leukemia....so SH*T happened.

You'll see several parts you'll want to know how I made them. As always, my work is by hand with basic hand tools and improvisation. I was able to source NOS wheels and a set of clean stars but the KH200 disc brake proved to be worthless, so I have an NOS one on order. Fenders were picked up on OldMiniBikes from @bbriggs. The "real" 69 Tecumseh mini bike engine is proving to be a real pisser--I can't get consistent spark despite two new coils, so I have an 80s 3.5 for now with a 74 shroud (I'll show you how I made that work). Karen did the 300SS seat, and it's killer. I put the shoe in one shot to show this is legit.;) IMG_0043.jpeg IMG_0044.jpeg IMG_0045.jpeg IMG_0046.jpeg IMG_0047.jpeg IMG_0048.jpeg
 
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