Picked up another CB750K

Alan F.

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This one may or may not get a Jammer on it.

Picked this one up yesterday,
1978 CB750K8 with Title
$300 Basket Case. 24,xxx miles
Serial numbers show it was originally imported directly to Canada.

Build thread here: http://forums.sohc4.net/index.php/topic,182592.0.html

I unloaded it this morning and found the engine wasn't turning with the kicker, so I backed off all 8 valve adjustments and Bingo, it turns 360 degrees and compression (finger test) seems very, very strong.

I found 4 stock pistons hiding in the tub of electrical parts, OK so what's in there now?

The PO used some kind of blue gasket sealer on the base and head gaskets, so tomorrow I'll tear it down to find out what's inside.

It appears from the seller's story that his Dad had bought the bike years ago as a basket case from the original owner who was a Professor at a College or University in Boston holds true. The original owner completed some sort of top end rebuild and never put the bike back together again.

Wish me luck.

20200516_114133.jpg
 
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Alan F.

Learning the Ropes
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Well, I got the top end torn down, those stock pistons are for the earlier bikes up to 76, this bike has stock pistons too but they changed for 77-78.

I've ordered up some parts (gasket set, HD studs, cam chain tensioner wheel, fork seals) and will try to get something done on this bike every day. Hopefully I can get it back together and running in short order if I cut some corners. I've got the exhaust spigots and Kerker 4:1 that arrived on my K3, and I can relace my K3's wheels for this bike when the time comes.

Wish me luck.
 
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Alan F.

Learning the Ropes
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Thanks, I'm away from home right now at a storage unit across town. I'm waiting for frame paint to set up a little longer before I wheel it inside to dry for a few more days. I've ordered up about 5 Bills worth of new parts from 3 different vendors, so far one has shipped. I'm trying not to get too far ahead of myself buying parts I don't need yet, that's not very easy.

So far the plan is I'll be using the spigots from my K3 and Kerker pipe, replaced wheels and K3 hubs with K8 sprocket carrier, spare early tank (not sure which side petcock is on, it's got bondo and is full of varnish but I got it from a friend who knows these bikes, he kept it for a reason...until he quit old bikes and purged his hoard.
Not sure what I can use for a seat that wont have a gap with an early tank, I may build my own for the $120 an ebay 64cm brat seat will cost me.
 

Alan F.

Learning the Ropes
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I've been ordering lots of parts and receiving a few orders. I don't really want to get too far ahead of myself and run out of parts. I've got stock cylinder studs to remove yet, lots of polishing to do, tapered roller steering bearings to install, forks to build and then at least I can bolt on the rusty wheels and have a roller. I've got another set of wheels to get the old bearings out of and disassemble the rusty spokes. I'll de-rust the hoops then relace with new spokes and bearings too.

I've been DIY Zinc replating a partial batch of nuts and bolts, they're in the vibratory polisher now.

Here's the finish after an acetone soak to clean, a vinegar soak to de-rust, an acetone rinse and a quick run through the plating bath:


And after 2 hours in the polisher with corn cob:


But this is the finish I'm going for:


For comparison here are the dirty, rusty exhaust studs I removed this afternoon:


Here's the frame with some shiny shocks:


I can't wait for the rest of my parts orders to arrive.