1970 CB350 project "Goldie McGoldface"
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Thread: 1970 CB350 project "Goldie McGoldface"

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    Member oklota's Avatar
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    1970 CB350 project "Goldie McGoldface"

    Time for a project thread for my latest Craigslist find, a 1970 CB350.



    The bike has 38,000 miles and has seen better days. Not currently running, and the compression is weak on both cylinders. Obvious oil leaks at the cylinder gasket, head gasket, and side cases. Carbs are caked with years of gunk from the rusty/flaking gas tank interior. Rust everywhere. Lots of electrical problems on a wiring harness that's been butchered over the years.

    Seat isn't original and was hacked to work with the rear hinge, but doesn't stay latched. Will keep an eye on eBay for a rear hinge original seat.

    At some point someone replaced the exhaust with CL and ratted it out. Will probably return to stock headers/exhaust, depends on what I find under the header wrap. The CL exhaust melted and discolored the side cover. Other side is cracked in three places so I'll try to find some replacements.

    In other words, a fun project! (We'll see if I'm saying that down the line).

    Drained the oil and found lots of metal and rubber, so will probably split to cases to see what's in there. I want to get the cases vapor blasted anyway...

    Current plan is to strip the thing down, see what I find inside the engine, powder coat the frame, vapor blast the engine cases and carbs, and go from there based on time and money

    Generally want to keep it stock, since I love the look of the early 350 paint and the original paint on the tank is in decent shape.
    1970 CB450 K3
    1970 CB350 K2

  2. #2
    Member oklota's Avatar
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    This weekend was spent cleaning and tearing down the bike.

    Scrubbed the bike from head to toe with Simple Green, which helped a little. Years of road grime a pretty hard to remove in one sitting. But it's good enough to start getting pieces off and the engine out.

    First discovery was that the wiring was in worse shape than I thought. For example, an aftermarket ignition was installed and this was how ground was wired.



    Bare wire splices (!) were shorting out on the frame in multiple locations. Wire colors weren't standard. I decided to save some sanity and order a new wiring harness from fellow inmate pawelzak. It's on its way from Poland.

    Found two broken exhaust studs. Bummer. Was to able to get them out after a PB soak. And holy cow, 3-4 exhaust gaskets stuffed on top of each other in the ports! Various sizes of picks were needed to fish these guys out. The lowest level of gaskets had been in there so long they basically disintegrated when any force was put on them.





    Has anyone else ran into trouble removing the foot pegs? One of the bolts on the left side wouldn't come out, it just spins. It looks like a nut was originally welded inside the frame and the welds came loose over time. I had to cut it out with a dremel. The nut was round on the outside, which explains why I couldn't get any leverage on it to hold it still. Looking for advice when it comes time to reinstall... maybe I can simply position a new nut in that box and hold it down enough to tighten the bolt?

    Lots of PB Blaster and impact driver got all of the fasteners out without too much drama. They are all in pretty rough shape so I placed an order with Bolt Depot based on the parts list spreadsheet pinned elsewhere on the forum, that was very helpful. For ~$80 I'll have brand new SS fasteners across the board.

    The front steering stem bearings are totally shot (lots of forward/backward play). The triple trees and bearing races all came out pretty easily with a few taps from a drift punch. If you haven't seen it, Common Motor did an awesome video on YouTube for replacing your steering bearings.

    Removed the swingarm bushings, I'm planning to replace these with new bronze bushings. Surprisingly these hammered out pretty easily as well.

    I could not say the same thing about the lower shock bushings. The powder coater recommended that I remove *everything* from the frame because oil and grease could be trapped in there and ruin the finish when it went into the oven, and I believe these were press fit at the factory. No amount of PB blaster and hammering with a socket were moving them for me. I was seriously worried about bending the swingarm with the force I was using. I decided to weaken them from the inside out with a dremel to relieve the pressure, and sure enough that did the trick!



    The center pipe bushings came out after lots of soaking and hammering. VIN plate removal was fairly easy. Debating whether to replace the original with one of the retros on eBay. The original is pretty damaged, not from the removal, but sometime in the past My wife thinks it will add character/patina to the finished product, I think it will stick out. Any other opinions



    Engine came out pretty easily since I could just lean the frame over at this point onto cardboard.

    Black metal is all ready for powder. Tomorrow I'll start the fun part and dig in to the engine.

    devilclown, ooneil and mjornerud like this.
    1970 CB450 K3
    1970 CB350 K2

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    Member oklota's Avatar
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    The bike didn't come with keys to the steering lock, so here's how I got it out in case it's useful to others. I know it's common to order keys from eBay with the code, but for whatever reason my steering lock didn't have a code on the face. I later found it on the side of the barrel once it was removed.

    Anyway, I am not a locksmith by any stretch, but I was able to get it out. Here's how.

    First, all you will need is a tiny screwdriver and bobby pin.



    Basically, all you need to do is:

    1. Apply torque to the lock like you are trying to open it, and
    2. Press down the 4 pins inside the tumbler.

    Applying torque is easy because there is an external notch you can use. In a normal lock you would need to do this inside the keyhole at the same time you are pushing down the pins, but in this case it's easier.



    As far as the pins, you can see the first pin by looking inside the keyhole, and you can practice pushing it down with the pin.





    Now push the bobby pin in to the back of the tumbler and rake down and then out. You may need to add a slight circular motion to the pin before raking down and then out to get all of the pins depressed. The whole time, keep pressing down with the screwdriver.

    Eventually you will notice that the lock has turned.



    Now you just need to pull it out. No need for a locksmith

    1970 CB450 K3
    1970 CB350 K2

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  5. #4
    Senior Member Old Putz's Avatar
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    So good to see such an original bike being rescued from its past! Nice work!
    Yeah, I've been doing this for a while...

  6. #5
    Member oklota's Avatar
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    OK, on to the engine. So far, my wife has been very understanding every time I come in from the garage and say "reasons reasons reasons.... so I need to spend more money." With that in mind, this is the part I was worried about given all of the oil covering the cylinder fins and all the crap I found in the oil.

    I figured this would be a good "before" pic for comparison after the vapor blasting work. The exterior really isn't too bad after another scrubbing, just oxidized and stained. But, lots of oil on all sides of the cylinder



    Separating the cam case, head, and cylinder weren't too bad, nothing that a few whacks with the rubber mallet couldn't handle. I *did* however have a hell of a time getting the camshaft sprocket retaining bolts free. I just couldn't get a good angle on it through the cam cover.



    I eventually got it free after soaking with PB Blaster and then whacking the end of the socket wrench gently with the rubber mallet. To keep the sprocket from rotating I used the old penny trick. For those that haven't heard of this one, you can bend a penny in half at a 90 degree angle and wedge it between the clutch and oil filter gears to stop the crankshaft from rotating. The penny is soft enough that it won't hurt the gears, and it beats buying a specialty tool to do the same thing.

    With the head off I could see the extent of the oil leak(s) in the head gasket area.



    Also looks like oil was leaking from around the cam chain tensioner (which looks pretty shot to me... anyone have recommendations for a new tensioner? I think I remember reading about an upgrade or something...)



    I'm guessing the problem is coming from the oil passageways around the studs, but I'm not sure. The gasket itself doesn't look to be torn. Either way, oil was getting out. And unfortunately it looks like the top end was oil starved, because the camshaft and rockers really did a number on one another.





    Every single cam and rocker had deep scoring and pitting. I called the guys over at Delta Camshaft and they had a very reasonable estimate for refinishing everything, so another set of parts is off in the mail.

    On the plus side, the pistons look good, and the cylinders were clean with no scoring. I'll measure everything to verify it's still within limits. 3 out of 4 valves passed the acetone leak test. I'm really hoping to get away with a hone of the cylinders and lapping the valves. We'll see if that plan holds water, er, acetone and go from there.

    In the meantime, I've got lots of scraping to do to get the almost 50 year old gaskets off. The cylinder and head are really bonded on there. Probably my least favorite part of working on old bikes. I still haven't found a silver bullet for this one, I always end up going back to solvent and a razor. If anyone has any clever approaches I'm all ears.
    1970 CB450 K3
    1970 CB350 K2

  7. #6
    Member oklota's Avatar
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    Thanks! This bike was definitely not destined to be cut up into a cafe racer or tracker. At least, that was my feeling when I looked at it... straight up restore, with upgrades where it makes sense, ignition and suspension mostly.

    So good to see such an original bike being rescued from its past! Nice work!
    1970 CB450 K3
    1970 CB350 K2

  8. #7
    Member oklota's Avatar
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    Small update tonight. Finally had some time to split the cases and get the crank and gear shafts taken out. The hardest part was getting the shift fork pins removed. The manual simply says something to the effect of "pull out the pins", but unless I am missing something I couldn't find anything to pull on. (Yes I removed the clips first).



    I finally got them all out by holding the case vertically and tapping the fork leg against the case until they fell out, but there has to be a better way?

    At this point I have a hollow engine ready for the vapor blaster. For the first time I'm gonna try vapor blasting the carbs too, will post pics when I get everything back next week.

    Quick question: My outside cylinder studs no longer have the rubber dampers midway up the studs, circled below. I found pieces of them everywhere. From what I've read elsewhere on the forum, these aren't strictly necessary and just serve to reduce the noise of the stud potentially vibrating against the knock pin. Anyone know for sure?

    1970 CB450 K3
    1970 CB350 K2

  9. #8
    Senior Member ScramblerCurtis's Avatar
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    Yep your cam tensioner is toast. Upgrade to a roller one and dispense with the rubber wheel - Honda CB250,CB350,CL350,SL350,CB750,Cam Chain Tensioner Roller Wheel Set | eBay
    Curtis

    1969 Honda CL350 K1 - Done (Project Log)
    1970 Honda CT70 Trail K0 - Duckie Mo-Mo (Project Log)
    1971 Benelli Mini Enduro 65cc - No project name yet (future build)
    1999 Honda XR400R - Project "Ranger" Adventure Bike (next build)

  10. #9
    Senior Member ScramblerCurtis's Avatar
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    BTW - your project name is epic
    oklota likes this.
    Curtis

    1969 Honda CL350 K1 - Done (Project Log)
    1970 Honda CT70 Trail K0 - Duckie Mo-Mo (Project Log)
    1971 Benelli Mini Enduro 65cc - No project name yet (future build)
    1999 Honda XR400R - Project "Ranger" Adventure Bike (next build)

  11. #10
    Member oklota's Avatar
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    Quote Originally Posted by ScramblerCurtis View Post
    Yep your cam tensioner is toast. Upgrade to a roller one and dispense with the rubber wheel - Honda CB250,CB350,CL350,SL350,CB750,Cam Chain Tensioner Roller Wheel Set | eBay
    Thanks for the link, exactly what I was looking for... but holy crap these tensioner replacements are pricey!
    1970 CB450 K3
    1970 CB350 K2

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