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Author Topic: My 1970 CB350K Winter project  (Read 2091 times)

Offline 23Maple

  • Posts: 19
My 1970 CB350K Winter project
« on: Dec 13, 2016, 21:48:02 »
I guess I should introduce myself and my project. 

A while back a cb350k came up for only 300, complete, with a clean title.  Downside was it hasn't ran in like 35 or 40 years. 

This is the best image to start. They get worse from here. 






Oh, and I've never even ridden a motorcycle.  I do have some mechanical experience, I do most of the simple maintenence and modifications on my cars. 

I took on this project as a therapeutic winter project,  a creative outlet.

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Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #1 on: Dec 13, 2016, 21:50:33 »

Almost disassembled! 

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Offline advCo

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  • Posts: 2079
  • Nick Ol' Eye
    • adventur Studios
Re: My 1970 CB350K Winter project
« Reply #2 on: Dec 13, 2016, 22:26:49 »
Nice find. That's a real low mileage motor. Is it seized?


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"He broke the mirrors off his Cadillac, 'cause he doesn't like it looking like he looks back."

74 CB360 - Luna - http://www.dotheton.com/forum/index.php?topic=63294.0
82 GS550L - Tracker-ish - http://www.dotheton.com/forum/index.php?topic=67229.0 - Sold
74 XL350 - The Turd - http://www.dotheton.com/forum/index.php?topic=70252.0
Suzuki FA50 "No-Ped" - http://www.dotheton.com/forum/index.php?topic=71189.0
73 Suzuki RV125 -http://www.dotheton.com/forum/index.php?topic=73875.0

Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #3 on: Dec 13, 2016, 23:25:06 »
I've no idea.

That is on the agenda to figure out.

Hopefully not, but if it is, I guess I've an excuse to bore it out a little, if neccessary- I'd prefer not to, of course, that's budget that could go other places.

Of course now I've got the engine out of the frame, unsure how to test for that.

Offline advCo

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  • Nick Ol' Eye
    • adventur Studios
Re: My 1970 CB350K Winter project
« Reply #4 on: Dec 14, 2016, 00:13:58 »
It would have been easier to evaluate the motor while it was in the frame, but it's too late now. I'd put it up on a stand and open the generator side up, you can manually turn the motor with a socket on the crank from that side. Chances are it will be stuck, I would try a 50/50 ATF and acetone cocktail into the spark plug holes and see if it frees up after a few days. You'll want to heat the block up with a lamp before draining the oil.


Sent from my iPhone using DO THE TON
"He broke the mirrors off his Cadillac, 'cause he doesn't like it looking like he looks back."

74 CB360 - Luna - http://www.dotheton.com/forum/index.php?topic=63294.0
82 GS550L - Tracker-ish - http://www.dotheton.com/forum/index.php?topic=67229.0 - Sold
74 XL350 - The Turd - http://www.dotheton.com/forum/index.php?topic=70252.0
Suzuki FA50 "No-Ped" - http://www.dotheton.com/forum/index.php?topic=71189.0
73 Suzuki RV125 -http://www.dotheton.com/forum/index.php?topic=73875.0

Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #5 on: Dec 19, 2016, 19:02:03 »
It turns!  Very smoothly,  in fact!  Wooooot!




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Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #6 on: Dec 19, 2016, 19:33:17 »
Pop open the head... looks fairly clean in here!  Gasket wasn't even in that bad of shape...




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Offline xb33bsa

  • Posts: 7727
Re: My 1970 CB350K Winter project
« Reply #7 on: Dec 19, 2016, 21:41:15 »
great project is there any signs of rust up top ?
dont turn the engine over with the head nuts off you stand a very good chance of breaking the seal on the cylinder base gasket as well as the head gasket
if you want to keep the bike and have good service from it probably should pull down the top end the rings are likely stuck and the bore will have some rust
plus the time is now to get a ka cam chain tensioner
there is very lilkely some rusty valve seats as well

Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #8 on: Dec 19, 2016, 22:48:16 »
xb33bsa- Internally I saw no evidence of rust, it looked great. The exterior aluminium is well patina'd but is cleaning up nicely- I'd like to get it blasted and polished up a bit.  *Most* of the exterior screws are coming lose with an impact wrench, but I'll have to use an extractor on a few (well, hopefully that does it, I suppose I might also have to drill out and re-thread, but I'd prefer not to.)

I'd feel awfully silly if I turned it upside down without resecuring the head. I can see that's how the topend stacks up.
I'd originally planned on a complete rebuild, but am pleasantly surprised at how well the internals seem to have kept so far- no rust visible and everything even seems to still have a light coat of protective oil to it inside.

Is it advisable (I think it sounds so) to retorque back the head to factory specs and do a compression test *before* I begin full disassembly? Provided it's got good compression and no obvious rusty internals, what other engine parts are considered wear parts and good to replace while I've got it apart? (other than all the gaskets)

This is the first I've heard of this ka cam chain tensioner- I suppose the cam guides are a weak link in this engine if you're mentioning it?

I ask because in googling it sounds like you've got to use a certain timing chain with it, which I would think would require splitting the bottom cases- not that that's a big issue, I plan on it anyways.

I'll be sure to research the valve seats when I've got it apart.

Thank you for your input! I'm a motorcycle beginner, but so far it seems fairly logical in it's organization. ;)
« Last Edit: Dec 19, 2016, 22:49:53 by 23Maple »

Offline xb33bsa

  • Posts: 7727
Re: My 1970 CB350K Winter project
« Reply #9 on: Dec 19, 2016, 23:11:04 »
xb33bsa- Internally I saw no evidence of rust, it looked great. The exterior aluminium is well patina'd but is cleaning up nicely- I'd like to get it blasted and polished up a bit.  *Most* of the exterior screws are coming lose with an impact wrench, but I'll have to use an extractor on a few (well, hopefully that does it, I suppose I might also have to drill out and re-thread, but I'd prefer not to.)

I'd feel awfully silly if I turned it upside down without resecuring the head. I can see that's how the topend stacks up.
I'd originally planned on a complete rebuild, but am pleasantly surprised at how well the internals seem to have kept so far- no rust visible and everything even seems to still have a light coat of protective oil to it inside.

Is it advisable (I think it sounds so) to retorque back the head to factory specs and do a compression test *before* I begin full disassembly? Provided it's got good compression and no obvious rusty internals, what other engine parts are considered wear parts and good to replace while I've got it apart? (other than all the gaskets)

This is the first I've heard of this ka cam chain tensioner- I suppose the cam guides are a weak link in this engine if you're mentioning it?

I ask because in googling it sounds like you've got to use a certain timing chain with it, which I would think would require splitting the bottom cases- not that that's a big issue, I plan on it anyways.

I'll be sure to research the valve seats when I've got it apart.

Thank you for your input! I'm a motorcycle beginner, but so far it seems fairly logical in it's organization. ;)

its been sitting idle that long proly better to not spin it over bores i would be suprised if they dont have any rust 
the cam chain is no biggee the hew one it uses a master link so you would just cut yours free 13k miles it may be toast
its the cam chain oem rubber rollers they go bad age and chemicals 40 years man
besides the ka slipper is just better
get the factory service manual it has everything you need all the service limit specs ,and procedures and is easy understandable
the good news is you have chosen the engine/motorcycle  with as much or  more aftermarket , nos and used support/parts/racing parts  than any other in history,for sure  at least at 350cc
and the bike was always very good probably best if you are like a 100lb oriental

Offline xb33bsa

  • Posts: 7727
Re: My 1970 CB350K Winter project
« Reply #10 on: Dec 19, 2016, 23:25:01 »
and the case screws are not phillips they are jis require the correct fitting tip
bottom line is the correct one will stick in place,it fits so good, the others will not take torque,cam out ,and knurl up the fit

Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #11 on: Dec 28, 2016, 03:13:25 »
Updates. Rearranged in the garage so I could get to the mediablaster.

Before

After


Before

After


Started cleaning the fins and such, just elbow grease and simple green.



Stalling somewhat to see what my finances allow going forward. May only have budget for gaskets, paint, and elbow grease going forward.  Though with some creativity that may go a fair ways.

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Offline revel.motorcycles

  • Posts: 111
    • Revel Motorcycles Chicago
Re: My 1970 CB350K Winter project
« Reply #12 on: Jan 09, 2017, 17:08:23 »
Cool!  Keep it up!

Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #13 on: Jan 24, 2017, 23:16:33 »
Dug into the engine a bit.
 





















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Offline 23Maple

  • Posts: 19
Re: My 1970 CB350K Winter project
« Reply #14 on: Feb 08, 2017, 00:54:37 »
More pics... one partly stuck piston later...


Oops. Starter bolt issue...














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