« previous next »
Pages: [1] 2 3 ... 9   Go Down

Author Topic: "Mile High" CB350 Four project  (Read 32994 times)

0 Members and 1 Guest are viewing this topic.

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
"Mile High" CB350 Four project
« on: November 07, 2015, 04:10:03 PM »
So I've got myself something new to keep me busy!  I've been trying to find a small bore Honda four to get my hands dirty with for a little while, and finally found this little guy for $500 locally.  Tear down will take a little while, but I'm going to try and bite off small chunks at a time and see about completely rebirthing this into a tidy cafe bike.  It hasn't run for about a decade so I have my work cut out for me I think, but I plan on tearing it down to the cases so I should be able to uncover any hidden issues.

Here is the day I brought it home:


Couldn't resist tearing into it that night and cleaning it up a bit:
« Last Edit: July 08, 2016, 06:14:27 PM by Denver_Larry »
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #1 on: November 07, 2015, 04:15:05 PM »
So I picked it up about a month ago, but finally had a chance to give the tank some attention.

After splitting the tank in half:


After a few hours of bead blasting, sanding, and banging dents out:


A bit more stripping to do, but it's getting there.  Then to find a badass welder..
Logged
2005 RC51
1973 CB350F...project

Offline 2strokeTrush

  • Can you get that back together sonny?
  • Hot Shot
  • ***
  • Posts: 608
Re: New CB350 Four project
« Reply #2 on: November 08, 2015, 05:46:45 PM »
Cool!
Logged
If You Aint First Your Last!!

 350F project-http://forums.sohc4.net/index.php?topic=133079.0

500F Project-http://forums.sohc4.net/index.php?topic=135660.0

Offline timbo750

  • Expert
  • ****
  • Posts: 759
Re: New CB350 Four project
« Reply #3 on: November 09, 2015, 12:11:12 AM »
I am curious to know how you split the tank and also how tricky it is to weld back together ensuring it is sealed properly.
Logged

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
New CB350 Four project
« Reply #4 on: November 09, 2015, 08:23:12 PM »
I'm a little nervous every about the welders bill to tack this thing back together, but if it ends up being too much I figure I can just pick up another tank.  The other benefit of this is inherently I AM ending up with a subtly modified tank by virtue of no longer having the pinch weld.  I like the clean custom tank look, and it's something that won't get noticed right away...

Cal, did you weld it back up yourself?  TIG or otherwise?
« Last Edit: November 09, 2015, 08:31:19 PM by Denver_Larry »
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #5 on: November 09, 2015, 08:26:01 PM »
To answer your question timbo, I spent some considerable time with an angle grinder removing the pinch weld entirely.  Followed with a file for clean up.
Logged
2005 RC51
1973 CB350F...project

Offline WhyNot2

  • I'm finally an
  • Master
  • *****
  • Posts: 1,852
Re: New CB350 Four project
« Reply #6 on: November 13, 2015, 04:44:33 AM »
Wow....purdy aggressive on that tank there...................
Logged
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline SOHC4 Cafe Racer Fan

  • Speak up, Whipper-Snapper! I'm a
  • Really Old Timer ...
  • *******
  • Posts: 15,556
  • SOHC/4 Member #1235
Re: New CB350 Four project
« Reply #7 on: November 13, 2015, 07:08:53 AM »
Good luck mating that tank back together. That will require some skill and patience.
Logged
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #8 on: November 13, 2015, 12:38:02 PM »
Thanks, the plan is just to get it tacked together in a dozen spots or so, and then bring it to someone who has some actual welding chops..
Logged
2005 RC51
1973 CB350F...project

Offline dbbrian350F

  • Enthusiast
  • **
  • Posts: 114
  • dbbrian350F
Re: New CB350 Four project
« Reply #9 on: November 13, 2015, 10:09:25 PM »
Thanks for sharing this.  Now I know what my 350 tank would look like on the inside.  The metal sure is in nice shape on yours.
« Last Edit: November 13, 2015, 10:11:02 PM by dbbrian350F »
Logged
Bound and determined to restore my...
1974 CB350F1

Lucky new custodian of...
1978 XS1100E

Offline two40

  • Full Member
  • *
  • Posts: 13
Re: New CB350 Four project
« Reply #10 on: November 16, 2015, 06:58:47 PM »
Like yourself, I tend to go too far with stripping things in order to restore them but often that's the only way to do things properly!
Logged

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #11 on: November 16, 2015, 09:16:53 PM »
No problem.  I'm hoping to get the cleanup work finished this week and get it tacked up.  I think the effort will be worth it in the end.
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #12 on: February 01, 2016, 10:21:57 PM »
A bit of an update.  Got the tank dropped off to get welded back up last week, hoping to have it come back soon...

Knocked off of work a bit early today and finally got some play time in the garage.  First things first I built myself a stand to get the project up to a decent height.


Since I had already started tearing down the motor a few days ago, pulling it from the frame went pretty quick.


And I spent my first real money on the bike this week...Cognitomoto is cooking one of these up for me:
Logged
2005 RC51
1973 CB350F...project

Offline sbeckman7

  • Glutton For Punishment And/Or
  • Hot Shot
  • ***
  • Posts: 304
  • Slow and steady
Re: New CB350 Four project
« Reply #13 on: February 02, 2016, 12:02:23 AM »
Good to see another 350F getting the treatment!  You paid 5x as much for yours as I did, but yours looks to be at least 5x better than mine as a starting point  ;D
Logged

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #14 on: February 26, 2016, 09:32:15 PM »
A bit more tear down work completed over the last few days.  Pistons are off, oil pump off, and the clutch assembly and shift linkage are all gonzo.  May split the cases this weekend finally.


Found out what may have been the main cause of the complete disaster area that is the left side of the motor underneath the sprocket cover.  The oil pump o-ring is supposed to be a complete circle right?


After a closer look at the pistons, one of them has a 25 marking on the skirt.  Does this mean it's oversize?  I thought the +.25 piston had 25 stamped in the crown?


And lastly, you all think these pistons are still serviceable (assuming the bores are still in spec)?



Also tried my hand at polishing the case covers.  I think I'll be deferring to a shop to complete the job since getting this relatively easy part done took HOURS! Lol
Logged
2005 RC51
1973 CB350F...project

Offline sbeckman7

  • Glutton For Punishment And/Or
  • Hot Shot
  • ***
  • Posts: 304
  • Slow and steady
Re: New CB350 Four project
« Reply #15 on: February 27, 2016, 12:45:08 AM »
Looking good so far, keep it up.
Logged

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #16 on: February 27, 2016, 02:31:16 PM »

Quote from: calj737 on February 27, 2016, 03:28:34 AM
Quote from: Denver_Larry on February 26, 2016, 09:32:15 PM
The oil pump o-ring is supposed to be a complete circle right?
Yes, else it would be a "C"-ring.

Sarcasm was implied
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: New CB350 Four project
« Reply #17 on: February 27, 2016, 03:19:23 PM »
Alright, need help!  Splitting the cases and something seems hung up around the tensioner and I can't get the thing apart.  Cases have broken free of each other but I can go no further!
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: "Mile High" CB350 Four project
« Reply #18 on: March 12, 2016, 04:43:17 PM »
Finally realized that I needed to pull the main shaft..

An update: After struggling with woefully inadequate internal ring pliers and failing, I ordered up a new Wiha one and had the main shaft bearings out in seconds!  Nothing beats having the right tool..

Also, decided to go ahead and order up som CI .50 over pistons/rings etc.  They got here in incredible time!  One problem though: one of the Pistons is a little nicked up...

It is just about enough to catch your nail on and I don't really want to slip it down (what will be) a newly bored and honed cylinder.  You all think I can get away with remedying the situation with a some careful work with a fine hobby file and 800-1200 grit paper?  Or should I hassle CI about getting a replacement?
Logged
2005 RC51
1973 CB350F...project

Offline neevo

  • Enthusiast
  • **
  • Posts: 118
Re: "Mile High" CB350 Four project
« Reply #19 on: March 12, 2016, 07:24:39 PM »
I would get a replacement.
Logged

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: "Mile High" CB350 Four project
« Reply #20 on: March 13, 2016, 09:22:21 PM »
Contacted CI and they are replacing the damaged piston no problem.  Refreshing to see a company standing by their product without a hassle!
Logged
2005 RC51
1973 CB350F...project

Offline sbeckman7

  • Glutton For Punishment And/Or
  • Hot Shot
  • ***
  • Posts: 304
  • Slow and steady
Re: "Mile High" CB350 Four project
« Reply #21 on: March 14, 2016, 12:19:02 AM »
Good to hear!
Logged

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: "Mile High" CB350 Four project
« Reply #22 on: June 09, 2016, 07:42:21 PM »
Finally an update since I've actually gotten some things done!  A couple of the key goodies came in: MotoGP Yosh-rep exhaust finally landed and looks nice, and Cognitomoto finished cooking me up a custom triple tree. I'm still deciding if I want to polish it, or powdercoat it, or leave the nice satin finish on it that it already has...

I sent my whole motor off to Nils at Restocycle, and couldn't be happier with his service and communication.  I judge folks by how they handle things when $hit hits the fan, and a minor snafu (likely caused by UPS...) was greeted with an immediate resolution.  He will have my business again and again because of it.  Pics to follow!

AAAANNNNNDDD I got word from my welder guy that he's finally got my tank all put back together, and he's only charging for about 1/3 of his time!  I'll pick it up sometime early next week.

Frame is mostly de-tabbed at this point but I still have some work to do before I send it out for blasting.  Question for you guys:  I feel like the grinding wheels that I've been using for this task are leaving a bit too much evidence in the frame tubes.  What is everyone's abrasive disk of choice for this to leave a reasonable smooth surface on the tube prior to powdercoat?

Now that everything is squeaky clean, I have now found that one of the spark plug holes has some pretty damaged threads.  The plug threads in just fine, but a lot of material is gone from the threads in the head and the plug is quite loose and even wobbly until it snugs up.  I'm afraid there isn't enough material left to torque down the plug and have it hold.  SOOOOO......Helicoil or find another head?
« Last Edit: June 10, 2016, 08:27:29 AM by Denver_Larry »
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: "Mile High" CB350 Four project
« Reply #23 on: June 09, 2016, 07:44:52 PM »
Logged
2005 RC51
1973 CB350F...project

Offline Denver_Larry

  • Enthusiast
  • **
  • Posts: 147
Re: "Mile High" CB350 Four project
« Reply #24 on: June 10, 2016, 10:47:38 AM »
Yeah I think you're right.  Polishing or powder coating can always happen later if I want to change it.
Logged
2005 RC51
1973 CB350F...project
Pages: [1] 2 3 ... 9   Go Up
« previous next »