Author Topic: Saving A CB350F (Read 11708 times)

HondaMan · « **Reply #25 on:** November 20, 2017, 06:14:53 PM »

Quote from: mwvachon on October 03, 2017, 06:48:14 PM

One huge bonus with this find was the fact that the bike was complete - including the factory exhaust. When I looked it over for purchase, I checked the mufflers for any sign or rust or rot. Was keeping my fingers crossed that they'd clean up well... you be the judge!

You must be the luckiest 350F owner on the planet, with those pipes! Wow!

mwvachon · « **Reply #26 on:** November 26, 2017, 04:08:28 PM »

So while watching the football game this afternoon, I decided to tackle one of the smaller jobs - the speedo drive hub. I pay particular attention to this because I failed to properly examine/rebuild the unit I put on one of my CB750 builds. If you've never had a speedo-drive lock up on you while riding, let's just say it can be an interesting experience. Typically the hub seal goes bad and moisture gets into the drive gear. this can tear up the drive pins in the hub and/or cause the speedo-drive to bind up and lead to things like a bound up speedometer cable.

Unfortunately, the internals of this unit are not documented in either the CB350F parts manual or the factory service guide. All you see in either source is a picture of the drive unit. Since there are two seals involved, you either have to read the seal size off of the old ones, or try to measure them once you pull them out. I threw together this bit of quick documentation to make sure I had noted this somewhere until I get said seals and go to put this unit back together.

For disassembly, I pulled off the hub seal first. A spring clip holds the hub gear and washers in place. Took a bit of fiddling to get the clip out as I didn't want to damage it (again, none of these internals are listed anywhere). Disassembly is a bit tricky for the drive pin. I had to buff the drive housing to locate the set screw (camouflaged with grime & oxidation). I tried to remove it but it didn't feel like it was going to budge. I hit it with the torch for a few seconds and was able to back it out. Driving off the end cap required patience and some tough but thin screw drivers. At this point it is important to note that the drive pin slides out of the same opening as the end cap (don't ask me how I figured this out - embarrassing moment)

You'll need a pick tool to pull out the drive pin seal from the same opening as the speedo cable goes into. I cleaned up all the old grease and inspected all the parts. Will be installing new seals. The unit buffed up nice on the buffing wheel, but I don't want it to be too shiny as the original finish is normally somewhat dull on these.

MauiK3 · « **Reply #27 on:** November 27, 2017, 08:05:28 AM »

Nice work, I wonder if these are the same as those used on 500/550/750.

mwvachon · « **Reply #28 on:** November 27, 2017, 02:49:40 PM »

MauiK3 - I think the overall design is similar, but the seals might be a different size - especially the hub seal. Also, I know the CB750's used a thin stamped plate to lock the hub gear to the wheel. On one of my earlier restorations (the gold K1), the speedo drive actually seized up and sheared that plate. Hence my increased interest in rehabbing these units. The hub drive link on the 350 is a bit more rugged.

MauiK3 · « **Reply #29 on:** November 27, 2017, 06:33:01 PM »

Where can I find your previous work?
I just finished this, it's not strictly K3 but I wanted the look of my K0 back in the day.

mwvachon · « **Reply #30 on:** November 30, 2017, 05:21:15 PM »

MauiK3 - I just fixed the links in my signature. You should be able to view the 'Family Heirloom' K1 CB750 and the later S90 project on YouTube via the links. The other K1 CB750 exists as another entry in the SOHC/4 Project Shop as a separate thread.

Bmoreau · « **Reply #31 on:** December 21, 2017, 04:55:45 AM »

Thanks for sending me the info on your blog, Captain Mike.
Looks great.....definitely like the silver color as well. I found a '74 in RI (350F) through a fellow Yama-nut in that olive green color.....so I may have to view it this weekend. If I do....I will send you the video I plan to take of it so you can give me your unbiased 2 cents......ok?

mwvachon · « **Reply #32 on:** December 30, 2017, 01:51:35 PM »

Not a problem at all - always glad to provide my two Lincolns!

glenncal1 · « **Reply #33 on:** December 31, 2017, 09:22:05 AM »

If your 350 turns out at all like the S90 you are going to have one fine bike when you are done. Excellent work. Will the 350 be a rider?

mwvachon · « **Reply #34 on:** December 31, 2017, 07:11:42 PM »

Yeah, I'll add it to the stable for a bit. Growing up with the early '70's Fours, I've always been curious about the 350F. At some point I'd like to snag a 400F as well. I may flip it eventually.

mwvachon · « **Reply #35 on:** January 07, 2018, 05:15:57 PM »

I tend to jump around on different parts of the restoration, working on whatever floats my boat from one day to the next. I recently located the new sprocket pin bushings (4) for the rear hub and they arrived on Friday. I had to ask advice on how to remove the old ones as they defied my initial (and fruitless) attempts. I was told it was best to just drill out the rubber portion, pull the center spacer and then wedge a small screwdriver between the outer bushing ring and the hub; collapsing it enough to be able to remove. This sounded logical, so I managed to drill a bunch of holes in the rubber section, but that wasn't enough to free the center spacer. After digging out what rubber I could, I resorted to my torch to heat the spacer enough so that I could pull it free with a pair of needle-nose pliers. I dug out most of the remaining rubber, but still had the outer metal band to deal with. I ended up using a slender punch to wedge between the band and the hub. Once I created some space, I was able to drive a flat screwdriver into that opening. I did this at 4 points around the edges of the band. I managed to collapse it quite a bit, but it still wouldn't budge. I then went from the opening behind the bushing and drove a heavy screw driver from the brake side. This finally freed the band! I still have to dress up the pocket where the bushing goes, before I even attempt to drop the new busing in. I think what I'll do is heat up the hub and put the bushings in the freezer - and then try to press it into place. BEFORE I do that, I'll get the other bushings out of the hub - only 3 more to go!

mwvachon · « **Reply #36 on:** January 07, 2018, 05:27:52 PM »

I almost forgot! I've been doing other stuff as well. Painted the top-end engine pieces. I still need to clean up the bottom end and repaint the upper & lower cases. Using the Duplicolor Ceramic engine paint - code is DE 1615 Aluminum. I also used their HT primer as well. 2 coats of primer & three coats of paint.

MauiK3 · « **Reply #37 on:** January 08, 2018, 07:38:36 AM »

Many years ago I used a trick to really freeze things so they would shrink. Get a small container and fill it with isopropyl alcohol, enough to submerge your parts you want to shrink with a little room in it. Drop some dry ice in the alcohol before your parts go in and watch it boil, pretty soon the alcohol will move like honey, that's when it's cold, it won't freeze. Put your parts in the "honey" and let them shrink. Fish them out with some long pliers or other similar grabber, don't put your skin in contact with the alcohol, it's too cold and will burn you. This method is good for tight fitting bearing races too.

mwvachon · « **Reply #38 on:** January 14, 2018, 06:12:35 AM »

Items back from the powder coat shop. I use a local place, Powder Coating Alternatives, 25 Alden Ave, Greenland, NH. I've done my last 6 restorations using them to one degree or another, mostly for full frame and structural parts (the stock black metal parts). Always been pleased with the results. These guys know motorcycles and do an excellent job of masking/plugging, so that finished parts are ready to bolt up - no thread chasing or surface rework needed.

spuds · « **Reply #39 on:** January 14, 2018, 11:54:05 AM »

Nice looking batch of bits there!!!

mwvachon · « **Reply #40 on:** January 14, 2018, 04:43:10 PM »

Back to work on the rear hub (after the distraction of the shiny parts from the powder coat shop).
Figured out how to remove the plugs under the dampers BEFORE destroying the dampers to remove them. I was able to take a couple thin, long screwdrivers and gently pry out the plugs from the other side of the hub. This became very necessary as I found out that the plugs are not available - anywhere! I even looked in all my not-so-usual sources.
The process became - pry out the plug; drill out the rubber in the damper; put enough heat to the damper to be able to pull out the center spacer; drive a punch between the outer damper collar and the damper pocket (hub) to begin to collapse the collar inward; then drive successively larger screwdrivers into that same opening to collapse the collar further; drive the collapsed collar out from the back side of the hub. I then took a brake cylinder hone to each damper pocket to smooth over any gouges left by destroying the outer collar. Was able to press the new dampers in place by hand to about 50% depth and seated them using light taps from a suitable mallet.

mwvachon · « **Reply #41 on:** January 20, 2018, 04:41:49 PM »

More quality time in the shop today. Didn't even bother to turn on the heat as temps 'soared' to 47 today! Tending to some of the powder coat parts I got back. Adding the OEM sticker to the chain guard and the tiny plug that serves as a rub guard where the rear shock passes near. Also put the hardware back into the valve cover (tappets, shafts, end caps, tach cable drive & seal). Using assembly lube on all internal moving parts.

mwvachon · « **Reply #42 on:** January 27, 2019, 05:46:17 PM »

Top end assembly today... Managed to get the pistons back into the bores without a lot of grief. Another image wit a quarter laid on the piston to give some perspective on just how small they really are! Head all buttoned down and valve clearances set.

MauiK3 · « **Reply #43 on:** January 28, 2019, 07:52:46 AM »

Very nice looking, those are such cool engines! So compact.
It will be nice to see it run.

mwvachon · « **Reply #44 on:** February 17, 2019, 07:21:50 PM »

More progress... Engine buttoned up (mostly). Still need to do points, put on oil filter and oil pan (that will come after getting this into a roller)
When doing builds, I always lay the engine over and drop the frame on over it. Really reduces the chance of dinging up the finish on the engine or frame. Also makes lining up the mounting bolts a lot easier. Being at this point really builds the incentive to get this together. Just got a flyer for a local car/bike show first weekend in May. Hoping this will be ready!

MauiK3 · « **Reply #45 on:** February 18, 2019, 07:00:17 AM »

Sure looks great, nice progress.

Can550 · « **Reply #46 on:** February 18, 2019, 07:38:44 AM »

Frame painted or powder coated?

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przjohn · « **Reply #47 on:** February 18, 2019, 03:07:07 PM »

Looking Very Nice!

mwvachon · « **Reply #48 on:** March 08, 2019, 05:03:11 PM »

Been pretty busy making progress on this. As of last weekend, I now have a roller! So many things left to do!

mwvachon · « **Reply #49 on:** March 09, 2019, 08:02:15 PM »

More progress... Bike is together enough that I can roll it onto the 'Big Boy' lift to do work. So much nicer to get things done. Today installed new hardware for the side stand, installed the center stand, hung the wire harness and installed that pesky air cleaner/battery box. Was able to find the 4 items missing from the original too kit. It is now complete and bag fits nicely in the new tool tray. Also did horn surgery today. Unable to locate a new CB350F horn, so compared it to a CB750 horn of the same vintage and noted the only major difference was the mount bracket. Snagged a new CB750 horn for a reasonable price. Was able to easily swap out the bracket by changing the position of one of the mounting screws (moved to different hole).

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Author Topic: Saving A CB350F (Read 11708 times)