1973 Honda CB350F Cafe Racer

Meticulously Documented Frame Up Restoration

This '73 CB350F is fresh out of a full engine-out cosmetic and mechanical restoration from the frame up. The work was done by a detail oriented ski-lift inspector (a good quality for that job) and Japanese motorcycle enthusiast who restores several bikes per year. He documented all of his work in detail in a 4 page document (see below.) He used quality parts only.

These included: Avon Roadrider tires with HD tubes and rim strips, professionally mounted and spin-balanced, Yuasa battery, 4 Sudco complete carb rebuild kits, Honda fork seals, Keystone engine gasket/seal kit, front and rear stainless steel spokes and nipples, NGK plugs and caps, MAC 4/1 exhaust with chrome muffler, Hotwingsglass bump seat and pad, Honda clutch cable, Honda caliper seal, EBC front brake pads, DID chain, Cycle-X fork gaiters, chrome headlight ears, horn, chrome drag bars and grips 

The bike currently shows 11,460 miles. It starts easily by electric or kicker, idles nicely, shifts well. Compression (warm) is 150, 145, 150 and 150psi. Charging system and all electrics are 100%. 

The frame, swingarm, triples, front hub, caliper body and all brackets were sanded and sprayed with 3 coats of matte black enamel. Every nut and bolt was either polished or replaced. Critical fasteners (axle clamp bolts, triple clamping bolts, shock bolts, swingarm axle nut, motor mounts, etc) were Loctite'd and torqued.

All aluminum has been polished for a soft luster (not show polish.) This included the rear hub, brake panel, brake stay, fork lowers, engine covers, carb bodies, caliper mount.

All chrome was polished: front and rear rims, headlight ring, front fender and stays, speedo/tacho bases, brake and shifter levers, kick-starter, throttle cable ends, and shocks.

The engine cases were cleaned only, and not blasted/painted. There was a concern about the blasting media getting into the engine itself.

The tank is very nice inside and out, with original paint and only a few minor imperfections. It has a bright luster. Side covers are solid with no cracks, but paint is original has some patina. The overall look of the bike is not over-restored or show quality. Instead it keeps its original character by using its original tank and sidecovers.

During restoration the carburetor jetting was left near-stock and the decision was made not to use pod filters. He did raise (enrichen) the needles one notch to compensate for the aftermarket 4/1 exhaust. As a result, the engine pulls strongly from about 3K to redline (10K.) A motion pro manometer sync might make things even smoother.

Swingarm bushings were perfect, and were not replaced. Cleaned and re-lubed only. 

By stripping off unnecessary weight, he dropped the weight of the bike by about 25 - 28lbs from stock. It is one of the quickest 350s we have ridden.

There is a small amount (less than a teaspoon) of oil seepage between cyl #1 and #2. This is probably due to the o-rings between the cyl and head being slightly small, or the head gasket being slightly thick, as it is brand new. The fix is probably just a head re-torque, or using Hondabond on the o-rings or next size up o-rings. It does not drip on anything or smoke. Its the kind of thing that could be left as is, or attended to easily.

The blinkers were removed with wires labeled and tucked away.

The wiring for rear light and brake light (checks ok using front and rear brakes) has been labeled and tucked away. There are many rear light options (under the bump seat, vertical side-mount, horizontal side- mount) and each has an effect on the "look". Therefore no rear light has been installed, am leaving this for the next owner.

Below is a copy of the 4 page word document supplied to me with the bike. It details every aspect of the work completed. 


Condition before restoration:

General Condition:
• Complete but needs full refresh
• Keihin 656c carbs (20mm)
• Change oil/filter after 300 miles 
• Electrics check -- everything works except left blinker, horn weak
• Long-term v-leak test -- all ok after 2m 


Spares included (when he got the bike):
• 4 Sudco carb rebuild kits ($52)
• Complete engine gasket kit ($72)
• CD rom service manual ($33) 
• Chrome spoke and chrome nipples (stock #1053c) for front/rear wheels ($75 )

Preliminary:
• new battery -- done 
• change oil, clean filter housing -- done 
• clean petcock and screen, replace o-ring -- done 
• check voltage drop over time -- done/ok 
• check spark -- has spark (needed to dress points and install all new NGK plug caps)
• carbs rebuilt w/new Keystone gaskets from Sudco:
 new D22 needles and clips (clips set one pos down from center, richer) 
 new floats/float valves with o-rings
 new fuel tee o-rings
 new #75 main jets with o-rings
 new #3 slow jets
 new air screws and springs
 new upper gaskets
 new float bowl gaskets
 air screws set at 3/4T out
 floats set at 21mm
 new fuel line, in-line filter, carb vent lines 

Refurb Plans: 
• full tune-up
o new NGK plugs -- done
o new plug caps -- done
o adjust valves -- done 
o adjust cct -- done
o set/adjust points -- done
o set timing -- done 
o oil/filter change -- done
o clean oil pan and screen -- done/perfect!
o clean airbox and filter -- done 
• clean / rebuild carbs -- done
• bench sync carbs -- done
• lapped valves -- done
• lighten throttle spring -- done
• new fuel filters and fuel lines -- done 
• sand/3 coats enamel paint on triples, frame, swingarm, caliper body, instrument base, headlight bucket -- done 
• clean petcock -- done, screen looks new 
• replace exhaust -- done, with MAC 4/1 with chrome muffler 
• replace seat -- done, with Hotwings glass bump seat
• remove blinkers -- done 
• install drag bars -- done 
• new clutch cable -- done, with Honda OEM 
• lube speedo and tacho cables -- done
• replace broken speedo cable -- done
• clean/check front wheel bearings -- done
• check/clean/re-lube speedo drive -- done
• sand/paint front hub -- done
• replace front wheel spokes -- done, with chrome spokes/nipples (#1052c) 
• disass/clean forks, replace seals, fork oil -- done w/Honda OEM seals and Belray 10w 
• polish fork lowers -- done
• disass/clean/rebuild caliper w/new seal -- done, with Honda OEM seal
• replace rubber brake lines with SS -- not done
• flush w/fresh brake fluid -- done 
• fab bleed screw cover -- done
• New EBC FA13 organic brake pads -- done 
• sand/paint caliper -- done 
• polish m/c -- done 
• polish banjo bolts -- done
• check/lube steering head bearings -- done
• remove/check swingarm bushings -- done (are perfect)
• sand/paint swingarm -- done
• check/lube rear wheel bearings -- done 
• replace rear wheel spokes -- done, with chrome spokes and nipples (#1053c) 
• done polish rear hub -- done 
• clean/lube brake pivot pins, axle -- done 
• disass/clean rear brakes, sand shoes -- done (shoes look new)
• clean/lube rear axle -- done 
• remove left cover and check/clean shifter linkage -- done
• replace chain and master link -- done
• clean threads, then loctite front sprocket mounting bolts - done 
• loctite engine mounting bolts -- done
• check tach seal -- done 
• clean all electrical connections and grounds -- done 
• spare key -- not done 
• fix instrument and indicator lights -- done
• sand/paint battery box -- done 
• replace left engine cover -- done
• replace headlight bucket -- done, with cb750k model
• polish all engine covers -- done
• relocate horn to beneath bump seat -- done
• relocate ig switch -- done

New Gaskets / Seals Installed 
• valve guide seals (8)
• oil galley seals (2)
• orifice seals (2)
• oil runner o-rings (1 large, 1 small)
• oil filter o-rings
• head gasket
• valve cover gasket
• clutch cover gasket
• crankcase vent cover
• valve adjuster cap o-rings (8)
• exhaust pipe gaskets (4)
• CCT o-ring
• oil pan gasket
• kick starter seal
• points cover gasket
• dipstick o-ring
• petcock o-ring 

Test Run on 8/1/13
• check oil flow to top end, both sides -- ok 
• check shifting -- perfect
• carbs have no leaks
• compression test (3 hours after test run)
 150 psi
 145 psi
 150 psi
 150 psi
• check charging system:
 1200 -- 13.6v 
 2000 -- 14.7v
 4000 and above -- 15.0v max

Lighting
• blinkers off -- done 
• rear sprocket chain guide off -- done
• chainguard off -- done
• centerstand/mount/spring off -- done
• chop front fender/stays off -- done 
• replace seat -- done
• remove rear fender -- done
• remove rear light/license holder -- done 
• remove passenger footpegs -- done
• remove passenger grab-bar -- done
• stock exhaust off -- done
• stock mirrors off -- done
• caliper splashguard off -- done
• fork covers/reflectors off -- done
• toolkit and tools off -- done
• stock handlebars off, replace with drag bars -- done

back on
• bump seat and pad -- 3lbs
• single, small mirror -- 8oz
• mac exhaust -- 8lbs 
• smaller rear light, plate mount -- 8oz
• wider rear tire -- 8oz

parts off weighed 31lbs 11oz
parts back on 4lbs

approx 26 lbs. lighter than stock
period tests: 373dry, 381 wet

Electrical Measurements, with battery voltage at 13.22v
• blue points -- 11.4v
• yellow points -- 11.36v
• blue wire at coil -- 12.1v
• yellow wire at coil -- 12.2v
• zero battery drawdown after 2m sitting without charging (12.5v to 12.1v)

Note: orange and blue female connects are for rear blinks

 

Please click the pictures below for an enlarged version of each. 

 

 

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