QUESTIONS ABOUT THE HONDA CB350 / CL350 / SL350
- Honda CB350 Specs
- What engine oil should I use for my CB350 / CL350 / SL350?
- How much engine oil do I need for my CB350 / CL350 / SL350?
- How often do I need to change the engine oil on a CB350 / CL350 / SL350?
- What fuel should I use in a CB350 / CL350 / SL350?
- What is the fuel capacity of a CB350 / CL350 / SL350?
- What size tires do I need for my CB350 / CL350 / SL350?
- What is the correct tire air pressure for my for my CB350 / CL350 / SL350?
- What size tire inner tube do I need for my CB350 / CL350 / SL350?
- What spark plug do I need for my CB350 / CL350 / SL350?
- What is the spark plug gap for the CB350 / CL350 / SL350?
- What size fuse do I need for my Honda CB350 / CL350 / SL350?
- What size drive chain do I need for my Honda CB350 / CL350 / SL350?
- How often should I lubricate and inspect the drive chain on my Honda CB350 / CL350 / SL350?
- What are the carburetor stock size jets for my Honda CB350 / CL350 / SL350*?
- What is the carburetor float height for my Honda CB350 / CL350 / SL350?
- How do I synchronize the carburetors on my Honda CB350 / CL350 / SL350?
- How often do I need to set the ignition timing on my CB350 / CL350 / SL350?
- How do I set the ignition timing on my CB350 / CL350 / SL350?
- How often do I need to replace the ignition points on my CB350 / CL350 / SL350?
- What type of fork oil and how much fork oil should I use in my CB350 / CL350 / SL350?
- How often should I change my front fork oil on my CB350 / CL350 / SL350?
- What is the valve adjustment / tappet clearance specs for the Honda CB350 / CL350 / SL350?
HONDA CB350 / CL350 / SL350 Answers
- Manufacturer: Honda
- Engine: 325.6 cc (19.87 cu in) OHC air-cooled 180° parallel twin,
- Bore / stroke: 64 mm × 50.6 mm (2.52 in × 1.99 in)
- Compression ratio: 9.5:1
- Top speed: 110mph (170 km/h)
- Power: 36 bhp (27 kW) @ 10,500 rpm
- Torque: 2.55 kg·m (25.0 N·m; 18.4 lbf·ft) @ 9,500 rpm
- Transmission: 5-speed
- Front: telescoping fork
- Rear: swingarm
- Front: Drum (Honda CB350K5 Disc)
- Rear: Drum
- Tires: 3.00 in × 18 in (76 mm × 457 mm)
- Wheelbase: 52 in (1,300 mm)
- L: 80.3 in (2,040 mm)
- W: 30.5 in (770 mm)
- 328 lb (149 kg) (dry)
- 374.8 lb (170.0 kg) (wet)
- Fuel capacity: 2.64 US gal (10.0l; 2.20 imp gal)
- Oil capacity: 2 US qt (1,900 ml)
Recommended oil viscosity for general riding and all temperatures is: SAE 10W-40.
We've also had success running diesel truck oil (Shell Rotella, Chevron Delo, Mobil Delvac) at 15W-40 viscosity. Diesel oil has the bonus of extra detergent additives as well as zinc which older engines need. Synthetic oils are are not recommended as they will cause your clutch to slip. We recommend adding 2-3oz. of Zinc additive with every oil change.
CB350 / CL350: 2.1 U.S. Quart / 2 Lit.
SL350: 2.3 U.S. Quart / 2.2 Lit.
Every 1,500 miles / 2,400 km.
We recommend premium (92+ octane) fuel; if it can be found non-ethanol fuel as well.
CB350: 3.2 US gal., 12 lit., 2.6 Imp. gal.
CL350: 2.4 U.S. gal., 9.0 lit., 2.0 Imp. gal.
SL350: 2.4 U.S. gal., 9.0 lit., 2.0 Imp. gal.
CB350 Front Tire: 18-100/90 (modern sizing) / 3.00-18 (old sizing)
CB350 Rear Tire: 18-110/90 (modern sizing) / 3.50-18 (old sizing)
CL350 Front Tire: 19-100/90 (modern sizing) / 3.00-19 (old sizing)
CL350 Rear Tire: 18-110/90 (modern sizing) / 3.50-18 (old sizing)
SL350 Front Tire: 19-110/90* (modern sizing) / 3.25-19 (old sizing)
SL350 Rear Tire: 18-120/90* (modern sizing) / 4.00-18 (old sizing)
*Off road tires will be wider due to tread size, measure clearance accordingly
Front Tire Pressure: 26 psi / 1.8 kg/sq. cm
Rear Tire Pressure: 28 psi / 2.0 kg/sq. cm
CB350 Front & Rear: 18" x 3.25" - 4" Inner Tubes
SL350 / CL350 Rear only: 18" x 3.25" - 4" Inner Tubes
SL350 / CL350 Front only: 19" x 3.25" - 4" Inner Tubes
UPDATE: As of January 2020, NGK has discontinued the B8ES and superseded with the BR8ES. The BR8ES is a resistor plug, which is designed to reduce electromagnetic interference of ignition systems for things like radios and phones while used in automotive applications. It is the new replacement plug for our vintage Honda motorcycles and performs just like the older B8ES spark plug. More info about resistor plugs can be found on the NGK FAQ page.
Gap specification: 0.7 - 0.8 mm (0.028 - 0.032 in.)
One 15A fuse
Standard (non O-ring) clip type master link drive chain with a 530 pitch will work.
Watch our YouTube video on how to count the links in your chain for the appropriate length.
Lubrication and inspection of the drive chain should be happening every 500 miles / 800 km.
Maximum slackness when measured by moving the drive chain vertically is 10 to 20mm (0.4 to 0.8 inches).
The Honda 350 family bikes went through various jetting changes over the years of production and here are the jet sizes to the best of our knowledge. We have seen combinations of all of these:
Main Jet Primary (Needle Jet): #105, #110 or #115
Main Jet Secondary: #68 or #70
Idle Jet (Pilot Jet): #35 or #38
*The K0 SL350 uses the CV style carburetors found on the CB350 and CL350. K1 & K2 SL350 use a round slide carburetor with different size and style jets from the CV type carburetor.
CB350 / CL350:
19 mm (Early Style Square Float)
22 mm (Late Style Round Float)
SL350: 26 mm (round slide carb)
Watch our YouTube video on synchronizing the carburetors on a Honda CB350 / SL350 / CL350.
Every 1,500 miles / 2,400 km.
Watch our handy YouTube tutorial on setting your ignition timing.
Inspect and set every 1,500 miles / 2,400 km. Consider replacing after 6,000 miles / 9,600 km.
CB350 / CL350: 200cc (6.7 ozs.) Early style with external spring
CB350 / CL350: 135 - 140cc (4.6 - 4.7 ozs.) Late style with internal spring
SL350: 180~190cc (6~6.4 ozs.)
Factory spec on the fork oil is of premium quality ATF (automatic transmission fluid), however we recommend a 10W (light rider) to 15W (heavy rider) motorcycle fork oil. ATF is approximately 5W and replacing it with a heavier weight oil will stiffen up your front end.
Every 5,000 miles / 8,000 km or once a year, whichever comes first.
The standard valve clearance is:
Intake: .05 mm (0.002" inch)
Exhaust: .10 mm (0.004" inch.)