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Honda CB350 / CL350 / SL350 Frequently Asked Questions

QUESTIONS ABOUT THE HONDA CB350 / CL350 / SL350

HONDA CB350 / CL350 / SL350 Answers

Honda CB350 Specs

  • 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
  • Suspension
  • Front: telescoping fork
  • Rear: swingarm
  • Brakes
  • Front: Drum (Honda CB350K5 Disc)
  • Rear: Drum
  • Tires: 3.00 in × 18 in (76 mm × 457 mm)
  • Wheelbase: 52 in (1,300 mm)
  • Dimensions
  • L: 80.3 in (2,040 mm)
  • W: 30.5 in (770 mm)
  • Weight:
  • 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)

What engine oil should I use for my CB350 / CL350 / SL350?

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. 

How much engine oil do I need for my CB350 / CL350 / SL350?

CB350 / CL350: 2.1 U.S. Quart / 2 Lit.
SL350: 2.3 U.S. Quart / 2.2 Lit.

How often do I need to change the engine oil on a CB350 / CL350 / SL350?

Every 1,500 miles / 2,400 km.

What fuel should I use in a CB350 / CL350 / SL350?

We recommend premium (92+ octane) fuel; if it can be found non-ethanol fuel as well.

What is the fuel capacity of a CB350 / CL350 / SL350?

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.

What size tires do I need for my CB350 / CL350 / SL350?

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

What is the correct tire air pressure for my for my CB350 / CL350 / SL350?

Front Tire Pressure: 26 psi / 1.8 kg/sq. cm
Rear Tire Pressure: 28 psi / 2.0 kg/sq. cm

What size tire inner tube do I need for my CB350 / CL350 / SL350?

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

http://www.common-motor.com/honda-inner-tube

What spark plug do I need for my CB350 / CL350 / SL350?

B8ES (NGK)

http://www.common-motor.com/honda-spark-plug-ngk

What is the spark plug gap for the CB350 / CL350 / SL350?

Gap specification: 0.7 - 0.8 mm (0.028 - 0.032 in.)

What size fuse do I need for my Honda CB350 / CL350 / SL350?

One 15A fuse

http://www.common-motor.com/honda-glass-fuses-15a

What size drive chain do I need for my Honda CB350 / CL350 / SL350?

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.

http://www.common-motor.com/honda-cb-cl-cj-sl-cb350-cb360-cb450-drive-chain

How often should I lubricate and inspect the drive chain on my Honda CB350 / CL350 / SL350?

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).

What are the carburetor stock size jets for my Honda CB350 / CL350 / SL350*?

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.

What is the carburetor float height for my Honda CB350 / CL350 / SL350?

CB350 / CL350:
19 mm (Early Style Square Float)
22 mm (Late Style Round Float)

SL350: 26 mm (round slide carb)

How do I synchronize the carburetors on my Honda CB350 / CL350 / SL350?

Watch our YouTube video on synchronizing the carburetors on a Honda CB350 / SL350 / CL350.

How often do I need to set the ignition timing on my CB350 / CL350 / SL350?

Every 1,500 miles / 2,400 km.

How do I set the ignition timing on my CB350 / CL350 / SL350?

Watch our handy YouTube tutorial on setting your ignition timing.

How often do I need to replace the ignition points on my CB350 / CL350 / SL350?

Inspect and set every 1,500 miles / 2,400 km. Consider replacing after 6,000 miles / 9,600 km.

What type of fork oil and how much fork oil should I use in my CB350 / CL350 / SL350?

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.

How often should I change my front fork oil on my CB350 / CL350 / SL350?

Every 5,000 miles / 8,000 km or once a year, whichever comes first.

What is the valve adjustment / tappet clearance specs for the Honda CB350 / CL350 / SL350?

The standard valve clearance is:
Intake: .05 mm (0.002" inch)
Exhaust: .10 mm (0.004" inch.)