End of 2009 Update
I've been having to replace the left spark plug about once every 2 weeks as it is oil fouled. This does not bode well. Ace Motorcycle and Scooter has it for the winter and took a look at it. It needs new pistons, rings, seals and cylinder; ouch. Found a guy with pistons and cylinder off a K4 model with 8,000 miles on it and registering 115psi cold. The Clymer manual says 120psi is good cold compression and the asking price is great. He also has NOS rings still in the original box with part numbers. If these parts check out this would save me some decent cash. Keeping my fingers crossed.Here is the upside of the top end repair: I think this bike performs pretty damn well for a now 37 year old bike. If it had bad seals and poor compression in this state I'll have a bike with an adolescent heart come spring. This both excites me and worries me that I may not want to ever let this CB go.
My guess is that a transmission job will be in the future as well. Second gear has slipped into neutral a couple of times this year and there are a couple phantom neutral gears between 2nd and 3rd / 3rd and 4th. With a supposed 300,000 bikes sold from 1969 to 1973 I feel my odds are good. With other bike purchases in my head this may be my first and last bike as other bikes come and go.
Keeping your Honda cb350 running:
Shop Manual:
This one is a no brainer. I found this cb350 twin shop manual some time ago. Enjoy the freebie.What oil should I use?
10W40 - says it right on the stock dip stick.What spark plug should I use?
NGK B8ES plugs seem to be the concensus in shop manuals, online and by mechanics.Step by step carburetor rebuild:
There is this excellent post on a Honda CB350 twin CV carburetor rebuild. For a first time carb rebuild on set of CV carbs Darth's post was extremely helpful. Nice step by step instructions and large pics to guide you through.Carb rebuild parts:
I've had my carburetors off at least 6 times after having stalling problems and have learned a little. First off most gaskets that come in carb rebuild kits do not fit the float bowl properly even the authentic Honda parts. I've tried a handful of carburetor kits and the float bowl rubber gaskets are always too big. The last time I had to cut it and shorten the length or I bleed gas all over the place.Update: The heavens opened up and a great light shineth down in the form of 100s of ebay searches. I kid, like I've sort of been saying I'm new to this, but figuring this new game out has been half the fun. Finally found the float bowl gaskets to buy. They look more like the outline of home plate. Round carb gaskets have never worked for me. These float bowl gaskets
have worked the best so far. I picked them up from Sirius Consolidated Inc and dealing with them has been awesome. The part number as of Jan 2010 is SCI2634. Sure it is two more gaskets than I need, but they are also less than $20. These gaskets also fit
Honda's
XL250 1972 - 1976,
CL350,
SL350,
CB500 K Four 1971 - 1973,
CB550 K 1974 - 1976,
CB500 F Supersport 1975 -1977,
and Kawasaki's
KZ250 1981 - 1983
EX305 1983
KZ305 1981 - 1988
KZ400 1977 - 1979
KZ440 1980 - 1983
ZN700 1984 - 1985
KZ750 LTD 1980 - 1983
KZ750 Spectre 1982 - 1983
KLT200 1982 - 1983
KLT250 1982 - 1985 float bowl gasket needs.Sweet.
Sirius also has plenty of other "consumable" OEM new parts, like jets, needles, points, etc.
Checking the Timing
Make sure your battery is fully charged if you are going to check it by hand turning the stator. The induction timing light gun will not up trigger properly if the battery is not fully charged.Oil Change
It's a pain in the butt but clean the teeth of the oil centrifuge for every oil change. There is no oil filter on the Honda cb350 and so that's where the junk ends up. Little bits of metal cling to the teeth of the centrifuge and cleaning it only adds life to your cb350.1973 K5 model
I ended up with a rare model and a one off in the Honda cb350 line. It's a 1973 super sport (cb350G) and the only Honda cb350 of that era to have a front disk brake. All other front brakes in the line are drum style.Is my cb350 a cb350g K5 model?
There are a couple of things you can check to tell it you have a cb350g K5 model. The most sure fire way to know is by the VIN number. Keep in mind that the engine might have been swapped at some point in the bikes life. Check both the frame VIN number and the engine VIN number. Maybe you have a frankenstein bike.Here is who you can check to see if you have a cb350g K5 model:
- The frame VIN number from a cb350g will start with CB350-50XX..
- The engine VIN number from a cb350g will start with CB350E-50XX..
- The front disc brake is a good sign you have a K5 model
- As far as I know only the cb350g models have a shifter pedal that doesn't have a connecting linkage
Hidden steering lock
I was about to buy a steering lock for my Honda cb350 when Chad of Ace Motorcycle and Scooter pointed out a built in steering lock located between the front forks just above the front wheel. It's a tiny barrel with the key hole pointing towards the ground at the same angle as the forks and pushes a bolt out that locks the front steering. Sweet! Chad at Ace just saved me a bunch of money with his honesty and I highly recommend them if you ride in Chicago.Conclusion:
Honda cb350s are amazing machines, powerful, nimble and timeless.Over all my Honda cb350 is an absolute joy to ride with plenty of power and maneuverability. This bike is great for the city and decent for a quick jump on the expressway. This cb350 was my first bike and it is like a first love in a way.
Resources for your Honda cb350:
- Ace Motorcycle and Scooter Hands down the best repair shop in Chicago, IL for your vintage bike is Ace. Everyone that works there are truly wonderful people. I trust them implicitly, but don't take my word for it, read their Yelp reviews. They just completed a top end rebuild job on the cb350 and worked with me to find the best and least expensive parts. They even went above and beyond to inquire through local online vintage motorcycle groups to find parts for me. Here is another big plus in my book; they don't charge you extra if you bring in your own parts unlike many other places I've gone to.
- Identify your Honda cb350 year and model here.
- A great site for parts MotorCycle Solutions LLC
- Another great site for Honda cb350 parts and other classic 70s Honda bikes North City Vintage Honda
- The Honda Cb350 Wiki Pedia site. Short and to the point.
Ace is the...! (copyright pending)
