[Derptin]

Hello!

My name's Justin and I'm based in the heart of Atlanta. I bought a 1973 Honda CB 350 awhile back, and I'm hoping to be able to learn enough to be able to stabilize it and make it a daily commuter. I don't have a car (sold it because I live in a 1 Bedroom condo with my girlfriend and we only have a single parking spot), and I'd really like to be able to turn this thing into a main source of transportation for myself. But let me say that I know next to nothing about motorcycle mechanics. I know how to ride motorcycles, and I'm a quick learner if given walkthroughs, but I will definitely need some hand holding (and please no judgement. I've found other forums where people can be very judgemental of how little I know. If that's you, please just move on. I'm just a new rider and lover of vintage bikes hoping to start learning.)



So. Quick breakdown of what's happened so far. I bought it for $800 non-running, and set it up in a motorcycle repair shop for about 3 months while they worked on it. They installed a new battery, new tires, new electric ignition, a new spedo cable, and resynced the carbs. When I got it home, it ran for a bit, but I'm having a tough time trying to figure out how to get it to idle. It was starting strong, and it would run for as long as I kept the throttle on, but then slowly it dropped past 1000rpm and died. I tried what I believed to be the adjusting of the idle screws, but then it went from starting and maintaining rpms with the throttle on to not starting at all. It sounds like it wants to start, but it's just not catching now. I could have messed something up when I went to adjust the idle screws (and I might have also ****ed up the settings for the air mixture screws because I know those are right there in the same place) but I really just need someone to help walk me through what to do.

Bonus points if some kind stranger lives in the Atlanta area and would be willing to come by and take a look at it. I've currently got it parked in an underground parking garage in front of our car, so I don't have a lot of space to work, but I can get the car moved while I work, I just need to have an idea of what I'm going to be doing so that I don't just totally tear the bike apart. I'm hoping to not have to take it back to the shop, for two reasons. 1. If I'm going to ride one of these sexy beasts, I need to learn how to maintain it or I'm never going to get anywhere. 2. I don't really have the excess money anymore to throw at the repair shop to fix a problem that they can't actually fix (me not knowing how to maintain my bike properly.)

Thanks a lot for those who took the time to read and offer help.

-Justin

 

[longdistancerider]

Welcome aboard, This forum unlike so many others is here to actually help you out. We don't do judgments, bashing or anything else and in the odd situation where that starts it gets squashed very quickly.
There's lots of info in the 350 section for you, I'm not a lot of help on these models but there's plenty of knowledge from others.
You'll need the FSM if you don't already have it, factory service manual. PM sent

 

[JamesTDoe]

I'm in Roswell, just off Exit 7 on GA 400 and I'm happy to help where I can.

I'm pretty new to Honda CB's myself, but I just bought a non-running '71 CB 350 a few weeks ago that is starting and idling pretty well after a few tweaks (valves, timing and carb issues).

I've been fixing cars and bikes for the last 30 years or so, and I don't think there are any Craftsman tools that I don't have.

I'll PM you my number.

For now, if you screw those idle mixture screws all the way in, and then back them out 2 full turns (on each carb) that should get you to a pretty good baseline. From there you should be able to adjust your idle (throttle) screws up to get it to start and idle.

 

[ancientdad]

On the CB/CL350s with stock carbs, there's another thing to consider - the diaphragms that control the slides. They're under the chrome cap on the top of the carb. They are prone to getting cracks in them after they age, and can cause issues with response and return to idle if the cracks are bad enough. There are aftermarket replacements available if you need them, here are a couple possibilities (they are out of stock at 4into1.com but if they can get them, the price is way better than CMC)

Reproduction Carburetor Diaphragm - Honda CB350 CL350 Twins

Honda CB350 / CL350 / SL350 Carburetor Diaphragm | Common Motor Collective

 

[Rob Axel]

Welcome.. these bikes are fairly simple.., that being said the carbs can be a bit "fickle"... tuning one carb with little experience can be tough, two is an animal all itself... me, havnt got the balls to take the 4 carb leap just yet...
AIR-FUEL-SPARK.... is all you need... granted timing and proportions aid in performance.
3 months at a shop and it isn't running? Was this due to finances on your part or the shop not delivering?
NEW ELECTRONIC IGITION? ... a set of points would have got u going and a whole lot cheaper! Sounds like carb issues.. if it wasn't running, dead battery, needed tires.... it has set for a while..
Your fuel system needs a good going through! As stated before 4into1 has great carb kits.. I've installed 5 myself, and the difference in the motor was night and day... and get new fuel lines and filters!!! Flush them before installing..
Doe... way to go for stepping up... I was gonna offer if he wanted to make a trip to savannah I would be more than happy to help..
.. check out "common-motor collective" on YouTube .. a lot of great info..
Find a gas staion that sells Non-ethanol or ethanol free gas... use this as much as you can, it's better for your motor, makes tuning easier, and won't destroy you rubber items....
Betting the low idle jets are clogged....it doesn't take much...get the carb kits, a couple cans of carb cleaner ... and you should be able to get her running better...
You don't have to be a rocket Surgeon to work on these bikes, but a lot of common sense helps..

 

[Polish]

Welcome aboard and really nice bike! As you can see, lots of help from very knowlegable people here on the forum. Some will even go out of their way to help you out. Keep us posted.

Here is something to help you out knowing your bike better: http://www.hondatwins.net/forums/67...n/16105-basic-checklist-new-you-old-bike.html

 

[jd50i]

I didn't see where the carbs had been torn down and cleaned, I would start there. You have no idea what a previous owner has done.

 

[slofut]

I'm betting the carb problem starts at a contaminated fuel tank. They're pretty old now and most have at least some rust. Ethanol fuel doesn't help the situation, ask any small engine mechanic.

 

[JAYinNY]

Check for intake manifold air leaks. Mine was showing similar symptoms and was cured by new manifolds.

 

[jakec]

Not judging you at all for not knowing what to do. I was the same way when I started my project and I've learned everything that I needed to know right here on the forum. It's also ok to not really care for being a mechanic... but if that's the case (just want to ride and not fuss), you bought the wrong kind of bike and will have to decide if you're going to buy the tools and parts needed and learn to do the work, or continue to pay out the ass for mechanics.

When I got my first bike I ended up having a similar starting issue and sending it to a mechanic. I didn't know it at the time, but in my area that is about $100/hour for labor. At $800 non running and in that great shape, you definitely got a great deal. But if you have everything done by a mechanic the money invested will soon outpace the value of the bike. I think if you stick around the forum here you will be able to solve all of your problems, especially the idle/air bleed issue you described which is pretty straight forward. Good luck and nice bike!