honda cb350

[dfreeman616]

anyone have some experience with these bikes? i'm looking at getting a 10/1970 build date for about $150-200 from a guy i know. supposedly a lot has been replaced on it, and it runs fine til hot. at which point, it stalls and needs to cool before starting. it seems to be in pretty decent shape, says a little under 9k miles on it.

[DJM/78]

Sounds like it sat around for a long time , problems with starting and ignition are common with a bike that sits . The fuel system would be my first guess considering it only takes about a year for the fuel to go bad .

Corrosion of the inner gas tank and fuel lines or pepcock valve are more common around here . I had a CB 750 that only sat for 9 months , it took me disassembling all for carbs and cleaning them spotless , replacing the the fuel

lines and the reserve grommet . New plugs and wires and I was good .

[dfreeman616]

it hasn't been sitting long from what i know, and it has almost everything replaced supposedly, including new plugs/wires/points etc and the carbs rebuilt. like i said though, it runs great for a few minutes, then stalls out only when hot. i know the basics of what to check for...coils overheating, perhaps some vapor lock, but was more looking for any specific problem areas, like the crank sensor is in the jeep 4.0L.

[DJM/78]

It sure sounds like something with the ignition , like the points grounding out once it gets hot , hard for me to remember what those things had in them . Good thing is , there isn't much to them .

 

I did the same thing with those carbs , spent all the time cleaning and replacing the seals , ran for about a full tank of gas until all the crap in the tank clogged them right back up . That time I pulled the tank , flushed it , relined

it and replaced all the fuel hoses new . That finally fixed it , turned out the fuel was corroding the liner from the inside out , every time I filled it up , it just threw more gunk in the carbs .

 

Your problem more sounds like something wrong with the spark or overheating of the plugs or points .

[tazjeeper]

coil or stater or rectifier... its about the only thing on bikes from around that year that make them stop when hot...

now with that being said can you rev it up when cold... if so its not a carb or fuel problem its coil, stater or rectifier.

if you can not rev it up when cold the carbs are probably not working properly

I have taken carbs of the old bikes that people have put togeather (hondas always for some reason) and they have putone or all the floats in upside down. this will let the bike run for a bit then after the bowl is empty it will stop becasue it takes to much time for the bowl to fill again..

also a micro speck of rust or dirt will clog a main jet. causing you not to be able to rev the engine up usualy when hot.

so if you can rev the engine up when cold most likly the above aplyes... where you have spark problem..

coil, starter or rectifier.

now their are some tests you can do.

use a muitimeter on the rectifier to see how many volts are comming out of it. it should be around 13.5 to 13.9.. do this when bike is cold and after it heats up..

also if the rectifier is realy hot when the bike is getting warm most likly its no go..

[Eagle]

I used to own a 1971 CB350. It was a great bike ... my first ... but a little on the small side for my 6'-2" height. But it got great gas mileage, and since I was living in West Philadelphia at the time (graduate school) it was perfect urban transportation.

 

However, I long ago moved up to a Honda Nighthawk, and even that has been gone for many years. I never had any mechanical issues at all with the 350 so I couldn't begin to help you diagnose what the problem might be.

[DJM/78]

I used to own a 1971 CB350. It was a great bike ... my first ... but a little on the small side for my 6'-2" height. But it got great gas mileage, and since I was living in West Philadelphia at the time (graduate school) it was perfect urban transportation.

 

However, I long ago moved up to a Honda Nighthawk, and even that has been gone for many years. I never had any mechanical issues at all with the 350 so I couldn't begin to help you diagnose what the problem might be.

 

I had two Nighthawk , CB750's . Other than the fuel tank issue I had , I've never had an issue with any of the Hondas I've owned .

[AmJay]

Don't know if you got the Honda 350 or not. One thing to check is the selenium rectifier. That's the reddish orange thing with the cooling fins behind the battery box. These get really hot which is why they have the big fins. Selenium has a shelf life of about 20 years so even a NOS one is probably past it's prime by many years.. If you have a good nose you can sniff around the rectifier and if it has a garlic or rotten onion smell it's probably what's going bad and causing the engine to stall when it gets warmed up. There is a guy on e-bay usually selling non-selenium replacement rectifers.

[JACKED88]

For $200 bucks if its all there and in decent shape just buy tha thing and worry about whats wrong with it later. If you don't git it running you could part it out for more than $200 bucks.

[pantera1973]

Someone here should be able to help:

http://www.hondatwins.net/forum/

Great folks. The Honda 350 twins are great old bikes.

 

Also old road test on CB350:

http://auction.netbikes.com.au/vjmw.php?dir=testcb350&page=cb350&PHPSESSID=f6lodg2oas25l8d5ik685a2mcqgkn4hi

 

Here's a photo of my Honda Twin, a 1971 SL350

[Jerry]

Dumb question alert :dunce: Choke ain't stuck on is it? Those old carbed bikes are very fussy with fuel mixtures, if it's over fueling it'll stall when warm :cheers:

[pantera1973]

It's probably electrical (coils breaking down, ignition switch, dirty/loose connection).

As the temperature increases so does the electrical resistance.

[JACKED88]

Someone here should be able to help:

http://www.hondatwins.net/forum/

Great folks. The Honda 350 twins are great old bikes.

 

Also old road test on CB350:

http://auction.netbikes.com.au/vjmw.php?dir=testcb350&page=cb350&PHPSESSID=f6lodg2oas25l8d5ik685a2mcqgkn4hi

 

Here's a photo of my Honda Twin, a 1971 SL350

Wow!!! That brings back some great memories. I had a 1974 SL350 for 3-4 years. It got stolen while I was visiting a buddy at tha hospital. He was there due to a wreck he had on his bike. To make things worst, the following week I rode with another friend in his wheelie pulling convertible 69 Camero to visit again and his car got stolen out of tha same parking lot. Never saw my bike again but we did find tha Camero. Or at least what was left of it.

 

I still have a little 1981 XL185. Its in in good condition but I havent ridden it in several years. I know a guy who has a 1987 XL250 I've been wanting to buy. Saw him a few weeks ago and ask if he still had it and he said he does. Said he wouldnt sell it out from under me so I hope to be able to go get it in tha next couple of months. Its also in good condition but it too hasnt run in several years due to needing a part for one of the carbs.