Honda Twins banner
1 - 12 of 12 Posts

·
Registered
1969 Honda CB350
Joined
·
7 Posts
Discussion Starter · #1 ·
Howdy fellas, thought I would reach out here and see if anyone could be of any help. I already asked this question on the Honda CB subreddit and didn't get any super helpful replies. A little backstory, I bought this 69 cb350 about 3-4 months ago and it ran but needed a bit of work. I replaced the foam air filters someone put on it with OEM paper filters, fixed a fuel flow issue, a few other minor things like that. Still needs a new wiring harness, at some point someone upgraded its rectifier and removed its turn signals(pretty sure they just disconnected them at either end and removed the lights themselves) It runs great now that it is getting air and I decided I should do an oil change since I know it sat for a while before I bought it and how knows the last time the oil was replaced.

From what research I did I found that Honda changed their guidance to recommend 10w-40 instead of 10w-30 that was recommended in the manual when the bike was new. I went on amazon and got a gallon jug of Honda GN4 10w-40. Drained the old oil no problem. Put 2 liters of the new 10w-40 in and gave it a test the next day. Engine sounded great but after shifting it into second gear it became stuck. Clutch still works but the shift pedal goes up and down without changing gears. When pressing it down it has a bit of resistance when it would normally shift but nothing happens. I had to feather it in second to get it back up the road and back into the garage. I can start it with the clutch held in but it will not budge out of second gear. I can only assume that 10w-40 is too thick for it and I shouldn't trust everything I read on the internet?

Possibly related is the fact that any time I run it now(tried getting it out of second a few times now) it will usually blow its fuse, not sure if it is the load on it from trying to start and run in second gear or just something bad in its messed up wiring.

I hope I didn't break any rules on this forum by posting asking for help on this. First time in the forum. Thanks for any insight y'all can provide.
 

·
Registered
1969 Honda CB350
Joined
·
7 Posts
Discussion Starter · #3 ·
The oil isn't the problem, there's a mechanical issue inside the engine. Starting out in second gear doesnt blow fuses, you have a wiring issue to sort out.
Thank you for your response, I know the wiring issue needs to be sorted and was most likely a separate problem. I'm more concerned about the shifting problem and why it would only start after changing the oil. I am going to drain the 10w-40 tomorrow and put the old oil back in just to do some more troubleshooting.
 

·
Registered
Joined
·
1,125 Posts
Thank you for your response, I know the wiring issue needs to be sorted and was most likely a separate problem. I'm more concerned about the shifting problem and why it would only start after changing the oil. I am going to drain the 10w-40 tomorrow and put the old oil back in just to do some more troubleshooting.
[/QUOTE

Well I guess there could always be a first time for the oil to be the cause but for those of us who have played with these engines for years have never seen it.

One thing you should do if it hasn't been done already is replace the sloppy shift parts with a single lever like the K5 bikes have.
 

·
Registered
1969 Honda CB350
Joined
·
7 Posts
Discussion Starter · #6 ·
Bit of an update, I replaced the 10w-40 out and while on the center stand I for shits and giggled pulled the clutch and pushed the shifting lever down and it came out of second. I am going to put the tail pipes back on(was starting to take them off to get to the crankcase covers) Messed with it a bit, able to turn the rear wheel and get it to shift up and down while on the center stand. Going to put some oil back in it tomorrow and see if it was just stuck for who knows why, or if it was the oil causing it to get stuck.
 

·
Registered
1969 Honda CB350
Joined
·
7 Posts
Discussion Starter · #7 · (Edited)
Thank you for your response. The bike already has a later generation style single lever instead of the original linkage. I had an issue with it not shifting down when I first got it but that was because the lever was loose and slipped a bit to the point it was just striking the top of the tail pipe. Adjusted it back up and tightened it and now it is in a good spot to no longer have issues traveling.
 

·
Premium Member
Joined
·
3,031 Posts
You do know that the transmission on these bikes is a constant mesh. the rear wheel needs to be moving or at least the output shaft of the trans needs to be rotating to shift.
 

·
Registered
1969 Honda CB350
Joined
·
7 Posts
Discussion Starter · #11 ·
You do know that the transmission on these bikes is a constant mesh. the rear wheel needs to be moving or at least the output shaft of the trans needs to be rotating to shift.
Yes, every time I attempted to shift the bike, it was in motion. Both with engine on, and engine off(as if I was push starting it)
 

·
Registered
1969 Honda CB350
Joined
·
7 Posts
Discussion Starter · #12 ·
A bit of an update, I was able to get the bike out of gear. I drained the new oil back out and put the old oil back in. While it was on the center stand, I for shits and giggles pulled the clutch and pressed the shift lever down with my hand and it clicked through neutral and into first. I rotated the rear wheel by hand and I was able to continue to shift it through its entire range.

The weather here has been getting pretty cold and rainy so I am prepping to keep it in the shop for the winter. For shits and giggles again I drained the old oil, replaced it with new GN4 10w-40 from the same jug as before. And lo and behold it ran and shifted like a dream.

I know this is an incredibly odd bunch of happenings. I changed nothing else besides the oil. Didn't adjust anything, replace/tighten/loosen anything. Just changed the oil. I have absolutely no idea what had gone on to cause the inability to shift after replacing the oil the first time. But apparently redoing the job fixed it. Would love to hear theories on why this happened or what odd coincidence could have happened during the oil change to have caused this.

Thanks again for everyone's input and thoughts on this issue.
 
1 - 12 of 12 Posts
Top