Honda Twins banner

1 - 8 of 8 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Here’s the video of the damn wretched noise

Hey guys!

I’m new to this amazing community. I have a 1972 CB350 (K4) Twin that I recently acquired. She runs great, but she has a couple of issues that i’m not sure how to diagnose. She starts up fine warm, but does have some starting issues when cold (of course). I have also noticed a weird high pitched grinding noise that occurs at certain times. 1) When sputtering out during a difficult start, 2) On the occasional stall, 3) Sometimes at the end of the ride when I park her.
I am doing a modern restoration, so the cylinders have been sent out to get rebored. I noticed the cam chain roller was in rough shape so i’ve ordered a new set.
If anyone much more skilled can help out diagnosing this issue, I would greatly appreciate it.

Thanks!
 

·
Registered
Joined
·
3,059 Posts
Check out the over-running clutch in the electric start sprocket, behind the alternator rotor.
 
  • Like
Reactions: Alan F.

·
Registered
1971 SL350 K1
Joined
·
219 Posts
It sounds like something in the electric start engagement. Not sure what engages those because I haven't used one in a few decades. I do remember from way back then when starting cold I usually used the kick starter to reduce wear and tear on the starter. If all is working well it doesn't take much effort. Once warmed up just a bump on the starter button and it's going. Probably not much help with the diagnosis but maybe helpful when you get it working correctly.
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #4 ·
Check out the over-running clutch in the electric start sprocket, behind the alternator rotor.
hey mike,

so i checked out the clutch basket. and when i took apart the front end and covers, i noticed the clutch basket with marred edges. i also have seen pics of other clutch baskets with the same marring pattern. is this normal? what’s the cause of this? there were bits of metal in the oil sludge but not TOO much. could this be the problem?
314532
314533
 

·
Registered
Joined
·
3,059 Posts
Forget that, go to other side and remove the alternator rotor, then check the springs/rollers on the back.
 
  • Like
Reactions: colvfrfg

·
Registered
Joined
·
109 Posts
It's the starter clutch behind the alternator. If the bike had been sitting for a while, sometimes the oil film runs off the rollers in the starter clutch and they chatter because they are dry. The starter seems to work properly to start the bike so the starter clutch must be engaging well enough, it just makes a chattering sound at the end of its rotation. Ride it for a while and see if the sound goes away. If it doesn't, and later the starter clutch begins to slip and make even more nasty grinding noises and the engine doesn't turn over during those noises, then it will be time to rebuild the starter clutch. It's a simple job and everyone's favorite pied piper of Hondas (Common Motor) has the parts you need to do the rebuild
 

·
Registered
Joined
·
3,059 Posts
Is it full of oil? lay it down on the left side for a few moments and the crankcase contents will run into the alternator cavity and lube the rollers.
 
1 - 8 of 8 Posts
Top