Backfire through carb

[The Plunger]

Oh, I found it, pages 191-192. Are you freaking kidding me?! So, in the meantime I'm supposed to ride it until the noise goes away or until the motor seizes up because it WAS a main bearing after all? Thanks, Tommy, we'll see...
BTW, the charging issue looks to be a bad rotor as it's showing continuity between the armature and commutator. Time for a puller and new rotor! This IS fun.

[312Icarus]

Sounds exactly like the sound my R50 was making! Turned out to be bad wrist pin bushings, leading to big end bearing failure! I would shut it down NOW and find the source before you do any more damage! It does NOT sound normal by any stretch!

Icarus

[The Plunger]

I’m a bit leery to run it as well! The sound is loudest at the rear though...and it is loudest when accelerating or decelerating being not quite so loud when at high rpm. It’s also not every time or constant and the clutch has no effect on the noise either. It’s got a grand total of 2 miles on it and half that’s been stationary. I’ll wait for a few more folks to watch the video and chime in before I start tearing into it.

[wa1nca]

Do you have the Barrington service manual
Page 188 talks about a new rear main seal will make a sound like this and should go away after 1st 100 miles

Tommy

[wa1nca]

Text from Barrington manual

Tommy

[The Plunger]

Tommy,
I've read that three times and I'm still not convinced enough to just let it go until it stops. I was hoping that someone that went through this with a new motor could confirm that MY noise is THAT noise.

[miller6997]

My '67 R69S still occasionally makes that noise, and it's been 20,000 miles since the rear main seal was replaced. Yours seems more persistent; mine often makes the noise on start-up and within half a minute it goes away as the motor warms up. I really don't give it much thought. In 1967 I saw my first /2 come out of the crate, and after it was set up and started, it made that same noise. I thought I had a lemon, but the tech advised that the noise was harmless. After that I rode it for ten years before I sold it.

Just to be sure, do you think Vech or Richard, or maybe Scottie Sharpe would be willing to listen to your recording?

Jon

[wa1nca]

Another thought
You did say you have a charging problem



I also had a rotational noise on my r69
My charging system stopped working
I replaced the armature and it fixed my charging problem and to my surprise the rotational noise also went away

Always need to do the easy things 1st
To disable the generator output you can pull one of the generator brushes
It also could be the field windings are touching the armature causing a similar noise
I would also pull the field windings and see their no shinny marks indicating that the field coils may be touching the armature
Just a couple of wires and 2 allen screws to remove to field windings and no need for the armature puller bolt to do this

Tommy

[The Plunger]

Tommy,
The generator case was off when I made the video. That was the first thing I suspected was making the noise! The rotor is bad. I suppose I could send the video off to Benchmark...

[miller6997]

I would definitely send him the link to the video. There's an email address on his website. You can be sure that there is no noise that he has not heard and diagnosed!