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The Plunger
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I revisited my running issue (see R67/2 progress thread). I replaced the carbs and it is still backfiring through the RHC carb. The left runs great but the right putt-putts back through so it isn't a carb issue. At start-up, smoke puffs out at carb flange so I took off the head to see if I had a sticking lifter...nope. It starts easily enough but gas (exhaust?) feels like it is puffing out the bottom of the carb but that is impossible so it's coming through the gasket between the head and the carb. I took off the carb and sanded a very slight warp out but that did not change anything. I suddenly now have a rotational noise when increasing throttle. CRAP!!!
I'm at a loss here. Here are the facts:

Plenty of fuel is getting to carbs
static timing has been verified at least four times
valves have been checked the same
Runs great on LHC only
Will not run on RHC only
The RHC is hotter and noisier

What, mechanically can cause this? If the cam timing is perfect on the LHC, when rotated 180 degrees, it should be so on the RHC, correct?

Brian

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Brian
'52 R67/2, '53 R51/3

The Plunger
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Ack! After asking my friend

Ack! After asking my friend Tony about the problem he suggested a head gasket leak. Sure as shootin', the new gasket has the paper burned off down to the metal 'wafflle' layer about the size of a dime and the head shows signs of exhaust leakage, PLUS IT'S RIGHT AT THE INTAKE! So, sanded the head face to true it up as well as the cylinder face. Now I have to get some new gaskets. BTW, is there a correct side of the gasket to face outward? And what's the rotation sound?

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Brian
'52 R67/2, '53 R51/3

schrader7032
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I'm not sure about bikes this

I'm not sure about bikes this old, but on my /7, the head gasket can only go one way. The way I can tell is that the wrong way covers up some of the opening in the cylinder for the pushrod tubes to fit through. Maybe something similar works for the plungers??

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

The Plunger
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Kurt, nope, either face can

Kurt, nope, either face can be out. I'll ask Vech when I order.

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Brian
'52 R67/2, '53 R51/3

Daves79x
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Your Sound

Your sound is likely the 'woosh, woosh' of the compression blowing past the leaking gasket. Fix that and you'll be good.

Dave

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Dave

The Plunger
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OK, the never ending

OK, the never ending nightmare continues. Got my new gasket on, head and valves on and adjusted, mounted the carb and tried to fire her up. Nothing. Pulled the plugs and checked for spark - NONE! WTF?! The only thing I did electrically in the interim was tighten up a loose kill switch wire (blk/red) because I hadn't been able to shut down via the spike and I charged the battery whilst in the bike. Now, no spark. Did I fry the coil or capacitor by trickle charging? It seems improbable. All the other electrical stuff associated with the battery are working perfectly, but... any thoughts?

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Brian
'52 R67/2, '53 R51/3

wa1nca
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Did I fry the coil or capacitor by trickle charging?

No
The charging system is independent of the mag for the spark
Maybe undo the last thing you did for the spark
Disconnect the blk/red wire and try it again

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

The Plunger
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This is getting silly. I

This is getting silly. I tried just that after posting and it magically came back! Decided to run her around the block on her maiden voyage to see if she'd even move. A few issues remain. The charge light stays on and the intermittent whine is still present. I Guess the next step is to take off the magneto and generator and work through those. Hopefully it's not deeper, as this is a Gunther Wurst built motor and gearbox. I swear, this chasing ghosts crap is not what I wanted in this hobby!

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Brian
'52 R67/2, '53 R51/3

808Airhead
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There are always bugs to sort

There are always bugs to sort out. Enjoy the challenge

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Thomas M.
R69s - R60/2 - R67/2 - R51/3

The Plunger
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The howl

Well, here is the awful noise coming from my brand new rebuilt motor...anybody heard this sound before who can offer me a clue as to what and where it's coming from? Does it sounds louder on the right side, or am I nuts.

https://youtu.be/B5AseA8M-yA

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Brian
'52 R67/2, '53 R51/3

wa1nca
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Noise

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

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

The Plunger
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Oh, I found it, pages

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.

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Brian
'52 R67/2, '53 R51/3

312Icarus
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Sounds exactly like the sound

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
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I’m a bit leery to run it as

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.

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Brian
'52 R67/2, '53 R51/3

wa1nca
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Noise

Text from Barrington manual

Tommy

  • dsc04316.jpg
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The Plunger
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Tommy, I've read that three

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.

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Brian
'52 R67/2, '53 R51/3

miller6997
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A familiar noise

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

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Jon Miller
'67 R69S
'13 F800GT

wa1nca
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Rotational noise

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

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Tommy Byrnes
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The Plunger
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Tommy, The generator case

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...

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Brian
'52 R67/2, '53 R51/3

miller6997
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Yes

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!

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The Plunger
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Well, the diagnosis seems

Well, the diagnosis seems correct. Vech responded to the video with this:

"Sounds like the rear main seal. The European seals sometimes do that. If you want to find out for sure if it is the seal, while it is running, making that noise, unscrew the dipstick. If it suddenly goes dead quiet when you lift up the dipstick out of the hole just a little, then it is for sure the rear main seal.
You see, when the pistons move down the bore, pressure is created in the crankcase. When the pistons hit bottom dead center, the window in the timed breather lines up with the crankcase vent, and pressure is released. As the pistons move up, a vacuum is created, and it will suck air in through the rear main seal. That is what they do. Now, depending on the seal design, sometimes it will cause the lip to vibrate as the air comes in, and it makes a squealing noise. That seems to go away at high speed but is there at idle when hot. It is harmless but irritating."

Also, "The noise may stop, but if it does not, and it drives you nuts, you need to change out the rear main seal.
This one won't make noise, we have it in stock: 11 11 0 001 120--$29.95--Viton rear main seal R26 R27 R51/3-R69S"

And, sure enough, the howl went away when loosening the dipstick. Yay!!

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Brian
'52 R67/2, '53 R51/3

wa1nca
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rear main seal

Very good news
Glad you didn't have to tear the engine apart

I was aware the seal can do this but never understood why
Thanks for posting Vech's reply

Tommy

  • dsc04137.jpg
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"And, sure enough, the howl

"And, sure enough, the howl went away when loosening the dipstick. Yay!!"

incredible diagnosis.

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mike wex/stagewex
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312Icarus
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Chalk up another one for

Chalk up another one for Vech!!!

Icarus

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Vech rocks!!!!

Vech rocks!!!!

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Thomas M.
R69s - R60/2 - R67/2 - R51/3

wa1nca
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Vech rocks!!!!

Yes indeed
One day I needed some advise
I didnt want to call without ordering some part
So I ordered a speedometer cable that I didnt need and then felt better to ask for some advise
I still have that spare cable but felt it was well worth the advise he gave me

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

wa1nca
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Generator

The Plunger wrote:

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.

Did you get your charging system working

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

The Plunger
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Tommy, I wish! I’ve been

Tommy,
I wish! I’ve been awaiting a rotor puller tool I ordered over a week ago from Cycle Works....patience is NOT a virtue when you’re in a hurry. As soon as I get it off I can try another rotor.

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Brian
'52 R67/2, '53 R51/3

miller6997
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May never go away...

In my experience, the howling noise never goes away entirely, and I have long since stopped fretting about it. If yours seizes, we'll grieve with you.

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Jon Miller
'67 R69S
'13 F800GT

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