Author Topic: Diagnose this engine noise, please.  (Read 5901 times)

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Sunbeam63

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on: August 18, 2021, 01:19:04 am
Hello All,

I'm coming to this forum to get expert opinions. I've done research on my own, have formed an opinion, and I now want to hear what others think. My motorcycle has recently started making a very unfavorable noise, as heard in this video: https://www.youtube.com/watch?v=_qviFJQ9BT0.

Some additional info: It didn't start happening until I added some seafoam to the fuel to clean things up. The bike seems to start as it always did. The noise doesn't happen until the bike was warmed up. It happens when I twist and let off on the throttle, and typically happens when it's idling and/or warm. I have not adjusted timing. The motorcycle is a 2004 Royal Enfield Sixty-5. I can provide more info at request.

I appreciate any help. I am not using this motorcycle until I get this issue resolved. Please let me know what your opinions are, and where I stand with this motor. Thanks in advance.
« Last Edit: August 18, 2021, 01:22:21 am by Sunbeam63 »
2021 Jeep Gladiator
2004 Royal Enfield Bullet Sixty-5 (Backdated)
1982 Fiat Spider (Backdated)
1964 MG MGB
1963 Sunbeam Alpine
1961 International Scout


mtrue77

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Reply #1 on: August 18, 2021, 02:09:12 am
You've come to the right place.  I'm afraid I can't help, though.  I was going to say that it sounds mechanical.  Now that I've listened twice, i'm not sure.
Michael T
Pittsburgh, PA
2009 AVL


Sunbeam63

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Reply #2 on: August 18, 2021, 03:13:31 am
Thanks for watching the video Mtrue77. Maybe someone else has input. With that said, I realize I posted this in the wrong thread, and I can't figure out how to move this one, but I am going to post in the Iron Barrel thread. You can go to that thread here: https://forum.classicmotorworks.com/index.php?topic=31514.0
« Last Edit: August 18, 2021, 03:18:42 am by Sunbeam63 »
2021 Jeep Gladiator
2004 Royal Enfield Bullet Sixty-5 (Backdated)
1982 Fiat Spider (Backdated)
1964 MG MGB
1963 Sunbeam Alpine
1961 International Scout


Sunbeam63

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Reply #3 on: August 18, 2021, 03:16:21 am
Hello All,
I accidentally posted this in the AVL thread, when it should have been in the Iron Barrel Thread.


I'm coming to this forum to get expert opinions. I've done research on my own, have formed an opinion, and I now want to hear what others think. My motorcycle has recently started making a very unfavorable noise, as heard in this video: https://www.youtube.com/watch?v=_qviFJQ9BT0.

Some additional info: It didn't start happening until I added some seafoam to the fuel to clean things up. The bike seems to start as it always did. The noise doesn't happen until the bike was warmed up. It happens when I twist and let off on the throttle, and typically happens when it's idling and/or warm. I have not adjusted timing. The motorcycle is a 2004 Royal Enfield Sixty-5. I can provide more info at request.

I appreciate any help. I am not using this motorcycle until I get this issue resolved. Please let me know what your opinions are, and where I stand with this motor. Thanks in advance.
2021 Jeep Gladiator
2004 Royal Enfield Bullet Sixty-5 (Backdated)
1982 Fiat Spider (Backdated)
1964 MG MGB
1963 Sunbeam Alpine
1961 International Scout


cyrusb

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Reply #4 on: August 18, 2021, 04:27:32 am
Rule #1.
Always go back to the last thing YOU did.
Just how much "Miracle in a can" did you add to your fuel?
Drain the tank . Seafoam is not a fuel.
I will be surprised if this does not resolve your problem.
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


Mr_84

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Reply #5 on: August 18, 2021, 04:28:02 am
You need to check a few things first , check tappet clearance as the sea foam may have cleaned some crud of your valves therefore making them a bit tight now, and check points gap and spark timing are all good things to eliminate and know where your at anyway, possibly have a look in the carb something maybe floating around now from the sea foam cleaning it off
« Last Edit: August 18, 2021, 04:33:22 am by Mr_84 »


axman88

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Reply #6 on: August 18, 2021, 05:58:42 am
Sounds to me like it's just running lean and misfiring.   Looks like it might have backfired into the airbox as it died?  You might have flushed a blockage downstream and clogged a screen, filter, or carb jet.

Does it run better with enrichment or choke on?


Paul W

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Reply #7 on: August 18, 2021, 07:56:20 am
My guess would be a valve gear problem, such as a broken valve spring.

But there’s only one way to find out….
Paul W.


Sunbeam63

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Reply #8 on: August 18, 2021, 12:57:30 pm
Thanks for the initial starting points all. This gives me a few additional things I hadn’t thought of to diagnose this weekend. Looking forward to the fun!
2021 Jeep Gladiator
2004 Royal Enfield Bullet Sixty-5 (Backdated)
1982 Fiat Spider (Backdated)
1964 MG MGB
1963 Sunbeam Alpine
1961 International Scout


cyrusb

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Reply #9 on: August 18, 2021, 01:22:42 pm
In your video are you adding throttle off idle, or is that miss occurring by itself?
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


Sunbeam63

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Reply #10 on: August 18, 2021, 01:29:58 pm
In your video are you adding throttle off idle, or is that miss occurring by itself?


Cyrusb, I am adding throttle off idle. 
2021 Jeep Gladiator
2004 Royal Enfield Bullet Sixty-5 (Backdated)
1982 Fiat Spider (Backdated)
1964 MG MGB
1963 Sunbeam Alpine
1961 International Scout


cyrusb

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Reply #11 on: August 18, 2021, 01:37:57 pm
Clogged main jet . Probably as MR_84 stated you probably shook something loose with the seafoam.
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


allanfox

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Reply #12 on: August 18, 2021, 02:52:04 pm
What's 'seafoam'?


mtrue77

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Reply #13 on: August 18, 2021, 03:27:23 pm
Seafoam is an engine cleaner.  You can Google it.  I hadn't heard of it until recently.  From what I've read on Seafoam's website, it doesn't contain any chemicals or abrasives that would harm an engine.  I'm not likely to use it, though.
Michael T
Pittsburgh, PA
2009 AVL


Bilgemaster

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Reply #14 on: August 18, 2021, 04:01:13 pm
Thanks for watching the video Mtrue77. Maybe someone else has input. With that said, I realize I posted this in the wrong thread, and I can't figure out how to move this one, but I am going to post in the Iron Barrel thread. You can go to that thread here: https://forum.classicmotorworks.com/index.php?topic=31514.0

I'm gonna go ahead and move this thread to the Iron Barrel's section, and possibly combine it with the newly-created one, just so we're all on the same page.
So badass my Enfield's actually illegal  in India. Yet it squeaks by here in Virginia.