Author Topic: Tappets playing maracas?  (Read 1806 times)

Offline East_Coast_BSA

  • A's Best Friend
  • ***
  • Join Date: Mar 2015
  • Posts: 82
  • Karma: 0
Re: Tappets playing maracas?
« Reply #15 on: 24.06. 2015 20:24 »
At those speeds, how sure of you where the noise is originating from?  Do you think it's coming from the rocker box area or somewhere in the bottom end?  You also have to remember that all the drive gears are straight cut, not helical.  They are anything but quiet.  Maybe you're getting some "Backlash" in the gear train due to harmonics?  Is the noise consistent throughout the RPM range or is it louder at some points?  Accelerating, decelerating, steady state?  It's really a tough game when your engine isn't silent when it's running correct.  There always seems to be some noises going on.  Just makes things more difficult to find.
Good Advice
0
No reactions

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5149
  • Karma: 49
Re: Tappets playing maracas?
« Reply #16 on: 24.06. 2015 20:42 »
Otto,

I don't recall piston slap coming into the conversation. During my last top-end work I ended up overhoning by at least two thou past book recommendations of "rebore cyclinders and replace pistons." I replaced the rings and all seems pretty good. No particular obvious slapping, so, if slap was the problem on your bike one might have to assume radical overhoning. Personally I don't think that's it. Right now, if it is actually a problem noise and not a usual noise, my bet is on rocker clearance adjustment being accidentally too big. In any case, at least that's easy to check.

Richard L.
Good Advice
0
No reactions
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Tappets playing maracas?
« Reply #17 on: 24.06. 2015 22:25 »
 I don't recall piston slap mentioned either until now. ... But I just had a thought that I've had a noise the past few weeks that I've been attributing to primary chain, but my dynamo belt flogged itself last weekend..... So you have a belt or a chain...?
  Someone (jachenbach?), had that issue recently
Good Advice
0
No reactions
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline roadrocket

  • A's Best Friend
  • ***
  • Join Date: Mar 2006
  • Posts: 188
  • Karma: 1
  • www.roadrocket.dk
Re: Tappets playing maracas?
« Reply #18 on: 25.06. 2015 08:40 »
I read some of the remarks on different expansion rates as a hint to piston slap, I was obviously wrong there. So much for the better. The noise mostly occurs at 40-50 mph, and I rarely go faster than 65, however, I did do a stint on the motorway, and didn't pay any attention to noises there. All went fine at 75-80. My dynamo drive is SRM belt. I will try to make a video to record noises. The one I am worried about should maybe be described as a bit like a cicada living somewhere near the right hand side top end.
Good Advice
0
No reactions
Otto in Denmark

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Tappets playing maracas?
« Reply #19 on: 25.06. 2015 08:43 »

 Chronic Tinnitus...?
Good Advice
0
No reactions
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 1492
  • Karma: 12
Re: Tappets playing maracas?
« Reply #20 on: 25.06. 2015 11:30 »
Long shot but could you have duff push rods? There were definitely some duff ally rods in the marketplace for quite a while which had an incorrect radius on the ends causing the rods to stick in the cups and rattle......
Good Advice
0
No reactions
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)

Offline roadrocket

  • A's Best Friend
  • ***
  • Join Date: Mar 2006
  • Posts: 188
  • Karma: 1
  • www.roadrocket.dk
Re: Tappets playing maracas?
« Reply #21 on: 25.06. 2015 11:34 »
I'll check the tappet clearances again, and try to check the rods also.
Good Advice
0
No reactions
Otto in Denmark

Offline East_Coast_BSA

  • A's Best Friend
  • ***
  • Join Date: Mar 2015
  • Posts: 82
  • Karma: 0
Re: Tappets playing maracas?
« Reply #22 on: 25.06. 2015 12:10 »
The one I am worried about should maybe be described as a bit like a cicada living somewhere near the right hand side top end.

The cicada noise mine was making turned out to be a head gasket.
Good Advice
0
No reactions

Offline cyclobutch

  • Wise & Enlightened
  • *
  • Join Date: Aug 2010
  • Posts: 1549
  • Karma: 14
Re: Tappets playing maracas?
« Reply #23 on: 25.06. 2015 12:23 »
The one I am worried about should maybe be described as a bit like a cicada living somewhere near the right hand side top end.

The cicada noise mine was making turned out to be a head gasket.

Ah yes, I've had that on mine. Used to chirrup under load only. Initially only under heavy load but then became more prevalent as the gasket further deteriorated.
Good Advice
0
No reactions
Warning - observations made by this member have a 93% unreliability rating.

Of Bikes; various, including ...
'58 Iron Head Flash Bitza


Online a101960

  • Wise & Enlightened
  • *
  • Join Date: Sep 2007
  • Posts: 1041
  • Karma: 12
  • BSA RGS BSA C12
Re: Tappets playing maracas?
« Reply #24 on: 25.06. 2015 13:16 »
Same here. No visible sign of anything wrong either. In my case the gasket had failed between the cylinders, and has been said, initially it started when the engine was under load. It then progressed to happening every time I opened the throttle especially on a gradient.
John
Good Advice
0
No reactions

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5149
  • Karma: 49
Re: Tappets playing maracas?
« Reply #25 on: 25.06. 2015 13:34 »
So, compression test.
Good Advice
0
No reactions
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline roadrocket

  • A's Best Friend
  • ***
  • Join Date: Mar 2006
  • Posts: 188
  • Karma: 1
  • www.roadrocket.dk
Re: Tappets playing maracas?
« Reply #26 on: 25.06. 2015 16:03 »
Head gasket! That sounds very plausible, thanks for that! Any point in trying to retorque the head?
Good Advice
0
No reactions
Otto in Denmark

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5149
  • Karma: 49
Re: Tappets playing maracas?
« Reply #27 on: 25.06. 2015 16:13 »
Compression test first, I believe. You wouldn't want to take off the rocker box just to tighten the head bolts only to discover that was not the cause.

Richard L.
Good Advice
0
No reactions
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline roadrocket

  • A's Best Friend
  • ***
  • Join Date: Mar 2006
  • Posts: 188
  • Karma: 1
  • www.roadrocket.dk
Re: Tappets playing maracas?
« Reply #28 on: 27.06. 2015 13:23 »
OK, a compression test showed 150 psi in both cylinders. But that does not rule out a clattering head gasket I believe?
Good Advice
0
No reactions
Otto in Denmark

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5149
  • Karma: 49
Re: Tappets playing maracas?
« Reply #29 on: 27.06. 2015 14:45 »
Others may know better, but I think that pretty much rules out the head gasket.

Richard L.
Good Advice
0
No reactions
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.