Author Topic: Opinions on noise... may be piston slap  (Read 1207 times)

0 Members and 1 Guest are viewing this topic.

Offline Garry in AZ

  • Full Member
  • Posts: 680
  • 500,000 miles and counting...
Opinions on noise... may be piston slap
« on: Wednesday, October 06, 2010. 02:36:26 PM. »
I have a 2000 FLHRI with 70,000+ miles on it. All original, 88 inches... the only things that have been changed are cam bearings, umbrella valves, cam chains and tensioner shoes, and a stator. Motor has not been apart in over 2 years, and runs well. Heads and cylinders have never been off.
My issue is, when I first start the motor and it's below about 60 degrees outside, there is a definite "knocking/clacking" noise coming from the rear cylinder. This is not tappet noise, it's slower and louder. As soon as the motor warms up, (5 minutes) the noise completely goes away.   :scratch:    I'm thinking I may have some wear and tear on the piston skirts and the piston is slapping in the bore until it expands with heat. If so, the easy fix is to go to a 95" kit I suppose. Do you think my diagnosis is on the right track, or is this something else? Doesn't sound like a bearing, but it could be... but when the motor's warm, it's quiet.

Opinions??    :wtf:

Garry
We have enough youth, what we need is a fountain of SMART!

Offline CraigArizona85248

  • HTT Slacker and All Around Photo Ho
  • Administrator
  • Full Member
  • *****
  • Posts: 3735
Re: Opinions on noise... may be piston slap
« Reply #1 on: Wednesday, October 06, 2010. 02:59:12 PM. »
Garry,

I have the same noise on the front cylinder on my panhead.  Really noticable since the rain yesterday cooled us off this morning  :teeth:  In my case, I've traced it to the exhaust.  The old panhead exhause clamps on, as you know, and no matter how tight I crank on the clamp is a little loose on cooler mornings.  The head pipe rattles for the first mile or so and then goes silent.  Maybe you had a loose head pipe on the rear cylinder?

-Craig

Offline prodrag1320

  • Premium Vendor
  • Full Member
  • *****
  • Posts: 3208
  • Country: 00
  • AHDRA & AMRA national champion & record holder
    • vee twin racing
Re: Opinions on noise... may be piston slap
« Reply #2 on: Wednesday, October 06, 2010. 03:05:08 PM. »
if your running a little on the fat side,rings may have cut into the cylinder a bit,opening up the clearances(piston to wall)once the piston warms up,clearances get back close to spec
www.veetwinperformance.com
NITRO P/D HARLEY 7.14 @ 189/4.49 @ 167

Offline Snuff™

  • Full Member
  • Posts: 2379
  • Country: us
  • Tipp City, Ohio
Re: Opinions on noise... may be piston slap
« Reply #3 on: Wednesday, October 06, 2010. 03:17:20 PM. »
Garry, Opportunity knocking.

Have the wife listen to it.  She'll insist that it needs to be fixed and presto, 95" kit! :hyst:

-Snuff™ :beer:
Every day, I'm one day closer...  WTF!  I'm not near 70 yrs. old!

Offline harleyjt

  • Site Supporter
  • Full Member
  • *****
  • Posts: 3451
  • Country: us
  • North MS, just south of Memphrica
Re: Opinions on noise... may be piston slap
« Reply #4 on: Wednesday, October 06, 2010. 03:25:23 PM. »
Same noise on mine.  Goes away as it warms up. '08 with 37000 mi - never been into.  Box stock.   I had a thread going on it last week.  I'm thinking piston slap as well.  Some other posters mentioned some issues seen with rod bearings and cranks.  One guy was getting a replacement engine under the Ext'd warranty.  Let us know what you find.
jt
2014 Ultra Classic - Mysterious Red/Blackened Cayenne

Offline Garry in AZ

  • Full Member
  • Posts: 680
  • 500,000 miles and counting...
Re: Opinions on noise... may be piston slap
« Reply #5 on: Thursday, October 07, 2010. 06:01:28 AM. »
Thanks for the replies fellas. I will have a look and report back what I find.
Craig, you may have something there, before my summer vacation ride this year I had the exhaust off to replace a clutch cable and install a progressive suspension bagger brace... I'll be sure to take a peek at the exhaust.  :embarrassed:
Snuff, I like the way you think!   :wink:

Garry
We have enough youth, what we need is a fountain of SMART!

Offline Max Headflow

  • Site Supporter
  • Full Member
  • *****
  • Posts: 17271
  • Country: tr
  • Not Admin
Re: Opinions on noise... may be piston slap
« Reply #6 on: Thursday, October 07, 2010. 06:13:06 AM. »
Try running some seafoam through the motor..   Max
Aka Mousinator, Another Wasted Minute With Max,
No Collar to the Bone

Offline greg02flhri

  • Full Member
  • Posts: 92
Re: Opinions on noise... may be piston slap
« Reply #7 on: Thursday, October 07, 2010. 05:10:20 PM. »
I know it's the same old story, but you might want to try shimming or trimming your compensator nut first just for the heck of it.  I thought I had piston slap on my 95" (sounded like the front cylinder though) that went away when it warmed up and found that a worn compensator was the culprit.