HELP! Primary Rattling Noise

Discussion in 'Transmission' started by bo54gey, Sep 30, 2010.

  1. bo54gey

    bo54gey New Member

    I have a 2010 FLHTK that is less than two months old and 1800 miles on it. The other day I returned it to the dealer for a rattling/banging noise in the primary case. The dealer confirmed the noise and said that it is probably the compensator nut. They took the bike in, disassembled the primary and did not find anything wrong. After putting it back together, the noise was still there. They took it apart again, compensator, clutch, everything and called HD Tech Support with spring measurements and whatever other info the dealer provided. Tech Support apparently did not have any solution to the problem other than to suggest that I switch back from Syn III in the primary to Formula +, which they did and gave the bike back to me. Well obviously the noise is still there and I am scheduled to bring the bike back in on Monday. Any suggestions would be greatly appreciated.

    Thanks in advance,
  2. Fastwalkin51

    Fastwalkin51 Member

    Try looking in self help tips transmission, clutch, primary (drive train) tip #43 "automatic chain tensioner adjustment". Basically three rapid accel/decells in rapid succession, this got rid of the noise in my primary on my 2010 Limited.
    Good Luck ! Fastwalkin
  3. mouthful

    mouthful Active Member

    I thought I had a compensator nut assembly problem also as my iron is under warranty also. I asked and was talked into leaving it for the weekend.Got a call and was told that the Automatic Primary Chain Adjusting Mechinism was stuck and not working. I asked about the fix and was told a twitch of the screwdriver set it back into place. Also asked about any damage inside primary and was told none. Fluid was replaced with Redline Primary Fluid. I trust the service writer, he is a good friend and has answered a lot of my questions. Also said that he runs Redline Products in his bike. Good luck.
  4. bo54gey

    bo54gey New Member

    Thanks for your help. I'll check it out and give it a try.

    They told me that the auto chain adjuster was working fine, but I'll bring it up to them.

    Thanks for the help.
    Last edited by a moderator: Sep 30, 2010
  5. dbmg

    dbmg Guest

    Why not just try the auto adjusting procedure. It can make a world of difference. You may save a trip to dealer.
    Automatic Chain Tensioner Adjustment
    Published by glider (Wise Member)
    Published date: May 20th, 2008

    Here's a trick to reduce the constant engine noise that sounds like valve train noises on the newer 96 Cu In. bikes that have the auto adjusting primary chain tensioners and no inspection port.
    I tried this on my RKC and can notice a definite improvement. The problem seems to be coming from the primary chain and not really the valve train at all.

    Here's what you do. Accelerate from a stop in first gear rather hard to about 30 MPH and then brake rather hard using only the rear brake without locking up the wheel and don't pull in the clutch until the bike slows enough.
    Do this 2-3 times in succession and you'll notice that the noise that you thought was the valve train is almost completely gone now. Low speed riding is a bit smoother also due to less play in the chain.

    By doing this, the automatic primary chain will ratchet up a bit tighter if it was loose before this. The acceleration and braking causes slack in the lower strand of the chain and will ratchet it up tighter if it needed an adjustment.

    If it wasn't loose there will be no noted difference.
    That is most likely the noise that was heard and not the valve train at all.

    Sounds strange but try it!
  6. d1hojo07

    d1hojo07 Member

    After you try all that, then check the runout on the crank. In my experience, when the crank shifts you can get alot of noise on the comp side.
  7. Christina

    Christina Member

    Rattling noise is much common...!! I'm sorry but don't have any solution. As I read your problem, thought of posting here... Do tell me about what exactly had happened, even I'll make a note of it... :p

    Last edited by a moderator: Jan 10, 2011
  8. Chopper

    Chopper Senior Member

    In 08 had a couple of bikes that had a rattle sound coming from the primary, mainly when the clutch was pulled in, found the clutch plates were never pre-soaked before assembly at the factory, you would think 1,000 or so miles they would soak up fluid, but they did not. Pulled clutch plates and soaked them over night in primary fluid, next day reassembled and never another rattle. If all else fails, might be worth a shot.
  9. glen073

    glen073 Active Member

    My 2010 has been doing the same thing and is driving me nuts. As soon as I get off my butt, I'm going to try that three times acceleration and stop method mentioned and will report back.
  10. Nigel Hawkins

    Nigel Hawkins New Member

    Hi all, Oct 9 2017.....I put a new Screaming Eagle compensator in, (the old stock one in my 2010 FLHTK was clacking loudly) now it has a whine and knocking, I dropped the fluid and see small shards of metal on the drain plug magnet,fluid (Belray primary fluid) looks and smells fine, I'll put Harley formula+ in tomorrow and try the 3 accel/decel routine, and see if it quietens down. Since putting the SE comp in, the noise IS getting quieter(200 miles)...but....still there intermittently