Engine Sounds Like A Machine Gun

Discussion in 'Technical Help' started by Thorcusmodee, Jul 6, 2018.

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  1. Sprinter

    Sprinter Kinigit

    Aug 17, 2014
    6,026
    1,000
    uk
    If you set up a you tube account ( takes two minutes ) then upload ( two minutes) then link to here.

    I know the covers off now Im just saying
     
    • Thanks Thanks x 1
  2. Ken walburn

    Ken walburn Noble Member

    Jun 28, 2017
    888
    300
    Essex
    Sounds like a cracked or broken tappet shim bucket to me
     
  3. Thorcusmodee

    Thorcusmodee Well-Known Member

    Jun 2, 2018
    175
    93
    Boston, Lincs
    I got some time today so I took the cams out, they are marked but I can't find any undue wear on them. I received the new pair and have been all over both with digital calipers and can't find a problem severe enough to give the sort of noise I am hearing. I can't see any damage to the tappet assemblies, I still think it's a bent valve sticking when returning to it's closed position. Looks like I'm going to have to bite the bullet and get the head off :-( My other option is to go the engine swap route, or to just strip it and sell the parts. I will have a further think first. There is evidence that somebody that didn't know engines has had it apart before - there is silicon gasket everywhere and the cam retaining caps were all in the wrong positions. Nightmare.
     
  4. Oldyam

    Oldyam Grumpy Old Git

    May 14, 2017
    613
    500
    ireland
    With what youre describing now I would bite the bullet and do the engine swap now, as you will have to remove the motor anyway to take the head off which keeps the bike a runner whilst you dig into the noisy motor.

    Just my 2peneth
     
    • Agree Agree x 2
  5. Ken walburn

    Ken walburn Noble Member

    Jun 28, 2017
    888
    300
    Essex
    :worried:Oh bugger . Good luck, enjoy! :rolleyes:
     
  6. Ken walburn

    Ken walburn Noble Member

    Jun 28, 2017
    888
    300
    Essex
    Is this a new bike to you or has this just happened out of the blue? If a new noise then bent (tipped) valve unlikely to be cause of noise, was it running smoothly on all cylinders?
    Don't wish to bring anyone's expertise into question, but have you checked the exhaust port gaskets, a crack in one of these would sound similar especially when revved. Just a suggestion. Happy repairing :tired_face:
     
  7. Thorcusmodee

    Thorcusmodee Well-Known Member

    Jun 2, 2018
    175
    93
    Boston, Lincs
    Hi Ken, I bought it last week, we couldn't get it started when I went to see it so I got it at a bargain price. The guy that owned it didn't tell me much about it other than the clutch was knackered - he wasn't lying :) I got it started once I got it home - the fuel tap vacuum diaphragm had failed and so it wasn't getting any fuel. The engine was warm when I got there so it had obviously run for a bit. It is definitely a very loud and obvious mechanical knock, there is no blow from the exhaust. I will give it a quick whirl with the replacement cams but I'm convinced a valve is sticking, I just can't think of anything else that would cause this. I think Oldyam is right, I will put my Sprint motor in there, I may then repair this one, sell it and convert my Sprint in to a cafe racer.
     
  8. Ken walburn

    Ken walburn Noble Member

    Jun 28, 2017
    888
    300
    Essex
    Sounds like the best plan
     
  9. Thorcusmodee

    Thorcusmodee Well-Known Member

    Jun 2, 2018
    175
    93
    Boston, Lincs
    Having put the finishing touches to my Trident I have now turned my attention back to my Trophy with the machine gun engine. I spent a most delightful afternoon getting the head off and was a bit surprised by what I found. It looks to me like there is significant evidence of water ingress - clean pistons, clean top of combustion chamber. Oh yes and a load of water in there too :) The head itself looks ok apart from on pot number 3 there appears to be a dark mark that would suggest combustion gasses escaping. The Tappets etc all actually look ok, I suspect my hunch of a sticking valve was incorrect, they all seem to move freely, I will confirm that by taking each one out and checking it. Here are some photos, anybody got any comments? would it be wise to get the head skimmed to be on the safe side?

    P1070121.JPG

    P1070122.JPG

    P1070123.JPG
     
  10. Tricky-Dicky

    Tricky-Dicky Crème de la Crème

    Dec 12, 2016
    2,445
    1,000
    Norfolk UK
    Did you check the cam chain and tensioner for problems IE slack spots in chain, although unlikely with that type of chain it can happen, did you drain down the coolant before lifting the head? if not that would explain the water, cant see any real signs of blowing head gasket but you don't include a pic of that,
    exhaust leaks can indeed sound quite strange in some cases,
    The fact that its quiet on cold start cold indicate a clearance that is opening up with engine temp, so maybe a worn little end bearing/piston clarence, i would be removing the barrels to check anyway, other than that i cant see anything obvious in the combustion except for no3 looks like its been burning a little oil.
     
  11. Thorcusmodee

    Thorcusmodee Well-Known Member

    Jun 2, 2018
    175
    93
    Boston, Lincs
    Yes, I drained the coolant although I was surprised how much was left round the liners, I need to get that all out before removing them. It has me really baffled at the moment as I can't see anything that jumps out and explains the horrendous noise I was getting. Cam chain and tensioners are fine, it's got me stumped at the moment.
     
  12. Thorcusmodee

    Thorcusmodee Well-Known Member

    Jun 2, 2018
    175
    93
    Boston, Lincs
    Yes, I drained the coolant although I was surprised how much was left round the liners, I need to get that all out before removing them. It has me really baffled at the moment as I can't see anything that jumps out and explains the horrendous noise I was getting. Cam chain and tensioners are fine, it's got me stumped at the moment.
     
  13. Oldyam

    Oldyam Grumpy Old Git

    May 14, 2017
    613
    500
    ireland
    There doesn't appear to be much I can see from the pics, however head gaskets have been a little problematic on the T3's.

    I would clean up the head and have it checked for distortion / twist

    As far as the head I would be reluctant to skim the head as there is very little to machine away without ending up in trouble clearance wise with valves & pistons, so its a last resort from that point of view.

    Once you have removed the valves I would be tempted to refit the cams and retorque the caps and check for bearing wear / lift in the head possibly due to the caps having been swapped around as cam caps are usually line bored in place.
     
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  14. Callumity

    Callumity Elite Member

    Feb 25, 2017
    3,358
    800
    Nr Biggar
    Sure you have not got an oval big end? Warm oil thins.......
     
  15. Ken walburn

    Ken walburn Noble Member

    Jun 28, 2017
    888
    300
    Essex
    Can you not skim the head & fit an oversize head gasket (does such a thing exist for this engine?)
     
  16. Oldyam

    Oldyam Grumpy Old Git

    May 14, 2017
    613
    500
    ireland
    Theres non listed by Triumph and its one of the multilayer things I believe, don't know if theres an aftermarket version in different thicknesses.
     
  17. Thorcusmodee

    Thorcusmodee Well-Known Member

    Jun 2, 2018
    175
    93
    Boston, Lincs
    I'll have a go tomorrow and see what happens. I'm not sure my spring compressor will fit, think it's too big, might have to get another.
     
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