cam chain tensioners

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by dbeck, Apr 20, 2012.

  1. dbeck

    dbeck Adventurer

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    Has anyone replaced their cam chain tensioners? It's an 08 and I have 25k on it and the top end just started rattling. It comes and goes but its there. Simmilar issues?
    #1
  2. spafxer

    spafxer Long timer

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    people have, but rattling cam chains are almost always low oil pressure.


    Water in your oil from the water pump seal leak?


    .
    #2
  3. TcRulz

    TcRulz Been here awhile

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    Make sure you water pumps not leaking and diluting your oil and blocking your filter.:eek1. The blocked filter lowers oil pressure and cam chains start ratterling. Is your coolant in your bottle disappearing ?
    #3
  4. dbeck

    dbeck Adventurer

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    Coolant is not dropping and no oil light. The oil is not milky either.
    #4
  5. ÖÖ.

    ÖÖ. Ajaa kuin mummo

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    I replaced mine because of rattling sound especially on low revs and cold engine. It didn't make any difference but the job it self is quite easy. The sound on my bike comes from the drive chain, if you tension it just right or a bit too tight it doesn't make any sound. I think keeping the chain loose enough is better so now I'm just enjoying one of the sounds which would make Honda guy sell his bike.
    #5
  6. BOB RAMSAY

    BOB RAMSAY Not in the Clique -

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    I had that (OH,SH*T!!!) rattle on start-up, last summer. 3 times, very loud - so loud I hit the kill switch. My laymans' impression was lack of oil, drained down from the top end. My '06 had 18k miles, I figured it was due for a valve check by a professional (I'm too much of a hack mechanic). Turns out, most valves were close to spec. From then on, the clatter stopped. I keep my fingers crossed as a top end repair would likely be $$$$.

    I've read here that the valves tend to tighten up their clearance as opposed to becoming looser. Imagine that!
    My mechanic said that now the valves are set, they should last for quite a few miles. Disclaimer - I don't flog my engine. If you do run the p*ss out of your motor, I would recommend a modified maintenance schedule.

    As for the cam chain, I would suspect a 'rubbing/whirling' sound. I had a top-end valve clatter - so maybe this will be of no help to you - but maybe someone else.

    Good Luck!
    #6
  7. 1stiski

    1stiski Ride that nasty thing

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    Until your oil light comes on and stays on, and if the rattling doesn't go away in a few seconds, IGNORE and flog.
    #7
  8. Boatman

    Boatman Upward and onward!!

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    Pretty much sums it up.

    Although,,,, my 04 with 29k was pretty disconcerting when started and idling. I installed a new pressure regulator. Now I get a couple seconds or less of rattle and after that it's pretty quiet. I was prepared to do the tensioners after the regulator but will just hold off for a while now.
    #8
  9. Sumi

    Sumi Long timer

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    what if it doesn't rattle at all? not even with a cold engine left for 2-3 days without starting it.

    Last time I had this, I had to rebuild the rear cylinder head, as the camshafts wore in the bridge and head - and with the bad cam bearings there was enough force to pretension the cam chains.. After the rebuild it did the startup clatter, but now , 3k miles later, it's gone again (no clatter at startup), so I'm thinking of the worse..
    #9
  10. Dieseljo

    Dieseljo n00b

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    2005.5 KTM Adventure 950
    Chasing Excessive Engine Noise

    I purchased this motorcycle with 8,000 (well cared for) miles from the original owner.

    At 10,600 miles I had the (by now) classic water pump shaft (seal) failure. Only to be noticed by a flickering oil psi light when the engine was up to temp (warm). The engine oil (when viewed with the human eye) did not look milky/coolant deluded. NOTE: With this engine, the paper type (stock) oil filter is one of two ways, in identifying a leaky water pump seal (before you destroy your engine.) Why? Because the paper filter clogs easily with coolant, reducing oil psi, turning on your oil psi light and drawing your attention to the problem. Or you could purchase a CJDesigns clear clutch cover, then you can see the moisture build up on the clear lexan face of the cover. With the Water pump repaired I headed back out on the trails.

    At 12,200 miles my motor developed this horrible noise, which after many years of turning wrenches sounded like a very loose cam chain. The noise was odd and would sometimes go away if I shut off/restarted the motor. Installing a temporary oil psi gauge I could see the motor had plenty of oil psi when cold or hot. As noted by KTM the oil psi relief valve (for my year motor) had some issues with the internal spring. Seeing that the cam chain tensioner was the next stop in the oil flow after the relief valve, I decided to update the oil psi relief valve with the new part number, running the engine after completing this update verified the problem had NOT been repaired. The horrible engine noise was still there. I then pulled out both cam chain tensioner lifters and proceeded to inspect them. There it was... I found the noise... the rear cylinder cam chain tensioner lifter would stick (like a hydraulic lock) when compressing the inner piston to the bottom of the outer bore (you can do this with your fingers). It would only become un-stuck after injecting 35+ psi of shop air into the oil side of the lifter. I replaced the cam chain tensioner lifter, started my engine, and no more horrible engine noise. In fact the motor is running smoother than ever especially at low RPM. Now I am putting the 17" wheels on with EBC HH pads (supplied by CJDesigns) to thrash the roads with my favorite most universal bike ever.

    IMPORTANT NOTES:
    1. Why did the lifter fail? We think it may have been (internally) scored when the coolant was running through the oil side of the engine during the water pump shaft failure.

    2. We know when the engine is not running the cam chain tensioner lifer is near fully collapsed in the bore. On one end the cap is holding the lifter in and the other end the tesioner slide is pushing the lifter towards the cap. At start up the lifter internal spring pressure is used to push the piston out (keeping some tension on the slide) until oil psi arrives to take over. In a motor without a stretched cam chain the oil psi takes over within a couple seconds of start up.

    3. I have read some posts about shimming the cam chain tensioner lifter. I do NOT recommend doing this. Especially after working out the math of the lifter travel and reviewing how the lifter cap keeps the lifter centered in it's bore. If/when your cam chains become stretched, it is time to replace, not shim.

    I am just sharing my experience... I did not sleep in a Holiday Inn last night.
    #10
  11. mdfehrmann

    mdfehrmann Been here awhile

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    :clap

    Good Info dieseljo!
    #11
  12. Gustavo.Ramos

    Gustavo.Ramos Been here awhile

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    Interesting development. Can you point the part number of schmeatic where i can seethe part you are mentioning? My 950 engine is quite noisy too, Since i have both 990 and 950, the engine sound is totally different,yet i cannot find a solution. already did the pressure valve mod/check, no visible results...
    #12
  13. dbeck

    dbeck Adventurer

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    Thanks all for the info. I just ordered a set of can chain tensioners and have a water pump on the way. Tensioners were relitively cheap. I will let everyone know the results.
    #13
  14. Head2Wind

    Head2Wind MotorcycleMayhem

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    Also keep in mind that the wear limits (range is 6mm -11mm if I recall correctly), when measuring the distance between the released cam chain tensioner cap to sealing surface (inclusive of the sealing washer). If its at or below 6mm, this will tend to make them noisy on start up as well.
    #14
  15. dbeck

    dbeck Adventurer

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    Turned out the water pump was out and clutch jet was plugged. What little coolant there was in it was contaminated and nasty. The rad cap was messed up and it was not pulling coolant from the res so I had no idea. I think I caught it in time so hopefull there is no bottom end bearing damage. So, new water pump, .5mm clutch oil jet, second cooling fan, 200 degree thermostat, CJ's extended oil drain hose, and some little odds and ends. Good as new!

    Thank again for all the info. Every problem is documented around here somewhere.
    #15