OzVMX Forum
Clubroom => Tech Talk => Topic started by: Curtis on July 04, 2016, 09:03:38 am
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Wondering if anyone has experienced this before?
My 76 XT500 has a ticking sound from the upper part of the engine, that is slowly getting worse.
Bike runs well, good comp etc. Had the top end apart not too long ago, everything seems in good order, Iv re checked the clearances many times.
Strange thing is, when its cold it quiet but the more it warms up the louder the tick gets! :o
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3 things come to mind.
Cam chain adjustment.
Conrod little end starting to oval.
Rocker pivot shaft worn or head pivots worn.
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well bugger me,i have one in the workshop,doing the same thing,this ticking in the top ends getting more noticable,was in for hard starting/tuneup,i thought it was just noisy tappets,won't start on k/starter,fires on rollers straightaway,idles,motors down the paddock ok,has comp,done all the usuals,(then checked them again ::)),i'm about to pull the motor out for a sticky,i'm thinking little end,or gudgeon pin wear,(pins best outcome??), :P
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I thought maybe cam chain? But they kinda get clacky at idle then quiten with revs. Its high in the engine, sounds just like a noisy tapped. Im hoping to get in there for a look this week.
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There's a little steel/rubber washer that goes on/in the camchain adjustment that screws into the back of the barrel. Without that it makes a ticking noise. Check all components there compared to parts book in camcahin adjuster
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I had the same noise years back done valves still had the noise ,
Get it running then take off cam chain ten cover and tighten adjuster until rod peice just moves in and out slighty then see if the noise stops.
Sometimes it's the cam chain taping on the guides if the chain is to lose.
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mick,i overadjusted slightly to see what effect that had,made no diff,will pull the tensioner assembly out as per 500fools idea,didn't really want to pull motor out,so hopefully this rubbers gone walkies,external fixes are the go 8),cheers
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Matcho mick , there should be a spring on the push rod to , to push the cam chain guide against the chain , I removed one once and some one had no spring on it and they put lots of 6mm nuts on the push rod to make up for missing spring :o
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bugger,mines all good,that rubber spacer (captive between 2 metal washers?),& it's in place,yeah mick seen some crazy fixes too,sorta needs must stuff,another commonish thing with these motors if tappetts are left loose they hammer a depression in the valve stem,you slip the feelers in around the edges ,then adjust & wonder why it's still noisy,this ticking noise is strangley similar to a noisy tappet,& it seems on the camchain side of the motor,but that can be deceptive,bloody echo chamber in there?,ha ha,more thoughts please :P
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long shot but its not a cracked piston with a bit of trapped skirt (the best kind) flapping at the top and bottom of the stroke ???. saw a bloke spend mega bucks on roller rockers in a v8 years ago to "get rid of that ticking noise" only to have mr McHanic say "out with that motor" and he had to find a new block as he had f*cked about so long with the rockers, the bore was worn past re boring.
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Himm I don't have much more .
I've had these old thumpers for 26 years and never had this prob ,
Cam chain flogged out worn ?
Could it be a stuffed cam bearing ?
Could it be worn stuffed cam chain guides ?
Brent j on here maybe of some help ,
I remember him telling me how he had some sort of noise I think ?
He had to pull it down a few times to fix it but he told me this a few years back .
Or just take the baffles out of it mick so you can't here it ;D
Or it's just a ticking time bomb due for a rebuild ::)
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As 500fool said check the rubber faced washer on the cam chain tensioner.
Set the tension as the manual describes, it can make a difference
Another source of noise is from the tappets where the adjusters run on the valves. I can't remember which way they wear but if I've got it right the adjusters are convex and they wear the valve tops concave. When you set the clearance the feeler gauge sits on the tip of the convex adjuster and on the edges of the concave valve stem. The concave valve stem lets the adjuster sit further in so increases the true clearance.
On one of my motors I used Porsche adjusters as they are a ball and socket arrangement. It made the motor quieter and needed some mode to the adjuster arms. It also cost about $160 for two adjusters
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Iv tried playing with cam chain adjuster in the past, no difference. Ill update if I find anything. Its a bit of a pain you gota un bolt the engine every time.
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Himm I don't have much more .
I've had these old thumpers for 26 years and never had this prob ,
Cam chain flogged out worn ?
Could it be a stuffed cam bearing ?
Could it be worn stuffed cam chain guides ?
Brent j on here maybe of some help ,
I remember him telling me how he had some sort of noise I think ?
He had to pull it down a few times to fix it but he told me this a few years back .
Or just take the baffles out of it mick so you can't here it ;D
Or it's just a ticking time bomb due for a rebuild ::)
I did spend a lot of time chasing a noise in my motor. It wasn't tappets, it was far more embarrassing than that
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I've had a couple of XT / TT motors with a broken cam chain guide, the one on the opposite side to the tensioner.
Foss
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Ross Merrick had the ticking sound and it turned out to be the big end. Piston was slapping the valves and head.
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Mine is missing the rubber dampner on the tensioner, I really want this to be the problem but im sceptical. The part is no longer available, does anyone have a spare? ;)
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concidering mines still there Curtis,dont think thats our problem,the ticking seems higher up than there too??,Foss's pointing in the right direction methinks,Dazzell,Rosco probably thought he was on his maico wfo :o, :P
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I've had a couple of XT / TT motors with a broken cam chain guide, the one on the opposite side to the tensioner.
Foss
Yep I have seen the same thing , I locked up a gear box years back and found part of the cam chain tensioner in the gear box , this caused the lock up .
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Mine is missing the rubber dampner on the tensioner, I really want this to be the problem but im sceptical. The part is no longer available, does anyone have a spare? ;)
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I just looked on kedo Australia site , they have the spring and rod separate,
No washer seperate, or the whole part for $170.00 ouch
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is the 400 using the same setup .or dose 500 just supercede to their part number anyway?
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I made a home made dampner for the tensioner and guess what, its quieter! Still a bit ticky but not like before. I just found one on ebay and ordered it. Ill take it for a proper ride tomorow. But yes it sounded like a noisy tappet
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Partszilla has new ones on there site aswell $10.00
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could it be the clearance on the decompression lever to the rocker arm
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That did cross my mind, but I checked it and there is plenty of clearance.
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There's a little steel/rubber washer that goes on/in the camchain adjustment that screws into the back of the barrel. Without that it makes a ticking noise. Check all components there compared to parts book in camcahin adjuster
on the money, well done.
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unlikely--but-- had a suzi quad 250/300 that has a manualy operated lever on the valve lifter & had worn the lever into the stop casting on the head by so much that it had gone back to far & just touching the lifter pad on the exhaust rocker arm. Could it do that if ya not running the cable on the arm, as in 'not' using the valve lifter to start or stop. Rubber steel pad under the spring on the tensioner adjuster is important from a noise & a bit more adjustment point of view but if [for a test] you wound the adjuster in while running--past the point of the pin still fluttering, which would be coil binding the tensioner spring i think--then if it still ticks it's unlikely to be tensioner related. [me thinks & been wrong before--wifey reminds me].
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use a big old screw driver as a stethoscope , wack you ear on the nice rounded handle end place the other end at key places and you will be surprised of what you can hear
Works Well !
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How do these giants push oil around? Might be worth checking oil flow around motor, if it's getting noisier as it gets hotter may not be getting enough lube....
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Bloke next door to me had a ticking sound in his Mercedes Vito Turbo Diesel Van. Determined it to be piston protrusion from the top of the bore, by about .01 mm.
He fixed it by shortening the piston in situ by .01mm, possibly using a brick wrapped in sandpaper.
I await the story about how it explodes.
Moral of the story, does the piston protrude above the top of the barrel by the required amount?
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Loose valve guide?
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I had a mystery noise in an engine (competition AJS 500 single) once and it took 3 or 4 tear downs, multiple head swaps etc to finally find it. When the engine first started up it sounded fine, but when it got to a specific temp a very loud clatter suddenly appeared. When engine was cooled down and started again it would come back when hot again. It would sound fine then the noise would come on like it had been switched on. Eventually i found it only after pulling the engine apart real quick while it was still warm and when the head was off i finally noticed that the cylinder sleeve made a click noise when pressed!. So what was happening was when the engine heated up the sleeve was comming loose and could move. It was not made/fitted correctly. It was a relief to finally find what the cause of the noise was.
A mechanics stethoscope is a very handy item to have as well, to pin point where noise is comming from. Pretty sure MCS has them.
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I had an XT with the same noise so I parked it for years as I was afraid it might cause more damage if something let go.
Turned out to be an easy fix...
I sold it!
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Does the noise go away when you labour the engine in first gear , when you just feather the clutch ? I had a TT500 C that had a ticking noise turned out to be the lash in the primary gears when the oil heated up
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500Fool!!! I owe you a big cold beer ;D You were bang on. Part turned up in the mail, fitted up the little washer/dampner and the noise is gone!
Who wouda thunk it.
Im very happy 8)
Off too Harrow in 2 days
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bugger,that didn't make any diff to mine,i even swapped/compared to another,unless they're both too compressed to damping??
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Yoo a strong man riding an XT at Harrow Curtis, I usually head up for a look but away werking till next week. One of these years I hope to ride my IT there, I'll leave the XT at home I think.
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back in the eighties one of our customers had a xt 250 with a ticking sound high up in the engine turned out to be a chip on the valve adjuster screw. only on the side but must have come into contact with valve stem at some point in the opening and closing. if it were me i would pull the valve adjuster screws out and check them, we used to keep a few of these screws in stock as it turned ou to be a fairly common ailment on the 250 i think one of my old 500 bikes even had this happen but was much less common on the big thumpers.
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Probably irrelevant to an XT but many years ago i heard of a honda single [175 i think] which you could get a needle roller conversion for the cam--maybe a powroll cam set up or something like that--& the needle bearing machining wasn't far enough out to the side by bugger all but the rocker pad was landing on the bearing outer shell. Think that was how the story went--45 years ago.