snippy
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 posted on 9/3/08 at 05:46 PM |
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R1 Engine - bad noises
I`m posting this for a friend who`s built an MK with an `98 4XV R1 motor. Called round his place today to check out his engine noise and what a noise
it`s making!
It`s a metal on metal sound like a very loud tapping and as you increase the revs, so does the noise increase (number of taps). So the problem is
associated to the engine drivetrain. It sounds more top end so I took the cam cover off to check the cams. Plenty of oil up there, all cams in very
good condition and all hydraulic tappets and springs compressing as they should. So, I`m now thinking either -
1) dropped a valve, slight piston contact on stuck valve?
2) Camchain tensioner guide problem? Camchain tensioner broke?
Anyone experienced similar problems with an R1 motor or any ideas to throw in the pot? A compression test should rule the dropped valve in or out but
my compression tester is car spark plug size so need to source a bike equivalent unit first.
Thanks all,
Nick
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indykid
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| posted on 9/3/08 at 05:48 PM |
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if one of the rod bearings had died, it could well be the piston crown hitting the head.
we once had a 7mge supra engine that'd run with very low oil pressure and the death rattle was horrific. marked the piston and the head.
tom
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bigrich
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| posted on 9/3/08 at 06:19 PM |
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i would agree with a poss rod/bigend brg failure, had the same on a zxr400 i used to own. just sounded like a top end rattle until it puked its guts
out
.JPG)
A pint for the gent and a white wine/fruit based drink for the lady. Those are the rules
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MikeR
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| posted on 9/3/08 at 06:25 PM |
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sounds like the same sound IrvineD had when a big end bearing went on his MX5. Horrible horrible sound. When he took it apart it was obvious, the
movement in the con rod on the crank made exactly the right sound.
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snippy
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| posted on 9/3/08 at 07:29 PM |
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Thanks for the replies so far, not looking good then! I did turn it over on a socket but there was no obvious sound. The sound therefore would seem
only to appear when turned over at high speed (tick over and above). That could suggest big end bearings or little end bearings as the play wouldn`t
show itself until under load/pressure. So, thats a possibility.
If it is the bearings, is it worth replacing them? Surely the crank would need refurbing too? Costwise, would it be better to just source another
engine with a known history?
Nick
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smart51
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| posted on 9/3/08 at 08:42 PM |
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mine made a rattling noise that got worse with revs. fairly quiet at first but got gradually louder. turned out to be the big end shells. It had
picked up slightly on the crank. If I'd fixed it earlier, it would have just needed new gig end shells. Luckily I had a spare crank from a
previous engine but I needed new crank shells when I fitted it.
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Coose
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| posted on 9/3/08 at 09:07 PM |
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You should be able to see if there's too much play in the cam chain with the cam cover removed. And just to point out, an R1 does not have
hydraulic tappets - they're bucket and shim.
If it'd dropped a valve you'd properly know about it - it'd be more than just a rattle. You could do with dropping off the sump and
have a look at the big ends - you can see them with the sump off.
Spin 'er off Well...
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snippy
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| posted on 9/3/08 at 10:36 PM |
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The cam chain seemed tight against the cam chain guides so no play there. Having spoken to my mate again this evening, he was out driving the car when
the tapping sound began. It gradually got louder and louder until he stopped and didn`t dare drive any further. So, with this in mind and the above
comments, I`m tending to think it has the hallmarks of a bearing failure.
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chunkytfg
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| posted on 10/3/08 at 09:57 AM |
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If it's the CCT then you will find it wont rattle on acceleration but on run down or with engine breaking it will rattle.
My money is on big end/con rod faliure.
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mad-butcher
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| posted on 15/3/08 at 03:09 PM |
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easy way is take the sump plug out and see what drains out, mate had similar but nothing showed up when we checked the oil, in the end we tracked it
down to clutch problem, noise went away when clutch pedal was pushed in slightly
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snippy
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| posted on 16/3/08 at 09:13 PM |
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Thanks everyone for the replies. My pal has also spoken to Malc at Yorkshire engines on this one who is also 99% sure its the bearings like most of
you suggest. So, we`ll drain the oil (through a sieve) and see if there`s any bearing remnants in the oil and then begin the strip down. Yamaha have
quoted £125 for a full set of replacement big ends and little ends, so costwise not too bad, just time consuming. Roll on summer!
cheers, Nick
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