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czakal |
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czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
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jaffa90 |
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jaffa90 World Chat Champion
Joined: 06 Apr 2016 Karma :
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doggone |
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doggone World Chat Champion
Joined: 20 May 2004 Karma :
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Posted: 07:32 - 28 Jul 2017 Post subject: |
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You could put up a short video?
It doesn't sound good if the drop in power was also real.
It is possible to have a partial seizure due to heat which frees off when it cools, so try again cautiously.
Otherwise big end bearings maybe - could be anything.
Perhaps just a bolt coming loose.
Sometimes putting a chunky screwdriver or similar on different parts of the engine, and pressing your ear against the handle helps locate the source of odd noises. |
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RhynoCZ |
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RhynoCZ Super Spammer
Joined: 09 Mar 2012 Karma :
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lilredmachine |
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lilredmachine World Chat Champion
Joined: 24 Jan 2005 Karma :
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Posted: 13:40 - 28 Jul 2017 Post subject: |
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Worst case:
Motor probably pinched up a tad. The rattle could be the 'little end' which is the bearing hole the piston gugdeon pin sits in. When these get very hot they can elongate as the metal stretches at high rpm with the weight of the piston acting on it, particularly if it is dragging on the surface of the cylinder. This will allow the piston to move slightly independently of the rod, causing faint rattlling sound. Whilst not immediately fatal, i wouldn't be counting on that motor being around for ever, once the metal has been overheated and the tolerances are borked it's all downhill from there.
Other causes might be valvetrain related, oil starvation in the head causes excessive wear very quickly, if it is OHV could have bent a pushrod slightly, common with high rpm use. I would take the valve cover off, get the motor to TDC and have a fiddle and see if there are any excessive clearances.
Best case:
Of course, something could have just rattled loose. Check the heat guard on the exhaust, i remember those are bolted on the stock pipes.
Have to be careful with modern 125s, they are tuned lean for emissions testing and are often in neglected states. Long periods of over or at redline can kill them whereas an old cg would just take it and ask for more. ____________________ Bikes: too many, too much for one man to maintain anyway. |
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Commuter_Tim |
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Commuter_Tim World Chat Champion
Joined: 09 May 2013 Karma :
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Posted: 00:51 - 29 Jul 2017 Post subject: |
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Cheap shit chinese copy bike you say?
Engine mount bolts worked loose and rattling? ____________________ The above post is most likely nonsensical.
I ride a Bandit 600... badly. |
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czakal |
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czakal Nitrous Nuisance
Joined: 11 Apr 2011 Karma :
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RhynoCZ |
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RhynoCZ Super Spammer
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Posted: 11:39 - 29 Jul 2017 Post subject: |
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czakal wrote: | The rattling began after a noticeable loss of power so likelier to be something in the engine. It was probably first caused by low oil. I'm going to refill it, then take it to the shop to check, unfortunately I don't quite have the skills to open up an engine. Will let you know how it goes... |
If it was low on oil, then it's too late to just fill it up. Low on oil means metal on metal grinding, generating heat, speeding up the wearing process. ____________________ '87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor |
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Johnnythefox |
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Johnnythefox Traffic Copper
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czakal |
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czakal Nitrous Nuisance
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Wafer_Thin_Ham |
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Wafer_Thin_Ham Super Spammer
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czakal |
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czakal Nitrous Nuisance
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Wafer_Thin_Ham |
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Wafer_Thin_Ham Super Spammer
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Old Thread Alert!
The last post was made 6 years, 270 days ago. Instead of replying here, would creating a new thread be more useful? |
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