NoNoNoNoNo !!!

[Jammy-G]

Just had a top end rebuild, rebore, new piston and the bloody engine still 'knocks' when under braking.

We took the engine in to the local bike shop to let the guy have a look to see if the big engs had gone, but he was sure that they hadn't and they were fine. He is a very reputable guy and knows his stuff, so we just got a rebore and small end and put it all back together.

The knocks are very occasional and ONLY happen when I brake and the bike is slowing down under engine braking.

Not sure if its a major problem or anything but it's a real piss off.

Anyone know what it could be if the big end, small and and piston slap is crossed out?

Any help appreciated !

Cheers,

James.

(Totally pissed off).
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RooRoo: just like the time i stuck my finger up my arse with no lube at all and she didnt talk to me for hours

[kev]

Are you sure your headstock bearings haven't worn out?
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20:02:36 Jammy-R6: any holes a goal
20:02:48 kev: even if its a hairy mans arse
20:02:56 Jammy-R6: hell yes

[Flywheel]

Hi

how many miles has it done? if its more than 20000 could well be the bigend if it hasnt been replaced before. Does it jirk a bit when you ease of the throttle cause thats almots defently the bigend.
I konw that the guy said it was fine but you can never be sure unless you find out for yourself.

good luck

[Jammy-G]

It only knocks when I let off the throttle. And even then it doesn't do it every time.. just on occasions.

When I'm accelerating or even cruising there are no knocks or any bad sounds whatsoever.

Oh and when we had the piston off, there was no free vertical play in the crankshaft. None at all.
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RooRoo: just like the time i stuck my finger up my arse with no lube at all and she didnt talk to me for hours

[binge]

Well if it is knocking when the throttle is eased off. Then it could well be the big end...

Are you Sure its coming from the engine. because i have got a friend with a Cagiva Mito Evo. and when he lets off the throttle he gets clutch rattle. He got a race clutch and its fine now...


Good luck...
Ben!
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[Sparks!]

Have you checked all engine mounts and bearings for headstock etc as Kev says... it may only make noise when letting off the power I don't know but it's well worth checking if you've already rebuilt the engine!!

Won't hurt to go around checking all the bolts and engine mounts, bearings etc anyway so well worth trying?
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Current Toys: 06 Yamaha WR250F | Nissan 350Z GT | Tech 4 Homes

[baldy]

Hi,

My nsr did this and i thought it was my big end. turned out to be my chain was loose and was slapping on the chain guard.
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One day i will rule the world, just not today.

[map]

Quick question if this isn't already sorted.
Does it do the 'knocking' under load (i.e. while being ridden) and/or when revved both in and out of gear on the stand?
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[Jammy-G]

Happens out of gear on the stand, when its under engine braking, and when you let off the throttle.

Doesn't happen when you give it some throttle (even a tiny bit).

And its not continous knocking either.. it's just a random knock that happens once every 5 secs or something.
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RooRoo: just like the time i stuck my finger up my arse with no lube at all and she didnt talk to me for hours