Odd noise

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belroy
Posts: 24
Joined: Mon May 04, 2009 6:42 pm
My Bike: N reg ZXR400
Location: North East Wales

Odd noise

Post by belroy »

Recently just did all my valve clearances, changed the cam chain and checked the guides in one fell swoop, now between 3.5k and 4k revs there is a horrible grinding noise, ive pulled the cam cover off again and re-checked all the timing marks, TDC, and valve clearances again and all seems spot on and i cant see any sign of grinding or damage in that part of the engine, it seems like its coming from that area though.

Ive been using it still for a month and has no perceived change on throttle response, power or anything else and is kept between the above mentioned rev range, any higher or lower than that and it all sounds sweet as a nut.

I did however re-set all my mixture screws back to standard at the same time so am wondering if its anything to do with my carbs.

The only thing I can think of is that there is something loose round that area and the resonant frequency of whatever is loose is the vibrations caused by the engine at 3.5k-4k revs So i am pulling it all apart again this week to triple check.

And before anyone asks no I did not drop anything inside the engine, I have also had my friend who is a Helicopter engineer and also owns a ZXR400 and ZX9R pull it all apart and check everything again and he couldn't find anything.

Any help guys would be a massive help.

Cheers
cargo
zxr400 oc member
zxr400 oc member
Posts: 3341
Joined: Sat Jan 08, 2005 10:33 am
My Bike: tomos moped
Location: Carrickfergus Northern Ireland

Re: Odd noise

Post by cargo »

Sounds like a cam chain problem to me...............

At a guess you have failed to reset the tensioner ? ?
belroy
Posts: 24
Joined: Mon May 04, 2009 6:42 pm
My Bike: N reg ZXR400
Location: North East Wales

Re: Odd noise

Post by belroy »

I dont think so, i pushed the bit that extends right back down into the housing, is that what you mean?

Also if was that wouldnt it make that sound all the time not just at specific revs?
twistedrigs
Posts: 1
Joined: Mon Feb 02, 2015 6:09 pm
My Bike: zxr400 L 91and Yzf750r 94

Re: Odd noise

Post by twistedrigs »

understanding that this is an older post from 2011 did you find out what was cuasing the rattle as am having the exact same problem with my zxr400
nettns
Posts: 5
Joined: Tue May 03, 2016 1:03 pm
My Bike: ZXR400 L2

Re: Odd noise

Post by nettns »

I'm also having this problem. It makes a rattling noise that starts at 3500rpm, peaks at 3750rpm, and stops above 4000rpm. Anybody have any insights? I just have one month left in my riding season, so I was going to start tearing things down to search for the problem over the winter.
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