GSXR 600 SRAD Engine noise

[tokai]

Wot ho chaps.

Would any of you mechanical boffins care to take an educated guess as to wot is causing my (franken)bike to make this new and loud 'whacking' noise?

https://youtu.be/KpNzvHGw8SA

Owned the bike for a year or so, had a recent problem with the oil pressure warning light coming on while riding.

Whipped the sump cover off and found the oil pickup tube to be mostly filled with pieces of broken up gasket material of unknown origin...

Cleaned it out, new oil and filter change, all seemed fine on a short test run but bike seemed reluctant to rev over 9000 when ridden in anger - then immediately this new, loud noise. Like what I has never heard before.

Muchas gracias in advance.

[Marmalade]

Sounds to me like you've got a spark plug come out, did the noise start suddenly?
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[tokai]

Yep, started at just over 9000rpm on the A1 about a week ago.

Interesting... I'll check that out in the morning. cheers.

[gavcarter]

Not sure if your model has it, but sounds like the PAIR system has disconnected itself or the valve is broken.
Look on top of the head - if your model has a PAIR system it will have a plastic drum ( sort of like a big fuel filter filter shaped cylinder) and 3-4 pipes coming out of it.

Some will go directly to the head, others off to airbox or breathers etc.

Make sure they are still connected. If appears normal, take valve out ( the plastic drum described earlier) and blow through it - then try opposite way - its supposed to be a one way valve.

[tokai]

Cool, cheers. Another thing to check.

Never heard of a PAIR system so not sure if the bike has one or not, so further goggling required...

The model is a gsxr600w, a '98 I believe.

[gavcarter]

Pulse Air Induction Recycling or some such shit.......
Basically allows clean air into the exhaust system directly through the head to meet emissions, cold air condenses some of the gasses into water or some such tree hugging nonce-ence

unsure of year as site wont load, but got this of google images
https://www.bugmanweb.com/gsxr/gsxrimages/pair/stock1-600.jpg

[tokai]

Nice one, cheers, very helpful.

Got the Suzuki service manual here and according to that the 600w '98 model does have a PAIR valve system. So tank and air-box orf the morn and I'll check the plugs while I'm at it.

[Marmalade]

Did you look?
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[Robby]

It could also just be a hole in a downpipe. If the downpipes are mild steel and mostly rotten through, and it hasn't been at high revs in a while, then the increase pressure on the exhaust from high revving could be enough to punch out a weak bit of metal.

Far more concerning for me is the fact that the oil light has been coming on. The oil light usually comes on as a courtesy to tell you that your engine is now scrap, the oil pressure to trigger it is very low. I wouldn't spend any money on it bar petrol for the next tank of fuel, in case the engine is gubbed. If it behaves for another 100-200 miles of normal riding then you might be lucky.

On a more general note kids, this is why instant gasket is bad. If you must use it, use a tiny amount. Don't be tempted to use more to make really sure you get a good seal, you'll end up sealing your oil pickup closed.

[tokai]

Aye, sorted it last night finally. First chance I'd had to get a look at it.

Robby was close - seems one exhaust nut had worked its way loose so the noise was the fumes escaping where the downpipe meets the block.

I replaced all the exhausts nuts when I sorted the oil pressure problem - have to remove exhaust to get sump cover off.

Suzuki/ebay wanted 12 quid for 8 hex head nuts so I got a bag of 50 A2 stainelss ones for 6 quid from screwfarce instead. A perfect match, but seems I didn't do them up tight enough or maybe need to employ some kind of washer to keep them in place?

Regarding the oil pressure problem, that is sorted. The light was coming on intermittently, so parked it up for a bit and took a gamble on some new fluids and gaskets and had a go at fixing it. Seems to have paid off for now as bike is running well.

Definitely wasn't instant gasket that was blocking the pickup tube. More like very old, varnishy pieces of excess sump gasket - there seemed to be loads of unnecessary extra material around the sump cover when I hoiked it off. Or maybe the starter clutch gasket has munched itself but its not visible extrrnally?

Had a look under the airbox for the PAIR system and there are a coupke of hoses coming off but it seems to be just a simple mesh filter inline with them, instead if a one way valve thingy.

Anyhoo, cheers for the help. Bike is running again and I'll keeping an eye on thoses exhaust nuts till I can get down the lockup again.

[Robby]

I would recommend brass nuts to go on exhaust studs. Mild steel nuts rust in place, stainless nuts make the mild steel studs and the alloy of the cylinder head corrode more quickly (galvanic corrosion). Brass nuts don't cause galvanic corrosion, and if they seize then the nut will fail before the stud snaps.

[tokai]

Top tip mon