New engine knock/clatter?

[Wayno]

Hi all, last time I had a knock you guys helped me diagnose it to a stiff link in the chain. Now I've got a new noise to diagnose.....



I commute 100 miles a day in and out of London on my pointy k5, I usually wear earplugs to stop the wind noise. Yesterday I noticed a knocking sound so I pulled out the earplugs for a good listen.



It's a light 'clatter' sound in time with the revs when I accelerate light to medium throttle and when I engine break. In idle it's fine and I don't think it's there under hard acceleration but it's hard to tell. The sound is almost 'plasticky' although it's something tapping a casing rather than a loud metal thud. It sound to me like something is lose rather than broken.



I checked the oil when I got home and it was below the sight glass when upright but the pressure light hasn't so much as flickered (the bulb is good) so I'm hoping I've not starved the engine and caused serious damage. I've topped up the oil and ran a commute this morning and it still sounds the same, although the engine feels awesome today, for some reason faster than usual. I did also fit an R6 throttle tube last night while I was fiddling so recon it just the ability to get to a full throttle for once



I've been told before that an engine runs best just before it blows, I'm just worried this is its last hurrah!



Anything particular I should look as first to diagnose the problem?



Thanks in advance!

[Bibio]

on the SV. no oil = not good. how much oil did it take to top up?

if you dont already have it then i would suggest you get breakdown cover with relay.

[Wayno]

Just under a litre to get back to the max.

I've got recovery

[Bibio]

just under a litre is 1/3 of your oil.

[jonny.boyd]

Oil is one of those things that is seriously understated! And that people just ignore.

It is the MAIN things stopping your engine from cooking itself (coolant helps).

Need to start an "OIL AWARE" campaign....

[Wayno]

I've learnt the hard way

Now I've had my wrists slapped, where should I start looking for the fault in order to make a repair?

Ta

[jambo]

There are a few possible candidates for the noise.

First up, the oil light is pressure not volume. It is handy if an oil line blows but if you get down to a level where the little the light comes on the engine is unlikely to be in good shape. Make this a regular check going forwards.

The big concern is that the rattle could be the big end bearings. If that's the case then the engine is beyond economic repair. A new crank, Rod and Shell set is around £900, plus gaskets and labour. Repairs to the old crank do not seem as easy as some would hope, so a 2nd hand engine is the most economic fix.

Hopefully this is not the case here, a few other items such as cam chain tensioners not advancing can cause a rattle too. See if you can find exactly where on the engine it is coming from. Use of a screwdriver as a mechanics stethoscope can help. Perhaps post a video. If in doubt, drop the oil into a clean container ideally through a strainer. If it looks good you can put it back, if the filter media or strainer is full of glitter, then we need to get a bit more concerned.

Fingers crossed it's not too serious.

Jambo

Sent without a real keyboard

[Wayno]

Thanks Jambo, I'm hoping it's not too serious too! I've been trying to work out where the noise is coming from but it's hard to get it to do it while standing and just revving the engine. As soon as I'm moving though and there is some load on the engine it comes in, it's also not consistent. I'll try and record the noise tomorrow.

If it was running poorly I'd be worried but she feels just fine if not better than usual. I went for a ride yesterday wither the mrs pillion and even with the extra weight it was still like a little rocket.

How hard are the cam chains to get to to check the tensioners? What would I be looking for?

Thanks!

[jambo]

Have a think and be very specific. Does it happen at different revs/throttle openings in neutral? Does it only happen in gear and moving? Where in the Rev range?

Try to separate the engine and transmission mentally. We've had a 'knock' turn out to be a lot of different things, including the drive chain to the rear wheel.

Don't go any great distance and if in doubt have a look at that oil. You can put it back.

Jambo

Sent without a real keyboard

[Wayno]

Thanks Jambo, I have GOOD NEWS!

I stopped by my local suzuki garage today as I had an unexpected day off. I explained the noise to the mechanic and he took it for a quick spin. As soon as he was back he reassured me it wasn't an engine noise! Yay! He couldn't figure out exactly where it was coming from and his advice to start looking for lose parts under the tank and air box is exactly what I've already been doing.

In the knowledge it wasn't gonna die on me I set about looking for the rattle again, this time removing anything that's not essential to the running of the bike and taking it round the block to see if the noise had gone.

When I removed the headlight assembly (it's a naked) and rode it all was quiet! It seems that one of the plugs had worked lose and was tapping on the back of the headlight cowl from inside. I've put it all back together making sure everything is secure and all is now quiet in my little world on my bike.

To celebrate I treated her to a good service, new oil, filter, air filter and pads.

I love my SV.