FZ400 engine noise (YouTube video attached)

[tatastha-sakti]

Hello. Noticed this metallic noise about two weeks ago. Seems that is comes from the right side of the engine. Is it valves?

[url=http://www.youtube.com/watch?v=hdmG968cBJY#]Yamaha FZ400. Движок барахлит.

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[CRH]

sounds like camchain to me?....

[darrsi]

I've never heard a cam chain rattle that loud before!
That one really does sound like a tractor!

[His Dudeness]

Might be an exhaust leak. Is the exhaust rusty behind the clamps at the engine?

[unfazed]

Is it runnng properly on all cylinders? As his dudeness says, it sounds more like and exhause problem.

[tatastha-sakti]

Thanks for replies, fellows.

Yes, it might be camchain, but the sound comes mainly from the right side of the engine and camchain is in the middle. Or it doesn't matter?

I've checked to temperature if the downpipes. The third one was just a little warm. Then I checked the spark plugs. The third one was all wet with oil and petrol, black as coil.







Then I installed the new spark plugs and the third cylinder switched on. Now the engine works better, the bikes goes better. The uplift that goes after 6000 came back.

Well, but the noise is surely still there. I made another video with new spark plugs. Here it is:

[url=http://www.youtube.com/watch?v=YycTOSAZbAM#]Yamaha FZ400. Движок барахлит ч.2

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Now, what about exhause. Well, His Dudeness, they don't seem to be rusty, I guess... Here are the pics:

[CRH]

they not blowing matey or they would be sooty!!...still think its camchain?...or something to do with one of the cams mabe?....

[tatastha-sakti]

hm, but they are hot. and when it wet outside, then there is a lot of white smoke from the exhaust. also, when i checked the compression two weeks ago, i put some oil in the cylinders and then i started the engine. there was a damn lot smoke from the exhaust and, I must say, from the point where the exhaust meets downpipe, but that place where downpipes meet cylinders - there was no leak there.

[CRH]

hm, but they are hot. and when it wet outside, then there is a lot of white smoke from the exhaust. also, when i checked the compression two weeks ago, i put some oil in the cylinders and then i started the engine. there was a damn lot smoke from the exhaust and, I must say, from the point where the exhaust meets downpipe, but that place where downpipes meet cylinders - there was no leak there.

...think you will find its quite normal when you have a wet day and the engine is cold to get white smoke?...its only condensation!!..when it gets up to temp that should desisipate ?...has for putting oil in the bores then starting the engine?...again normal?...all its doing is burning the oil off?  ........i would think if comp is down it will mostly be your valves?....very rare it being your rings?...if it was you would be puthering blue smoke out of exaust ..and it would be using alot of oil?.....

[darrsi]

Yeah white smoke can be a bit deceiving in the cold/wet weather but it's normal, it's when it does it in warm weather you've gotta start worrying.
A bit like when you take your oil cap off in winter and it's covered in mayonnaise. 

[CRH]

Yeah white smoke can be a bit deceiving in the cold/wet weather but it's normal, it's when it does it in warm weather you've gotta start worrying.
A bit like when you take your oil cap off in winter and it's covered in mayonnaise. 

...like old darrsi here says?...if it does it in warm weather you got probs ?...more likely to be headgasket /water in oil etc .....

[darrsi]

I presume your oil level is correct?

[unfazed]

hm, but they are hot. and when it wet outside, then there is a lot of white smoke from the exhaust. also, when i checked the compression two weeks ago, i put some oil in the cylinders and then i started the engine. there was a damn lot smoke from the exhaust and, I must say, from the point where the exhaust meets downpipe, but that place where downpipes meet cylinders - there was no leak there.

If you put oil in the cylinders to do a compression check you can expect smoke when you start it.
Seal the joint between the Exhaust pipe and the Downpipes as there should not be any smoke from that area..
 It sounds like it is not running properly on all cylinders  as I said in my first post and the plug colour seems to prove this.
You may have a bad plug, carburettor jet blocked or carburettor flooding.
I would do a valve clearance check also to rule them out.
What was the compression measurement before you added the oil and after adding the oil?
 
 

[tatastha-sakti]

I understand that there is nothing wrong with smoke in wet weather. I mean that the smoke was visible and if there had been any leakage, I would have seen it.

unfazed, compression is a strange thing. here in Moscow nights were cold in the beginning of October, it was -3C, so I could start my bike only by pushing it on the 2nd shift. then I decided to check compression on COLD engine. and it was 6-0-1-4. After two days the weather became a little warmer. I warmed up the engine and it was 9-8-8-8. Then I put 5ml of oil and it jumped to 11-10-8-14.

And yes, I'm planning to do valve clearance check in winter. I have 45000km already and I don't know if previous owners cheked it. I changed the rings this spring, but valves are unobserved.

[unfazed]

When you checked the compression was it with the throttle fully opened or fully closed.
It is to be done with a fully opened throttle. The compression specifications are 15 max and 12 minimum on a cold engine and yours are below specification. It is always recommended the valve clearance are checked before you do a compression check, as incorrect valve clearance will affect the compression test result
You say you changed the rings, why ? Is it possible that the rings were fitted incorrectly, they should be fitted with the manufacturing numbering/marks on the ring are facing the top of the piston, a common mistake is have them the wrong way which drops the compression and the engine burns oil.
The compression measurements 6-0-1-4 is too low to start any bike on the starter motor and -3C is not low enough to give such a reading unless you have a compression leak problem.  This can be caused by two things compression pressure leaking past the valve seats or leaking past the compression rings. Does the figure 0 in the compression refer to cylinder 3? Since adding oil increased the compression then it relates to rings
 
 

 

[tatastha-sakti]

The throttle was fully opened.

This is my first bike. I bought it last winter and purchased engine repair in our local service, They said I have to put new rings, so I agree. They put new rings and told me that compression was 9-9-9-9 and that's damn good for 18 years old bike. throughout the season (since May to today) I've added about 2 litres of oil. Well, of course, they could have mistaken by fitting rings incorrectly, but I prefer not to think about it.  Hope valve clearance check will solve the problem. I'll do it myself.

Here in Russia it's very difficult to find 400cc bike in good condition, because it's considered to be a bike for a newbie (not by law, but by bikers themselves). People buy old 400cc from 90s for 1-2 years, ride like madmen and then change it 600cc/1000cc, not bothering too much about compression and so on. It's considered to be unwise to spend money on 400c. But I love my bike and I feel, that its 53hp with 180km/h is enough for me, so I've already spent more than a half from its start cost for different repair works. Well...