Loud noise coming from engine and loss of power.

matthew

matthew

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Hi Everyone. I have a 2000 SV650 with 120,000 km.

The last few days I've been hearing a noise which I think was coming from the front cylinder. I only heard it under load and only between 3-5k rpm. It sounded like a loud ticking noise. I know that my bike is normally pretty noisy, but this was definitely a new sound.

Thursday night when coming home on the 401 I felt that the bike was down on power, and took forever to accelerate and rev up. It felt like I was trying to accelerate from 50 km/h in 6th, but I was going 100 km/h in 6th.

The noise I heard got worse and I pulled off the highway at Weston / 401 with the engine making a terrible noise. It saddens me to say it sounded like ice cubes in a blender.

I shut the bike off as soon as I got off the highway and used my CAA membership for a tow home.

I've taken the heads off the engine and the connecting rod on the front cylinder seems to have a bit of play side to side when compared to the rear cylinder con rod.

Is this a symptom of a bad bearing?

The front piston itself looks fine, the rings look fine, cams, chain and cylinder are all good.

Im not sure what the problem is but I'm worried I have to drop the engine and split the case and say good bye to the rest of the season.

I may just bring the bike to Rocket Motorcycle or Heritage Auto and have them try to figure out the issue.

Thanks
 
How can you see play in the rod with just the head off? Or do you mean play up and down? Sounds like a big end bearing on the con rod. Could also be crank damage. Can you check the valve clearance? Could be valve noise. Check that before you pull the bottom end apart.
 
Sorry, I have the head and cylinder off. The rod does have some lateral movement. I'm used to hearing valve chatter, but this noise was different and eventually resulted in loss of power, so I don't think valve noise would cause that.

Here comes a stupid question: With the heads off, can I check valve clearance or does the head need to be on with the cams and the cam chain installed?
 
matthew said:
Sorry, I have the head and cylinder off. The rod does have some lateral movement. I'm used to hearing valve chatter, but this noise was different and eventually resulted in loss of power, so I don't think valve noise would cause that.

Here comes a stupid question: With the heads off, can I check valve clearance or does the head need to be on with the cams and the cam chain installed?
Click to expand...

You can check them but you have to manually rotate the cam so that it's on the base circle and then check the clearance for that valve.

If the valve went way bad it wouldn't be opening or closing on time and could result in some fair power loss.

If the piston or rings went way bad it could also cause power loss. I'm not sure that just having increased bearing clearance would cause too much power loss, although it's certainly a bad situation.
 
Thanks for the reply.

The valves were opening and closing while I still had the heads and rotating the engine. The piston rings are in good shape, no cracks or broken pieces. The pistons themselves are in good condition as well, no marks from valves hitting them and they moved up and down in the cylinder.
 
With 120k ks we're suspecting some cylinder wear.

Measure the bore in at least five places.
Is it round? Are the cylinder walls parallel?

Measure the ring gap.
 
bitzz said:
With 120k ks we're suspecting some cylinder wear.

Measure the bore in at least five places.
Is it round? Are the cylinder walls parallel?

Measure the ring gap.
Click to expand...

Could be. If the compression is down it'll lose power and the piston will make noise. I also wonder if the cam chain was loose and messing up the timing as well.
 
The top end was serviced about 40,000 km ago, but the same rings were reused. i'll look for my caliper and measure the cylinder bore and the ring gap.

i checked the tension on the cam chain and it was tight. i also checked for any damage that would have been caused by a loose cam chain and couldn't find any.
 
What does the plug look like? how is it compared to the other cylinder?
 
I wonder if the exhaust valve sunk far enough in the seat that the cam held it open? This noise sounds more like valvetrain than conrod to me, but I'm only listening through the internet. Can this motor lose a valve shim if the springs get tired?
 
Without hearing the noise, and being there to look at the motor I'm gonna guess a Spun Rod bearing.

If you're willing to pull the oil pan off you can check for play at the crank at that connecting rod.

Might also be a good idea to see what's sitting in the pan and up against the oil pickup screen.
 
There is no oil pan, its part of the case. I might just tow the bike to a shop and let them deal with it.
 
Drain the oil into a clean container and have a close look at it. If it is filled with visible metal particles and looks to some extent like metallic paint, you've got trouble. Take the oil filter off and see what's in it. Filled with metal-flake particles? You've got trouble.

How much side-to-side play are we talking about with that con-rod? The actual side clearance down at the bottom is magnified by the length of the rod compared to the diameter of the big end. A millimeter or so of side-to-side play measured at the top is in a normal range. Just enough to be able to feel it.

If there is any play in the con-rod in the up-and-down direction that you can feel, that rod bearing is done. Checking it properly requires splitting the cases.

Also make sure there is not any play in the piston pin at all. The piston pin to piston clearance, and the piston pin to con-rod small-end clearance, is supposed to be a tight clearance fit.

If it's not something simple, given that that bike is a common model, it's probably easiest to just get another engine (or another bike, if resale value compared to cost to repair the bike is worth considering).
 
Thanks Brian, I was hoping you would chime in. I've already checked the oil and the filter and they looked fine. I'll double check in the morning to be sure.

Side to side play is more than a mm, its enough to give me cause for concern, especially when compared to the rear cylinder. There is also a bit of up and down movement while the rear cylinder has none.

There also seems to be some play in the piston pin which also worried me and I'm glad you mentioned it.

I guess the bearing is finished like you said

I've already started looking for another engine but they all seem to be in the states. I'll have to get a price on replacement parts tomorrow and weigh my options.
 
Have you pulled the filter out out?
 
Is there a screen somewhere in the SV's lubrication system? Some kind of bell is ringing in my head, related to a possible bearing failure but no visible metal in the oil.
 
On a street bike, it is plausible that the bearing surface just slowly wore over time.
 
Brian P said:
On a street bike, it is plausible that the bearing surface just slowly wore over time.
Click to expand...

I just had my neighbour, who is a TTC bus mechanic check out the con rod and he said there is too much play and suggested the bearing is shot. It looks like I'll be dropping the engine tomorrow and opening it up.
 
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