A Vstrom 650 mystery

[DavidFL]

The Vstrom in the shop has some issues.

There is a noise coming from under the tank / top the motor.
It resembles a "clacking," "clackety-clack" sound - a cam chain or a tensioner?
Ride the bike at a steady 30 to 40 km/h, and you cannot hear it.
Only when the throttle is closing can you hear it.

Place the bike on the centre stand and run the engine in both gear and neutral, and you are unable to replicate the sound. Everything is normal.
You can only hear the sound when riding the bike.

The front sprocket checks out all ok.

The mechanic has removed the cam chain covers to check the cam chains and tensioner.
Everything is ok he says.

If you run the bike engine for 20 minutes, get it hot, you still cannot replicate any unusual sounds. Everything sounds normal.

So, my only suggestion now is to dump the engine oil & check for any excess metal.

Any ideas - what or where to look next?


I'm mystified by all this as this is my 3rd 650 Vstrom & have 300,000 kms trouble-free mechanical kms up so far.

Vstrom # 1 had 190,000 kms on the clock when i sold it.
Bulletproof. Absolutely 100% standard motor. Only ever changed engine oil & filter, spark plugs, air filter. It never burned any oil.

Vstrom # 2 was the same, sold it at 90,000 kms. Zero mechanical issues.

Vstrom # 3, bought 3rd hand, has been reliable the same too. Until a few days ago riding home in the dark.

 

[DavidFL]

An interestring AI analysis.

First: Is the V-Strom 650 an interference engine?​

Yes — the Suzuki V-Strom 650 uses a DOHC 645cc V-twin engine (same family as the SV650), and it is an interference engine. This means that if the cam timing is significantly off, valves and pistons can collide.

Potential Damage from a Jumped Cam Chain:

If the chain jumps more than 1–2 teeth, you risk:

• Bent valves (most common damage)
• Damaged pistons (due to valve contact)
• Broken valve guides or seats
• Camshaft or crankshaft timing misalignment
• Possible head damage from valve breakage
• Damaged cam chain tensioner or guides (if this is what failed originally)

️ What to Check:​

If your bike has jumped timing, you’ll want to inspect:

1. Compression test – Low or zero compression in one or more cylinders is a red flag.
2. Cam timing marks – Verify if cam timing is out of sync.
3. Borescope inspection – Look into the cylinder for piston/valve damage.
4. Cylinder leak-down test – Can show if valves aren't sealing properly.

Worst-Case Scenario:​

If the chain jumped badly and valves hit pistons:

• You'll need a top-end rebuild at minimum (new valves, possibly pistons)
• In severe cases: complete engine replacement might be more cost-effective