sick drz

I wonder if anyone here has had this problem (or similar...)

Was out greenlaning last night and noticed the engine on the DRZ was getting progressively louder - was not overly worried at first as I was wearing a new helmet and no earplugs so i thought it was something to do with that at first. I limped the bike home and at the bottom of my road there was quite a loud clonk and then the valve gear (i think) started making a very loud chatter.

I am wondering if one of the valves is stuck? the engine turns over and runs on a little throttle but will not idle. I plan to take the rocker cover off this weekend to see if anything (perhaps a shim) has slipped or worse....

Does anyone know how much a good second hand engine is, or more importantly does anyone have one (in case this engine / or head is shot)

Cheers

The valve-gear is actually pretty robust - I would be surprised to learn that your problem has anything to do with shims or buckets.

If you think that the noises are mechanical (as opposed to, say, a blown exhaust), it could be the timing chain. These are known to give problems at around 15-20k miles when the auto-tensioner runs out of travel.

The auto-tensioner is a spring-loaded ratchet which presses on the reverse edge of the rear cam-chain guide. It all works well, but what wears most is the guide. The manual tensioners give longer life because they put LESS pressure on the chain guide - but I reckon that there's a risk of the chain becoming too slack.

To see where you're at, removed the centre-cap bolt from the tensioner and pull the spring out. Then carefully remove the two Allen bolts that hold the tensioner in and carefully pull it out. When you have the tensioner in your hand, pull the nose out (ie what the spring would be pushing) and see if there is any movement left. If there's none, it's come to the end of its adjustment. You can check this before stripping the bike to see if that's your real problem.

If your chain is too slack you'll need:

• a new chain (Suzuki dealer)
• a rear cam-chain guide (Suzuki dealer)
• a clutch cover gasket
• oil and filter
• New antifreeze
• Workshop manual (cheap CDs on eBay)

About £50 for all the parts.

It's not a hard job, but you need to be slow and methodical in a clean environment.

• Drain the oil and water
• Tank etc off to get at the cam cover
• Remove the camshafts
• Take off the clutch cover
• Remove clutch basket

When you've taken the cams out, turn the engine to TDC and leave it there ready for reassembly.

You can now access the timing chain and guide. IIRC, there's a small retainer that's got to be removed to take the rear guide out. Pull the guide downwards to remove. You cannot change the front guide without taking the head off, but that's not the part that wears.

When you get the rear guide out, you'll see a dimple on the back where the tensioner has been pushing against it. That's where much of the wear actually is. I measured the length of my new chain against the used chain and there was hardly any difference - but, as I'd already bought a new chain, in it went.

Reassembly is straightforward subject to getting the cam timing correct. Put the cam tensioner in last and you'll see that the spring is MUCH harder to get in than when it came out.

Oil and water and job done!

Greg

Greg,

Thanks for your detailed reply. I think you may be right as I have thought that the cam tensioner was worn since the valve gear / chain did appear to be noisy when I first bought it (about 4 months ago) but no-where near as noisy as now. If the tensioner is too worn would it prevent the engine from running? - unless the chain has lifted off/slipped on the valve cog (pretty unlikely i would have thought on a chain driven cam?)

I will try ringing around a few suzuki specialists for some prices for the parts - or look on ebay.

Mike

If I remember, there is a guard that sits above each of the cam sprockets which should stop the chain from jumping a tooth, but if the chain were that slack it'd be pretty noisy too!

Greg

Yep, I'll go along with Greg.
I've also heard of the seal failing on the front sprocket/gearbox output shaft, causing the oil to dump out. This leads to immediate camshaft damage as the oil flow ceases.
Check that you have a s/steel spacer on the shaft as the stck spacer in mild steel and corrosion encourages seal failure.

As Greg says the valve mechanism is very robust and typically never has to be adjusted (shims). The cam chain tensioner however ...

make sure you have an 03 auto tenstioner or newer - the ones before this fail and place excessive strain on the chain when new. Alternatively run a manual.

A.

Greg, Snoopy and Timpo

You are all BRILLIANT! onyack Greg you were spot on. The spring in my cam chain tensioner had broke so it wasn't applying any pressure at all! Off to the dealer tomorrow to hopefully get a new one.!

I owe you all a good few drinks , or alternatively tell me a charity and I will bung a few quid in.

Mike.

I'm really glad that you don't have to buy a new engine!!



Greg

Gone again...

Bum. Out laning again tonight and the same problem has just reoccurred. engine died (luckilly just after quite a boggy run and back to tarmac) and had to be trailered home.

I think maybe the cam chain has stretched too far and the tensioner just cannot keep it tought any more. I will let you know when i commence the disassembly again.

Is it a straight forward job to replace the chain?, I am just not sure how to get to the crank cog to get the chain off (will delve in the service manual tomorrow).

Mike

To see where you're at, removed the centre-cap bolt from the tensioner and pull the spring out. Then carefully remove the two Allen bolts that hold the tensioner in and carefully pull it out. When you have the tensioner in your hand, pull the nose out (ie what the spring would be pushing) and see if there is any movement left. If there's none, it's come to the end of its adjustment. You can check this before stripping the bike to see if that's your real problem.

If your chain is too slack you'll need:

• a new chain (Suzuki dealer)
• a rear cam-chain guide (Suzuki dealer)
• a clutch cover gasket
• oil and filter
• New antifreeze
• Workshop manual (cheap CDs on eBay)

About £50 for all the parts.

It's not a hard job, but you need to be slow and methodical in a clean environment.

• Drain the oil and water
• Tank etc off to get at the cam cover
• Remove the camshafts
• Take off the clutch cover
• Remove clutch basket

When you've taken the cams out, turn the engine to TDC and leave it there ready for reassembly.

You can now access the timing chain and guide. IIRC, there's a small retainer that's got to be removed to take the rear guide out. Pull the guide downwards to remove. You cannot change the front guide without taking the head off, but that's not the part that wears.



When you get the rear guide out, you'll see a dimple on the back where the tensioner has been pushing against it. That's where much of the wear actually is. I measured the length of my new chain against the used chain and there was hardly any difference - but, as I'd already bought a new chain, in it went.

Worn chain (about 18k miles) on left; new chain on right:




This dimple is not present on a new chain guide:


Reassembly is straightforward subject to getting the cam timing correct. Put the cam tensioner in last and you'll see that the spring is MUCH harder to get in than when it came out.

Oil and water and job done!

Greg

Shouldn't you rotate the engine to TDC on the compresion stroke before removing tensioner & cams?

Possu said:

Shouldn't you rotate the engine to TDC on the compresion stroke before removing tensioner & cams?

Click to expand...

It doesn't make any difference!

If the cams are not present, there is no specific compression stroke. What's important is that, when you reassemble the engine, the piston is at TDC. When you then reinstall the cams, you mount them in the TDC position for the compression stroke.

Greg