RD04 Rattle - the video !!

[Shire]

Wow, those selection of bits sounds great, I'll need the gaskets for sure but to be honest I'm stripping the engine but not really sure as to what the main cause is or will be, so i might need the tensioners and chains as well.
I've had two cylinder heads fitted then Thunderoad in Bridgend said it was a worn conrod (to much rock in the pin). As they were to expensive to do the job I decided to do myself.
I dropped the bike down to a local bike shop earlier (because they have a tool to pull the alternator rotor off) and the guy there says there is nothing wrong with the conrods!
So I'm starting to pull my hair out a bit, I'm hoping to split the crankcases and find something now.

[Shire]

I am from Newport, South Wales and yes i would be grateful of a hand.
I don't mind coming to you this saturday if you have a spare 5 minutes to see what you think.
I'll have some of those parts if they are the same.
My number is 07790156406
Thanks Mike

[jik1219]

Hey, Not to sound full of myself but I have had quite a bit of experiance with all types of moto engines and I would have to call theat a tich or tap not a rattle. Cam chains have a particular rattling sound which is nothing llike what I heard in your vid. I would tend to agree with others that it could be exhaust or valve noise. Maybe even spark jump to the head through a bad plug wire. Because each cylinder has two coils and two plugs if one were to fail you may not notice an obvious miss but you could be hearing it. Even if you haven't done the tappet adjustment correctly you should have heard a change in the pitch of the tap. I would lean towards the spark plug wires especially since it comes on above idle and goes away at higher rpms. Try eliminating one wire at a time by disconnecting one coil at a time and starting the bike. Repeat this with each one and if it is a bad plug wire the noise should subside when you hit on the bad one.

[AlanH]

Have a read through the whole thread...

It was difficult to tell from the sound on the video but in real life the rattle sounded far to heavy to be camchain and was too deep in the motor to be tappets. It sounded much more like a small end problem than a classic camchain rattle.

However, it was the camchain making the noise as the tensioner was on the verge of catastrophic failure. The bottom one (from the front cylinder) is bending backwards and is delaminating. Incidentally, both wear indicators were within limits so don't rely on them as a 100% indicator that all is well with your camchain.



Everything else was fine in the motor and the clearances were spot on.

The noise was far too loud to be arcing which is more like a 'tick' noise than a metallic rattle.

[Cabby]

Bloody Hell Alan.....After all this time you just described the symptoms on my Alp.

Definite loud tapping...diagnosed as small end eventually...Although I knew the oil hadn't been low.

NOW....Still tapping loudly but with a definite chain rattle goin' on.

Does that sound like the progression of the tensioner slowly breaking down ?....Methinks very possibly.

How far do you have to strip to get the tensioner out.......A lot accrording to Haynes but you've got real life experience.

Anyhow...I'm ready to do the tappets on my ebay engine, then I'll swap it with the noisey one and see if I've been done....

Either way..I'm thinking....if it's a chain tensioner on my old one It's gotta be worth fixing...maybe....

[AlanH]

On the RD04 you can do the work with the motor in - although you won't be able to replace the fixed blades as they are retained between the barrel and the head - but these are generally not a problem.

Take both cam covers off. Remove the clutch cover (zorst needs to come off too on the AT) and the clutch basket on the right hand side. On the left side you remove the alternator cover, alternator rotor and starter clutch. Remove the cam sprocket bolts and then remove the cams. Unbolt the tensioners and feed them up through the top of the motor. Lower the camchains on wires and manipulate them to disengage them from the crankshaft teeth on each side. Assembly is the process in reverse.

Stuff you'll need:

• Puller for the alternator ( I use a yamaha XS650 layshaft which has an M22 thread I think and is as hard as anything).
• Exhaust gaskets
• Alternator cover gasket
• Clutch cover gasket
• Thread lock for the cam sprocket bolts
• New clutch centre nut
• Tensioner assembly x2
• Camchains x2

Now, the low mileage RD07a motor I saw in bits last night (Hi Mike!) looked like it had got small end issues - looked like the front one was slightly oval. It had some significant tappet and exhaust valve stem damage but these were off another bike. There was no sign of overheating or lubrication failure so I thought a likely cause may have been over-revving at some point causing the small end to stretch. Mike said the rattle was very similar.

I guess what I'm saying is there are a pile of things that can give an almost identical rattle on these motors and it's just a case of inspecting and eliminating them one by one. If you do the camchains and tensioners (about £200 in parts and 4 hours if everything comes apart well) it may still rattle if it actually is a small end - and you'll then need to strip the entire motor and split the cases if that is really what it is.