My camchain SNAPPED today SRX600

[J Hop]

Yes the camchain snapped while the bike was warming up on tickover, anybody changed a chain on this model before ? Anybody know if the valves can hit the piston on a standard engine (it didn't make any bad noises) ?

Am I lucky ? Should I buy a lottery ticket ?

[Steve H]

The valves get quite close to the piston in normal operation so any change in piston/valve timing is likely to cause contact. Since it was only ticking over you may have got away with it. The only way to be sure will be to take the head off, even the slightest knock will spoil the valve/ valve seat sealing.You should be able to spot contact marks in the soot on the piston.  It might be worth removing the flywheel to start off with and check the front camchain guide mount is still in one piece, I've found them to be fragile if the camchain gets wrapped round the camchain sprocket. I suspect your chain ran straight off so may have missed it.

[GB500nz]

strangely enough, I once had to replace my camchain downtown, miles from home. Fished the ends out with a wire coathanger and a parts grabber, clipped the new one on, threaded it through and did the timing thing. Not a problem. No point taking the motor to bits if there ain't nothin broke. Make sure you've got a really bright pencil torch and plenty of wire.

[andy230]

Wow!

Never heard of that before. 

Nope, sorry, never changed it.  You'll be taking the head off I presume?  try a leak-down test with paraffin in the combustion chamber...

Good luck!

a

[J Hop]

Bought the engine from a breakers a few years ago, haven't rode it yet just started it up a few times while fitting it into different frame.
Not going to do anything rash and take the head off straight away, gonna try and peer down the plug hole with pencil torch and look for signs of contact on the piston.
Somewhere I have got a metal sparkplug body with an airline coupling welded onto it for changing car valve stem seals in situe, will connect that up and listen for air in the ports.
Besides I know that if I take the engine apart I wont be able to resist sending it to Slipstream Racing before reassembly. And I want to ride it for a year or so in standard form first.

[GB500nz]

if I remember correctly: Get one of those grabbers with a plunger at the top that pushes 4 springloaded prongs out the bottom of a long shaft. Take off the cam cover. Peer down and see the chain curled in the sump. Winkle the end up and as soon as you can, hook the end with a wire and tie the wire to a safe place. Look on the other side of the passage and grab the other end of the chain. This will be a bit more fiddly, but with a little patience and cunning you should be able to get the other end up with the bight passing under the crank sprocket. Then it's easy to connect up the new chain and zip it in. Last thing is to remove the sparking plug and turn the engine over until it seems to be in agreement with where the cam is. Put the snap link in and check the timing. If it's out, remove the snap link and adjust. Snap link has to be on the cam sprocket when it's being removed or replaced. You can turn the camshaft with waterpump (slip-joint) pliers on the sprocket.

[J Hop]

I don't think the SRX's camchain is thr type you can split and join (it doesn't look like a smaller version of a drive chain) the inside of the chain forms "teeth" which run on the sprockets (a bit like a cambelt does).

Anyway I'm still sulking about the failure and haven't done a thing about fixing it yet.

As it has failed I will do the job properly and fit a genuine chain and follow the worshop manual instructions, BUT I dont want to take the head off unless absolutely nescessary.

[peterj]

You shouldn't need to take the head off. I think you can change it OK if you pull the flywheel and the bottom mount of the chain guide off. You can probably rivet a hi-vo chain with the right tools, but I don't recon it would be worth the hassle.

[J Hop]

I dont have to take the head off to change the chain, but I will have to if I have hit the valves :-(