Camchain rattle.

[yorkie_chris]

I've had a funny rattling from the front end of the engine. Sounds like camchain rattling a bit. Loud enough to warrant investigating.

Hmmm easy fix, wind tensioner back, ping it back. Noise gone!
100 miles later. Problem returns.

Try another tensioner, fixes noise for 100 miles. Back again, most audible 500rpm lower...

Tensioner #3 out of the box o bits... still rattling.

What the hell are the chances of 3 dodgy tensioners, says I. It must be a loose tappet or something, very odd for it to keep disappearing, but it can't be the tensioner after all that, can it? Especially not only 7k after checking them last, JHS cams high-lift, but shouldn't wear so badly!

Valve clearances SPOT ON.

Looking at the camchain, it's certainly got more slack in it than I would expect, not enough that it seems imminently in danger of jumping teeth, but definately slack.


So now the big question, are the tensioners dodgy, or is something else broken? I reckon the tensioning blade pins snapping would allow similar rattle. But, they're a right **** to inspect. Next step, swap the tensioners front-rear and see if the problem moves with it...


Answers on a postcard.

[Bibio]

tensioners are doing their job... accelerated chain ware due to it coming to the end of its life?

[yorkie_chris]

At 35k?
Fair enough my cruising rpm is higher than most but it shouldn't be so marked.

Anyway, the chain can be moved up and down by hand, they're normally tighter than that by a fair margin.

[Jamiebridges123]

Can you just replace the chain yc? Dx

Or are they expensive? :confused:

[yorkie_chris]

Not sure if you can get soft-link camchains for SV. To replace one normally is a full engine strip.

[Jamiebridges123]

Oops, I see.. well something to do over the week? haha. :x

[Bibio]

intermittent water or oil pump noise?

how is the cam chain on the sprockets? can you lift it off or move it back and forwards atall (freeplay)?

[yorkie_chris]

Measuring the center run of chain there is 5.5mm of play. You can't lift it off the sprockets or move it forwards/back.

[rictus01]

Sounds like the cam chain, but could also be a cracked guide.

I haven't done it in some time, but you used to be able to rivet cam chains (like drive chains) and get links for them, but that could be a thing of the past like oversize shells :smt102.

Cheers Mark.

[Bibio]

hmmm.. normally they start to get a bit rattly on the sprockets when they start to stretch.. could it be the guide blade is bending?

you know more than me m8... i'm only making suggestions... its verrrry unlikely the cam chain would ware that quick... and 5.5mm is not that bad?

[yorkie_chris]

Going to pull rear head cover off and compare. That one is not noisy.

[rictus01]

Going to pull rear head cover off and compare. That one is not noisy.

What a good idea..............;)

[DarrenSV650S]

The topic title fairy has been doing his rounds again

[yorkie_chris]

Yes regarding the excess slack, that was just me being paranoid. Or the rear one is too slack as well...

They both show 5.5mm play when set to valve clearance checking position. (less when there is tension on there from a valve opening)

All valve clearance in spec.

Also both camchains show the exact (to within the accuracy i can measure) same length between 16 pins.

[Alpinestarhero]

What should the slack be?