Triumphrat

John Martin

Hi All. Hope you can please offer some advice. Went out for run yesterday (Sunny day in Northern Ireland) and my 2000 tt started to rattle and knock from the top end. Its wasnt speed related as in rockers or buckets and didnt sound like valve clearance as this wasnt an issue before. Took timing cover off and chain seems ok but there is 1-2mm play on side of chain that isnt on tensioner side. Visual inspection under cam cover - nothing loose and no damage can be seen. How tight should timing chain be????? Is this a common fault with TT. HELP John

KitNYC

Moving to 600 forum...

BombFactory

Timing chain issues are not common with these engines. Chances are it is not a timing chain problem from the loud knocking/rattling sounds you describe. If the timing chain were loose enough to cause loud knocking and rattling noises, the chain would most likely jump teeth resulting in a destroyed engine. 1-2mm sideplay doesn't sound excessive. You should be able to look down along the chain and see the tensioner ratchet plunger. Is it up against the chain?

Have you checked to see that a spark plug has not backed out of the hole? This can cause an exhaust leak that sounds similar to valve train noise.

__________________
I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other. -Macbeth knew I.VII

John Martin

Yeah the plugs are all in fully. I fitted new tensioner and timing was triple checked. When started it rattled and knocked from head area. I've taken head of now and it shows slight contact with exhaust valves and pistons. Have sourced replacement head rather than change valves (£500 a set) for £100 and plan to use cams from bike. Will check clearances statically with head off then refit when head fitted. Fingers crossed. Thanks for the tip

BombFactory

Multiple cylinders show signs of piston/valve contact? Do you know why? Were the valves dropped (i.e. the retainers came off and allowed the valved to drop down)? Where were the crank and cam markings lined up with cylinder 1 firing on TDC? If the marking were not aligned per the manual, I'd consider replacing the cam chain and inspecting all three sprockets very closely because of the chain's jumping teeth.

__________________
I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other. -Macbeth knew I.VII

John Martin

Yip - followed manual re no.1 tdc then after cam marks aligned at tdc rotate crank x 4 revs to check tensioner takes slack and marks still align. have head off now and got other head, which is newer model with breathers on ex side. My head doesnt have breather and separate ports for throttle bodies and injectors. Must be very early bike. Will check part numbers to see if valves are compatible (Speed 4 and TT have same part number). If so will swap ex valves/ do valve seats/ and rebuild old head. Will also replace timing chain. There's no reason why this shouldnt sort problem. Cheers
John

Will

You could have had valves that were too tight, or you could also have bottom end problems. Bottom end problems will result in a fairly spectacular failure. Let's hope it was just valves adjusted too tight.

__________________
Will
It's a squid thing. You wouldn't understand.
SponsorHouse profile

Go soothingly on the grease mud, as there lurks the skid demon.

BombFactory

It sounds like the head you purchased is not necessarily an earlier head but an smogger head (California emissions head). Those aren't breathers but Secondary Air Injection (SAI) ports. Essentially, upon closing the throttle, a burst of air is injected into the exhaust ports that mixes with the extra rich exhaust fumes so that they burn up in the exhaust, thus emitting less raw fuel into the atmosphere--it does nothing to performance, good or bad. In the event you end up running the SAI head, you'll need to block off these ports. The best way is to build steel or aluminum block-off plates and bolt them on using a bead of hi-temp exhaust silicone (the copper stuff) as a gasket. If you leave them open, the exhaust can pop open the reed flaps in the valve mechanism and create exhaust leaks.

So do you know why this happened? Were the valves too tight? Were the timing marks aligned before you removed the head? I ask because it would be beneficial for you to know what caused the valve/piston damage before you throw on another head to have the same thing happen again.

__________________
I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other. -Macbeth knew I.VII