Cylinder head O/haul

[Sylvester]

As with most airheads, I cannot be sure of the exact mileage of my machine. She's running well, not burning any oil. My question for the masses today is at what stage should I start to think about changing the inlet/exhaust valves and the timming chain? The chain is slightly rattling in hot weather and balancing the carbs makes no difference. My current approx milleage is around
100,000 kilometers. The bike was fitted with a new 1000cc conversion around 20,000 kilos ago so I know the bores/pistons are fine. I'm just getting a list together to plan my winter.

 

[(RIP) pastyman]

I think I am right in saying that the recommended mileage for valves/guides is about 40000 miles. The valve heads are prone to breaking and that could cause a mess of your new bores.. Its not a difficult job to get the heads off an airhead so I would go ahead and do it. same with the camchain, easily doable with the engine in the frame.
As an aside, When I did the valve guides on my 100, I went with a system where the existing valve guide is drilled and fitted with a liner. It was cheaper than new guides and without the risk of damaging the head. Might be worth asking about.

 

[Steptoe]

R80/100 valves 80K miles.
R45/65 valves 50k miles.

Timing chain when your fed up with the noise - the difference between a very noisy chain and a new chain is about 2 mm's

What wears more on a noisy chain is the fibre chain tensioner.

I've had a timing chain snap on my own airhead. It was only 15K miles old and completely quiet.
Fortunatly it caused no other damage as i was just pulling away when it happened so it was just like stalling, which meant the valves and piston never met each other that day.
They've made other arrangements to meet in the future

 

[bumpmuncher]

R80/100 valves 80K miles.

ah is it 80k intervals on the valves then?
having read the threads about changing the valves and guides at 40k i have been getting a bit paranoid that i have not done them yet, or am i getting the wrong end of the stick again (sorry for the slight hijack sylv) cheers Bm

 

[Sylvester]

ah is it 80k intervals on the valves then?
having read the threads about changing the valves and guides at 40k i have been getting a bit paranoid that i have not done them yet, or am i getting the wrong end of the stick again (sorry for the slight hijack sylv) cheers Bm

BM, yep same with me. I was begining to suffer from valve stem failure paranoia but it looks like we may be ok for the time being. Thanks for the info Steptoe and Pastyman. As the timming rattle is only slight, I may put it off for a while. But then again..............

 

[Kenny]

R80's last longer than the R100 exhaust valves...if it was me I'd do R100's at 50,000 miles Then again I do bow to St.Eptoe