Hey guys, took my pipe off today to clean and fettle and it has a little rattle inside! I tapped it onto some wood and got some hairy fibres out and some coked up material.

anyway I thought you'd appreciate my initial plan - I have no MAP gas so I've shoved an old sweet potato in one end and filled it with petrol.

Even with our fuel prices this is my cheapest option right now to try!

what are symptoms of a blocked pipe?

I would remove the baffle and see if it's clear or not.
A lot of guys recommend putting the exhaust on a camp fire or BBQ (with the chrome removed).
Have a look at the one I did on my CT1C as that will give tou an idea of how the baffle will look when clear.
It's on thread #86 www.yamaha-enduros.com/index.php/forums/...restoration?start=80
All the best, Pete

PS, I'd leave it a day or two after pouring out the fuel you've put in it before introducing fire, don't want to blow anything/one up

Be careful there. Burning out "not with petrol" is the best way. I know you're only soaking at the moment. But more importantly it sounds like the perforated sheet stuff holding the noise deadening packing against the walls has fallen to pieces. So 'i think' it needs cutting open in the middle area but might need two cuts when you can see whats going on & fish out the damage. I did my AT1 about 40 years ago as was all rattly inside. No easy answer but thorough burn out first & see what happens before going 'in'.