well when I pass my test and got on the road the DT went about 30 max speed on a flat... then a week later I refuelled her and went off, i heard a rattle at one moment (I think) and the bike got much louder now going at 40mph couple days later the bikes seems like it has lost all compression. Now struggling to go 20mph on a flat in top gear... Before I could reach 20 in 2nd gear! It is going so slow I had to push my self up a hill. evenb when starting it struggles to give a nice loud smooth rev.

The only thing that happened was there was a hole in the downpipe, and a split at teh top end of the expansion chamber which leaked oil onto the engine, I temperally used GUN GUM and patched it up solid, I should be getting new downpipe soon.. But Since The split appeared and I patched it up it has been going slow slow slow.

please give advice I need the bike running as it takes me to work almost everyday.

have you done a compression test?

a blowing exhaust could cause a loss of power for sure, see what happens when you put your new downpipe on!

other than that it could be caused by a number of things, although i dont know too much about 2strokes.

I'm no mechanic but isn't the shape and integrity of the expansion chamber in a 2-stroke exhaust critical in bouncing back the exhaust pulse towards the engine creating back pressure? If you had a split and gun gummed it, and if it isn't smooth on the inside I guess you would muck up the exhaust pulse and reduce your performance.

The exhaust system on a 2 stroke is critical. Usually when they get to the won't pull the prick out of your trousers stage it is time to give the exhaust system a good internal clean out.

how eloquently stated papasmurf

IM at the stage of chekcing bits over and cleaning carbs, I got my bety onthe expasion chamber as it started when a little split acourd and it started to leak oil!??! whats that all about

many many..............MANY! years ago i had an old FS1-e that did something similar, a big lump of carbon came off and blocked the baffle, result 20mph flat out, the oil could be something to do with built up back pressure from the above..
the rattle could be the restricter plate breaking off and and jamming up the zorst aswell

woodz u hit the nail on the head, the thign shot outthe exhaust cloggin the chamber, building up pressure caused split and oil leak, fumes was going out of the tube going into chamber, when gun gummed that there was no where for the fumes to go, loss in compression. drtilled hole in exhaust tube for temp fix till my new downpiep arrives in two days and it is allready faster than when i first got it.

Thanks guys you svaed me 30 minutes plus stripping the carbs (again)