Ty80 Problems?

[mickmc]

Hi hoping someone can help me

my lads ty80 having problems, i put crankcase oilseals in, then did a trial, then because it was back firing , smoking, didn't even want to start(this was after trialing for a few hours, started running lovely at first then started playing up) i replaced them again, thought maybe made a mistake

was doing a mentoring day yesterday and now it's back firing , smoking and don't want to start, somone mentioned there is a screw to drain the crankcases of gases but i can't find it

but when first changed the seals runs lovely , just after a few hours (think only 2 hours yesterday starts playing up)

any help and advice appreciated

thanks

Mick

[andy.t]

Hi,if you think the bikes sucking in oil past the seals I would just drain the oil from the geabox into a measuring jug to see how much you have lost,then you could prove if its an oil problem by running the engine up with no oil in,should be fine so long as you dont ride it around,if the engine runs fine with no oil in the gearbox then I would say it could be sucking it in when filled.

Only saying this is what I would do and have known others to do it also with no problems.

Regards Andy.

PS did you notice any scoring on the OD of the crank where the seals contact, as this could chew up the new ones.

[kevin j]

two cautions: I would not run without gearbox oil, as even with no load everything is turning, just not dogged to the output shaft. Second, you might need to run if for several minutes probably to see the effect. Once a film of oil is sucked into engine via seals or via normal premix inlet, it takes quite the time to purge out. SAE research tests with radioactive traced oil showed rapid decreases in the oil effect in seconds/minutes, but some traces still there as long as 30 minutes.

You could spray some water or wd40 on the alternator side so see if sound changed for air leaks. Since you suspect oil side leak, and deending on what you run for premix oil, maybe run on gearbox oil and see what the sound and exhaust smell are like. Then change to synthetic premix 2 cycle oil in the gearbox. If the exhaust now smells way different like a modern bike, might indicate it is sucking in from the clutch side seal.

Are the main bearings in good shape? loose mains tends to suck through seals, and drive the ignition points settings goofy.

kcj

[andy.t]

OK, Kevin is correct in what he said,its not the best of my ideas,but I would say if the bike is your sons pride and joy then dont try it,if its going to end up getting busted for spares if it looks like a serious engine rebuild then I would still give it a quick kick over with no oil just to see if it fires up.But then thats just me doing what I do.