Is a piston kit worthwhile?

[mikecotterill]

Been having problems with an fs85t combi engine that was running bad. I've stripped it down and found the piston scored, is it with spending 30£ on a piston and giving the bore a quick hone? Or does it generally not give good results?

Thanks mike.

[Jonesie]

Looking at the state of that piston you will need to replace the Pot as well.

Has it been run on neat fuel?

[mikecotterill]

Don't know to be honest o bought it second hand and it wasn't till I put the pole saw and extension on I got from you recently I realised something was wrong. The bore feels ok to the touch except for a bit of a "bur" hence thinking of a piston and a hone. Out of interest how much are your kits?

[Jonesie]

I'd have to check on the work computer, send me a PM or email and it will remind me in the morning to have a look for you.

[leedeerman]

Thats a proper sieze up mate, you can replace the piston and pot but you need to split and wash every part of the crankcase to get ALL fragments of metal out or it'll happen again, its not worth messing with it, spares bin for it!

[rorymoon]

I'd have a go for £30 had a couple of saws in similer states and done exactly what your saying it can be a gamble but as long as theres no real damage to the pot just pistion residue then it's allways worth a shot in my book, was it still running before you took it apart?

Edited March 12, 2011 by rorymoon
cant spell to save my life.

[mikecotterill]

Yeah it was running before I stripped just seemed "not right" hence the strip down. As above for 30£ I'll probably have a go, it won't get much use anyway.

[ScotClayShooter]

I would have a go, But Try to clean the pot without honing.

2 strokes only have a thin layer of Chrome/Nikasil and a re not meant to be honed and are meant to wear out many pistons before the bore goes.

 

Some strong toilet cleanes have Hydrachloric acid and thats better for cleaning off the Aluminium. Mr Muscle oven cleaner works. but may take a few very careful applications, As in you dont want to get any on the exposed Aluminium parts of the pot like the exhaust and inlet ports.

[rorymoon]

For barrel cleaning I use wet n dry paper with a fine oil, it can take a while but is very hard to go to far this way and dose give a good finish.

[spudulike]

Clean the bore chemically - any acid will remove the aluminium and leave the nikasil plating and a light hone with fine grade wet and dry will sort it. Fit a new piston for £25 and the job will be a good one.

 

Just be aware why the thing seized in the first place, if it has an air leak then it will happen again so a pressure check is worthwhile to ensure it doesn't happen again. 9 times out of 10 it is no oil in the fuel or old fuel oil mix that kills these engines.

 

The old piston looks heavily seized but have sorted worse in my time:thumbup: