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:smt013 :smt013 :smt013 :smt013 :smt013 :smt013 :smt013 :smt013 :smt013 :smt013 wow this is annoying

whats the secret to getting the pistons back in the bores? do you do all 4 at once, or 2&3 together first? or 1&4 ??

never done it but it can be done from what ive read. There are compression tools to help you do it.

surely there isn't space to use them? Given up for the day now, it's beer o'clock

i think when i did it i did 1 and 3 first but it is possible with patience you have to be careful and squeeze the rings in 1 at a time on each piston slowly working your way down, i also put some oil on the bores to make it easier.2 pairs of hands might make it easier, but just be careful not to damage the rings.

there is a really easy way to do this but it reqires a bit of lateral thinking


Place the barrel upside down on your bench and fit each piston with conrod attached into each bore one at a time.............now lower the crankcase half onto the barrel feeding the conrod big ends into the crankcase use a block of wood or something similiar to support the crankcase in the correct postion and level to have it sitting on the barrel...............now fit the crankshaft into place moving each piston/conrod one at a time so that the crankshaft sits into it's place now trun the crankshaft and move the pistons in and out so that the bigend finds it's crank pin and bolt the conrod cap into place............fit the gearbox and any other bits and lower the crankcase bottom half into place................bolt it up and turn it over making sure the barrel does not fall off.............easy really

cargo wrote:there is a really easy way to do this but it reqires a bit of lateral thinking


Place the barrel upside down on your bench and fit each piston with conrod attached into each bore one at a time.............now lower the crankcase half onto the barrel feeding the conrod big ends into the crankcase use a block of wood or something similiar to support the crankcase in the correct postion and level to have it sitting on the barrel...............now fit the crankshaft into place moving each piston/conrod one at a time so that the crankshaft sits into it's place now trun the crankshaft and move the pistons in and out so that the bigend finds it's crank pin and bolt the conrod cap into place............fit the gearbox and any other bits and lower the crankcase bottom half into place................bolt it up and turn it over making sure the barrel does not fall off.............easy really

You're assuming -

a) he has the engine out of the frame, and

b) he has split the cases

What if he's got the engine in the frame and / or has just taken the head off without dismantling the bottom end?

I put 2 in at a time, squeezing the rings with my fingers.
I had an extra pair of hands to wriggle the top end about for me.

fiddly but not too bad.

Unless new pistons rings and gudgeon pins were fitted or a new base gasket..............there would be NO reason to remove the barrel in the circumstances of still having the engine in the frame even then why would you replace those items as part of an engine refresh and not continue into the engine and give it some new bearing across the crank and inspect the gearbox................so I await news of the reason for removing the barrel in the first place..............

Either way my method works and is very much easier than the 2 at a time method................lest ye not forget not only do the pistion rings need to be compressed but they need to be held in the correct position in relation to each other............

whilst you're in there...

i've got the engine out, and am planning on doing hg and cam chain and shims. how much extra would I be looking at to split the cases, and check all the bearings and gears etc. It doesn't jump out of gear, but does get quite a few false neutrals. I can then see myself ending up with a rebore, then I might as well big bore, then new carbs (fcrs) etc. £££££££££££......... I imagine the actual plain bearings are cheapish, but then it leads to pricey gears, etc.

Engine's done nearly 40k.

thoughts?

i'm the middle of changing the rings due to low compression, engine is still in the frame

good luck.................it's not the way I'd do it

cargo wrote:good luck.................it's not the way I'd do it

Ain't that the truth, it's pretty easy to remove and replace the motor and a whole lot easier to work on the motor on the bench.