Splitting the casings

[Cathal]

Ok, i got everything out, now all i need to do is open the casings, How can i do this properly without damaging? I got a heat gun if that is any use,

Please help, I don't wana damage anthing,

 

[Cathal]

btw there was oil on generator side that means one of the seals was bust yea,

 

[CrossRally]

First you need to remove all de screws in the casing to split.

second: You take a gas burner or heat gun then you starting heating up your casing on the left and the right sides. Then you also heat the engine pipe on top of the casing. If your casing is at the good temperature you take a wooden hammer (not iron hammers) and then you ticking @ your crankshaft.(turn a nut on before you get ticking a the crankshaft, always ticking horizontal or else you might ruin your crankshaft)

If you do it right the casing will fall apart. Then ticking your oil seals out of the casing and the bearings if they are left in your casing.

 

[Cathal]

ok, i got the casings off useing just a heat gun and no hammer hehe, not must get the bearings out, whats importamt when putting everyting back on?

 

[CrossRally]

are the bearings still in the casings? You can tick them out with a pipe or something else and a hammer offcourse. Also ticking the bearings out of the casings.

Then clean your casings with petrol, or terpentine. Then you need new bearings.

I don`t know what bearings you need for your setup. Mostly your need C3 bearings for the crankshaft. If you have a tuned evo, mhr speed like that(70cc), you can beter use c4 bearings.

Then if you have the good bearings. You lie them on een heat plate so the will much bigger. You need to putt the crankshaft in the refrigerator to schrink. So the bearing fit on the crankshaft. Now you be able to put the crankshaft back in the casesing.
Remove first the old gasket. Then again you heat up the casing (where the bearings must placed) First you could stick the crankshaft in the big side. Keep the crankshaft straight, so it will be placed straight in de first casing. Let it cool down so it will getting fixed. Then place the new gasket on the big casing. Then heat up the small casing. Then place in straigth about the other casing en press it too the big casing. Now fix the bolds again in the casings. Now you need to `center` the crankshaft. Take a wooden hammer, or rubber or plastic. First place one nut on the variators side, and a second nut on the ignition side. Then tick a few times on the left and on the right sides. Now you probable turn the crankshaft then before. If you can turn te crankshaft 3 or more times then it its good placed. Then put the bearings back. But look good, because put them not to deep. Or else the bearings will not be lubirated. Now you can boulding up your engine.


P.s leuk howt0 voor in het engels.

 

[David]

Pakking = Gasket.

 

[CrossRally]

Pakking = Gasket.

dank je, ik kwam er niet op. Zal het even editten.

 

[Cathal]

ok i don't understand how you center the crankshaft, I have a gilera 172, so different bearings but don't matter, How do ya center the crank? Lets say i have new bearing on and crank is in position it's connected to both cases and in position, Then what do ya do?

 

[Browni]

But look good, because put them not to deep

You can't push it too much, you can push it to the edges!

 

[Browni]

ok i don't understand how you center the crankshaft, I have a gilera 172, so different bearings but don't matter, How do ya center the crank? Lets say i have new bearing on and crank is in position it's connected to both cases and in position, Then what do ya do?

Cathal

I've already write it down the crankshaft installing somwhere, but I insert it again, the exact values is for the Piaggio 50 cc engine with original type bearings!

Remove the crankshaft from the Piaggio crankcase, first you remove all of the parts from the two axle I don't detail it (flywheel, variator) then you remove the crankcase screws, after that you heat the each side of the crankcase where the bearing is with a heating gun. Then you use a crankcase puller (at the heated side) or an universal puller with home made adapters, but never stretch the crankcase everywhere even the surface where the two half touch each other. so when you push out the crank from the each side then, you can do it the same method at the other side. Removing the bearings from the crankshaft needs a special two arm bearing puller (or two very soft wedges).

Now I don't detail the cleaning and other things, so the reassembling: There are two way: 1. if you put the bearings onto the crankshaft first, or 2. when you put the bearings into the cases first. The first is the easiest, and the second is the reccommended by the manufactures.
All of the two method maybee very similar. I write the 1. method. So you can heat the bearings with heating gun (and not with fire!!) you can put the crankshaft to the freezing if you want more easier job. So you can put the 2 bearings to it's end place. Then you cool down the crankshaft and heating the each halfcase, so you can put the crank to the halfcase, then you put the positioning washers and put the Loctite to the sealing surface, then you can make this on the other halfcase. After that you can assembly it, but even if the crankshaft falls into it's place maybe it can be tense. So you need a crankshaft assembly tool (this tool pull, the crankshaft to it's place -> a very simple tool, like a very thich iron sheet with holes). then you can tighten the crankcase srews crosswise (don’t use the original crankcase srews for the pulling together). You can test the rotating before you put the oil seals in their place. If it rotates very easy you can check it's axial play: this is 0,10-0,12 mm if the crankcase is hot and this value must be 0,06-0,08 if it’s cold, if it’s less than 0,02-0,03 you can split it and reassembly again!

 

[Cathal]

ok i know how to put bearings back in, Cool crank heat bearings, I already have the crank out and the bearings out, the bearings stuck to the casing so easier to get out,

U said don't use same screws why not? And i understand what u are saying only thing i don't understand is the figures i.e 0,10-0,12mm i don't understand this,

And what is the crankshaft assembly tool, can ya do it without it?

 

[Browni]

ok i know how to put bearings back in, Cool crank heat bearings, I already have the crank out and the bearings out, the bearings stuck to the casing so easier to get out,

U said don't use same screws why not? And i understand what u are saying only thing i don't understand is the figures i.e 0,10-0,12mm i don't understand this,

And what is the crankshaft assembly tool, can ya do it without it?

No, no you misunderstood (or I write it bad) you can use the original srews, but not for pulling the to half case together, cause you can tear out the thread from the case!!

It's very hard to put together the two half if you don't use a puller!

The 0,1-0,12 is for the 50 cc engine, for the bigger bearings like in the 172 cc engine this value is bigger.

This value is for the axial play of the crankshaft, when you finish the reassembling you can measure the axial play!!


I draw you a very simple drawing

 

[Browni]

ok i know how to put bearings back in, Cool crank heat bearings, I already have the crank out and the bearings out, the bearings stuck to the casing so easier to get out,

U said don't use same screws why not? And i understand what u are saying only thing i don't understand is the figures i.e 0,10-0,12mm i don't understand this,

And what is the crankshaft assembly tool, can ya do it without it?

Here is the pic (this is the axial play):

ANd here is the crankshaft puller/assembly tool (with this tool, you can push out the crankshaft and you can install the crankshaft) this tool is a big thick metal sheet with holes, and one big screw: