engine rebuild

Hey I rebuilding a puch 1 speed engine and I want to know if I can split the caseings if I don't take the flywheel off. I need a special tool 050.7012 flywheel extractor. And if I still need to get it off does anyone know another way to get it off with out the tool? And it says later in the rebuild to dismantle the crank shaft to have tool 905. clutch hub puller tool to dismantle the crank shaft, I was wondering if there is any way to get around that either and not have to buy the special tool. I already got the flywheel nut off and it said I had to have a special tool so I believe I can get around these tools in some way. Can someone help me?

Re: engine rebuild

The only help i can offer is to suggest you either buy or build the proper tools.. or find a shop that has the tools and will dismantle those parts you need dismantled.

hmm.. dismantle the crankshaft?

What is the reason for this engine rebuild?

Re: engine rebuild

Well the reason for the rebuild is to change the two seals on the crank and to change the seal on the counter sprocket. I was wondering if I even have to take the flywheel off to spilt the case. And I was thinking I could just use an automotive puller and I was wondering if anyone has ever done that.

Re: engine rebuild

Gregory Mcintire /

Don't spend your money on the special pullers. Get a standard universal puller at any hardware store like I use shown in the pictures. To pull the flywheel, bolt a piece of strap iron onto the flywheel with 5mm bolts. It will need a hole in its center large enough for the puller's main screw to go thru.

For the clutch hub it is even easier. Screw two 6mm bolts into the hub with a washer on each and use the same puller as shown.

The tapered shafts in this engine are very wide tapers meaning you don't need a lot of puller pressure. A gentle 'tap' on the puller screw (once it is tightened) will usually pop the flywheel and clutch hub off with ease.

I just scrounged the parts out of my junkbox to make these pictures. Hope you get the gist of what I am trying to say.


Re: engine rebuild

ok.. as far as dismantling the crankshaft, i doubt you will need to do that.. you had me wondering.. no way in hell can it be done with a hammer and a vise.

These little bikes are kinda tender. I dont know about your specific model but as far as using an automotive puller on the flywheel, it depends on the design.

If the proper puller pulls/pushes on the center hub and shaft of the wheel, then whatever you substitute should grab it in the same place. The wheel probably has a threaded hole into which the puller screws, providing lots of force right where it's needed. If you try and pull on the perimeter of the wheel you might tweak it since you are applying force far away from where it should be applied.

Careful examination of the manual's exploded view of the engine sometimes tells you what you can get away with.. (or ask a mechanic who works on those things). Splitting the case may be possible but if you are replacing crankshaft seals, i dont see how you can replace the one between the flywheel and the crank without eventually removing that wheel.

btw.. A good way to damage the oil seals and bearings on a crankshaft and other things is to use the wrong tools when assembling/disassembling the engine.

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