OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines How do I remove this?

I'm stuck.I just want to pull this apart and I don't want to break anything.
See attached photo.I have circled the bit I need to remove.
Thanks

Andy, that is the blade boss. It is firmly pushed onto a taper on the crankshaft, and it takes a special trick to remove it. The usual way of applying the special trick is to rest the boss on a heavy piece of metal like an anvil, and hit the opposite point on the boss hard with a heavy hammer. Anvil and hammer-face both have to be parallel to the surface of the boss. It may take several hits. There may be an advantage in rotating the boss a bit between successive hits. Remember, the idea is to deliver an impact, to shift the inner surface of the boss momentarily so it can spring off the taper, so a very few, hard heavy hits is way better than playing pat-a-cake with it.

Thanks for the tip Grumpy.I will try it tomorrow.
Lucky I have an anvil

I'll state the obvious Andy: do not allow the anvil or the hammer to touch the aluminium crankcase when you do this. You may need a wide, flat steel packer in between the anvil and the boss to make sure this happens, depending on how you set it up. Never use anything in between the hammer and the boss - it dulls the impact. Hammer speed is just as important as hammer mass, so hit it sharply. And, of course, wear safety glasses. Occasionally bits fly off things, even hammers.

My vice has a circular 'crook' in the back of it behind the fixed jaws. I just sit the victa bosses in it and hit them with the hammer, they pop off the crank pretty easy.

Basically you are hitting the steel to deform it so it will let go of the taper lock. They are not that higher grade of steel and can be damaged, take care with the corner where the blade disc sits. More so the power torque ones as they are thinner but you can flatten them to the point where they will split.


Not all full crank bosses are the same either. Depends what motor it is off. See blumblys thread on the cranks.

Some can be buggers to remove, others ocme off with barely a tap at all... I dont do it that often, I just sit it on the back cement door step and give em a good wack usually.

Mr Hammer and Mr Anvil were very helpful.Boss removed.
The conrod is really floppy at the crank end.Does that mean I need to look at the crank pin now?

Thanks

It sounds as if it needs a rebuild, Andy, but 2 stroke Victas are not my thing (anything with a built-up crankshaft isn't my thing if it comes to that). I'll leave it to Joe Carroll to discuss that one.

I just use two heavy hammers. Keep one hard up against it, just like an anvil, and give it a whack with the other. Works for me, but I love bashing things with hammers!!! lol

Just need to figure out how to get the pin out.Might need to borrow a press.
It's more an exercise for me just to pull it apart and rebuild it.If I get it back together and running,I might build a frame and make a go kart or mini bike for my son.It's been laying around in my shed for years(among other motorized crap)

If the crank bearings are really sad the main bearing can be replaced but you need specialised gear to push it apart and put it nack together cleanly and straight a really good idea to have a engine reconditioner to do that (Darryl and I were talking about that tonight actually!) they are very hard to get aligned straight.

The main crank bearings are a slide on and off affair, sometimes require a bit of encouragement using a suitable drift carefully to put them on, being careful only to push on the inner part of the bearing.

I agree. This job is extremely dificult. I've done this....once, although it wasn't a Victa crank. Since then I try to track down a replacement crankshaft.

Pressing apart, and back together wasn't the issue. It was getting it all to run true and balanced again, and at the same time, continually checking the side clearance on the conrod.

You have to put it between centre's, like in a lathe, and spin by hand. Use 4 dial indicators, 2 to check the runout of the two halves, and 2 to check for parallel.

VERY time consuming and frustrating to say the least.

I agree that is where the challenges are. The main issue, aside from the risk of making a mess of getting the crankpin to enter each counterweight straight, is the need to end up with the two main bearings in line with each other. The crankpin is just a parallel, it does not have a key or other device to align it, and even if it did, it wouldn't align it well enough. A combination of a good jig, and a lot of experience, is what it takes to get a decent outcome without having to correct a major error to get it straight. Don't even think about it without a proper hydraulic press - and I don't mean a glorified car jack, either - but you still need a jig, and some V blocks and dial indicators for checking and correcting. The correcting part calls for another proper jig.

See why I don't bother with built-up crankshafts? For a home repairer, they are not really a rebuildable component.

I think I'll just leave it as is and replace the broken piston ring.It's just not worth the trouble. It's only a bit of fun on my part to have a go at a lawnmower engine.I don't need it for anything other than something to do.
Thanks for the replies anyway.

Theres a guy not far from me that has a machine shop set up in his back yard.
I bought a crank cheap off eBay that he did for a customer that never got picked up.
He said he used to do lots and lots of Victa stuff when the motors were used on karts. He also made mention that another big drama with them was the crankcases were rarely square and parallel.
I suppose this is all stuff you need to get into if you want to double or triple the output of something thats rather 'rural' by design.

I could chase up his info if you want.


It would be considerably cheaper to just find another good used motor.