Modern Vespa

So I got the nut that retains the flywheel off and the flywheel itself will not come off. Any suggestions??

If it's threaded on the inside where the nut goes, get a flywheel puller. Otherwise there should be a channel for a circlip which, when installed, will give the nut something to push on as you loosen it, removing the flywheel.

EDIT: I highly suggest NOT using a piece of wood or metal to pry the flywheel off. I used to do this all the time and I'm amazed I didn't damage the engine case. Also, NEVER use a three prong gear puller. Trust me.

Yeah - this is a common problem. Your flywheel has a magnetic hold and in your case, it seems quite strong. This same thing happened to me once. The nut came off, but between the magnetic hold and a bit of rust, the flywheel wouldn't come off. So, I GENTLY used some leverage with a 2x4 and lightly tapped at the crank arm threads (with the flywheel nut on loosely, so that the crank wasn't damaged). Eventually, the flywheel popped off. It took some time and finesse, but it worked. Don't be too rough though...

Let us know how it goes.

Jason

You're not actually supposed to remove that nut.... sorta.


See, the nut is attached to the flywheel, in that it's held to it by a big circlip ( that you WANT to be there, in place solidly ).


In UNTHREADING the nut off the crank, the nut should be pulling the whole flywheel off with it. It's what they call a "self-extracting flywheel".... compared to flywheels like on P200's or Lambrettas or whatever that require a special tool- a flywheel puller ...to do this job.

*sorry to dredge up a post but....


i need to replace my circlip. it is no longer flat. is there any thing i should know besides its 3.5mm wide?

you know all these bearings, circlips and woodroof keys are all standard sizes. I have been picking them up at the local tractor repair centre in their parts dept. I bring in the old ones and we match them up cost almost nothing compared to the Vespa dealer and they have it all.

So what do you do if you've tried a few circlips, but the nut always squeezes them out of the groove, rather than pushing off the flywheel?
(Yes, the groove is clean).

- Eric

Maybe you are already doing this, but once you have the nut backed up against the circlip you can tap lightly on the nut a few times. This can help break the frozen crank/flywheel taper connection.

so no probs using standard size, not metric?

No, No.

There are standard Metric and standard American sizes - Vespa didn't invent their own.

So, you can find the right one from any general supplier, so long as you know what the size is. Odds are it will be Metric, [edited typo] especially for Vespas - it's probably the same as the one in your washing machine or oil burner. I'm not familiar with the exact standards for Woodruff key sizing - they MAY be the same American or Metric, with different nomenclature in each system, or they MAY actually be slightly different sizes, like a 9mm nut vs a 3/8" nut. I have tried tapping - the circlip just sort of gets a little conical and springs out of the groove. I've tried different circlips and a new nut, too.

- Eric

you are right they come in standard and metric so do the woodruff keys. I used the term standard loosely sorry to confuse. I had this issue when I first got this super(stored 20 years) I didn't know it but the woodruff key was sheared. I went down to the tractor dealer and bought several spring clips both standard and metric that were close I think I ended up using one of the standard ones that was little harder fit. I also knocked on the nut under pressure, tried holding the clip in with plyers as I backed off the nut and I may have tried to heat it as well under pressure. It hadn't moved in twenty years so it was a mission but did come off. As a last alternative I have done this before as well. On one of my 150s a few years back the flywheel had two of the inspection holes for some reason it was made that way. I manged to get a two prong puller in and pulled it out. You can drill directly across from the other hole but you have to make sure it is lined up so you don't hit the coils. there is a spot and can be found by looking through the inspection hole. Last resort. Spray it with Wd 40, a little heat, keep trying clips all before drilling. good luck

Get the tool:


http://www.scooterwest.com/item_detail/Tool-Fly-Wheel-Puller-Vespa-Piaggio/1963/

Its cheap and you will think it pays for itself the first time you use it. And I used mine about six times the first time I tried to do anything with the stator plate. It's too good not to have.

You need to put a screwdriver in the space between the eyelets of the circlip. This will force the circlip to stay in the groove and it leaves enough room to a 14mm socket. This will only work if you have a flywheel holding tool because you will need both hands. Tor2ga - that tool doesn't work on those flywheels.

Screwdriver - I'l try that next time.

Thanks,

- Eric

Its not a PX flywheel with the tread on the inside?

Well...

The OP in Sept. '08 seems to have had a PX motor in a '68,

-- BUT --

The thread resurrector was asking about an earlier "self-extracting" flywheel, so...

Depends on how you look at it.

- Eric

Oh yeah. Missed the dates and resurrection. Gotta start driving a holly stake through their hearts.

Or firing aluminum bullets.

No, no, silver bullets!

Okay, if I can have silver case halves, head, and body trim!

Doh. Double post.

my question was answered here:

If the circlip keeps popping off, try putting a little tension on the nut against the circlip, then tap the flywheel around the rivets with a soft hammer a few times, then turn the nut 1/8 turn and tap again. Repeat until the flywheel becomes free of the crank.

Sooo...

I have a VBB... the circlip is in the slot and actually kida bowing out...
My nut is uber stripped now. I guess now I understand why I could loosen in about 2 turns and it stops and then tighten and it stops and vice versa. My nut is mostly stripped because it was soft with rust. A 14mm six point is the last thing to be on it. I take at this point, about tow turns "off" there is a lot of tension on that little clip?? So do I thump it with some wood? Heat it?

I was working on a 2hp Johnson and the flywheel just popped off when I walked away to scratch my head. What a sweet sound.

Personally, since it's been sitting, and may be really on there, I would use a judicious amount of heat (remember that you don't want to heat the magnetic portions enough to reduce the magnetism) and a fiar amount of tapping and patience.

I would also try some good penetrating oil (I like KROIL) - that stuff can really get into small spaces, and can sometimes help loosen taper connections like these. Leave it on for a few days at least, giving it a few good taps every now and then.

- Eric

Thanks... The nut is destroyed now... there is a small area near the clip that is not. So if the clip were off, the nut would come off, but then a traditional puller would be used? I have traditional puller, not sure if I can back the nut off, and remove the clip though.
While you are on this... I am a total newb to this Vespa does the flywheel fan rotate clockwise or counter clockwise? Can't tell on the you tube vids.

Thanks

The crank turns clockwise when looking at it from the flywheel side.

It's been a while since I've had mine off, but I just remembered that after I had more trouble than I needed with that darned C-clip, I splurged and dropped about $20 on a small puller (has to be darned small to fit the screws right around the shaft), which I keep in the tool kit on the bike, in case I have to pull the flywheel on the road.

- Eric