Nuovo Falcone flywheel removal, How!!

[criftycraft]

I am trying to remove the flywheel from my nuovo Falcone but progress is nil. I have made a castleatted box spanner to remove the outer lock ring but this will not budge it. Penetrating oil, much hammering and copious heat have failed to help release the thing. How does one lock the engine to stop the flywheel rotating whilst trying to belt this off. I have put it in gear jammed the standard broom handle through the backwheel spokes and simply succeeded in breaking a spoke nipple and slipping the clutch. Is an impact wrench the answer, someone must have suffered this problem and found a solution I hope.

[Guzzistaracing]

If I remember correctly the flywheel itself is not screwed on, it sits on a taper! Get a big extractor (or puller or what ever you call it) and pull it of. Bare in mind it is a while since I had mine off!

[Mi_ka]

Not screwed, at all? No locking/latching/pin mechanism to hold it in place ???

[pehayes]

First, I'm not specifically familiar with the NUOVO, but I am with the older singles. Guzzi has a tried and true flywheel system and I can't believe that they would have changed it for this model.

First, the castleated outside ring is LEFT HAND or REVERSE threaded. If you are trying to unscrew it counterclockwise, you are just making it tighter.

Second, the ring is NOT to be removed. It is an integral part of an automatic flywheel puller.

Third, loosen the castleated ring (clockwise) about one full turn.

Fourth, loosen the crankshaft center bolt which is NORMAL threaded (counterclockwise to remove). That bolt has a stout collar which will com up against the inner face of the loose ring. As you continue to loosen it, it forces against the ring and pops the flywheel off of the crankshaft. BE READY TO CATCH IT! Be prepared to use a LOT of force to remove this center bolt. Air impact works best. Probably in excess of 100 ft/lbs of torque. Once the flywheel is off, you can now fully remove the ring and the center bolt for easier reassembly.

Fifth, the crankshaft is tapered and the flywheel has a tapered central cone. There is a keyway which 'locates' or 'registers' the flywheel on the crank, but the holding force work is done by the smoothness and mating of the two tapers.

Sixth, when you reinstall the flywheel, you first lock down the center bolt. After that, you install and lock down the external ring nut. The fact that these two devices are threaded in opposite directions is what provides the crucial security locking of the flywheel. The system can't loosen up by vibration because any loosening action on one part is the equivalent of tightening action on the other part. Brilliant, Carlo! Built in puller and locking mechanism all in one.

Seventh, go join the discussion forum at guzzi-singles@googlegroups.com Lots of folks there with knowledge about these old ones.

You can download further advice and manuals here:
http://www.devce.demon.co.uk/falcone.htm

Patrick Hayes
Fremont CA

[Mi_ka]

Aha, now I understand the strange reports I once read of tricycle "furgone" lorry drivers chasing their flywheels in the streets of post WWII Athens: A lot of italian war bikes were left after the end of the WWII and almost all of them were converted to "furgone" tricycle light lorries. The low level of contemporary roadside mechanics messed things up and so unlucky truckers had their flywheels going loose in the middle of the road and in some occasions they had to chase the fallen off and fast rolling flywheel in the middle of the street!

[criftycraft]

Thanks to pehayes.
Thanks for the comprehensive explanation. I have read the suggested methods on the sites and in the workshop manual but my problem is that the castleated nut will not shift however much I attempt to twist it in a clockwise motion. It has obviously never been off since first assembled as there was not a mark on the castleations. I am having a half inch drive socket welded to my castleated box spanner and will hire an impact wrench to see if that will release it. Thanks again for your input.

[Guzzistaracing]

Sorry, I thought you had the nut and bolt off. Guess I did not read the post properly. The center bolt is right hand threaded and the castelated nut is left hand threaded like said above and the flywheel sits on a taper with a keyway....(I used a hammer and a driver!makes dents in the nut but it was allready done on mine and it sits behind the cover so I did not make the effort to make a special tool needed.)

[pehayes]

It is a wise choice to cough up the money and buy or make a proper tool. Sounds like you are doing well on the welding plan. You might also need some heat on the face of the flywheel to expand the threaded recess and thus release grip on that nut. Good luck and keep us posted.

You might wish to join the guzzi-singles@googlegroups.com We just had a racer in New England with a REALLY REALLY bad flywheel mounting. We all thought it might have been welded on in some way. It took a lot of heat, air impact wrench, and a full lexicon of foul words but it finally came off. You should go read the archives to see that story.

Patrick Hayes
Fremont CA

[criftycraft]

Patrick,
Thanks for your help, I have had the tool welded up so the next thing is to have a go with the impact wrench but as I am away on holiday for a while it will have to wait until my return. Having spoken with a couple of engineers who have tackled similar problems they seem pretty certain that the impact wrench will shift it. I have like you belted the castleations to try to turn it but to no avail save for minor damage to the thing. I will let you know the outcome after the impact attempt.
Best regards
Brian

[criftycraft]

Patrick and all others who lent an ear and a hand.
Just to be clear to all concerned my problem initially was undoing the castleated retaining ring nut in the centre of the flywheel. As I wrote earlier I made a castleated box spanner out of an old 1 & 3/4 AF box spanner to do the job of the proper tool. I am no machinist so this was achieved with a hacksaw, file and grinder, it took a careful bit of measuring but was fairly simple to make. Next I found an old socket with a 1/2 inch drive which was welded into the box spanner. Not by me, but by an expert welder. This then provided me with a tool I could use with a socket wrench with which I did attempt to remove the retaining nut but to no avail. All of my attempts at removal having failed I took the bike to the local garage and asked if they would try to remove the nut with an impact wrench. This was a battery powered but good quality tool which undid the stubborn nut instantly. Amazing! The workshop manual and info on the web do not allude to this being a difficult task and simply tell you to remove the retaining ring nut making little or no comment on the possible difficulty of the task.
Whilst there we then loosened the 29mm nut with the impact wrench and then a few bashes on the flywheel with a dead weight hammer and the flywheel came away from the shaft. Success.
Considering that it is necessary to remove the flywheel to change the dynamo belt let alone replace the kickstart spring and any other major engine work I am greatly relieved to now know that the flywheel is now removeable.
Thank you all for your help and I hope that my findings are of use to someone in the future.
PS. I have owned the NF for nearly 6 years (4000km on the clock when I bought it) and covered some 35,000km since with no problem apart from a gear selector spring and the kickstart spring. It is a great bike to ride provided you are not after fast acceleration and I love the way it goes about its business.
Enjoy your riding .
Best regards
Brian