stuck flywheel!

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steveffs
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stuck flywheel!

Post by steveffs »

Hi. I am starting work on a kangaro for the first time, I am trying to take off the flywheel to get access to a faulty stator. I have undone the main nut and have taken out the spring washer but even using a flywheel puller and impact driver I can't get it to budge. I am being a muppet? is there something I have missed? any ideas would be helpful.

Ta. Steve.
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Re: stuck flywheel!

Post by EVguru »

What kind of 'impact driver'?

I have found one flywheel that was extremely tight, the tapers being the most perfect I've ever seen.

You might need to use heat to expand the flywheel taper, but that heat has to be applied FAST. You need to create a differential expansion and you won't get that by heating the flywheel slowly.

With the puller good and tight, try pouring on copious amounts of boiling water. If that doesn't work, you may have to move to flame heating. Fill the holes in the flywheel with clay to protect the stator. A big propane burner, or even oxy-propane or oxyacetylene torch might be needed.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
steveffs
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Joined: 31 Jan 2016 18:23
Location: epping essex

Re: stuck flywheel!

Post by steveffs »

Hi. been trying with a Air Impact gun running off a full 50l tank, Gun set on the highest torque setting. I know its a mid range set up but I am surprised its not budging. have put the engine on its side and filled the hole with plus gas.
penman
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Re: stuck flywheel!

Post by penman »

Hi Steve,
For what it's worth I agree with Paul's suggestion. I had this exact problem on a Velocette LE some years ago and I'd been faffing about with it on and off for days with no success. In fact I was beginning to worry about damaging the threads on the puller or the flywheel. Eventually I tightened up the puller as much as I dared and then hit the flywheel with a propane blowtorch. After just a few seconds there was a faint "crack" and the flywheel was loose. It wasn't even all that hot to the touch and there was no damage to anything else.

I'm not sure this does the magnets any good!
Good luck,
Joe.
1984 Moto Guzzi V65
1969 Honda CB450
1975 Triumph T160 Trident
2019 BMW F750GS Sport
1978 Morini 500
steveffs
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Re: stuck flywheel!

Post by steveffs »

Success. Ending up borrowing two 70cm long ring spanners from a mate who works on JCBs. Had Blow torch on standby but not needed as after a strong coffee and arm and shoulder rub from the missus it came of at the first attempt. Just needed massive leverage. Thanks for all the advice. Now to box it all up and send off to NLM for a refurbish.

Steve
julianharty
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Re: stuck flywheel!

Post by julianharty »

Thanks to a couple of suggestions here I managed to unstick my seemingly welded-on flywheel rotor. I'd already tried an industrial battery-powered impact gun, and the bolt in my flywheel puller was starting to bend! What worked for me in the end was a combination of using boiling water (about 2 litres) poured on the flywheel combined with using the impact gun to screw in the bolt of the flywheel puller. After less than a minute the flywheel was loose (and too hot to hold for a while).

I was then able to find and fix the poorly soldered wires for the red-wire for my split-tap stator on my old pre-electric start 350.

Thanks again for sharing tips and experiences.
julianharty
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Re: stuck flywheel!

Post by julianharty »

A quick note to say how much I appreciate this forum. I had another engine (from my Kanguro X refurbishment project) with a flywheel that refused to come off when I used the puller. After some faffing I checked the forum and found this article. Then I noticed I was the last person who updated it over 14 months ago. That reminded me of how I'd managed to remove the last engine's rotor, so I tried the same technique on this engine and it worked again. So 2:0 to for the forum versus the stuck rotors. Thank you all. Let's see if I remember or if I end up checking here again for my next engine... :)
Exmoor beast
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Re: stuck flywheel!

Post by Exmoor beast »

I always coppaslip ( love the stuff!) on the flywheel removal tool threads and on the bolt where it bares on the crank, when you nutgun it off it helps by being quicker and applies more torque. Did mine the other day and the alternator loom was nearly rubbing on the belt, could have been nasty!
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themoudie
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Re: stuck flywheel!

Post by themoudie »

The STORY so far! On Paul Compton's YouTube channel "Cambelt change on a Morini 350."
"Aye Paul, thank you for the clear and informative video. Any suggestions for tackling the job after somebody has used a 'Loctite' type material on the taper? :¬( It is white in colour after curing (inside of generator nut threads). I am using an air gun and extractor as you do. I have also used the extractor, locked by a 18" adjustable spanner and applied torque to the set screw using the impact socket and a 600mm bar, resulting in twisting the 12mm set screw! I have also applied heat with a hot air gun to the central boss of the starter motor/alternator rotor until it smoked after 4 minutes application and then using both the air gun and the 600mm bar methods, has so far resulted in no movement! Thank you for your time. BillR"

Paul Compton's reply: "I've had one rotor defeat me. It had the cleanest tapers I think I've seen on a Morini and had been fitted way to tight. I ground off the rivet heads and removed the magnet housing and then ground the hub off the crank. Grind over the keyway to avoid any damage to the crank. Rotors are fairly easy to find, stators more difficult and/or expensive."

Todays reply from me: "Aye Paul, thank you for taking the time to reply to my query. Further developments today, before receiving your reply. After heating the area around the rivets, evenly, with a gas torch (MAPP torch) until the metal was a dark red/black, I tried the extractor, with the air gun and had no success. So, after reheating again applied the bar and sheared the 12mm 8.8 HT set screw!!!**********!!!! Now to extract the extractor from the rotor centre! I have left hand drills to remove the broken set screw and will likely give the grinding technique a try. As an aside; the extractor appears to be 30mm across the flats, but when measured exceed this by 0.4mm! So, a little patience and removal of metal should enable the use of a good ring spanner rather than the worn socket or 18" adjustable spanner that I possess. The socket due to a lack of depth, only grips half the face of the extractor body flats and this too could be rounded off unless I am carefull. I note from the MRC forum "RE: Stubborn flywheel removal", 16, July 2017, that plumbers freeze spray worked, so will give that a try before applying the grinding wheel! My regards, BillR" Tomorrow is another day and I will give it another try! :twisted: :twisted: :twisted: :twisted: :twisted: My regards, BillR :wink:
Vitesse
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Re: stuck flywheel!

Post by Vitesse »

Bloody hell! I thought mine was bad (kettle of boiling water, hot air gun, 3 foot extension on extractor bolt, mallet blows to flywheel, etc) but now see I had a doddle.
mbmm350s
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Re: stuck flywheel!

Post by mbmm350s »

Many years ago I was down at Phil Smith's in the dingy back streets of Croydon. He had an engine in for repair as the end of the crank had snapped off.
Actually what happened was the punter being unable to shift the rotor thought he might be able to spin it off by starting up the engine :oops:

Bill, I would take care with naked flame, I have never used that because I worry about cooking the windings. I have used rags in boiling water
as well as a whack on the extractor though don't go mad with it as it might damage the bearings- I didn't care as the engine was being rebuilt anyway.
May be you could get a better bolt for the extractor as well.

Generally whenever I had something stuck, i would call up my mate Jim. Most of us have a mate like Jim, hands like shovels and an ability
to do things like drink copious amounts of tea (kettle required) and shift the un-shiftable.
good luck !

Mark
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Re: stuck flywheel!

Post by EVguru »

Rotors are relatively easy to find compared to stators in good condition.

A mistake that many people make is thinking that just getting things hot is going to help.

Metals expand when heated and different metals expand at different rates.

When you can take advantage of the different expansion rates, things are going in your favour. Heating up an alloy housing to remove a steel bearing for example. Get both to 125C or so and there's a good chance the bearing might just fall out, depending on how tight it was fitted in the first place. I usually find than you need to lightly tap the bearings out of a Morini crankcase, but new bearings at room temperature will just fall in (no need to mess about chilling the bearings).

Where the metals have the same expansion rate, you have to create a temperature difference. It's not about how hot you get it, but how hot is is compared to the other part. You can try and heat just one part, but do it too slowly and you'll just end up with the heat being conducted from one into the other.

At some point the time being taken and the risk of collateral damage may mean that another solution is more suitable.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
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themoudie
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Re: stuck flywheel!

Post by themoudie »

Good evening and thank you all for your responses and advice.

The reason for heating this rotor is that there is a suspicion that some type of thread lock, filler or similar industrial adhesive may have been applied to the crankshaft taper. Loctite 'Red' stud lock weakens at 250°C and heating components is the 'official' method for releasing items locked by this glue. An alternative to this is to soak the component in chlorinated brake cleaner. This from DIY trials weakens the bond but doesn't remove the glue. However, if the components are then heated, phosgene gas is produced and it WILL KILL YOU! So, I haven't used a chlorinated brake cleaner.

To have another crack at removing the rotor, I first had to remove the extractor and the sheared set screw.

After much contemplation I phoned a friend. Before he arrived I fabricated a rotor holder from 2 pieces of 3mm x 40mm strip steel held together with a 8mm set screw and nut and with two prongs made from 40mm x 8mm bolts and nuts. The latter where inserted into two of the three equidistant 8mm holes in the starter motor clutch drum on the outside of the rotor and the end rested on the concrete floor. When my friend arrived, the scheme was outlined and using a 30mm combination spanner, with the ring on the extractor and another large double ended ring spanner over the open end, giving us a good 55cm lever. I then held the bike down, whilst my friend put his not inconsiderable strength into slackening the extractor and succeded. As a professional motor engineer he reckoned that it was tourqued to a similar value to that of an air-cooled Beetle rear drive shaft nut in the hub (~136 ft/lbs) :shock: I used a scaffold pole for mine! :twisted:

In conclusion, it appears that the P172 MCA M27x1.25mm and M30x1.5mm double ended extractor is not "up to the job". I shall be investing in an extractor with better quality steel used in it's construction and will report on whether this has been successful, or whether I have had to resort to Paul's grinding the rivets and then the rotor hub off the taper method! In the meantime the bike is on it's sidestand with a plasticine cup formed below the taper and soaking in a penetrating oil and diesel mixture.

Good health to you all, BillR
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themoudie
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Re: stuck flywheel!

Post by themoudie »

Success! :D Popped the rotor off today on the K2.

Borrowed a Sealey high tensile steel extractor (M27x1.25mm) from my mechanic friend and having soaked the taper in 3in1 release oil and diesel using a plasticine cup to retain it, overnight, with the bike on its sidestand. Put the bike back on the centrestand, applied liberal amounts of copper grease to the extractor threads and between the set screw end and the crank. Backed the set screw a quarter turn off from the crankshaft end then applied the air gun at full power and the rotor popped off after less than 15 seconds! One happy chappy! :D :D :D :D :D

It appears that the combination of a good taper, maybe an over torqued retaining nut and a cheap extractor, not made from high tensile steel and with a coarse metric thread set screw, rather than the fine metric thread of the Sealey tool set screw were the cause of my woes! :?

I hope this helps others who encounter this problem.

Good health and my regards, BillR
mbmm350s
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Re: stuck flywheel!

Post by mbmm350s »

Nice one Bill,
I was getting ready to send Jim your way.
Mark
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