Author Topic: EW350 Clutch/Flywheel Torque Settings  (Read 3555 times)

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Offline 916nik

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EW350 Clutch/Flywheel Torque Settings
« on: 18 Jul 2012 at 10:52 »
Hi, I am a complete newbie to all that is Douglas and jumped in the deep end by purchasing a 1926 EW350. On my first ride the flywheel/clutch decided to undo itself from the crank shaft. I was lucky enough to be stationary at the time and all the springs and associated bits just fell onto the running board. What I am now needing to understand is what are the torque settings for the bolt/nut that holds the flywheel to the crank and also how tight to you do the spring cup washer/center nut (not sure of the correct term) locking ring thing up? Thanks for your help!

Offline RA23

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Re: EW350 Clutch/Flywheel Torque Settings
« Reply #1 on: 18 Jul 2012 at 20:29 »
Hi  Newbie hundreds maybe thousands of flywheels have left home and headed in different directions,like the ten pound Poms in the fifties, the torque is not  likely to be the problem but taper and fit will be ( loctite or some other gorilla snot and a tight nut is only a very temporary fix (not recommended ) and is bad engineering practice, firstly apply medium lapping paste to crankshaft taper and lap flywheel left to right several times and at quarter turn increments repeat the process after one turn wash the tapers ( kerosine ) and look for contact points should look like a bead blasted finish then apply sparingly engineers marking blue, if not available use a felt pen or a soft lead pencil to determine contact points, its a time consuming process left right several times quarter turn etc wash, inspect ,blue, inspect, if necessary use a coarse paste then medium then fine to finish, you need to have at least 80% surface contact  if  it's not looking hopefull the next step is to re machine both tapers and then the blueing and lapping again process begins THE MACHINING OF THE TAPERS IS SERIOUS WORK (NOT FOR BEGINNERS) FOR EVERY COUPLE OF THOUSANDS OF AN INCH REMOVED THE FLY WHEEL WILL BE TRYING TO MAKE LOVE TO THE CRANKCASE ( NOT WITHOUT A WASHER I HOPE )THE PROBLEM HERE BEING  THE PRIMARY CHAIN ALIGNMENT AND  FLYWHEEL BOSS ( MALE ) AND CRANKCASE BOSS ( FEMALE ) CELIBACY HERE  PLEASE, HOPE FULLY YOU WILL ESCAPE THE MACHINING  PROCESS REMEMBER  THE TAPER  DOES THE DRIVE NOT THE KEY AND AND A TIGHT NUT 60 FT/LBS SHOULD BE FINE  I AIM FOR 100% AND 75 FT /LBS ON MY OHV MOTORS if you were in Brisbane I could give you a hand, good luck Bob Barlow  RA 23.

Offline 916nik

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Re: EW350 Clutch/Flywheel Torque Settings
« Reply #2 on: 19 Jul 2012 at 00:27 »
Thanks for the advice Bob I will get lapping!

Offline 916nik

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Re: EW350 Clutch/Flywheel Torque Settings
« Reply #3 on: 30 Jul 2012 at 11:52 »
Lapping worked a treat! first run this afternoon and no seperation! thanks Bob

Offline Chris

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Re: EW350 Clutch/Flywheel Torque Settings
« Reply #4 on: 30 Jul 2012 at 13:30 »
Hi Newbie
  Everything Bob says about the taper making the drive and the importance of lapping between the flywheel and crankshaft taper is true but the jerk from a high speed change-down of gear at high revs on a steep hill can shake the best flywheel joint loose unless the nut is also tight. The problem in getting the nut tight is holding the flywheel while the nut is tightened. I made a tool for this comprising a pair of pieces of angle iron about 12" long pivotted about a bolt at one end. At the other end of each is a stud 1/2" diameter one being longer than the other to compensate for the overlap of the angle iron arms. The arms can then be spread and the tool applied to the flywheel so that the studs enter opposing spring holes in the flywheel. A deep socket to fit the flywheel nut with a standard 1/2" drive socket set Tee bar or better still a torque wrench can then be entered onto the flywheel nut between the angle iron levers and the nut simply tightened by applying equal pressure to the ends of the pair of tools. Chris.

Offline 916nik

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Re: EW350 Clutch/Flywheel Torque Settings
« Reply #5 on: 31 Jul 2012 at 12:17 »
Hi Chris,
I think a sharp change was what might have loosened the clutch in the first place. I got a mate of mine to grip the flywheel when I tightened it but the tool sounds like a simple one to make and will allow me to obtain the correct torque setting. I am lucky enough to have access to a well equipped workshop at my place of work so tools like torque wrenches are easily borrowed. Makes this type of maintenance a lot cheaper. I will make up the tool you described as this will allow me to tighten the nut properly. Thanks for your assistance!
Regards
Nik