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tightening magdyno bolts

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Hi all - found the magdyno on my mid-fifties ES2 had worked loose. Is there any way of tightening the bolts without removing the whole timing cover and re-timing the ignition? I really don't want to unless I have to! But the access is terrible.

I'm just getting lazy in my old age!

George

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It's just about possible to get at two of the screws...but best to remove the assembly, clean the thread, Loctite and stake properly.

 

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George, We 'oldies' may have lots of time on our hands in the near future, bite the bullet and do a proper  job.

Are the bolts the three  that hold it to the crankcase? my M50 has coil ignition, so may be different.

Regards John O

Thanks guys.Yes John. those are the three, neatly tucked in behind the magdyno chain drive.

You're both telling me what I know is right. I was just hoping there was an alternative. That's probably why it's worked loose in the first place!

I take your point, John, about more time on our hands. Keep well!

George

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I use square drive screws which I can then tighten with an Allen key. Most sellers of nuts and bolts can supply correct length. Then a little drop of Loctite 290 when properly tightened.

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I'm still trying to find a loophole! I notice that confusingly the good book states "Tightening of the bolts should be done after the the timing cover had been repaced and the chain has been re-tensioned." Surely this is the stage I shall be at when I've re-tensioned the chain? This means I should be able to tighten everything up with the timing cover in place. Is there a special spanner for getting to the bolt head behind the magdyno chain drive?

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The three bolts below the platform can be reached although last time I did it I think I had to use an open ended spanner from below the bike up behind the primary chain case. The timing cover stayed in place but obviously(?) the mag chain cover had to be off to key the chain tension be checked.

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George,

You're going to have to remove the mag to do this.

The four screws holding the mag onto the platform are Whitworth.  As Ian suggests, use countersunk head Allen screws with some Loctite.  Assemble the mag onto the platform and tighten these four screws; these are not used for any adjustments.

Replace the mag between the engine plates and insert the long bolt, hopefully your nut is on the clutch end.  Then screw in the 5/16" BSC (silly fine thread in aluminium) lock bolt loosely below this.

Replace the timing chain / sprocket so that it is firm on the mag taper, but not locked fully.  Partially tighten the large nut and bolt, just enough to grip the mag platform, use a lever to adjust the mag chain by gently pushing the mag backwards.  When you have the chain adjusted, tighten the large nut and bolt to hold everything in place.  Now tighten the 5/16" lock bolt and your mag is now secure.

Loosen the mag drive sprocket so that the mag can be timed i.e. points just opening at 5/8" BTDC with lever fully advanced, then lock it up. 

Now just check the mag chain adjustment so that it isn't too tight.  If it needs any chain adjustment do this by loosening the large bolt and lock bolt that holds the mag platform in place.  You shouldn't have affected the timing with this adjustment.

Whilst the mag is out, clean the points and check the gap, it's much easier when it's out of the bike!

Spring is coming and it is getting warmer, so it needs to be ready to ride when any lock down is lifted.

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All done.

Phil - the magdyno was not loose on its platform. It was the adjuster nut/bolt that had loosened plus maybe one pinch bolt so a full blown dismantle was not necessary.

In case any one else has the same prob here's what I did;

Undo and push to one side the reserve fuel line from the tank (for spanner access)

Drain oil tank (already done in this case)

Undo both oil tank conns.

Undo oil block from crankcase and remove c/w oil lines (for spanner access)

Remove timing chain cover

Push and hold magdyno with appropriate leverage to achieve correct tension and tighten retaining bolt plus pinch bolt.

Replace all in reverse order.

Start bike - all fine

Recheck chain tension.

Sorted!

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I really did think that it was the four countersunk fasteners which were the subject here as they can work their way loose. If the platform is moving then it's probable that  the engine is loose too. Tile to give everything a check-tighten.

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Sorry Richard if I gave the wrong impression. It was simply the bolts that are used to adjust the timing chain tension. . My initial query was whether I could get at them without removing the timing cover. The answer to the query is "yes" it is possible. And indeed, it is necessary as the timing cover has to be in place in order to adjust the chain tension. It all becomes obvious once one has to do it!

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Once again I was wrong. Apologies all round. Despite thinking I's tightened it all up (which idid) , after a 50 mile trip last week I've found the unit is once again moving slightly. It is indeed the magdyno/plate connection whcih is loose. Where can I source the recessed allen key screws and what length/tpi are they?

Thanks for the full description, Philip.

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George,

The countersink screws are 3/8" Whitworth x 5/8" long.  Have a look on ebay with the search: 3/8" Whitworth countersunk allen screws" and there are some at 3/4" long.  So you may need to file or grind the ends down.

Philip

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Thanks Phil. Found and ordered.

Let's hope they hold a bit better than the originals!

George

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I went through the same issue and bought a box of them on eBay  so have some spare, let me know if yours don’t turn up! 

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Thanks Dan. They're scheduled to arrive next Mon/Tue.

I'll keep you posted.

Cheers

George

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New countersunk Allen head bolts now, bought, shortened and fitted. But in the process I found that a PO had fitted a long stud, screwed at both ends as the centre retaining bolt ("A" in the Instruction Manual) instead of the correct bolt. I've lock-nutted one end and refiited it but if I choose to get the correct bolt, what is it? ie length (which I can measure) and tpi (which i can't). It doesn't appear to show up in the parts list. Is it simply a standard bolt? No rush!! George

 

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