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For the preservation and enjoyment of 1928 to 1931 Indian Scout Motocycles
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Advice Needed - Primary Cover & Magneto

  • 24 Mar 2020 6:11 PM
    Message # 8855168

    Working on my '29.  A couple of issues I'd appreciate your advice on.

    1:  The bottom-most primary cover bolt has been replaced with a modern 1/4-20 x 2 1/4" hex bolt.  There is no "catch" with the female threads - it just spins.  It was held in place with silicone sealer - not a good long-term solution.  This goes into a blind hole so I don't know if the female threads are stripped, or if this is the wrong size bolt.  Anybody know what size bolt belongs here?

    2:  Tried to remove my magneto.  The right rear mounting bolt is right up against the engine case.  I can't fit an open end or closed end wrench or a socket in there.  Is there a secret tool used on this fastener?  Seems like the only way to remove the mag is to separate the engine from the frame.  Suggestions?

    Thanks,

    John

  • 25 Mar 2020 9:43 AM
    Reply # 8857621 on 8855168

    1:  The bottom-most primary cover bolt, if I remember right, in the transmission case 1/4"-20 and on the nut side 1/4"-24. 

    Stripped threads there is very common, most because the hole is filled with crud and the stud is threaded in too short, or the nut jams on the stud, or torqued too hard or/and the stud is repeatedly screwed in and out. In short, the threads are easily stripped.

    There are several ways to repair this, but to do it good it usually require taking the gearbox out.

    A very common mistake is to drill the hole through and insert a helicoil, but then you risk to have a constant oil leak as oil migrate through the threads, fill up the channel for the bolt in the covers, and leak through! the nut threads to the outside. Been there, done that.

    In fact it happens also on other places than there. It can be very tricky to find out a small oil leak behind the nuts or through the threads when that is the case. I tape good a piece of towel paper anywhere on suspect (more than once on unsuspected) areas and go for a ride, the paper never lies.

    Another way is to machine the hole with an end mill, not through but bigger and thread that with a bottoming tap. Then make a custom bolt with a larger thread at the end. The original hole is 13mm deep, but because of the shape on the inside, the larger hole can't be drilled more than 10mm deep or it risk to break through. Remember that if you opt to use a helicoil or similar thread insert.

    Next is to drill through and put in a threaded plug, make the plug of tough  aluminium that has similar expansion rate as the gearbox and have the outer thread dimension as large as possible with a tight fitting in the threads, that produce lesser strain per thread area, and glue it with strong thread locker. Of course the plug has a dead end thread for the stud. There is some distance inside the gearbox until it touches the cluster gear so the plug can protrude a bit in order to make a longer thread for the stud.

    Best is to drill out and weld the hole shut, drill and thread a new hole.

    At last, the hole cleaned and the stud can be glued in place with construction glue, epoxy reinforced with mixed in aluminium dust.


    2: Tried to remove my magneto. Buy 3-4 cheap spanners, cut, grind, bend them so you can grip the flats in different positions, sometimes it is just 1/16th turn before a new spanner with another positioned grip is needed...then throw the bolts and use bolts with 12 grip bolt heads or fabricate bolts with smaller heads than standard. Buy 6-7-10 other spanners and cut and shape the same for the, to put it mildly, infernal front cylinder base nut there...that's the one - right there! Oooh, how infernal that one is...! 

    Ps. Make a dedicated puller for the magneto gear. 

     

    Last modified: 25 Mar 2020 10:13 AM | Carl-Erik Renquist
  • 28 Mar 2020 6:54 AM
    Reply # 8863815 on 8855168

    Carl-Erik, thank again for the outstanding advice.  My disassembly has progressed almost to the point where I'm ready to remove the engine.  Letting some Kroil seep into the exhaust nuts while I look for a suitable wrench.  Any advice as to how best to remove the engine & transmission?  I was going to lay the bike on it's left side (on some appropriate padding), remove the engine mounts and then remove the frame from the engine.  

    John

  • 29 Mar 2020 7:13 PM
    Reply # 8865932 on 8855168

    If the bolt for the transmission cover is the only reason for remove the engine and only repair you need to do, then in fact I would leave the engine in the frame and resort to the simplest method and try to glue the bolt in place. Reinforced epoxy is astoundingly strong but good preparation is key for success. If it is just the bolt for the magneto, the engine can be lifted up even turned a bit with the front mounting spacers removed, for better access. The gearbox frame fastener nut has to be really loose.

    At removing the engine, the problem is the chain cover and in some regard the kicker. The wheel must be removed before the chain cover can safely be removed without scratches and bending. With a rearguard without the hinge, it is difficult to remove the wheel even when the tire is deflated. The lazy way with the wheel and engine in place, 'someone' told me it is still possible to pry out the chain guard forward with the kicker tied down but it is reallyreally tight. Really.

    With the wheel out it's difficult and I think risky to lay the bike down so you need to put that wheel back again. And frankly it pose another danger to damage the engine cam cover and fins with the bike lying down. But if you don't have the strength for the lift, that is the way you have to do it. It is doable but I haven't tried that. Remove the fragile carb for safety's sake. The engine with gearbox weigh 50 kg (110 lbs) pretty precise. I think that was without magneto.

    Warning. The clutch cover can become indented if the engine is laid on, or hit on the clutch lever worm. You can check if the cover has been damaged from for example a bike tip-over at some time, the flat surface where the worm is should be flat, not concave. A indented cover is problematic as the clutch worm release range is compromised.

    With the kicker and brake pedal simply tied down in the right positions, technically it is not difficult to lift the engine out especially if the tank is removed (and that darn chainguard). Just lean the engine toward you a little bit and lift it out. There is plenty of room but you need to have the strength for it. I have always lifted the engine out from the right hand side of the motorcycle, maybe I have done it wrong and the chainguard can stay when lifted from the left side, in fact I don't know! Ah, then you have the clutch pedal in the way...and the shifter.

    A block of wood under the engine prevents the engine tipping forward and front cylinder to hit the frame when the front long bolt is removed. Put padding on the front frame tubes and cloth on the bottom rails for good measure.


    Last modified: 06 Apr 2020 10:27 PM | Carl-Erik Renquist
  • 30 Mar 2020 12:16 PM
    Reply # 8867473 on 8855168

    Carl-Erik, thanks once again for your thoughtful and detailed response.  I am not removing the engine just because of the primary cover bolt nor the magneto.  Since I have no detailed history of the bike, I am not taking anything for granted.  There may be cracks, broken parts, missing parts anywhere and everywhere.  I have already found lots of "field-expedient" repairs as I've been preparing to remove the engine.  I will not be surprised to find others once I get into the engine and transmission.

    I have already removed the kicker, carb, and most everything else except the exhaust headers.  Waiting on the Kroil to seep in and to find a suitable wrench for the exhaust nuts.  Once they're out of the way, I'll get some help and will try to lift it out as you suggested.

    I've attached a photo of the current state of the Scout.  I am taking lots of photos as I go, and copious notes.   Also running all fasteners through thread restorers.  One of the benefits of being covered in oil and grease is that every single fastener has broken loose cleanly after an application of Kroil.

    1 file
  • 31 Mar 2020 3:00 AM
    Reply # 8869113 on 8855168

    Good idea to check ite engine over. If you come upon problems, it's better to take a moment and ask before you do something, here or on some of the very active Facebook sites where good tips and tricks can be had from experienced Indian motorcycle mechanics.


  • 31 Mar 2020 8:28 AM
    Reply # 8869470 on 8855168
    Tim Raindle (Administrator)

    Hi John, as usual, Carl-Erik offers good advice. Apologies for not replying, I have been experiencing difficulties logging in to the site, unable to do so on usual browser, but seem to be able to with firefox.

    Any issues, I am only a phonecall away.

    regards,

    Tim

    860-482-9215

  • 05 Apr 2020 5:43 PM
    Reply # 8880356 on 8855168

    Thanks to Carl-Erik's tool advice and Harbor Freight, I was able to get all of the mounting bolts removed from my magneto.  I thought it would just pull free from the engine - but no luck.  New guy question.  What do I need to do to remove the magneto from the engine?

    Thanks,

    John

  • 06 Apr 2020 8:53 PM
    Reply # 8882701 on 8855168

    You need to remove the cam cover and use a puller to remove the magneto gear. It is tempting to pry on the gear or knock on the shaft, but the shaft is thin and can bend. And the bearings are small, has few balls and is risk of crack or dislocate. The magneto is a precision apparatus.

    Before you remove the cam cover, turn the engine to exactly ignition point on one of the cylinders and make note of which one. Preferably with the cylinder head off and note distance before top dead center that the ignition point is. That way you can reconstruct the gear positions more easily. Remove the oil pump so you can push on the shaft to make the cam stay in the crankcase. The important thing is to avoid move the crankshaft, cams or magneto gear.

    When removing the cam cover be careful and try to keep all the gears in the crankcase, especially idle gears has a tendency to follow the cam cover.  If possible poke with a blade in the crack to push the gears back. If unsuccessful and some gear is coming out with the cam cover try to avoid turn on any gear and carefully replace the missing one in the same position. Valve spring force or magnetic force in the magneto can however turn something and make that fail.

    Idle gears exact positions are less important as they don't decide the relation between crank, cams and magneto, but placing or which way they are turned over can be important as the bushings or shafts might be dissimilar..

    If all fails, it is possible to reconstruct gear positions with help of the ignition point and piston position.

    Finally before you remove the magneto gear, turn the engine with all the gears in place and check that the markings on all gears line up, sometimes the magneto gear is changed at some time in history and must be put one or several cogs off! Make markings and take pictures, note and mark also where the shaft key is placed on the magneto gear because it can be more than one key slot in the magneto shaft.

    The benefit with all this kerfuffle is that you can put the magneto gear back in the same position as it was and get the engine running on first try. Something that many Indian motocycle mechanics has failed with...

    Last modified: 06 Apr 2020 10:36 PM | Carl-Erik Renquist
  • 07 Apr 2020 9:15 AM
    Reply # 8883475 on 8855168

    The Shop Manual has been very useful to me, as have some of the WoW articles and past postings to this forum.  In the old days, guys like me would have apprenticed to a master mechanic and learned by doing.  I can't thank you all enough for helping with my newby questions.  Especially Carl-Erik who freely shares his time and expertise to keep these great old machines alive.  And all the way from the land of my great-grandfather to boot.  Thanks!

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