1972 commando rebuild

BERT

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Back at the task after slowly gathering parts. Oil pump is reassembled after eliminating the end float. Frame checked out OK for bends (relief) , crankcase halves welded up, and all powdercoating removed to Old Britts tutorial and painted, steering sorted out- new bottom 750 yoke, swinging arm reamed out, finally starting to rebound from the teardown and get her back together. It is a slow process for me but I have patience to make sure everything is correct. This forum has been vital help for this project and I am very grateful to all the contributors.
 

BERT

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I have renewed fittings to assemble the crankshaft. 2 studs with plates and nuts, and 4 bolts with with nuts. This was the configuration I disassembled . I noticed the shanks of the replacement studs are longer, which gives better bearing(contact) with the clearance holes through the assembly. The replaced studs were 1/2 thread and 1/2 shank bearing (contact) on the cheeks. Definitely better.
Question please: is the reasssembly normally done between centers to align the journals? It baffles me there is one dowel for locating. It is in line with the crank center, but can the assembly rotate around the dowel ( with reliance on bolt clearance sizes) enough for concern to keep the journals aligned? Any thoughts or input would be appreciated. Thanks in advance.
 

Time Warp

.......back to the 70's.
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Two of the fasteners at the upper locate also.
They should be evident when you fit them.
 

Conrad

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Here is a close up of the plate. Oops on the double post- sorry.

My Commando is only 60 or so earlier from yours. I bought the Mick Hemmings teardown and build DVDs and the tech materials from the NOCShop. Highly recommend it. I wish they weren't out of the John Hudson teardown DVD though. Maybe someone here will part with their copy someday.
 

BERT

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Two of the fasteners at the upper locate also.
They should be evident when you fit them.
Thank you TimeWarp. All 6 through holes on each of the 3 components seem to have the same clearance. The top 2 holes on the D/S (where there is a spot face counterbore to clear the flange radius) hang the bolt up from complete insertion. I filed the 2 inside hex's on the new top bolts to allow full entry and contact so the torque value will be true. Maybe once the assembly is tapped together the 2 top bolts will locate the journals. So the way I see the proper fitment sequence is 2 bottom studs, 2 top bolts tapped in, then the 2 remaining bolts. I am considering blue permatex threadlocker on the new fittings without staking them. I noticed the oil feed through hole on each journal was countersunk on one side only. Is it OK to countersink the other side to relieve the sharp edge or is it this way by design. I am not assuming anything on this one. I have really appreciated the input forum members have provided and will look forward to being able to share my knowledge with others as I gain capability to.
 

BERT

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Back at her today. Assembled the crankshaft and shimmed it for end float. Something to take note of is the replacement top 2 bolts needed to be filed on the 2 hexes to allow them to be seated, which should be done before they are installed. Prefit them before assembly to avoid unnecessary thread damage tapping them in and out more than needed. The minimal diameter of the spot facing on the crank cheek hung up the bolts on the radius. I am glad I checked before assembling as it may have resulted in a false torque setting. A bit of careful filing took care of it.
After heating the case, I had to tap in the DS outer race after it was squarely started to seat it home. The TS side was shimmed .015" for a .010" end float without goop. The camshaft rotated freely during the end float measuring, as did the crank, after the welding repair possibly distorting things I was very happy to see that crankshaft and camshaft rotating freely. The seam also checks out quite sealable.
 

BERT

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Back at her. I have done a dry fit assembly with bare cases in the cradle/swinging arm with the new oversize swinging arm spindle installed into the frame with the corrected isolastic mountings properly spaced. So far so good, the assembly slid into the frame without a snag and looked fine for alignment. Back apart for final assembly. The only heavy oil I can readily get here is 75/140 synthetic gear oil for the swingarm bushes. Are there any issues using synthetic oil for the oilite bushes? Input would be appreciated. Thanks.
 

BERT

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The crankcases are now ready to mate and I cannot m decide whether to install the camshaft spacer with or without the tab.
Looking at it, the form was made after the bronzing and indeed the bronzing is cracked along the outside, the base material does not show any sign of forming fatigue. New spacer washers show the same weakness, for sure the design could be better, but to remove the tab would mean the spacer could rotate which it is not designed to do. I am going to install the tab, but beforehand, will carefully file the sharp edge off the contact area of the adjoining surface of the crankcase, and relieve the sharp edge of the inside radius of the tab. Any thoughts would be welcome, and if anyone has any updates on this issue, please share them. Thanks.
 

BERT

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More progress between dog walks, bicycle rides, fishing, and planting. The front fork assembly is sorted out with the proper bottom yoke. The existing tapered roller bearings have been properly loaded with the required spacer length. The crankcases are together and installed with the gearbox in the cradle/ swingarm assembly. The wiring spagetti is back in, the connectors and sheaths are in decent shape and should last a little longer. The new hep pistons are in the deglazed jug and I will try to install using Mr Comstock's method without ring clamps. Those oil rings were a bastard to squeeze together for entry.With the engine in the bike, I can drop the arse end down so the base is more level. Grandpaul's rebuild order has been helpful for the reassembly, also Mr White's chapter on the rebuild has been helpful, and also the wealth of information shared by Forum members. After the jug is on I will do the timing side and time the trispark with a dial indicator on the piston, as the Alton alternator has no timing mark references that I remember. So far I am pleased with the ease of assembly, with forethought to think each procedure through, there has been no struggle so far. As a newbie I need lots of time each step. She is starting to look like a motorbike again. Thanks to the folks helping me and showing interest, and others in the same boat as me, I hope you are making headway also. Cheers,Dave
 
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More progress between dog walks, bicycle rides, fishing, and planting. The front fork assembly is sorted out with the proper bottom yoke. The existing tapered roller bearings have been properly loaded with the required spacer length. The crankcases are together and installed with the gearbox in the cradle/ swingarm assembly. The wiring spagetti is back in, the connectors and sheaths are in decent shape and should last a little longer. The new hep pistons are in the deglazed jug and I will try to install using Mr Comstock's method without ring clamps. Those oil rings were a bastard to squeeze together for entry.With the engine in the bike, I can drop the arse end down so the base is more level. Grandpaul's rebuild order has been helpful for the reassembly, also Mr White's chapter on the rebuild has been helpful, and also the wealth of information shared by Forum members. After the jug is on I will do the timing side and time the trispark with a dial indicator on the piston, as the Alton alternator has no timing mark references that I remember. So far I am pleased with the ease of assembly, with forethought to think each procedure through, there has been no struggle so far. As a newbie I need lots of time each step. She is starting to look like a motorbike again. Thanks to the folks helping me and showing interest, and others in the same boat as me, I hope you are making headway also. Cheers,Dave
sounds very good progress. Obviously, alternator can be marked up for future timing, and strobe checking when running.
 

BERT

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Hi again guys. Those of us north of the equator are enjoying longer days and those of us south of the equator are enjoying longer nights.
More done today with help from a friend. The jug is on and torqued down to spec. Why is the front center nut (06.2651) shorter than the others (06.2652) and can it be substituted. The reason I ask is the spanner size is different and I made a crow foot for the torque wrench to fit the others and during the assembly procedure realized this, along with it being a shorter nut than the others. So I substituted it with an extra one of the others to be able to use the torque wrench. Since the cross section of the bearing surface of the substituted nut is a wee bit smaller I added a washer, which is not required like the rest.
So may I ask 2 questions: why the different nut and why no washer required for this nut? Thank you in advance, advice would be welcome.
 

BERT

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Decent progress the last few days. The rear wheel assembly went together well, and the chain tracks nicely with the drive sprocket and well centered between the gearbox and inner primary. I have dry fitted and touched up when needed the timing side, it's ready to go when I can lock the engine. The Alton stuff has been preassembled to reassure the airspace between the rotor and stator. The chaincase stud gap has been measured for the shim. The jugs went on nicely with the help from a friend and torqued up. Presently waiting for clutch locating shims and a new circlip. I will get the thicker one and lap it down to fit the groove. I don't like it sloppy when the basket is torqued against it. Thanks to the Forum for all the guidance, and the kind folks who have answered my questions to get me out of a few conundrums so far. I am happy with the assembly so far, the bike is straight and I am enjoying the constant fettling to make sure it is done correctly. Cheers, Dave. 20210619_122559.jpg 20210619_122538.jpg 20210619_122524.jpg 20210616_162153.jpg 20210616_162121.jpg
 

BERT

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The inner primary chaincase is rocking a wee bit on the crankcase. I checked for burrs and protruding threads. I found on a surface plate the chaincase to be slightly bowed on the mating surface concentric with the big center locating flange on the crankcase.
I checked with feeler gages and with the top screw snugged up, the 8:00 screw has a .010" gap. The 4:00 screw has a .005". Is it okay to shim at these screw locations between the chaincase and crankcase? I worry if I tighten them up against the bow I will damage one or the other. Advice would be appreciated.
 

BERT

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There should be a gasket between them?
Thanks for replying L.A.B. It is an Alton starter kit and the installation instructions call for sealant instead of a paper gasket between them. I am apprehensive about tightening up those screws as something has to give and I don't know if it is a good idea to rely on the malleability of the case casting. The shimming I am proposing for positive contact with the 3 screws will also create a good air gap between the Alton rotor and stator units.
 
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