Musky's Plunger rebuild.

[Swarfcut]

  If bushes are to be line bored then in the raw there must be excess material on the ID to enable the boring process to result in finished bearing surfaces perfectly in line and to the appropriate running clearance. Bushes that slip onto a camshaft are  maybe OK for simple replacement into matching cases, and  a used cam, but certainly can't be relied on for the perfection sought by some.....Good enough for me, though.

 Swarfy.

[muskrat]

G'day Swarfy.
Correct, even in matching cases there will be discrepancies. Thinking hard about making my own.
 

[muskrat]

G'day Fellas.
Not much happening whilst waiting for parts. Yesterday I took the drive side case to the local engineer to weld up the broken primary cover screw holes.
Cheers

[RichardL]

Muskie,

I hope that wasn't too big of a hurt. Did you also build up the ones that appear to have been flattened out by a loose chain?

Richard L.

[RDfella]

Word of warning, Musky. Welding those areas will likely distort the case.
Check it on a flat plate after - if it ends up curved (on the face mating with the cover) don't try and straighten it out, as it'll likely crack all over the place. DAMHIK!
I had real problems after welding my SA rear primary case. Hairline cracks everywhere after trying to straighten it. I ended up with another cover and annealed it after welding - around 300*C in my Rayburn cooker for a couple of hours before letting the temp drop slowly to around 180 before removing and air cool. Removed the work hardening and allowed easy re-setting with no cracking.

[muskrat]

G'day Richard, RD.
Norm (the engineer) said he will be "cooking" the case before and after tig welding. I will certainly be checking when it returns.
Cheers

[muskrat]

G'day Fellas.
Got home from work yesterday to find a box of goodies waiting for me. I put in an order with Andrew at Priory Magnetos on the 15/03 and it arrived 24/03  I can't get bits from Sydney that quick. Thankyou Andrew.
Still have to source a few more bits and waiting for Norm to weld up the primary screw holes. Don't want to rush things.
Cheers

[CheeserBeezer]

G'day Fellas.
Got home from work yesterday to find a box of goodies waiting for me. I put in an order with Andrew at Priory Magnetos on the 15/03 and it arrived 24/03  I can't get bits from Sydney that quick. Thankyou Andrew.
Still have to source a few more bits and waiting for Norm to weld up the primary screw holes. Don't want to rush things.
Cheers

Thank you, Musky. Andrew

[muskrat]

G'day Fellas.
Got the case back from the welder. He had some issues but got it done (not very pretty but it's inside.
My cover is a little miss matched (pic 6).
Spent a few hours bolting the cases together then bolting on the g/box and clutch to check clearances. Dremel to the rescue.
Next, while the box is on I'll make a boss for a proper seal for the mainshaft.
Cheers

[stev60]

I know from experience with a damaged cover, that the oil that penetrates the aluminium , makes tig welding awkward and thats after, warming it up to try and sweat the absorbed oil out

[muskrat]

G'day Fellas.
Been very slow the last month (life gets in the way).
More parts have arrived from Mikes Classic Cycle Spares including a set of NOS con rods.
I've shrunk in the cam & main bushes into the cases. New reamers arrived yesterday. Bored the d/s case to take the crank seal (NOS 67-2071 cush drive sleeve also from Mike) to stop the wet sump oil entering the primary (shouldn't happen with the new SRM pump).
The new mainshaft/primary seal is a nice fit in the original hole in the case and I can use the old seal housing to hold it in.
Tonight I'll make a new dowel for the crank case halves and bolt them together. Make some pilots for the reamers and not have a beer till done!
Will take pics and post tomorrow.
Cheers

[muskrat]

G'day Fellas.
As posted elsewhere I've got the bottom end back in the frame. So I thought I'd better update this.
I successfully reamed the cam and main bush using my home made pilots and expanding reamers, all were given 0.0015" clearance. Dropped in the cam & crank and the cases went together nicely. Both spin with no perceivable play.

[trevinoz]

How did you ream the blind bush with an adjustable reamer, Musky?

[muskrat]

G'day Trevor.
I didn't. I spent another $78 on a 19mm hand reamer and cut the tapered end off. Then used a similar method as the main bush.
Cheers

[Topdad]

Hi musky, really going to town on the motor to say the least , don't stop and count up how much you've spent or my guessing would be a heart attack would result ,good job mate !