Musky's Plunger rebuild.

[muskrat]

G'day Fellas.
Came across my first snag. Thought I'd put the barrels on to check the rods are central. They wouldn't go onto the studs!  I opened up the holes but still wouldn't fit.  I was working from the back side of the motor and didn't notice the rub mark on the crankcase bridge. The back of the r/h barrel skirt was hitting. First I ground a little off the skirt but didn't want to go too far as I've had one break there on the racer. So I took the dremel to the bridge! Was surprised how much I had to take off, nearly 2mm . Then I made three dowels to fit neatly over the front and two rear studs and into the enlarged barrel holes. Barrels on and checked the rod positions. All good central and square 
Cheers

[Swarfcut]

 Was this originally an A7 case used with the shorter spigot A7 barrels? I'm thinking your build is A10, but nevertheless reckoned all basic crankcase castings were the same. Another conundrum.

 Swarfy.

[muskrat]

G'day Swarfy.
The "new" cases were ZA10 but all A7 & A10 cases of the same year group are the same. The cases are a # stamped matched pair and although the bolt/stud holes and the case/barrel face align there is evidence that one side wasn't quite square in the machinists jig. Most barrels I have seen have grinder marks on or around the skirts to account for this.
I doubt very much if the removal of material at this point will weaken the cases.
I still can't find any A7SS +40 pistons. I could reuse the old ones but they do have scoring. A set of std T150 rings will fit. The bore is good, only a 0.001' taper. The barrels had been sleeved so I can't open them up to +60.
Cheers

[chaterlea25]

Hi Musky
Would these work for you?

https://www.ebay.co.uk/itm/275236096768

John

[Minto]

G'day Trev.
Thanks M8. Just another part to hunt for.

G'day Swarfy.
I have two good bearing/seal shops close by. I'll annoy them.
Wondering if I can turn down the plunger one to match a seal?

Been quite a while since I visited the bottom end of the plunger. It's starting to come back yo me now.
I've joined another group, "The Sons Of Alzheimers"
 Cheers

Musky, I will soon have a 43mm drive sleeve surplus to my requirement, it’s on the bike at the moment but needs replacing with the correct 46mm one which should arrive next week.
I can drop the 43mm one in the post but it might take a while to reach you. Let me know if you want it.

Also really interested in how you’re going to improve the main shaft oil seal arrangement, though I doubt I have the skills to follow your lead.
Jase

[muskrat]

G'day John, they will do nicely. Thank you.
"May not post to Australia." I'll send him a message.

G'day Minto.
Thanks for the offer mate. I found nos one up in Queensland.
Re the mainshaft seal. I ground off the rivets and removed the two plates. Got a double lip seal from the local Engineering Supplies that fit the shaft and was a neat fit in the case. Riveted the original plates back on with just a smear of silastic. Time will tell.
Cheers

[chaterlea25]

Hi Musky
I put a "watch" on them on my ebay and received  an offer to buy for £125 
Then I noticed they are JP's  so I wonder if you could get the same in Oz ?
If he doesn't post maybe a UK member could step in as a broker 

John

[RichardL]

I think that the  "May not post to (wherever)" line has to do with the seller not indicating the method, rather than a prohibition. I any case, if it is, indeed, a prohibition, I'm sure someone in the UK will help. I'm not expert in this, but I'm guessing there are commercial brokers who deal with such eBay restrictions from shy or recalcitrant sellers.

Richard L.

[Minto]

G'day John, they will do nicely. Thank you.
"May not post to Australia." I'll send him a message.

G'day Minto.
Thanks for the offer mate. I found nos one up in Queensland.
Re the mainshaft seal. I ground off the rivets and removed the two plates. Got a double lip seal from the local Engineering Supplies that fit the shaft and was a neat fit in the case. Riveted the original plates back on with just a smear of silastic. Time will tell.
Cheers

No worries pal, I’ll stick it on the bay.
That’s pretty much what I did with mine, though my confidence in it’s oil-tightness is pretty low, everything else on my bike seems to leak, why shouldn’t that.
What kind of rivets did you use? I’ve only got a pop riveter, you reckon those would be up to the job next time?

[muskrat]

G'day John.
I just checked and have no response about postage. What I did notice is the price going from 150 to 165 GBP  The only JP's down here are 6.6:1.
Any offers to buy and forward on to me 

G'day Minto.
I just used normal pop rivets and glue.
Cheers

[Greybeard]

Any offers to buy and forward on to me

I'm willing to help if I can. Are you able to identify a seller in the UK?

[trevinoz]

Musky, ring JP and see what they can do for you.

[muskrat]

G'day GB.
That would be great mate. I'll take Trevor's advice first and if no luck I'll give you a hoi tomorrow night (your day).
https://www.ebay.co.uk/itm/275236096768?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
Cheers

[muskrat]

G'day Fellas.
Next installment.After getting the barrels to fit properly I marked where the through studs are to be. This time I made sure they are in the middle of the case, only moving them 0.5mm. Drilled and tapped them and made new studs. 5/16" into the case and up to 10mm at the top. The 5/16" thread I made large by about 5 thou" to be tight into the case. All good, nice and square.
G/box on with new sprocket and seal. The yellow hose is from the breather exit to under the motor.
Pics of the ms and crank seals. Lump back in the frame and primary on. Much easier to man handle without the top end on.
Cheers

[Colsbeeza]

Looking good Musky. I like your degree disc and pointer - think I spent too much on mine!!
Col