E: Engine Do Big Bore Cylinder Muffs Need Special Head Studs?
- Thread starter ericg
- Start date
Anybody know how much bigger the hole has to be in the Crankcase mouth ?.
That depends on the liner being used.
On my 90 bore Comet I know there was not much meat left on the stud holes in the crankcase.
I also had to true up the joint face as it wasn't true to the crank and rod.
Neil
These 2 pics may help may help I cant measure it as its now cleaned up and in place its the top hat converter back to standard bore, the engine always had standard studs at a guess there was a 1/16" or so twixt hole and stud dont forget even 2 piece studs are same thread into c-case
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If it's not much I was wondering if I could File it out !!,
Me being a road side bodger !!.
The last "standard " Barrel I fitted to the L/ning had smaller stud holes in it ,
As was said in another thread.
Me being a road side bodger !!.
The last "standard " Barrel I fitted to the L/ning had smaller stud holes in it ,
As was said in another thread.
Yes, probably they are all different ;-)
I got this response from Steve at Conways, June 2020 :
Nikasil coated 90mm cylinders complete ? £600 each 8 weeks
Pistons 90mm (8:1 or 9:1) ? (Make ?, Forged / Cast / Low exp. ?) £190 Cast low exp, either 8:1 or 9:1 2-4 weeks
Conventional cast iron cylinder liners in 90mm bore for use with my own bored cylinder muffs ? £150 each 4 weeks
Will I need special cylinder studs for your 90 mm bore cylinders of either type ? No
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I ended up buying a set of Terry Princes 600cc Top End Kits with 92mm bore, the dimensions for fitting that can be seen here :
https://www.classicmotorbikes.com.au/tpv-top-end-kit-fitting-instructions/
(I have not fitted it yet).
I got this response from Steve at Conways, June 2020 :
Nikasil coated 90mm cylinders complete ? £600 each 8 weeks
Pistons 90mm (8:1 or 9:1) ? (Make ?, Forged / Cast / Low exp. ?) £190 Cast low exp, either 8:1 or 9:1 2-4 weeks
Conventional cast iron cylinder liners in 90mm bore for use with my own bored cylinder muffs ? £150 each 4 weeks
Will I need special cylinder studs for your 90 mm bore cylinders of either type ? No
-----
I ended up buying a set of Terry Princes 600cc Top End Kits with 92mm bore, the dimensions for fitting that can be seen here :
https://www.classicmotorbikes.com.au/tpv-top-end-kit-fitting-instructions/
(I have not fitted it yet).
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A couple of points to look out for with the new TPV kits.......Check the push rod tube gland nuts spin freely into the head, I have had several of the new kits and found the threads to be undersize, had to use a 1" x 20 TPI tap to open up the threads a bit more.........and yes I tried various different gland nuts, they were all too tight.........Before you assemble the liners into the muffs I strongly recommend you lap the liner top hat into the head recess with fine lapping compound.........It says in the instructions that this is not necessary, but I have found they will leak if the extra attention is not taken. The Harley solenoid decompressors work very well, you need to plumb some banjos' with these and run a line from one to the other, then vent this line down to the rear of the engine........If you simply vent them from the top of each head, if you have an electric start it will sound like a machine gun when cranking over, it can also make a mess as carbon and fuel/oil can be blown out........So this is best vented away and keeps the noise down...........Good luck with it all.
The piston supplied with my kit is an Omega 8:1 (my choice).
There is absolutely no way for the standard studs to go through the 10,9mm holes in the muff I've been supplied with.
The delay was 16 weeks in my case.
My first intention was to go for a TP cylinder and piston as well but unfortunately Terry doesn't wish to sell anything but complete top ends kits so the price wasn't in my range.
Bill, if you are looking for 90mm bore, I would have a look at Maughan's price list. Seems they have both pistons, liners and 2-part cyl.studs at ok prices.
Thanks Sten, I think I am just dreaming at the moment, But the Conways standard type barrel
Sounds like a good way to go for me, A lot cheaper,
I can't seem to get started on the welding and boring of my Flywheels for the long stroke,
Fear of messing it up I think, Getting old !, I have had the short Conrod for many years,
If I didn't already have Vincents that I can ride, It would be different I think,
Good Luck with yours, Bill.
Sounds like a good way to go for me, A lot cheaper,
I can't seem to get started on the welding and boring of my Flywheels for the long stroke,
Fear of messing it up I think, Getting old !, I have had the short Conrod for many years,
If I didn't already have Vincents that I can ride, It would be different I think,
Good Luck with yours, Bill.