I bought my Wiseco 904cc big bore kit from BellaCorse in November of 2004. I paid $399.99 +tax s/h for a total of $409.94. Not a bad deal considering many sell the same kit for much more. It can also be bought from Brent at NewSpeedmaster.com. The kit is Wiseco part number CK 149 Bonneville Big Bore Kit. It takes the Triumph 790cc motor and bores it out to a 904cc motor with 10.5:1 compression.
The kit comes complete with 2 new piston sleeves, 2 pistons #4817M09200, 2 sets of rings #3622XR, 2 circlips and 2 grudgeon pins. It also includes a COMETIC gasket kit, #W6193, which includes a new base gasket, #B0644 and a head gasket, #H1822.
The first thing you need to do is to get all the tools needed together.
At a minimum you will need:
Tunes: Gotta have some good tunes while you work. You're gonna be here awhile.
Rags, lots of rags. I use old cotton clothing I cut up and remove all zippers and metal from them too. Get twice as many as you think you need.
A good set of metric sockets
A good set of metric combination wrenches
A good set of metric allen wrenches as well as a real hard 8mm one for your socket set
A set of Torx bit drivers, a T-30 for your socket set is also very useful for the camshaft removal job
A good set of screw drivers
Some needle nosed pliers with strong tips
A small hammer and some small wood blocks for gentle persuasions
One of those little magnets on a stick tools
A small oil can for lubricating parts as they go back on (I filled mine with 20w oil)
A lift so you can work on the bike off the ground
A 5 gallon bucket or a stool to sit on saves your knees and legs quite a bit of discomfort
Metric feeler gauges capable of measuring 0.010mm increments
A shop light
Some small wire for holding the camchain up out of the way. I used drop ceiling wire.
A current Triumph service manual for your year/model - Don't try this without one!
A good torque wrench for re-assembly work
A lot of clean space (about 50 square feet) to neatly spread out all the parts you take off
A well lit large work area
A spiral notebook for taking notes and drawing any diagrams necessary for re-assembly
Beer, or your refreshment of choice
An assistant with two good hands for the piston re-assembly procedure
Beer for your assistant
Lots of patience - Take your time, do it right, do it once!