In preparation for an upcoming trip I got the engine rebuilt to replace this suspect 3rd Drive Gear. Engine had 26K miles on it, 1998 model year.
24231-12D21 Gear 3rd Drive ($58)
09380-25003 Circlips (at least 2) ($2)
25211-37401 Fork, Gear Shifting No. 1 ($44)
25221-37401 Fork, Gear Shifting No. 2 ($44)
16321-32E00 Oil Pump Plastic Gear ($15)
there are 3 oil seals that should be replace if splitting the cases
09283-25096 Oil Seal, Drive Shaft to Sprocket 25x44x7 ($6)
09282-16002 Oil Seal, Crankshaft to Clutch Cover 16x30x6 ($5)
09285-12006 Oil Seal, Gearshift Cover 12x22x9 ($4)
Gaskets to be replaced when splitting the cases:
11400-32874 Gasket set (includes below items) ($76)
11485-12D01 Gear Shift cover Gasket
11241-04F20 Crank to Cylinder Gasket
11141-32E00 Cylinder to Head Gasket
11482-32E00 Clutch Gasket
11483-32E00 Magneto Gasket
11177-44B01 Valve Inspection Gasket
12837-24A10 Tension Adj Gasket
14181-22D01 Exhaust Gasket
09280-15007 Oil Filter Gasket
09280-17003 Oil Filler Gakset
09280-46002 Intake O-ring
09280-72001 Oil Filter O-ring
50 mm Rotor Remover Tool, Dennis Kirk P/N 281965
($80) (Note: 09930-33720 PN from manual is a 42 mm wide tool that will not fit)
09917-23711 Ring Nut Socket Wrench (or make your own)
Plate to split the cases
Transmission puller tool
My mechanic charged me $450 for the rebuild. He let me help out as much as I could and also taught me how to go about this in case I need to do this on my own.
Removing the engine from the frame. Pushed up from the bottom as she was slid out the side.
On the workbench at my mechanic friend's place. Her home for the next 2 1/2 months.
Old piston being replaced. 1998 stock with 26K miles, not bad.
The 50 mm rotor puller
The engine sitting level with bolted supports
Special tool made to release the ring-nut from pipe section
Ring-nut socket in place
Puller plate with threads to match the DR (also used for SV650 motor)
The cases being split.
Gus, twisting the threaded rod to split the cases.
And Voila! beautiful internal engine components.
The transmission. Left side: Drive gears (3rd gear in the middle), Right side: Driven gears (output shaft)
Cases put back together. Parts and new gaskets installed.
Putting the clutch basket on
Cam and chain installed
One sweet rebuilt DR650 engine
Spinning the crank around and going through the gears to make sure everything is in its proper place.
Putting the engine back in the frame with the help of a buddy who acted as an engine hoist while I lined it up. Went in much easier than I was expecting, took about 15 mins only.
She fired up on the first try and sounds so sweet
My original 3rd Drive Gear looked good, along with everything else in the engine: cylinder walls, valve seats, stems, cam, chain, etc. No marks or damage on any gears or parts . Good to know that there'll be no surprises from the engine (touch wood