I keep the exhaust valve seat "on the wide side." I've read where a wide seat on the exhaust helps dissipate heat when the valve is shut . . . cooling the valve. I could easily cut a 60 and a 30 and narrow the seat, but I'll leave it wide. The 60 takes away material (which a guy might need for future valve jobs on this old iron) !
Above: I refer to this SHOP DOPE update when fitting lower end rollers on big twins and 45s.
This motor was supplied with the wrong cages. I had the correct steel cages as per the information supplied, so I'll update accordingly. I have a good stash of NOS Sonnax rollers, and the perfect +.0002 set for his pinion race. All good, but tedious work.
Above: I try different flywheel thrust washers to achieve correct endplay. This is done by bolting the cases together multiple times, and re-checking the end play. More tedious work !
Above: I have a place on this heavy steel bench to bolt(and clamp) flathead cylinders for cutting valve seals and lapping. These reproduction cylinder kits always need honed, and seat work done to be right. No exceptions here. More tedious work......
On a WL (45") Model: I use the standard seal kit available from Colony Machine. This kit will eliminate the "reverse oil screw-type" insert. The new-style double lip seal is the same seal for a 4-speed main drive gear. You can replace the seal if needed (usually get it worked out) without taking the cases apart.
On a WR (45") Model: I use the big twin seal kit available from Colony Machine(since a WR sprocket shaft is larger). I press the seal into the left-side sprocket shaft spacer after it's modified to fit this seal . . . (since a WR does not have a left-side sprocket shaft race. (they run a ball bearing).
I'm fortunate to get an invitation every year to this. It's a good time to meet everyone at the beginning of the week, see what's up, make plans . . . and I get to see some builds from all over the country. Thanks Michael !
First year K-Model gear cover . . . No "A" after the -52 casting number.
The generator idler shaft boss is a bit different on these. It has a floating (spring load) bushing that rides on the generator gear oil slinger - to let air pressure out - and keep the oil in . . . usually.
You know it's an early cover from 20 feet away by the grease zerk boss on the shifter shaft (it's on the bottom, at 6 o'clock) Only the first few years of gear covers are like this. I'll blast the covers and get the kicker boss built back up - all restored. This kicker cover is actually a later version.
These carburetors (mfg. by Tillotson) are popular on all types of engines. 4 cycle and 2 cycle. They were the common fuel delivery system on many 2 stroke snowmobile and boat engines. Harley-Davidson had this model as standard equipment on Sportsters and Big Twins in 1967-1971. The KRTT, XR750 and XLR ran Tillotson carbs (single and dual) for all their race engines. I restored this one for the iron XR750. The motor had a version with no accelerator pump - but this model may aid in starting, and be a bit more practical. I'm rounding up the correct throttle(internal) control, correct handlebars and cable control. May as well do it right - like the factory did . . . This carb has a fuel atomizing "bomb-site" in the bore, and a unique 2-piece choke disc that spring loaded to relieve pressure upon a backfire. I also found this rare velocity stack.