your carb.

Unknown

Tom - someone has put/adapted a '29 carb. (note pot metal cover you

say is cracked) to your '28 ('28 carb. a bronze casting + is turned

180 degrees from '29 on heat riser).

Whether you have a '28 heat riser modified to take the '29 carb. or

an entire '29 heat riser assy. put on, your photos don't tell.

I believe both the '28 & '29 carbs. bolted on with 2 bolts, but

the '29 has a small heat exchange pipe going up into heat riser

the '28 doesn't have. All the linkage is different too as carbs. are

reversed ('28 air cleaner at front of heat riser, '29 to rear).