A1 and A7 carb differences
Since I’m starting my A1R rebuild from a set of empty cases, it’s time to rummage through my boxes of bits.
Here’s a comparison beween the various carbs found:
A1 Samurai carbs are always 22mm and require their specific covers. The calipers show the inlet stub inner diameter.
Now for the A7 first series of carbs. Early A7 had Vm 26 SC Mikunis, these also require the use of the correct covers.
This is the later type of covers, with the much bigger inlet stub (around 34 mm). These are the ones you want to use if building a tuned or race version.
The carbs that fit are 28 mils VM 28 SC, these have a different jetting arrangement, primary type with a shroud and round main jets.
This cover has the oil injection welded shut.
You can make the 26 carbs fit these stub by removing the phenolic bush at the inlet, but there will be a small step between the stub and carb.
Note that there is also different version of the crank cases for each of these carbs & covers!
Buyers beware! Most people selling their stuff on eBay have no idea of these differences.