I looked at same thing you are, I have the jackshaft on my CT now that the TAV came off of and it aligns perfectly. When I put either on the new frame they are both off by around 7/8" yet the jackshaft drive gear appears and does measure out further than the TAV. But they are actually on the same alignment. Do you have an alignment issue with your jackshaft with engine mounted to riser ? If not then I would be looking at a prob with the TAV back plate. Using a riser in no way affects the alignment, other than raising the geometry. Unless you have a messed up riser. I would start testing all of it with a straight edge. If there was a big issue using these risers with a TAV, then we would of heard about it. I'm on multiple FB pages dealing with minis and here. I've personally helped numerous new owners, by suggesting that riser and a TAV, with no alignment issues. I can't imagine that your particular model mini should be any different. One thing for sure, the QC on these minis and upgrades is very lacking !!!
The alignment with the jackshaft was close, unfortunately I didn’t snap a pic of it before I removed it.
The back wheels are offset in the frame roughly 1/2” with more clearance on the sprocket side. The back wheel and the motor plate are parallel to each other.
The riser isn’t distorted and the TAV plate is straight.
Everything points to the difference in the offset of the sprocket between the jackshaft plate and TAV plate.
I posted this on a minibike Facebook group and there are others who have found the same problem and redrilled the riser to move the motor over.
My guess is that there are a lot of minibikes with an alignment problem. I bet 99% of people who buy the riser and a TAV just bolt it on and assume that everything lines up. Also the majority of people wouldn’t have an alignment bar to check it with. Given the distance between the sprockets the chain is very forgiving to misalignment and would likely work with without any noticeable issues.
I’m curious what the sprocket offset is on one of the Chinese TAV’s. It would be great if someone could measure one.
