here is a little info as far as belts go . and i was right there is no adjustment on that back plate so u have to have the right belt and that bushing .
here is the source site
https://www.*****************/tcbelts.htm
Asymmetric 30 Series 3/4" Top Width Belts
Ignore the Letters A, C or DF Printed on Some Comet Belts, Match the Numbers Only
Part Number
Description
Center Distance
O.C.
Price
Add to Shopping Cart
6" Driven
7" Driven
12-8487
BELT 203589A
6 5/8 to 6 11/16
NO FIT
27.00
24.95
5959
BELT 5959
6-15/16 to 7
NO FIT
27.40
29.95
Belt #5959 is a Custom Belt by Manco/American Sportworks. Fits Go Kart Model 285, 286, 485, 486 & 606.
12-13053
BELT 203590A
7 1/8 to 7 3/16
6 1/4 to 6 5/16
28.32
26.95
12-10052
BELT 203591A
7 9/16 to 7 5/8
6 13/16 to 6 7/8
29.28
24.95
Comet Belt #203591A is also known as Yerf Dog Belt #Q43203W and Kartco Belt #7655.
12-13243
BELT 203592A
8 3/16 to 8 1/4
7 5/16 to 7 3/8
30.25
26.95
12-13050
BELT 203593A
8 11/16 to 8 3/4
7 3/4 to 7 13/16
31.23
26.95
Comet Belt #203593A is also known as Manco Belt #8192. Fits Manco Model 806B, 806-01E and 806U.
203594A
BELT 203594A
9 3/16 to 9 1/4
8 5/16 to 8 3/8
32.20
26.95
203595A
BELT 203595A
9 5/8 to 9 11/16
8 3/4 to 8 13/16
33.18
26.95
203596A
BELT 203596A
9 15/16 to 10
9 3/16 to 9 1/4
33.78
26.95
12-10042
BELT 203597A
10 3/4 to 10 13/16
9 13/16 to 9 7/8
35.14
29.95
Comet Belt #203597A is also known as Murray Go Kart Belt Number 37 x 98
203598A
BELT 203598A
11 11/16 to 11 3/4
10 15/16 to 11
37.11
29.95
203599A
BELT 203599A
13 1/16 to 13 1/8
12 1/8 to 12 3/16
39.77
32.95
These 30 Series 3/4" top width belts are flat on one side and angled on the other.
The Comet 30 Series has a Green Tension Spring in the driven pulley (rear pulley).
The Letters A, C or DF Printed After the Belt Part Numbers are Not Relevant.
The 20 and 30 Series Driven Pulleys Both have a #20 Stamped in Plain View.
The Number 20 Stamped on the Driven Pulley is NOT a Series Indicator at all.