My HM100 on my super bronc came with a 5/8 spacer off the engine it was also 19mm inside dia my carb is 26mm so not good . Also the fuel inlet is on exhaust side and the inlet and head pipe touched , so when it got hot motor ran like sh-t . So got one of those drop down type manifolds that turn the carb 45 degrees , didn't like the two 90's it turned and the upward travel it would have to make . So i cut down welded it back and have me custom manifold that gets the carb away from the exhaust . Here some pics
