Dennis, I have the same clearance issues as many CR-125 drivers do when using the stock 15 deg intake manifold. I’ve found that the oval shaped K & N RU-1380 (6″ long) works very well for me. Mike LaGrone saw it installed on my kart at the most recent ProKart Challenge race held at Sonoma. In fact, he raced and pitted with me for that race too :)
I like the RU-1380 best because it’s a “straight” oval shape, not tapered like the SN-2550. I find that the “straight” oval shape tends to fit the Hegar air filter support that I use the best.
I also use the Sharkshifter engine mount that allows side-to-side adjustment. I understand that other engine mounts also allow side-to-side adjustment. This allows the engine to be moved to the driver’s right to provide more clearance. Beware though…the engine mount can move the engine to the right side enough to potentially cause clearance issues between the axle sprocket/chain and the center axle bearing support and/or center axle bearing/support hardware. Don’t ask me how I know…. :) I had to change to the Sharkshifter engine mount due to the Sonoma kart track requiring the use of airboxes, which are large and cause even more clearance issues… :(