I have just about finished a massive up date on my 1976 Ty 175. Most have been to the power system itself. New cylinder bore, ports, intake, exhaust opened up and flowed. 250 reed cage and Boyesen reeds and a new OKO 26mm carburetor. The main thing I did afterwords is to build a straight flow high capacity air box. I thought I could maybe buy one, but all I saw was about the same as stock except for being made out of aluminum. After riding my bike extensively, the straight flow is the absolute ticket to optimum performance for the power plant. You guys need to do this modification, it’s a must if you want your bike to be at peek performance.

Cool mod. Curious though, did you run this airbox with the stock carb, or the OKO with the stock airbox.

Reason I ask is that the OKO is a superior carb in many ways.

I ran the box with the stock carburetor and the OKO after I got it. The OKO carburetor is the absolute ticket, and with the straight high flow air box the 175 is a trials animal. I’m also running a expansion chamber and the motor has extensive modifications done to it. Frame is modified extensively also.

Hi PMK.
Would like to see the air box you fabricated. Any details would be great.
Did it require re-jetting?
Thank you.

You need to modify the frame, but its possible to fit a custom-made 3 litre air box to a TY, which with a better carb, exhaust, and ignition, really improves a 175. www.tysport.uk/ty175-tuning/