TY175, TY250, TY350, IT175, IT200, IT250, WR200, SR500, DT1
OKO Kits for Yamahas
TY250 A, B, C, D
Our TY250 kit is for all TY250s from 1974 through 1977 which are disgnated as A, B, C, or D. We use a 26mm that we jet for the TY. The carburetor spigot fits nicely into the TY's manifold, and will also take the air boot once it is heated (boiling water for a minute). Once softened, the air boot will nicely stretch over the OKO's intake. Your stock TY throttle cable will work as well. We do recommend that if you are using the stock air box, two or three half inch holes should be added to the upper left side of the air box. Alternately, you can eliminate the air box and fix a UNI filter to the air boot directly. The TY250 kit can be ordered by itself or with the UNI filter.
TY175 Twinshock
Our TY175 kit is for all TY175s from 1975 through 1977. We use a 21mm for 175s with the stock exhaust. If you use the WES exhaust with the Sammy Miller head pipe and either a modified airbox or just the UNI filter, you can use the 26mm. This makes a huge difference in performance with the 175. Since the throttle cable free length needed is longer with the OKO over the stock carburetor, we offer the Venhill Universal Cable as an extra here. You can also add UNI filter (above) if you want to eliminate the air box.
Yamaha IT175, 200 & 250
Yamaha TY350
Our TY350 kit uses the 26 or 28mm carburetor. We prefer the 26mm since it gives the best low and mid-range power, and makes 4th gear wheelies easy. The carburetor fits nicely into the 350's manifold. We didn't have as much luck stretching the air boot to fit over the OKO's intake. You may have more success, but we include an air boot sleeve as shown in the middle photos in case the boot won't stretch. The stock throttle cable won't work with the OKO so we offer a Venhill cable with the kit. You can use the drop-down box above to order that. This kit will make a nice improvement over the stock carburetor.
IT200
IT200
IT200
IT200
IT250
IT250
IT250
IT250
We have kits for the IT175, the IT200 and the IT250. On the 175 we use the OKO K-104, 32mm. For the IT 200 and the IT250 we use the K-104, 36mm. The OKOs fit nicely into both the manifolds and the air box hoses. The stock throttle cables would need to be modified to work so we offer the Venhill Universal throttle cable as we do for other Yamaha kits, and one can be ordered from above. The OKO carburetors give improved power for all three of the ITs, especially noticeable in low and mid-range.
Yamaha SR500
We recently purchased and fitted a 36mm K-104 OKO carburetor to a nice 1981 SR500. We did a little modification to the engine, putting in a 10:1 compression piston, a mild cam and had the head massaged some. We believe this jetting or possibly slightly leaner jetting will work fine for stock engines, both for the SR and the off-road models. We include extra jets for fine tuning. We also have a couple of SR manifolds that you can order, listed on the right side, below.
Yamaha WR200
Our WR200 kit comes with a 30mm OKO D slide, jetted tor the 200. It fits nicley into the manifold and the air boot, but the throttle cable may need to be changed. You can add one to the order from above if you like. The OKO eliminates the mid-range "blubber" and increases both power and throttle response.
Yamaha DT1
The Yamaha DT1 as seen to the left, was recently fitted with our 28mm OKO carburetor kit. The kit includes a flange adapter for mounting to the manifold, 28mm K-101 OKO carburetor jetted for the DT1, extra jets for elevation changes and a hose to the airbox. When ordering, please tell us the distance from the intake to the airbox so we can provide the correct length. Shown, is a customer's bike, and we haven't gotten that information from him. This kit is a noticeable improvement over the stock carburetor, giving better throttle response and power, especially noticeable in low and mid-range.
