When using powerfilters you need to match fuel ratio by putting other main jets in.
For instance, CB650z with cheap pods needs 120 but with K&N pods 125
There is NO rule to calculate these numbers. it’s a trail and error process.
If you don’t change jets but do run pods, you WILL DO SERIOUS DAMAGE to your engine.
Price is for 4 main jets.
Pro tip: Price is for a set of 4 jets. To prevent buying the complete wrong sizes, you can make an estimate by drilling the old ones (in small steps) out untill you’re satified with acceleration, plug color and such. Let’s say you drilled them to 1.3 but 1.2 felt better, you order 115, 120, 125 and 130 and go from there. Yes, we know it’s expensive buying 4 sizes of jets but it’s still waaaay cheaper then new valves or rings…
We also got these for Mikuni and the CR Kei-hin types. Please shoot us an email with further questions.