I have ordered a 170,175 and 180 Mikuni Main jets. So far I have a modified end cap and I plan on pulling off the air box lid when I jet it. Which jet should i use with the air box lid off and the stock filter? For now. Eventually I will put on a K&n filter after the K&n what jet should I use? Thanks

 

Also about how much more hp over stock will a slip-on(end cap), jet and the air box lid pulled off give a DS 650?

 

Dude I am going to save you a great big headache and alot of time. First thing you need to do is order you a jet kit from K&N or Dynojet. They are the same thing but whichever you can find cheaper isthe one to get. The reason I say to do this is because you will have every jet that you would ever need to ride and they are supposed to be a more effecient jet setup. More power with better economy. I did notice after I did mine that it seemed to run smoother, not as rough. I know that money is a issue but it truly is the way to go to solve the jetting problems. Take it from someone who spent two and a half months trying to get his dialed in. One day later it was done.

 

I have worked directly with 3 DS's with the end cap mod and the best jetting I have found is Mikuni 180 or Dynojt 190. Move the needle down one notch and the air screw out about 1/2 a turn. The End cap improves the low and mid power vs stock and the top is about the same.

 

Hurycne, Did you mean move the needle clip down a notch? which in turn would make the needle move up a notch. That's how my setup is with a mikuni 180 main jet.

 

There is a nice big article about jetting in the April Dirt Wheels. From what I read, the fastest way to find the best jetting is to start out very rich, so the throttle kicks out at full throttle. Then go down one size at a time untill this stops.

If someone trys this, let us know how well it works.