Jump to content

Correct Main Jets?


02Banshee88

Recommended Posts

The only mods on my Banshee is FMF pipes and a K&N filter with no air box lid. If I'm running 27.5 pilot jets and the needle jet on 4, what size main jets would you guys recommend? Is 280-290 okay or should I go to a 310 or 330? I'm around 600ft above sea level with the temperatures anywhere from 20-60 right now in the year. Spring and summer will get anywhere from 60-100. Thanks and if you need more info provided about the bike in order to answer the question I'll do what I can!

Link to comment
Share on other sites

I would start around 310 main. You will be richer as the temp climbs so in the summer you should be leaning it out a size or two. Definitely err on the side of caution when putting smaller jets in it. Keep an eye on the plugs and feel for the motor to run crisp or stuttery. Anything but a clean pull get out of the throttle slowly so you don't cut all the fuel abruptly and shut it down to check plugs.

Link to comment
Share on other sites

Thanks for the reply. You've been a big help. So as it gets warmer go down on my jets? Is that what you're saying and are the mains the only ones I adjust?

Yes, lower jets in warm temps and raise them in cold temps. Cold winter air is far more dense then hot summer air. Denser cold air charge means there will be more Oxygen molecules packed tighter and there fore you jet up in the winter to give it more fuel to compensate for additional air.

 

There are three jets in most typical carbs. Pilot, needle, and main. Typically the pilot if it is dialed in only needs to be bumped up a size of two in cold weather. The needle typically only needs to be moved one notch. Mains can be 2/3 sizes if you get weather that is freezing temps.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...