Jetting For Fully Rebuilt Banshee

[banshee1999]

So I am pretty new to all this banshee stuff, and especially jetting, so I don't even know where to start. My mods are CPI pipes, V-Force reeds, slightly ported cylinders (stock bore), advanced timing (about +4). I'll probably get a UNI filter replacement for the stock air filter since I ride in dusty conditions and heard that K&N filters do not work well in that sort of stuff, and maybe a cut airbox lid, but I do hit water now and again so I'm not sure if that is a good idea. I also ride just around sea level. pretty much everything on the bike has been replaced, so there shouldn't be anything stopping airflow in that regard. i don't know the pilot size off the top of my head, but the mains are 280's right now. Any help is very appreciated, thanks!

[ClaudeMachining]

So I am pretty new to all this banshee stuff, and especially jetting, so I don't even know where to start. My mods are CPI pipes, V-Force reeds, slightly ported cylinders (stock bore), advanced timing (about +4). I'll probably get a UNI filter replacement for the stock air filter since I ride in dusty conditions and heard that K&N filters do not work well in that sort of stuff, and maybe a cut airbox lid, but I do hit water now and again so I'm not sure if that is a good idea. I also ride just around sea level. pretty much everything on the bike has been replaced, so there shouldn't be anything stopping airflow in that regard. i don't know the pilot size off the top of my head, but the mains are 280's right now. Any help is very appreciated, thanks!

Stock carbs??

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[banshee1999]

Yes, stock carbs

56 minutes ago, ClaudeMachining said:

Stock carbs??

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[locogato11283]

You should end up about 280-290 main and 27.5 pilot.

Do a wide open throttle run and shut it down. Pull the plugs. The straps should be cardboard color.

[banshee1999]

On 4/4/2025 at 11:25 PM, locogato11283 said:

You should end up about 280-290 main and 27.5 pilot.

Do a wide open throttle run and shut it down. Pull the plugs. The straps should be cardboard color.

okay perfect, thanks for the reply. I've seen a few videos on jetting and the guide for jetting on here so hopefully I don't blow up my engine right away lol.

[locogato11283]

You'll be fine.

[banshee1999]

I was messing around with the bike today, and the bike seemed to be lacking mid power a lot, and the idle seemed off aswell. When I was pulling the plugs, they would have oil on them but the actual strap wasn’t colored, just silver metal. Maybe I just didn’t run it long enough? It was a very noticeable powerband pull though, so it may just be the needle is leaning it out too much. There’s also cracks along the top and bottom welds on my CPI’s, which have black exhaust oil leaking out of them, so I’ll have to get that fixed. Main concern is not getting a reading on the plugs though, I don’t think I’m lean enough to see nothing on them.

[locogato11283]

How long did you run it?

[banshee1999]

For the idle circuit, probably around 5-10 minutes, and for the needle and main jets at 1/2 and WOT I don't have a long street so it was probably only a few minutes if that. it might be worth it for me to find another longer stretch to do the pulls on. Also is it even worth it to have a lid on the airbox? I do run into some water, but I can go slow through it and usually just can go around. The jets i have at hand seem to also run better with no lid, The bike has a really rich bog with one on.

[locogato11283]

Pull the lid.

What’s the jetting?

[banshee1999]

Jetting is at 27.5 pilots, 1.5 turns out on air screw, middle needle clip, and 280 mains. I mainly just don’t want to get a new pilot jets as I don’t think my local dealership carry’s them. And I’ll lose the lid, it seemed to like that better anyways. In the next week I’ll do some more tuning and try to get better plug reads.

[banshee1999]

Just need a bit more help to get this thing running right. Without the lid, the idle from cold is high, and then gradually lowers to a decent rpm, but after I ride it for like 5 minutes it doesn’t idle at all. I don’t choke it at all to start it either. 27.5 pilot, and I tried air screw at .5, 1.5 and 2.5 out. Also, I accidentally left the gas running to the carbs, and there was a puddle of gas under the bike today, and I think it came out of the carb overflow thing, not sure though

[locogato11283]

You set idle with knobs?

I always set it with the perch adjustment.

[banshee1999]

Oh like you tighten the cable things on top of the carbs to set idle? I’m also thinking the float needles either are stuck, or are not sealing as there’s was gas on the floor, when the snow clears up I will try the jetting again