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

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

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.

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.

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.

I think I am going to wait until all the parts come in and get the bike running before buying/making J-Arms. No point in having new arms on a bike that doesn't run!

I thought it was a joke, but I'm always up for a challenge , and you're right; I am stubborn and cheap and don't really want to spend a grand on some arms, but that's just me. I've made some custom billet parts with my university CNC machine, but ik suspension is a lot different. ill reach out to Tfaith to talk suspension, thanks!

Actually, this is now what I'm planning on doing. I have knowledge of suspension design from FSAE, and I am a pretty good gas welder, so it's worth a shot. worst case i just waste a few hundred bucks. just gotta figure out what chromoly tubing to use. I might make another thread outlining my process but we will see.

Okay I’ll check em out, thanks!

As the title says, im looking for some extended j arms, but they seem few and far between. I see that Fireball racing but they are getting up there in price. I am considering making my own chromoly ones, but I don't know if I can fully trust my suspension design skills. is there any other companies that make them, or is Fireball the only option?

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.

Yes, stock carbs

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!

would it really be that bad though? I would have access to precision machinery and would get sleeves made by a sleeve company. I just don't understand how they are so much worse than cast cylinders. Would it be due to the very specific port timings needed for an engine to run well

what do you mean?

I am almost certain all banshee frames were painted from factory. the way I stripped mine was with a sandblaster, but I have heard of people getting them dipped in acid or something, usually powder coating companies have them. maybe you can pay them to just strip it for you? just an idea.

Since I am in university, I have access to CNC mills and lathes, as well as manual ones and I wanted to try and make a set of cylinders or a Monoblock. the only cylinders I have seen that are billet for banshee's are the old twister ones, but I can find almost no information on them. if anyone has and information or pictures of twister cylinders, or any billet cylinders, it would be greatly appreciated. Thanks in advance!

The vin is on the clutch side frame tube below the engine. there's no indication of another tube being welded in. sorry I don't know how to compress an image below 50 kb without making it impossible to actually see.

From my frame. I asked the local Yamaha dealership If they could run the VIN, and it apparently came back as a 1999, but it seems a bit odd that someone would do an A-arm to J-arm conversion. Maybe someone re-engraved the vin? but the vin seems to be factory, so I don't really know.

Alright, thanks skeeter

I do not think so, its just what came on my bike when I bought it and I just wanted to make sure it wouldn't hurt power.

My bad, I am new to this, first time owning a 2 stroke, just trying to figure things out.

Did you use an oil and fuel resistant gasket maker on the cases? If the gasket maker is disintegrating, it can cause a leak. If there is a crack or imperfection in the mating surfaces or something causing oil to leak through the case to the stud, you can just fill the hole with yamabond, but that could cause issues down the line; its better to get it welded and milled down to be even with the case.

I second that, mine had a leak in the carb boots due to cracking of the rubber, as well as the base gasket.

A few months ago, I bought a banshee sight unseen, which was probably my first problem, and only rode it for 3 days, each day something went wrong, and on the third day, I blew a base gasket and overheated the engine, melting the pistons to the cylinder walls. Anyway, I bought brand new Niche cylinders + head, Wiseco pistons, V Force reeds, and a hot rods crank. The old crank was probably fine; it was a Wiseco A1 crank, but it was at the upper limit for big-end connecting rod side clearance. This full backstory ties in with me knowing the owner of the Yamaha dealership near me, who said that porting was the way to really wake up a stock bore banshee. he said that he had his sent out to I think one of the sponsors on here, but his is also a big bore 520 or something. I am fairly mechanically inclined, as I have tinkered with things since I was a kid and am currently in school to become a mechanical engineer, so I decided to do my own very slight porting on the new cylinders. Porting is such an in-depth topic, so it really led me down a rabbit hole, which showed me that I really have no clue what I'm doing and that I really should not go crazy porting on these cylinders. I ended up coming across a video from Herr Jugs Racing called "Banshee porting 101 simple start" which is the video I followed much exactly. I raised the exhaust port roof about 2mm and widened the exhaust port by about 3mm. also cleaned up the intake port a little bit and knifed the divider a little bit. just wanted to come in here and show my results and get some feedback for if I ever do this again or if it will blow up immediately after building it.