tfaith08

I wouldn't say the end of the road, but there's gonna have to be some new ways of thinking before significant improvements can be made. It's evolutionary at this point, not revolutionary.

It will, however, show when something is way off. If its garbage without the piston flying by at 9000rpm, it sure as hell will be garbage with it. It's more for a visual idea. It isn't a diagnostic tool or any other tool for that matter, it's only to get a visual sense of what's going on and to help tie things together. Any modern CFD program can run it. The software I had could run a model like that, but the computing time for even a basic 1 intake, 1 exhaust port model running at 6000rpm and all other conditions as accurate as I could manage had a computing time of over 100 hours. Even on a 16 core setup, you're looking at a full day of computing time on a model THAT basic. Throw 6 more ports in there and you're looking at hundreds of hours of computing time. No builder that is relevant to this community is going to dedicate the time and money into a new way of viewing an already known process that may not even pan out for them because they lack an extensive background in college level fluid mechanics and thermodynamics. With builders already pushing 80hp on trail-ported stock cylinders, there isn't much else to improve upon. On the other hand, I did have a lot to gain by learning that way, only I didn't have the resources to pursue it. What little I did get to model showed me a very similar version of blowing cigarette smoke through the transfers. With a single port and a static model, I was able to see just what a piston did to affect the flow of the transfers and how cylinder and crankcase pressures affected each other. Combining that with the smoke was how I started making things faster. All in all, the time spent funding the means to model a near perfect port far exceeds the time spent going through cylinders and tons of gaskets and solvents and finding a close enough option.

I think I've read about those claims before and they never made sense to me either. The 2 main types of flow (laminar and turbulent flow) with the same fluid are dictated by velocity. To make something turbulent doesn't mean that you've effectively increased flow, it's the other way around; higher velocity creates turbulent flow. Once explained like that, most think that laminar flow is possible with the pressure that the intake charge sees upon the transfers uncovering, which causes the charge to slow. I don't know the figure right away, but the velocity for atmospheric air to flow in a laminar state is far below what is going to be seen in any engine. The first part of the quoted concept, I do agree with. I got my start by watching a guy build hotsaws. That's purely a free for all because of the vast difference between stock and race condition. There'll be ports all over the place and you won't know what made any one cylinder work, only whether it did or didn't. Throw nitromethane, big ass carbs, custom heads and domes, custom pistons, etc. into the mix and shit gets wild. I was fortunate that A: I even had a guy guide my way of thinking and B: that the guy I had around that had won several national champoinships. But his ideas were different than what most people are after with Banshees. His powerband width was around 300-400rpm. Translating that to an MX or dune port concept for a Banshee is an entirely new dynamic on what I knew and is a large part of why I ovethink things with porting. Every time I ever read a book, I felt like all my questions were answered until I started back grinding. You'll always find more questions, usually within 5 minutes of when you started. Every angle can be very close and every port to an exacting duration, but the port will be shit if the remaining geometry is off. If you call any builder, they'll tell you what durations they use for whatever you're thinking about building. Smoke, at least in the way that I described it, is a good way to visualize the ports in action. That's about it. There's simply so much going on with pressure differentials all over the place that you could never hope to see it all with just a cigarette. I'd imagine that a super-stuffed crankcase would make the ports flow more like they're intended. There's a few other ideas that I have floating around about small crankcases, but I'm working some extreme overtime and can't quantify them all now. As for what happened to me, I was robbed of a huge chunk of tools and a customer's bike, plus I was scammed by 2 customers working together. It was about a week after I started contacting blasterforum to get everything lined up to be a site sponsor. I'd planned on seeing how well I did there and then moving here, but things change. It's a big relief to let go of that challenge.

The best route is to buy a non-running engine and have it built for when your engine either lets go or starts to show significant signs of wear. That way, you aren't missing any rides due to it being out at a builder. It's an added expense or $400-1k, but I've known people to miss 4-5 rides while waiting on an engine. Benefits of a builder: you know the work is done correctly, you don't have to do shit Cons of a builder: shipping and labor will total 500-600 depending on the builder and shipping. Fwiw, I was quoted a 4mil stock cyl plus labor and extras at $1900ish. Serval was around $2600 including more extras.

There's a limit to how much you can cut (obviously). Cutting the spring will actually make the spring itself stiffer, but shortening also reduces the preload of the spring which has more of an effect. The end result is minor. I'd leave it where you are now so that you still have stiffness in them to force the slides down incase something tries to stick a slide open. A good cable that has been lubed properly can go a long way. I got a pressure/vacuum bleeder and forced lube through the cable and some pretty nasty shit came out the other end and it made it much easier. You can rent one from most parts hosues. Buying a new cable will likely benefit you and those DO need to be lubed. I've got one on the way from FAST and will be adding metal tubing around all of the bends and gluing them in place so as to keep any tight spots from forming. I also ordered an extended thumb throttle. Lastly, make sure the components in the thumb throttle housing are clean. Removing the spring there makes a nice difference, but you will find out very quickly if your cable is binding up. That is a mod that I do not recommend.

Make it easy and call a builder and say that you wanna price a 4mil. You don't need to know part numbers, only whether they recommend something and whether you can afford it.

Can you post a video?

Often times, "what's up your sleeve" isn't going to be a good idea unless you're talking about which color you're going to paint it. Pics would potentially allow us to stop a bad decision.

Have you leak tested? Is the choke tube connected? Have you set the floats as per the manual? Did you replace the float valves? is the fuel inlet clean? Can you blow carb cleaner through all fuel circuits? Is the washer under the main jet? Are you jets of the same size on each carb? Junk the boost bottle and revert to the stock crossover. No performance gain and they can contribute to cracked boots over time. If that doesn't answer it, look up videos and pictures of these carbs. Something will pop up after a while that you forgot to do. Also, read into other instances of people having the same problem.

What I'm using is effectively a CCS setup minus the right angle piece and a different label. All the parts are interchangeable. I really only need a right angle CCS piece and I'll be back where I was. The market for cleanups is larger down my way than anything. Most guys want a B-series, SR20, 1/2JZ, SBC, or mustang head cleaned up and port matched on the cheap. I occasionally get a turbo to port (which is my profile pic) and some intercooler tubing to smooth out, header to clean up, etc. I almost never get to grind on a 2-stroke. Even when I do, it's usually a 125 or smaller dirt bike or a cylinder that the owner may (yeah, right) have bored or replated. The latest trend has been getting more airflow out of some high-end eCigs. Basically, about the only thing I don't port these days is a Banshee. I had a handfull come through about a year ago and a few spares, but I never had a test mule to really dig deep like I did with the 250Rs.

The angles of the boyesens has always intrigued me since I never got much of a chance to build a test mule. I think (keyword: think) there's a correlation between the downward angle of the boyesens and how they feed the transfers at different RPM ranges. Flatter angle seems to be better for high-rpm, more vertical seems to work for more low end power.

Before my tools were stolen, I had a CCS right angle and a grizzly straight piece with CCS bearings (whatever those were) and a grizzly motor. Worked well enough for me. I'm back to just the grizzly setup for now since I only really only work on 4T heads and mild 2T cleanups.

Put that money toward buying a set of used shocks that'll work. Option 2: buy those and be sure to bring a camera on your next ride so you can show us the carnage.

The one you pulled off of eBay looks nothing like the ESR ported cylinder that I've seen, nor the one on his website (which I'm not sure that it isn't ported for looks to begin with). I've seen one in person and the Boyesens look very, very similar to yours. I didn't criticize you as trying to copy him, I said it looked similar. If you wanna take that as an insult, that's fine with me; that's all the explaination that I'm giving as to what I meant. Of course, eBay is pretty credible... There's nothing wrong with a knife edge if you know the exact direction of the flow and tailor the edge to it. People say that knife edging will slow flow, but most issues assiciated with kinfe edges are going to come with the wrong choice in placement and poor angle selection. The issues pile in when the knife edge doesn't split the flow in a way that it can easily flow around it. More often than not, there's more gain to be found elsewhere with the same amount of trial and error. Rounging edges is an easier way to get close enough to the potential that an area has, but knife edging will ultimately be more effective if you know EXACTLY where and how to place it. How much that will help is dependant on how many different directions of flow that area will see and the geometry of the edge and surrounding areas, to inculde the length of the divider. The 2 extremes of that would be the transfer divider (longer and can take a knife edge without compromising flow after the divider) and the divider between the intake and boyesen (shorter and difficult to knife edge without forcing flow in a particular direction). If I have one shot at porting a cylinder that I'm unfamiliar with, I'm going to round nearly every edge I come to. Ultimately, proper duration selection and having a port that flows well and whose areas work well together is going to be what makes or breaks a porting configuration. UR, I'm not going to turn this into a shit-fest if you aren't.

$20 that RU gets pissy with everybody and tells us that we're all wrong.

That's strikingly similar to ESR's stuff. Eating away at the intake side of those dividers has shown me very little gains, if any. Lining the outsides/rears of the boyesens up with the cases and making it a uniform curve can (emphasis: can) show a slight bump in response and make jetting a little easier. The trick there is to make it easy for the AFM to flow in and not back out. That's the only time I've ever heard of the intakes on THAT type of intake showing anything significant on a dyno. There's more gain to getting a boost port design down pat than anything. As for the banshee, there have been several cases of near-stock intakes making 70hp, and numerous claims on here of near-stock intakes making +80hp (which I can't vouch for), but the hardest running set that I've ever my hands on looked pretty damn close to stock. In the way of looks and logic, there's much to change and improve upon. but those 2 don't get you anywhere. All in all, a super-streamlined, to the .0001" intake is going to be negligibly better than one that was given significant thought and executed reasonably well. Even then, the intake isn't going to make or break a port. If you could find someone with the CFD capabilities to model and measure everything and run it in as dynamic of a way as any 2-stroke crankcase and cylinder are, you could see some improvements to be made, but that stuff is way above anyone's head that I've ever spoken to. HOWEVER, to say that the intakes are too restrictive for most porting designs on the basis that reeds offer gains doesn't hold water.

Intakes look good enough, but that's largely unimportant.. Transfer shaping is very important, as well as durations. Power hides in the transfers. This subject can go on for weeks and never exhaust everything. It's best to do your own research and define the intended end-state. If that goal is pretty high, you may want to find a builder because the odds that you hit the mark on the first go are very much against you. But since you have it together, that's pretty useless info.

I don't know how many people I speak for, but I have no clue what stage 2 carbs are. Stage 2 jetting, maybe? If that's the case, I'd start with a box full of jets and make sure you aren't lean. That's an easy way to start having to look into the rebuild process or to find a builder. I'd look into these: Pro-Flow adapter w/ choice of filter OR pods timing plate aftermarket head and domes You can have all of that for under $400 if you look around a little, even less if you buy used. If that still isnt enough, I'd consider what mike0chek said.

70hp is pretty simple these days if you know your way around an engine. My recommendation would be to call Jeff at FAST and get a serval kit ($1723) with everything you need, minus pipes, filter, timing plate, jets, and a clutch. As with anything, it comes down to the measures you take to keep it running properly. A solid build with great parts selection will leave you with a tanked engine if you don't tune correctly. The lack of research and attention to detail are why so many platforms have a reputation of poor reliability, namely banshees. Of course, if you mean reliable on all fronts, general maintenence will get you 80% of the way there. At the end of the day, the difference between an engine that lasts a week and one that lasts 4 years is often a matter of skimping on less than a day's worth of work and a day's worth of income.

Here I am with my stock link, near-new elka rear. Wish I had the money.

Man, I want this... Good seller. GLWS.

Don't forget about Redline.

Son of a bitch I wish I had the money for this... Damn good price. GLWS.

Not sure. I do know that '07 is different from the earlier ones. I did a side by side comparison when I got mine in with an 07 and wasn't happy. There are only a small number of casting differences between the banshee and early YFZ units, but no performance upgrade whatsoever. From what I understand, any '07+ YFZ is going to be a performance upgrade if that's what you're wondering.

An '07 YFZ has a larger bore master cylinder. I have a friend with one and it is definitely larger than the older YFZ and Banshee units.