blowit

I agree. also put brand new plugs in. A few hours old does not cut it. You just need to rule that out. Also check for blue spark and check grounds. Also unhook all the TORS stuff to rule that out as well. A jetting check will help tell the story on this one. Brandon

Sorry, I don't want to be the one the guy that is full of crap but just like some defense contractors, it called "proprietary info" so I have to decline on some data. I think there are some sharp people here so I have to watch how I present. We spend months engineering our products and we don't like it when others are too lazy to do engineering. I also try to "dumb" things down a touch because I even get peeved with other engineers' chat. Call it what it is. Also in reference to the intake flow data, and I think we know that that "indicated" value depends a bunch on where the measurement is taken. It has been a huge problem in V8s of having nice flow across the carb and then dropping to sh** in the intake and causing fuel to accumulate. The tunnel ram helped a bunch and the port injector was a biggy.

What I want to know is where did the near mach intake flow velocity come from? You might have your intake and exhaust numbers mixed up a bit. I cannot give you exact numbers because of the type of work we do but we have employed flow sensors in the intake to give the correct data and it is not mach. One thing to look at is the "pressure" of the air. I would also have to disagree with a 2mm boundry layer. We do have aerospace engineers and that data has been well documented by us. Sorry, can't give that up either. I would say there are way too many assumptions made here in respect to flow in the intake tract. "tumble" is a standard word for 2-stroke intakes. The reason has to do with the frequency of the reeds inducing a push-pull effect in the intake. The vanes in the V-force are simply used to isolate each reed element from affecting another. All in all, the V-force has solid engineering behind it but a crosshair in the intake is reaching and for what I am not sure. They will not increase velocity. You will have to induce throttling to do that.

Without actually riding it, it sounds like a lean condition if you are experiencing this at full throttle situations. Since both cylinders should jet the same, you need to do a plug check from WFO to see if it is indeed lean. If so, you may have a clogged carb, poor porting (if applicable) or an air leak drawing air in and leaning it out. Cracked intake boots can cause this as well. Also a good idea to check your carb balance. Brandon

IN reference to our shift star modification that you saw on ebay, many elements are considered when modifying OEM parts. We designed a unique cut in the stars to help the banshees shift as easy as possible. Our modified shift stars are a good addition for any banshee, trails, drag racing, general rec. riding. One thing to remember is these parts are face hardened from the OEM and must be re-treated after cutting to minimize wear on the part. The compound radius works on the same principles as the compound hunting bow. Brandon Mull Engineering

Glad to help but as mentioned above, I did mislead and I guess I need to stay on my toes here. I forget that the banshee does indeed run an isolated regulator with no means of rectification. The above post is a sketch of a bridge rectifier that does not exist in the stock banshee lighting system. Most newer bikes will all have the rectifier diodes and one glance at a bike tonight and I remembered I dropped the ball on that. However, my explanation still stands. The banshee regulator does not have anything to do with your ignition. Regulators are rated in the amount of power in watts that they can dissipate and this is why the upgraded stators need an upgrade on the regulator. Yes, if the regulator has to wires in and two out, then it would be a bridge rectifier. L1, L2 input and +/- DC output. Many times the regulator is piggied on with the rectifier in one package. The way the bridge rectifier works is rather simple and basically separates the + from the - of the fully oscillating sine wave form of the AC power. Even with a rectifier, you need capacitance to further smooth the power. The caps act as a shock absorber to "smooth" the current. Light bulbs don't care AC or DC much because they are resistive loads but inductive loads such as motors care a lot about the form of power. OK, that is getting off the subject. Check those connections and let us know. Brandon Mull Engineering

OK, the regulator has zero to do with the CDI ignition circuit. The regulator that we refer to is called a bridge rectified, regulator. It functions by by first rectifying voltage or smoothing the ripple AC voltage created by the a stator. Because the flywheel rpms change all the time, so does the AC current produced by the stator. When you test your lighting circuit on a constant loss ignition like the banshee (with no battery) the power will be very dirty thus the reason it will read with your meter set on AC and not DC. Make no mistake though, your lighting system IS DC. The reason for the dirty power is because your rectifier does not include the extra capacitance needed to suppress all the ripple voltage into a flat line +/- DC. The extra caps are just not needed on the banshee because the power is clean enough for the lights to work. A battery acts like a big capacitor thus the reason that electric start bikes will have much cleaner voltage. your regulator functions to drain excess voltage to the chassis through ground of the component chassis or a remote wire. Either or. Now if that regulator is not grounded, the part can still be good and your lights will still blow. Ground is a must. your CDI box is "potted" which means you are not going to open it and see what is happening. The reasons for potting are many but mostly moisture lock, vibration damping, heat dissipation through conduction. The CDI is all DIGITAL which I think is always funny when people market a "digital" ignition. The CDI has many diodes built in to rectify it's current and prevent overload and transient failures. The common voltage regulator can be many shapes and sizes but all serve the same purpose. I am convinced in this instance that something else is going on that is very simple. The exciter coil or pulse generator only creates a very small voltage to offer a reference voltage to the CDI for timing. It does not contribute any sizable amount of power thus it can be grounded shorted or whatever and would never cause a complete ignition failure. I would be looking closer at wiring and let that multimeter be your guide. Resistance checks all around and unplug those coils and reference them to ground. Shorting is easy to find. Hope that helps a bit. Brandon Mull Engineering

Oh, I did do a search and quit when I read a post that someone says that octane is the most explosive compound. Ouch, I don't want any then. I think Heptane and Octane got rather interlaced there. I would not that the hydrocarbon chaining of AV fuel is much closer to that of common race fuels than that of standard pump fuel. Either way, we still cannot use all the potential of Gasoline because we cannot break that darn fuel apart during combustion

I guess I should not make generalizations here but "generally" speaking, most AV fuels ARE leaded and so are racing fuels. I am well aware of unleaded race fuels but I am not aware of any 110 octane unleaded fuels. You cannot achieve higher amounts than 100% iso-octane in a given fuel chain. Anything over 100 octane is a calculated "performance" number based on data back side of the 100 octane limit and the Engine test data. As I recall, most of this power 110, Trick 110, VP110, which I believe to all be the same fuel, all share the same specific gravity, and lead content which I think was 4.23 grams/gal. Yes sir, I do know what blow down time is and the term is used in two strokes as the port time in degrees in which the exhaust port is open and the transfers are not thus blowing down the pressure in the cylinder. I guess I should have used power stroke for you. Yes, you do need to light race fuel sooner because it burns slower. That is not my opinion, it is in the books. There are burn rates for every fuel out there and the lower the octane, the faster and less controlled it is. Fuel "tuning" is something that few people do but we have proven more power just by adding a few ounces of Acetone with some of our fuels, for example, and helps a bunch to speed the burn rate. I am very familiar with Alky and the O2 numbers are based on the H molocules bonded to that carbon. The reasoning behind the O2 content at any given time gets very exhaustive. I am sure you know that H is very attractive to O thus the reason it is a Hygroscopic fuel. This is also why it takes so darn much fuel when running methanol. It is also slightly acidic and likes to attack the oxide protective layer of Al. there are so many variables with gasolines like how the fuel was cracked, how it was blended, what additives were used. Also with race and AV fuels, you just have to know what you are buying. Alky on the other hand, is a very simple compound. Only drawback is it does not have as many BTU's/gal as gasoline.

NO, the regulator will not cause this problem. It is also rare for a CDI failure but I have had to replace a few. One this to check is those damn spark plug caps. pull them off and check the coil without them. then remove the plug wires from the coil and check all that. You should not just loose your CDI over this but I am not the one looking at it right now either. Brandon Mull Engineering

AV fuel is absolutely fine to run and will not hurt an engine at all. Its higher octane is is mostly achieved by the introduction of lead in the fuel. Lead retards detonation by absorbing shock waves at at molecular level and, as being a non-ferrous metal, absorbs heat readily. This means it will actually extract heat from the combustion cycle and carry it out the pipe. Lead also acts as a lubricant to further reduce the chance of detonation. Anytime you purchase a commercial fuel that must meet so many criteria and EPA guidelines, it has to have special additives. These additives lengthen shelf life, reduce fuel gel, minimize deposits, and so on. These additives can be as much as 15% of a given fuel by volume. These fillers do not contribute to the combustion cycle thus acting as "inert" fillers in the cycle. No good for HP but when your flying, fuel gel can be a much bigger concern. Racing fuels by design are refined with different guidelines and additives are drastically reduced thus allowing more burnable fuel in the combustion cycle. They generally have more lead as well to also raise the octane number as well. In short, race fuels are far superior to AV fuels, BUT, please keep in mind that as the octane of a fuel is raise, so is it's rate of combustion. This means DO NOT buy more octane than you need. Please use octane as a " safety" number as this is only the rating of a fuels resistance to pre-ignition. I think someone was asking about 175psi static with 4 degrees advanced. That setup at sea level might indicate a 21cc chamber with a stock port height and a corrected comp ratio of 6.8:1. That ratio is within the safe limits of standard pump fuel. Will someone make more power with AV fuel with that setup? NOPE. With race fuel? only if the ignition is further advanced to compensate for the slower burn rate. You have to "get the party started" a little earlier with race fuels. The nice thing with race fuels in thumpers is the slower burn rate really helps by applying for to the piston through most of the stroke, not just 20 degrees like pump fuels. Unfortunately, two-strokes do not have a long enough blow down time to take full advantage of this. In short, you should only use AV fuel over pump to supress detonation, not the make power. The big power gain is in Alky because it has extra O2 bonded in the fuels molecules thus acting like a small chemical supercharger. Methyl fuels will contain almost 50% O2 by molecular composition.

Your voltage regulator is designed to pass any voltage above 15V direct to ground through the chassis. If your regulator is not properly grounded, this can cause an over voltage condition same as having a bad regulator. Your regulator is part of the "charging" system and is is completely separate from your " ignition" system. The only thing they share is the flywheel and housing. Wiring is completely separate so one will NOT affect another. If you have a lack of spark, there are many things that can cause it but most common are the safety switches associated with the TORS carb tops and thumb throttle. The very first thing to do is resistance checks across your source coil, and ignition primary and secondary coils. Also look for simple issues like severed or unplugged wires. The banshee electric is stupid simple so the problem should not take very long to find. Brandon Mull Engineering

Listen, fi you have pitting on the top of the piston that looks like sand blasting or a similar appearance on the head, you have detonation and like I said, when the motor calls for 110, you use 110. You should have don't a comp test because this would have told me what I already know. The noise your hear is most likely ping and it will kill that motor in short order. The crack looking vanes you saw in the dome are actually fuel additive deposits and do not contribute a problem. These additives do not burn during the combustion process thus they like to stick to things. Those vanes not an indicator of trouble but pits ARE! You can either rechamber that head to displace more or run the better fuel. Actually if you would do a comp test, I can tell you if you can get away with just a 50/50 blend. You might want to check those rings in the piston about now. They like to seize to the piston which is never a good thing.

Your compression numbers are almost right on. Your elevation is lower than most so your number will come in a bit higher due to a denser air charge being delivered the the engine. 175 is right in the window for pump fuels in the banshee. Now, if you want things to get even better, remove the pistons and carefully shave 1mm on the exhaust port side to increase your exhaust port duration. This will increase port duration by 4 degrees and drop static compression by 10 psi. Your bike will run sweeter in the higher rpms and reduce the chance of detonation. In regards to the squish clearance, I am thinking we have a measuring problem. You need to make sure and measure the farthest part out right at the sleeve surface. As you move toward the center, that number will grow. You can also pop the head off and inspect for a zero deck condition that the banshee should have which means the piston edge comes up flush the the deck of the cylinder. You can then measure the gasket and squish depth in the head and calculate your squish in this manner.

Oh there is no doubt our flow bench would quickly discredit it in terms of flow. The question is, would the reduction of flow somehow improve performance by more organized airflow to the reeds? I know engines, but I am constantly learning new ways to make HP. I am betting this ain't one of them though. Brandon

Listen, I would NOT ride it until I knew what was going on. It IS going to pop if it is "knocking" for attention. If you engine is calling for 110 race fuel and you put pump fuel in it, that could be fuel knock and it is not to be ignored. Knocking can put holes in pistons, kill rod bearings and more. I can't honestly remember if that bike is air cooled but if so, overheat is doubtful however, 380 is HOT!! I would check that temp meter. You need to do a compression test and if you don;t have 130+ in that motor, you don't have a motor. Sounds like your rings may have welded to the piston and you have piston slap. This is common in overheating. Either way, I would not race it. JMO Brandon Mull Engineering

Um, I would second that though these intakes will direct flow, they WILL however restrict it. Anything within an air stream will disrupt it to a degree. Also, the more air contact surfaces you have, the more static boundary layers of air you will have. This is basically saying that the air very close to any surface does NOT move and forms a layer of air for moving air to "ride" on. This WILL induce drag and reduce CFM in the intake. Further more, why would you straighten the airflow pattern just before the reeds? The reeds induce air tumble caused by the frequency of the reeds opening and closing. Sounds like another BS product. We might just test that theory on our dyno. Kinda go me thinking.

Um, that motor is toast! I am an engine builder and it sounds like a failed rod bearing and your piston is "tapping out" or hitting the head. This noise is also heard when the skirts break off a piston and bounce around in the crankcase. Either way, roll out the check book. Brandon

The push/pull style brake switches cannot be tuned to near the precision repeatability of a contactless switch. Our kits are designed with overload, regulation, and highly precise circuits to ensure exact shift settings. Common switches just won't work for this and our kit allows the rider to tune the cut point and duration with the turn of a screw and the switch can never fail due to no moving parts. Sorry, we don't have any pics of the kit installed but it installs with a small braket on the shift shaft and it totally invisible to other riders. You can hear it work but not see it. Please don't don't confuse the kit with just a simple timer. All components are very precise for professional riders. Hope that helps a bit. Brandon Mull Mull Engineering

Hey, your problem is in your carbs unlesss the problem followed you when you switched the carbs. I build high end engines and have a shop around Wichita, KS. Drop me a line and I will help you along. Your crank is not "out of phase" or whatever that means. Things just need a bit of tuning and you carbs are out of sync. No biggy and 1hour is all it needs more than likely. PLEASE don't change the pilots because that is not the problem. Brandon Mull Engineering

Hey, I really need more info to help you. I build engines and have a shop near Wichita, KS. Things I need: Head type, CCs, comp. static at your elevation, pistons, pipes, any thing else you have. Sounds like you need a new SU. Tires will need to be haulers 10 paddle, bump the 6in swing and run 2in. Trust me, you are not hooking down track. Also you need high comp. with race gas min oct. 105mon. If you have the FMF pipes, go the CPI or toomy. If you can give me more info, I can get you to the front with that motor. Actually strokers decrease rpm potiential by decreasing rod linear speed, and this increase inertial forces at the crank causing more wear on it thus reducing life. However they increase the rods mechanical advantage over the cranks center offering better torque. Long rod works great with a little of both worlds. Drop a line and I will try to help. Brandon Mull Engineering