SLORYDER

This is confusing. You mostly drag race, or you mostly ride off the roads? You mean trails?

Whoever's got the most people swinging off their nuts. IMO RDZ will do the best job I believe they offer a tripple exhaust job if you are building a drag bike. Any of the site sponsers here do a great job though.

On a stock head? I put it the way I did just to get the point across that there are more factors involded with this than compression vs. cut If you are sticking with a stock head and are running a drag port, the best bet will be to get it machined by someone like Blowit (mull engineering)if you are after every last hp. And I'm sure that 98.634% of the people looking to mill their stock head will not be building an all out drag engine, so it is pretty much irrelevent anyways. Exactly what factors influence UCCR? Do you have a formula to determine it?

I just wanted to add to this that if your engine is ported, than you can shave a little more off the head to get the same compression as stock, to what extent is determined by the level of porting that is done. For instance a drag ported cylinder with the head cut .035" which is pretty much the max will likely be ok to run with pump gas, due to the fact that when the exhaust port is raised the piston does not begin compressing the mixture until later in the stroke; it decreases the amount of trapped volume. Even with a dune ported cylinder, you could probably shave .035" off and get away with pump gas, if the squish clearance will allow. Again always measure squish before cutting and compression after.

Anybody recognize this one?

After more thought, it seems like the side that is suching would actuall pull some charge out of the other cylinder as it is trying to force it through the transfers. Doesn't seem like it would let the transfer phase be as efficient.

Your weakest link right now is your compression. Also your porting. Doing the clean up port will help you more than the vitos pistons, and you will have a dremel for when you want to unleash big hp. Unless you are looking for bling, and plan on changing setups 3 or more times,lose the cool head idea IMO What bore size are you at right now?

Yeah but even if they stopped pulling at the exact time the other started pulling, the carb would just be constantly"on" and shouldn't have a problem, unless there is overlar of the two intake cycles

Yeah but if the other cylinder is drawing mix the reeds are open...

Yeah I was going to recommend the vitos pistons, but I figured the money would be better spent on a dremel and some weiscos... true and welding the crank is definately a good idea IF you plan on splitting the cases. Then you should go ahead and buy new seals. How old is your banshee?

I'd go with 39's over 34's Depending on your budget, the port work is prolly not necessary.

I'm assuming you need an overbore?.... Wiseco pistons, bore- $300ish Shave stock head .025"- $50 Top end gaskets- $40ish Boysen reeds-$40 ish Dremel w/ bits-$100 Mod your timing plate to give you +4 advance Port your reed cage to look like this. Make sure the pedals have 1mm of surface all around to seat on Nexy open your intake to look similar to this. You will narrow the bridge by 2mm, and raise each side of the port 3mm, and lower it 1mm. When you do this make sure you don't leave any sharp edgaes on the inside of the cylinder where the piston rides; chamfer the port. Go over the chamfer with very fine sandpaper oiled with wd-40 Next, smooth out these sharp edges at the botom of the cylinder; the transfer port tunnel entrance To look like these, even smoother if possible Finally, you need to clean up your exhaust port. This is looking through the exhaust port of a non-banshee. See how the sleeve isn't even with the aluminum? Grind the sleeve until everything's flush, like this Sand all the carbon out of the exhaust port, then go over it with a fine sand roll until it's as smooth as you can get it Follow the instructions on chamfering that I gave for the intake. This is your basic clean up port job, and really hard to mess up. These mods will REALLY bring your shee to life. And if you feel confident about your dremel skills, I can tell you hor to get another 10-15 hp out of the exhaust port.

First let me start off by saying Please don't post if you read from some guy on the forum that the intake sucks if you have no idea how a banshee engine operates. From what I understand 90% of you can't even tighten your chains so please don't give me your brainwashed babble. OK. I've been thinking about this. The cylinders are 180 degrees out of phase, so theoredically only one cylinder is pulling charge at a time. What this theort suggests is that one 35mm carb would perform the same function as two BUUUUUUT What is happening inside the cylinder that isn't sucking? It appears that it would be putting a positive pressure on the reed cage area as it drops during the transfer phase. Now would this be benificial to the other cylinder trying to suck, or would it put back pressure on the carb to the extent that it places resistance against the intake charge?

Have you ran them? I know some people who have and say they have breat bottom end.

Send them to HJR to get them dune ported. It will run you I think 3 or 350 but if you are hooked now you will be a certified fiend when you get your cylinders back

What is your current bore size? Mods? Riding style? Are you comfortable using a dremel on your cylinders? Budget?

How much did you shave? Elevation?

Depend on the dyno. Should be around 46-48 Porting should get ya up to 60-65

Uhm, I'm not sure Let's see Stock squish is around .068" using stock gaskets, .080" with a moose head gasket. You shave off .025" to safely run premium, typically, which puts your squish at around .043" Another .010" would put yout squish at around .033", which is about the limit. You could probably get abay with 50/50 race gas/ premium unleaded at this stage. If you plan on running race gas or alky, you should get the head re-chambered. Mull engineering does it for a good price. Pump gas or 50/50, a stock shaved head should work.It is always recommended to check your squish first and your compression after. .025" is definately be safe for pump gas though, unless you run no head gasket.

I don't think there is any proof that a cool head lowers the coolant temperature, which would signify a decrease in the intake charge temperature, which imo is the only way to make more power by lowering the temperature inside the cylinder. Yeag but I still think it is a stretch to say that by forcing a little more coolant to the exhaust port side will give a significant increase in HP. Definately sounds better for the life of the engine, but to say it adds power is a stretch. You can do 2 setups with stock heads and still be in it about half the price of two cool head setups. Not trying to start any arguments guys, just please try to say things that make sense.

Not when youre talking about performance. The exhaust port and the header both provide the same service by providing a passageway for the exhaust gasses to exit. The exhaust port length is used when calculating the tuned length of a pipe. I don't see how a cooler exhaust port could add horsepower.

Round...

I was always under the impression that a hot passageway was benificial to to gas flow, which is why people wrap their headers with fiber-wrap....?

Based on your selection of pipe I assume you ride mostly tight woods. I think you would be much better off with some t-6's for that. Dynoport is a loud stock pipe. If the engine is ported it will likely perform better with the dynoport (questionable though), however on a stock ported engine you are throwing your money away IMO

I believe the general consensus on a stock bike with stock gaskets is .025" to .030" off the head. Check your squish first though to make sure it has never been milled. If you are not going for bling no it would not be wise to get the coolhead imo