WHAT CAN YOU TELL ME AOBUT THE 370 LONG ROD BANSHEE. IS IT WORTH THE MONEY? I'M THINK OF HAVING PORT MAGIC TURN MY BANSHEE IN TO A 370 LONG ROD. I NEED HELP.

 

I have a 370 built by bruce at C&O racing, it is pretty much the same identicle motor that Rudy builds at Port Magic. I love mine. It pulls way better, and the power is much broader. I run long rods on all my cranks, even the stroker. The longer rods keeep the piston at BDC for a split second longer which allows more fuel to enter the cylinder. Mine is a drag racing only prepped engine and it lasted for over a year, and then, only the pistond were to be replaced. Rudy builds awesome motors and I would not hesitate sending one to him. Check out my web site, I have some port magic bikes on there and my 370.

 

I personally am not a fan of the 370 kit. The theory of them is fine as far as reliability due to reduced rod angle ect. But I don't like the idea of using a blaster piston. There are two ways to adapt this piston to the banshee 1.) you need to machine alot of material from the head since the pison on the blaster is shorter (wrist pin is higher on the piston). I believe you machine about .040" from the head or more. This makes for a seriously thin head mating surface witch promotes head gasket leaks and head warpage. 2.) you can take material from the cylinder base, which effectively lowers the ports and junks your cylinders and reduces power anyways. The method we use at the shop I work at is the first one. OH, I almost forgot, you use an RD 400 rod on this motor. You shim out the bottom end bearing with 3 thrust washers (2 on one side 1 on the other) this makes the side clearance almost zero (not good). To me this is Mickey Mouse engineering. I don't know, but there might be somebody who makes a long rod just for this combination (banshee crank, blaster piston, with RD 400 rod length). SO, to sum it up, I have built a couple of these and don't like to do it. My friend with a 360 banshee with Toomeys raced a FMF piped long rod and lost by 1 length due to lack of traction on gravel rod. I prefer to use more conventional means to make power. The 370's aren't what people think. If they saw what was in there motor when it came back from the shop they would laugh. I know I did when I was done building my first long rod motor. Besides, the last one I built had about $800 in parts (the rods and lower bearings go for about $130 ea.) Plus labor it was about a $1200 operation and no port work was involved WOW. Well, this is long enough. by the way everything above was a long rod big bore, not just a long rod, to clear up any confustion. Later
eric

 

Eric;
I have to agree w/ OhtonRacing.. as you know I have had the 370 long rod since 96'. The only problem I had with the crank was when I had an air leak and leaned out one cyl.... b00m! I run cut blaster pistons and reshaped domes. If you get a chance... go to MacDizzy's site and read up on the 370. In my opinion the 370 is how the banshee should come from Yamaha!

walter
88 banshee 370
95 Dodge Ram 4x4
99 Quadbuddy

 

Walter and Ohton Racing,
I did not know that there was a rod out there for this application. I am only stating what I have seen. Other shops probably have a better way of doing things. I don't own this shop, only work there after my day job (aircraft mechanic) 3 nights a week. We have several 370's out there that are doing just fine. Walter, I know you love yours, CT builds good motors. I do know that at this shop the owner mills a bunch off of the head, when I asked him why, he told me that instead of taking material off of the base he prefers to take it off the head. His theory is that if you ever want to go back to stock you can have the stock cylinders. I guess I like the 370 idea, maybe I just don't like the way he has us build them. If Hot Rods or IMS Pro Series makes a specific rod for this kit, I should let him know, so he can take some of the "engineering" out of his long rod kit. I did not mean to offend anyone on this topic, I was only stating what I have seen and built. I did not design it only built it. Thanks for the info guys.
eric

 

I did not know a long rod kit using a banshee sized upper bearing existed , is the bottom bearing as wide as a banshee original , or narrow like a RD400?
I built a long rod crank using factory yamaha
rods and bearings , with different washers of correct width . Also I aquired a o-ringed spacer plate spacer so I could still use banshee pistons. I have heard some opinions that it will work great , others that it will not . The owner has not assembled it yet to find out . This setup was a special request by the owner .

 

So who is wright? do they have rods made just for this 370 banshee or do you have to ues a rd400 rod with wishers? i know that i would hAve to use a blaster piston, but what is this all about having to cut down the cylinders? i would realy like to know. and does ims or wiseco make rod that will work for the 370 long rod banshee. if i get this done i would like to send it to port magic because he has done the porting and carbs already. i dont know what to do. PLEAS HELP?????

 

Probably the best thing you can do is too call Rudy and ask him exactly what he is going to do. Different shops do different things. Personly I hve never heard of milling the heads and cuting the cylinders down. The purpose of using the blaster piston is that the pin position is 4mm lower than the banshee piston, which compenates for the 4mm increase in rod length. This keeps the port durations in tact and doesnt allow the pistons to come up ito the head. Another way of doing it is to use banshee pistons, with a spacer plate beneath the cylinders to raise the ports and all up to match the increased heigth of the rods. I have a friend who has a motor set uplike this and it ran great. I think the best set up is the blaster pistons. The spacers increase crankcase volume which can be good,but with the increase in area, comes a loss in crankcase pressure which can be bad. Call Rudy and ask him what he plans to do. I'm pretty sure that he does it the way ohton mentioned. The 370 is my choice for building a non-stroker motor. Its the best all around motor possible.

 

I know this is kinda off topic but not too far off.
OhtonRacing Backcountry or Brandon; What do you reccommend for carbs on a 370? I am talking race fuel and not alcohol. I have been running the stock carbs w/ dynojet needles for the last 4-5 years. I was told that I will actually lose power if I went w/ anything bigger.... but then from talking to Rick(MacDizzy) I now understand that what I have been told is false. I am about to order a set of 35PWK's but I am unsure if those will be too big. I dont have my port timing specs right now but I can get them if anyone would like to have an idea as to where I am at now. I had my motor done by CT back in 96'. I cant say that I am unhappy with his work... but I understand alot more now...... He did "decent" porting, but now I understand alot more and have learned alot about cookie cutting portwork.
So... what do you think would be my best bet. Since I live out here in hell...... errrrrr... I mean Connecticut I dont see dunes that often so I can always switch back to the stock carbs for trail riding. I dont race.... so its only for play ridng.

Thanx in advance
walter
88 Banshee 370
95 Dodge Ram 4x4
99 Quadbuddy

 

OhtonRacing:
Thanx for your input..... I just dont understand why so many people put 35's on there banshee's if there is no hp gain. Brandon stated in another post that he thinks the 28's bored to 30's is a great setup. What carbs do you recommend on your 370's that you build?
Is it logical for me to be running 390-400 mains? What is your opinion on rifle boring carbs?

thanx again

walter
88 Banshee 370
95 Dodge Ram 4x4
99 Quadbuddy