Banshee modification ?'s

I am thinking of getting a Banshee that is trashed. My plan is to rebuild this into a keeper quad that is reliably fast. So here is my question. If I bore the stock sleeve 80 over and put the 5mm longer rod into it how big is this going to be? What are the best mods that make the best results on these quads??? We want a fast reliable Banshee for sand dunes & ice racing / maybe even some Hatfield McCoy trail riding also. :applause:

Well what year is it? Since you are talking about one cylinder I am assuming old, does it have one pipe or two?

my bad.. its in the 2000 year range-I believe. Comes stock with steel sleeve 350cc twin cylinder banshee. i was told that I can bore it out up to 80 over so I was wandering if I did bore Both sides to 80 over and added a 5mm longer connecting rods with the cylinder spacer, how many cc's is it and is it worth it... Right now it has 2 pipes but I am putting a 2 into one pipe on it from years ago. i know the crf450's inside out and after some research and building i am sure i'll know these motors after a while also. I remember my friend in 87-90 always having problems with his tranny, he would land on the shifter and mess up the internals.

If you bore it 80 over and put in the 4mm stroker crank with 5 mm rods you will be sitting with a 400 cc banshee but you will then need to have it ported to compensate for the new port timing to see any big gains out of it. The great thing about banshees is there are so many parts for them on ebay. 87-05 the only difference is that the first three years of the banshee had j-arms instead of a-arms on the front. I also think you would be better off to get the head cut or buy an aftermarket head rather than run the spacer kit. You can also use blaster pistons. Back before I decided to sell my shee rather than put a new crank in I was looking into the stroker and did a lot of research on it. Theres quite a few options for how to stroke it and I'm still not sure whats best.

I have already been researching some things and see that e-bay is loaded with parts for it. buy it now prices for just the bare cases sits around $150. Thanks for confirming around 400cc after an 80 over bore and 5mm stroke. that is what I was looking for, There are so many mods available I woulsd like to here from people with experience from what mod did what. :applause: So far to fix i need a lower end -bearings are junk and a bore cause of scratches not 80 over though I may go that much and a top end. So I figure why not make this a faster quad. I'm only gonna use it a few times a year cause I like my bike way too much. The Banshee will be for my brother to take when I travel far from home.

Man what happened to that thing? 2000 is not old, my wifes is a 96 and the only thing I have done to hers is 1 top end. Its got 9 years of Glamis and w/end desert riding on it. Banshee's are really reliable as long as they are taken care of. I used to race quads MX from 98-2000. The biggest bang for the buck is having the fly wheel shaved and the head whacked. Should only cost $100 total. This will give it alot more bottom which would be good for tight ridin. Get the crank welded, especially if you are gonna put pipes on. Toomey T-5's are awsome for a Banshee. Get a clamp on air filter, foam is better in the sand. I also only needed to run pump 91 and that bike was fast.

Any time you start thinin out cylinders and put in big bore kits you are killin reliability and most of the time you gotta run race gas :applause: I would pick up stock parts left over from guys buildin hill shooters and build from there. If you don't like it then you can always go to big bore kits. The mods above will give awsome results and not hurt reliability, or your wallet. Oh yeah I always use Yamalube mix. Its really thick and plugs are cheaper than pistons.

if your looking for a set of cases I still have mine that I need to sell. Still have the transmission, clutch, and carbs which are aftermarket if your interested in any of it.


I've had my banshee for a few years now, when i bought it i put it together from scratch. There is not very much that I do not know about it. I recently honed my cylinders(from .040 to .050) I definatly would not go to .080 right off the bat. measure how deep the gouging is in the cylinder, I would be impressed if it were more than .010 deep. Then go from there. Wiseco pistons call for about .003 clearance. They also taper(wider at the bottom about .001-.0035 usually)

My quad(not to sound like i'm boasting, but to give you an idea of what it all has) has a tony dukas racing crank(balanced trued and welded) ims hotrods, wiseco .050 over pistons, pro design cool head with 20cc domes, keihn pwk 28mm carbs, um alluminum airbox, pro taper windham mx bend bars, denton steering stabilizer, adjustable upper a-arms, stock lowers, beadlock rims all around, razr fronts, razr 2 rears, durablue(bend) axle, stainless bolt kit (can find on ebay) powdercoated candy blue with some black, dyno port 2-into-1 pipe that was blasted and jet coated, i also have some toomey t-5s, ims clutch perch, smith grips, black plastics with blue radiator and gastank shroud. I don't know what it will run like, because i just re did the whole thing over summer and am waiting to get my engine cases clearcoated(i bead blasted them and am going for the alluminum look of the newer bikes) There are so many ways you can go with these things. They do need to be maintained though, The motor is over 32 years old(originated in the rz350 street bike) and the quad itself is growing on 20.They are hard to tame by a novice rider, and are no joke. Anyone who says their quad is faster than a piped and jetted banshee, is either lieing, or they have a r1 motor in it. The motors, even though twin cylinder, their still twostroke, and can run on a hope and a wish. the motor comes apart rather easily. top end rebuilds about an hour(once you know how to do it, and thats out of the bike, apart, back in the bike, break in.) They handle like poop though. So make sure your brother is aware of this, before he decides to take a turn a bit quick and highsides. It takes alot of weight transfer(moving your @$$ to whip one around, and will give you quite a workout, if you can rip a banshee, you can rip anything) Other than that, nothing comes close power and speed wise, so do it up, I've had to replace 2nd gear in my tranny cause it got real hot and siezed to the shaft(low oil :cry: ) If you have any other questions about it, let me know. But, the best thing for that quad as is, good shocks, pipes, jets, filter and some good general maintanence. Well, good luck, have fun, let me know how it works for you :applause:

later on


get some toomeys, jets, and filters....ive watched modded shees and they are amazin...dont get me wrong, even the stock ones are wickedly fast..too bad this is the last year, id say its due to the YFZ450 and the Raptor 700's outselling the shees and blasters.

Hi I have a banshee with the +5mm long rod and +4 mm stroker crank and with first bore over at .50mm which wiseco offers for that crank. That makes mine a 379cc engine now. If you want to go .080" over that is 2.00mm with the long rod and no stroke, it is 370cc that is the biggest piston that wiseco makes for that crank with the +5mm rods. :cry: This is because they move the wrist pin up higher in the piston. I don't think I would go max bore right off the bat. If you went with the long rod stroker crank like mine and bored it out to .080" over then you would have a 397cc. With just the long rod crank you do not need a spacer because the wrist pin placement is different and takes care of that. If you go with the long rod stroker crank then the piston kit comes with a 2mm thicker head gasket to compensate for it. I have a aftermarket head and had a machine shop cut the domes deeper into the dome so it would still work. Mine runs great I have Paul Turner midrange pipes and I love how mine runs has the grunt power down low and up on top. :applause::bonk:

Have fun!!!!!!!!!


Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now