bigborebanshee

Those pistons look like they have at least a season on them? i have never seen that much carbon and surface wear on pistons with that low of hours.

I had a couple banshees,then a 05' special edition yfz450,then a 06' YZF450 and now Im back to banshees.I like the handling and powerband of the 450 ,especially the dirtbikes,completely different animal than the quad version. But they are way too expensive to maintain...the titanium valves will only take so much abuse , those pancake pistons are not worth a shit IMO. and the oiling system still sucks on those engines. I think the YFZ is definitely the best of the 450's..but i would not invest in another 4 stroke.

I would go no more than .003 " piston clearance on forged pistons with at least .0027 The ring gap on off the shelf pistons will almost always have the ring gap set for whatever the recommended running clearance.I have never had to remove material from the rings to get the correct gap,if anything it is usually wayy on the high side. Ask your builder what their "tolerance" is..if they think .005 is acceptable,i would run!

I think everyone has a personal preference.I ran lectrons on a asphalt drag bike and liked them because thats what i had and learned how to get the most out of them.Not to mention the bike was only ran 1/4 at a time at WOT I can tell you on a banshee,i would never go the lectron route if i was going to use it for anything other than straight up dragging.I think the Pwks give the best feedback when it comes to tuning individual circuits.

700ft

If your into cutting your own tires look into making one of those hot knifes like the knobby knife.i made one out of an old industrial soldering Iron and a piece of Ti carbide.

K&N airfilter with airbox lid or outerwear. Non ported i think 150 main and 50 pilot will be real close needle in 3rd clip Ported,maybe 152-158 main and 50-55 pilot depending on pipes.Torque pipes generally like bigger pilot and raise up needle 1 clip,top end pipes can get away with 50 maybe even 48 pilot.I run a MX ported 4 mill with FMF gnarlys and Im 155 , 55 needle 2nd clip from bottom..1.25-1.5 turns out I love these carbs,they are very easy to tune.

I would have to check the port timing.Im sure Vitos does not do much on those cylinders other than raising them to match the 4 mill,it does have the triple exhaust port though.The transfers definitely were untouched. i just don't want to lose too much bottom,but if we are talking 10 or more HP peak,i don't care where it peaks

Im currently running a vitos 68mm big bore cylinder(10 port cylinders) set up by vitos for a 4 mill crank I just cleaned up the transfers and polished the exhaust port,other than the porting that come on the factory big block,thats it.Compression is 160 psi I run a 30mm oko,stock reed cages with vitos carbon fiber dual stage and an FMF gnarly pipe. Are the FMF pipes holding this engine back a little? a lot?..would it be better to go to a shearer or CPI at that point? The bike is a beast on the mid range and bottom,it walks 4 strokes out of the hole,but its almost too torquey for the woods,i rarely ever see past 3/4 throttle.. Will a CPI or shearer retain some of the bottom end or will i just be shifting the powerband further up the RPM? Would a small bore CPI work better than the big bore pipe to retain some low end torque?

I am running this exact same top-end with a 4 mill crank.They are ported for 4 mill but no where near their potential.If you bolt them straight up,they will do great on trails with a fatty or PT pipe....If you have a port clean up done(transfer tunnels need work) and throw a set of CPI or T5 on them,they will pull dune/drag duty. The best bang for the buck from vitos!..make sure you buy the blaster piston domes,i think they are about 60 bucks from vitos. Best thing about them is they look bone stock on the outside.

They look really nice but maybe weak for MX or trail? Do you make one in a boxed frame instead of tube?Or one with an X brace?

I think that may be part of your "cold' problem..I don't run anything over 40 wt,but i change it often..If it clears up when the engine is warm,that explains your problem. Also use the adjustment on the clutch cover to set the arrows up,that way you can have plenty of room on the perch for adjustment

The only problem i had with an older RS stator was the ground from the winding broke off.Since it was still there it would run but would cut out....The anchor for the winding was cheap and poorly soldered. I took a soldering iron and repaired it right on the quad... The picture shows the suspect ground for the winding...even if it looks like its anchored down,make sure it is..mine looked like it was connected until i touched it with my finger and the wire showed a gap.

If your talking about the big o-ring that goes inside the basket behind the clutch plates,then yes,i would reccommend keeping it in there.the rubber o-ring works like a spring and pushes the plates off the inner hub when the clutch is disengaged. The newer engines like the yz450 use 2 conical shaped discs that act like a corn spring or beveled washer,they are strong enough to deflect the clutch when its disengaged but light enough to compress under the force of the clutch springs. If you remove that that O-ring,you will experience "creep" . Barnett and some of the other manufacturers tell you to discard it when installing their clutches,i never have and never had any problems as a result. It does help if your clutch basket isn't grooved really bad,the cushion or metal deflectors cannot compensate for that.

Thats what i was tryn to figure out.Im not going to invest much since it will be ridden sparingly.A plate is much cheaper..as long as the timing is corrected

But what about on a 4 mill that does not run a spacer plate and uses cut domes?The current cylinders have stock port timing? Can i get similar results with a cut piston or should I just invest 60 bucks into a spacer plate?

Before, it was some shade tree dragger Now its a woods terror.

I got a spare engine with a 4 mill crank,stock cylinders that were template ported.Neither the transfers nor exhaust ports have been raised,just cleaned up and widend a bit. The cool head has cut domes,so i would not be running a spacer plate.My question is this...could you run a Vitos Superstock piston to get the exhaust port timing closer to stock(vitos claims the exhaust port cutout on piston is 1.75 mm) Has anyone had any experience with these pistons or can advise on the setup? Reason being,i have a banshee that i am putting together for the GF....I know without a full port,it will be limiting it,but Im not ready to drop that kind of coin on a quad that will see minimum action. Anyone with input on port timing?

This was for sale on Ebay about a year ago,this guy did a real nice Job..so is it possible,the answer is yes!

I think this is a huge part of your problem..You are wayy under geared for the power that thing is putting out.On 18 inch tires you should be running a 16-41..I would go 15-41 on 20's Your engine should make enough torque to pull those gears and then some.I run a knarly pipe on my 4mill and Im running 15-41 with 22's!

There is not much you can do other than what others have posted above,but Here a neat little trick that will benefit even stock banshees between the radiator and shrouds,there is a significant gap on both sides,the banshee radiator shroud is a great air catcher,but these gaps will divert more air around the radiator than it should. My solution is to take an old stock radiator grille.You can cut out the bigger fins along with the mesh and position them to divert incoming air into the radiator,not around it.The screws that actually hold the stock grill in can actually be used to mount the air deflectors. I can't explain it but if you look between the shroud and the radiator itself,there is a significant gap.I saw someone using a 1 inch thick foam tape to seal the area around it,but the foam acts like an insulator IMO.If you can fab up something that will redirect better into the radiator it will only benefit the cooling.

I agree,considering the type of "drive chain" can alter output,the less variables to consider..the better Yea,but now you can subtract the traction,gearing,tire and drivetrain factor...much more accurate on an engines performance numbers.Chassis dyno add too many variables that if not calculated correctly will reflect on output numbers. Not to mention crank dynos that are designed for smaller engines are better than +/- 10% on accuracy. What your doing is comparing a carpenters ruler to a machinist scale.

I Poor track conditions and poor setups. should not be a factor in an engines true performance. I have beaten a handful of quads that should have destroyed me according to the $$$ that was sunk into them and the power they produced,but the person behind the wrench and rider handicapped it. Thats why i believe you cannot accurately gauge an engines performance solely on its ET and MPH. There was nothing wrong with those quads i beat other than the mechanic who tuned it and the rider who piloted it.i guarantee if i was running those quads,i would have never lost to a weaker bike like mine. Performance can't compensate for ignorance. I think we are thinking the same,its just not coming out that way

I guess that is where I lost you..I never said that a bike with more horsepower will win,I specifically stated that it should win if it is set-up accordingly. I thought that was what the argument was about.I don't agree that ET and MPH are the best measures of performance,you stated it yourself..weight,setup and rider are conditions to consider and none of which can be considered when measuring an engines performance.Its not fair to the engine to introduce these variables and pass judgment as a result.Thats why engine dyno's are an accurate assessment of an engines performance. A bad rider,poor suspension tuning and lack of traction can give the best built engine a bad rep. A great example is tire choice.With the right paddle,the bigger hp bike is untouchable,with the wrong one,its getting its ass handed to it.Does that make you question the engine performance itself?,or the guy who's tuning the chassis?..that was my point.

I think a safe assumption can be that"the banshee engine design is still king of drags"There,hows that