americanmusc1e

$2000 firm.......

99 Yamaha Banshee. I rebuilt the motor a couple of months ago. Its only got a couple tanks of gas on it. The cylinders were ported by HJR motors in California. It has a trinity coolhead with 19cc high-compression domes (which unfortunately means you need at least 100octane gas..... I use avgas... or switch to 21cc domes). It has a rebuilt and welded stock crankshaft, modded shift star, billet water pump impeller, pancake bearing, FMF fatty pipes, Powercore II silencers, Durablue axle (+4" i think), beadlock wheels with new GBC dirt devil 22" tires, new JT 13/43 sprockets, new DID o-ring chain, new brake pads and custom recovered seat. I have a new driveline products 70hp clutch for it.... but it really needs a billet clutch basket before its put in. my Daily driver just bit the dust.. need to sell fast...... $2300 O.B.O.

considering how grooved my basket is I'm going to have to think its the clutch....... I'm gonna order a clutch and basket first and put it in..... Once I do that I'll work on my jetting some more...... If none of that does it I'll have to start checking ignition.... whatever it is, after thinking about it, my bike is slower than before I rebuilt it. Back then it was missing 20lbs of compression on one side and running 21cc domes, FMF Fattys and K&N........ back before I rebuilt it I barely lost to a Raptor 700 GYTR and I was a much more terrible driver I'm also building a secret weapon to improve my launches

I weigh 142 pounds.... The clutch might be slipping. its not the best.... I'm not sure When I called Kevin at HJR I told him I was thinking about getting a trail port.... but he said fattys work best with a dune port.... I did my own timing mod.... maybe I did something wrong and my timing is way off..... is there a way to stick a timing light on a banshee.... I did it one time on a suzuki 185 four-stroke using a car battery because the fourwheeler didn't have one..... here is a video running through all six gears.... I went easy on the launch... less than 1/2 throttle in first gear.... then I nailed it halfway through first.....

Alright..... I'm not sure on the domes... I'll have to check on that.... or Maybe 19cc's domes provide too much compression and its heating up the air too much I can't ride WFO in sixth gear really because my front tires are really bad.... they are #1 on my list to replace....... they start shaking about 50-60mph and they show signs of dry rotting ... I don't want to push them that hard..... the 13/43 gearing with 22" tires returns me to the factory 14/42 gearing on 20" tires....... on the 20" paddles its barely more than dropping one tooth on the front sprocket I haven't check the electrical system.... but the bike usually starts on the 2nd kick on a completely cold motor with the choke pulled...... on a warm motor it kicks over the first time with no choke...... how do you check a stator??? I don't loose any coolant at all...... I'll try to get some videos this week......

I swapped in my 340 main jets. The only sizes I have are 350, 340 and 300 (the 300's were on the bike when I got it). and the local Yamaha dealer doesn't stock mikuni main jets bigger than 280 or so. I have to order any jets I get. here is what I got.... now I'm really confused.... what does this mean??

My banshee seems to run really good when I'm riding by myself.... but when I race my buddies almost stock YFZ450 it just can't keep up... we have raced on pavement with full traction and even if I leave him off the line he still chases me down...... we also race 250' dirt and his times are consistently 1-1.5 seconds faster The banshee seems to run hard with no flat spots in acceleration or bogging. I'm not the best driver but I don't think its just my driving skills either. I thought my jetting might be off, but its really close now. I was running just a little too rich (The smoke ring was about 3-4mm wide and about the right color brown) but I changed the mixture ratio from 32:1 to 20:1 (which is about the same as dropping 1-2 jet sizes). I think the jetting is really close now. more info on the carb stuff I did here:http://bansheehq.com/forums/index.php?showtopic=144636 both pipes seem to kick on at the same time and I just checked the carbs to see if they were out of sync I did a compression test and got 170 psi on both cylinders. I have no Idea what to check next.... Clutch??... it dosen't seem to be slipping..... anything else??? His YFZ has: Slip on FMF exhaust, K&N, Dropped one tooth on the sprocket...... that's it.... no hidden tricks... I've seen him loose to fully piped YFZ's I have: stock stroke welded crank motor on 2nd oversize FMF Fattys HJR Dune Ported Cylinders 19cc swirl-cut domes...... Trinity Stage IV coolhead +4 timing mod stock reeds and cages stock carbs w/TORS delete cable...... 350 mains...... 27.5 pilot K&N filter with modded airbox running 20:1 Yamalube 60% VP racing C12 and 40% 93 octane pump gas I run 14/43 sprockets and 20" paddles or 22" dirt devils (14/43 brings me really close to the stock ratio with 22" tires)

I usually run 100LL avgas.... but my current tank is from a 5 gal can containing: 20oz Yamalube 3gal VP racing C12 (10.60 a gallon ) 2gal Shell 93 Octane Now I'm not sure I need smaller jets..... I might want to go bigger..... I warmed the motor up..... put new plugs in..... made one full throttle pass..... pulled the clutch.... shut it down..... and here are the results

that makes good sense...... I'm going after jetting tomorrow..... I have a set of 340 mains I might try..... I guess I'll have to order some more jets.... because the next size down I have is 300

I was racing on 22" tires (which return my gearing to stock) except for last night I was racing on my 20" paddles I did a compression check today just for the hell of it...... 170psi on both cylinders (on a cold motor... I didn't bother to warm it up)....... the plugs looked a little rich...but I'll do a more thorough test later.... what seemed funny to me is that even with the throttle wide open it took 8-10 kicks to hit 170psi (any kicks after that yielded no increase).... like there might be an intake/exhaust restriction

the carbs were still really close..... they didn't really need syncing fixed my leaky carbs with two new needle and seat assemblies........ my Yamaha dealer only had one carb kit in stock (Go figure ) but apparently the needle and seat is the same in a blaster carb so a blaster carb kit did the trick...... the bike runs a little better... but I'm not sure its 100% yet.... I did some racing tonight but it was all screwed up because one side of the track was WAY wetter than the other..... I won against a lightly modded Raptor 600 (he was in the slow lane) and lost against a stock Brute Force 750 (I was in the slow lane)....... now to wash my quad tomorrow I think we are set up to do some runs against the same YFZ on pavement thursday...... that will be the test....

I guess I have some issues...... I'm gonna sync the carbs .... check the float levels again..... fix my needle and seat problems..... then race him again today.... If it doesn't get any better I'm gonna start a new thread.... and try to figure out what's going on....

the carbs are overflowing out the overfills if you let it sit not running..... sometimes one..... sometimes both.... the floats are set to 21mm...... saturday I will put a new needle and seat in both carbs..... and see if that helps.....

stock stroke welded crank motor on 2nd oversize FMF Fattys HJR Dune Ported Cylinders 19cc swirl-cut domes...... Trinity Stage IV coolhead +4 timing stock reeds and cages stock carbs w/TORS delete cable...... 350 mains...... 27.5 pilot K&N filter with modded airbox I just lost to my friends YFZ450 with a slip-on exhaust (I can get him off the line but he chases me down)........ but I know the carbs are out of sync a little (I think my new cable stretched a little)..... I'm still wondering if something else isn't tuned right though...... I mostly just ride for fun (trails and open roads) and I drag race 250' every other weekend First......... which would do me more good....... chariot reed cages or bigger carbs??? Second....... what size carbs do I need..... I'm trying to be cheap. I have one 35mm Mikuni off of a 2-stroke enduro can I just get one more and run matching intakes or would that be too much carb???? Any other bikes I can steal stock carbs off of??? streetbikes???

what caused the piston and head damage on cylinder #1 that looks just about like a dropped valve on a 4-stroke???