Pincushion

Got an 03 that isn't starting. Fresh rebuild (.020 Wiseco's), FMF fatties & silencers and K&N pods. Jetting 320's, 27.5's and stock needles in 3rd clip. The bike will not fire unless I pull the pods and cover the carb openings with my hands (Thanks to motor builder for discovering this starting technique!). So, if air flow is SERIOUSLY restricted then the motor will hit and fire. Also, as I cover the openings and kick my hands are getting doused with fuel. It's pulling fuel into the carbs, but I dont know how much fuel is making it to the cylinders. Or maybe there's too much fuel making it into the jugs!?!? Any input? All I can think is worn reeds, incorrect jets (as in they're not genuine Mikuni's) or carb float levels off. The carbs have been cleaned numerous times with carb cleaner and compressed air, so I'm seriously doubting a plugged circuit. Any other input?

By pilot screw, do you mean air screws? And yes, I need to sync the carbs. I dont have much faith in the 'look and listen' method of syncing the slides. I'm sure that will get it in the ballpark, but I want it spot-on. This 350 motor is throwing me for a loop. I've been riding and wrenching on smokers for 15+ years. A single cylinder, mild compression 2 stoke 250 is a much different animal. My compression numbers will go from 260# fresh down to around 220 (15-17%) after approx 50-60hrs tun time. Compression readings seem a much more accurate and usable on a 250 single as a general gauge of engine compression. And I do agree that it should not be used solely as a tool to gauge engine life. It's a tool to gauge cylinder compression, which is just one aspect of overall engine health. Thanks for the reply! -Brandon

Thanks for the replies folks! It fired right up with a shot of starting fluid. It looks like my choke and/or idle circuit needs some attention. These damn carbs are finicky!!!! The compression numbers worried me at first, but I realize I dont have good ring seal yet and with the stock head I wont be seeing any numbers too high. It just seemed odd that my WAY worn out pistons/jugs blew 120# and my fresh motor blew 130#. I'm still learning. And getting pissed off at the same time Thanks again!

I finished up with the rebuild last night. Stock jugs punched .020 over with some wiseco pro lites. I buttoned her up, filled the radiator and she fired up in 3 kicks. Idled fine and everything was good for the 10-15 seconds I ran it until I woke up my son and caught hell from the wife. Today I go out to fire it up and do a heat cycles and the fugger wont start. Compression feels low to me, but I'm used to my high compression YZ so its probably just me. A little history: Got this quad last summer. Stock internals, FMF fatties/silencers, TORS removed and K&N pods. Compression was low (120#), so I decided to rebuild. The stock pistons were in there too long as there was piston blowby and cylinder scuffs from the piston being sloppy in the bore. Today I did a compression test and both cylinders blew 130# (isn't that low for a fresh motor at 300' ASL?) and the bastard wont start. Jetting was 27.5PJ, 320 mains and stock needles in 3rd clip. I tried putting is some 40PJ (which is what was there when I got the quad) and no difference. Any ideas why it wont start after it fired right up last night? I've got a camp spot reserved at Florence tomorrow and I'm going to send this thing off a cliff soon. Any input will be appreciated!

On my smokers I do the heat cycle method. Using the same gas and ratio as I normally would, I'll start the motor and constantly vary the rpm's for 3-4 minutes until the motor is at operating temp. Let it cool completely and repeat this step once more in the garage. For the 3rd cycle, I start the motor and let it reach operating temp and then go for a 10 minute ride dragging the rear brake or climbing hills to put a load on the motor. I also build my motors dry. I will put a little premix on the rings to assist in getting the jug over them, but that's all. As soon as you kick and it draws in fuel it's seeing lubrication. Just checked the compression today on my 18hr old YZ285 built using this method and it blew 255#. That's a fine compression reading if I do say so myself...... :thumbsup:

Is the disengagement adjuster the piece on the pressure plate with a phillips head screw in it? If so, I'm pretty sure my new pancake bearing will come with a replacement. And when you say stock rod angle.... are you meaning the con rods? Thanks for the replies!

I'm in the midst of doing a top end job on my 03. What parts are prone to breakage and should be upgraded while I have it apart? I know about the pancake bearing and I have one en route. I also know the clutch baskets are weak points, but what else? This is a play Banshee only dune ridden. Stock internals with a few bolt ons.... not an 90hp monster. I just want to save myself the headache of problems down the road and would like to iron any issues out now. Thanks!

After 20+ years of riding bikes I much prefer a twist throttle. I only ride dunes on the quad though. Not sure I would like riding quad mx with a twist, but I love it in the sand.

I dont see any number stamped on the crown, but there is a 'G' stamped on there. As well as the arrow indicating exhaust port direction. I sanded the carbon off to verify. I went to sears and 'borrowed' some calipers. 64.5.. on the nose! Measured in multiple spots on the piston. It's possible the calipers are off, but by a 1/2 mm is doubtful. Thanks for the replies. I'll have the jugs miced rather than play the guessing game.

My 03 is in dire needs of a top end job. The previous owner told me the motor still had the stock pistons in it, which may or may not be true. I tore the motor down and they are cast pistons with no markings to indicate they are oversized, but they measure exactly 64.50mm on my calipers. That's .020" over, right? Would OEM .020 over pistons have any kind of markings on them to indicate they're oversize? Thanks!

I checked the slides and both have the top cutout facing the rear. As far as putting the left slide in the right carb and vice-versa, that is possible. I put the slide into the carb based on the throttle cable routing..... one slide naturally wanted to go to the left carb and the other naturally wanted to go to the right. I can swap them and test. I'm certainly getting fuel into the carb bodies as the slides has a nice coating of fuel on them from yesterdays kicking session. Just doesn't seem like its getting into the cylinders. Wiz, I'll send you a PM. Thanks!

I've tried from 1/2 turns to 2 full turns. Doesn't matter. I just tested the compression again and both cylinders blew 120 on a stone cold motor. I also pulled out both plugs and they're dry and I dont smell fuel coming from the holes. Time to look into the carbs again.

I got this low hour 03' a few months back and haven't really had much time to dial it in. It's been at least 2 months since I've even touched the Banshee and I'm going strictly off memory (which doesn't work too well), so please bear with me. It's an 03. Stock carbs, FMF fatties & silencer and K&N pods. Compression was 125/120 when I got it and I've only ridden it maybe 5hrs since. I got it with the TORS removed, but I've since added the idle screws. If I remember correctly jetting is 320 mains and 30 or 32.5pj's.....cant remember. I ride at sea level in the Oregon dunes only. After getting it I drained of old gas and cleaning the carbs I filled her up with some 91 octane pump fuel and klotz r50 32:1. The motor was a bear to start. It took a lot of kicking to get it to light and it would not idle due to no idle screws. Once it got up to operating temp then it would start easy. After installing the idle screws (which was done correctly as per the instructions) it absolutely will not kick start. I can bump start it and even that is a pain in the ass, but once it starts and gets up to operating temp it will fire up 1st kick. After getting it fired up and up to operating temp I adjusted the idle screws. They both had to be all the way in for the motor to keep a steady idle. Is this correct? I was thinking maybe I need to remove a little more material from the carb to allow the idle screws to fit further into the carbs, but this still doesn't explain the hard starting issue. Why would it be near impossible to start when cold, but fires 1st kick when warm? Is 120/125 respectable compression numbers on a stock motor at sea level? Does my jetting sound reasonably close for my mods, elevation and riding style (WOT in dunes)? Any other advice? thanks!

Shell Rotella 15-40 Been running it for years in everything from my YZF big bore, YZ250 and recently 03' Banshee. Also been running it in my wifes 250 Raptor and CRF150. Thousands and thousands of miles without one oil related failure. At $12/gallon I can afford to change it often. It's additive pack is very close to that of an motorcycle-specific oil at 1/3 the cost.

Tell him after he ports it and fucks up the integrity of the nikasil around the port edges and it starts flaking off then he can buy his kid the big bore kit that will be required to get it running again. To properly port a nik'd jug you need to strip it, port it and then re-nikasil the jug. Otherwise the piston is going to rip that shit right off the walls. Anyone can 'port' a cylinder, but very few can do it right.

I just got through the same experience..... got an 03 w/ TORS removed and no idle screws. I got some off ebay for $25 and installed them last week. It was easy. Just take your time and follow the instructions closely. Toomey's website has a nice write up

I see..... the cutaways are facing the rear and the slides appear to be in the proper carbs. The cable 'memory' has each one going to the carb the cable naturally wants to go to. If that makes sense. Are the slides the same and only the cable length different? Or is each slide unique to the L and R carbs? If performance is any indication then they're good. The bike fuggin screams and idles like a kitten once I got it past the initial pain-in-my-ass starting procedure.

Awesome. that's the info I was hoping for. Thanks man!

My 03 only has 20-25hrs on it. Bone stock internals, including clutch. My engagement point is about 7/8 of the way out. Meaning only the last 1/8 of lever play actuates the clutch and the other 7/8 of play does nothing. Every other bike I've owned or ridden in the past 10 years are the opposite, 1/8 play and 7/8 engagement. I've only ridden 2 other Banshee's and that was 10 and 15 years ago, so I dont remember how they were. I assume this isn't normal operation, but this bike is almost new and not abused. Any input?

Air screws are 1.5 turns out. I haven't messed with them, but I think they need to come out further. Tube is in place. And the slides are correct as they will not seat properly if installed incorrectly. I'll try adjusting the air screw out as I flooded it while trying to start last Saturday at the dunes. After push starting it, she fired up first kick all day. It seems a 27.5 doesn't deliver enough fuel to start and the 40 delivers too much. Going to shoot for something in the middle and test. thx for the reply!

The plot thickens..... I got some 27.5's today. They're original Mikuni's and are the correct ones. I thoroughly cleaned the carb, reinstaledl the 320 mains I'd been running and swap the 40's for the 27.5's. I button everything up and the SOB will not start. I kicked it 100 times and triple checked everything. I had just installed some idle screws the night before, so I try every different depth combo possible. One turn out to 20 turns out, nothing! By now I'm shitting my pants thinking something went wrong with the idle screw install. For giggles I reinstall the 40 pj's, button it back up and the fugger fires right up and purrs like a kitten and revs up fine. WTF!?!?! I set the idle screws and everything is great. My motor will not start with 40's and those carbs are cleaner than new! I dissasembled everything and cleansed them like nothing has been cleansed before. The dude I got the quad from said the motor is bone stock, only the bolt ons I mentioned above. It was 80f, 300ASL and low humidity today. One change I did make was change the stock needles from #3 to #4, but that wont affect the pilot circuit at startup. My compression was 125L/125R and I checked it about 2 hours (run time) ago. Odd, eh?

Thanks! I'm guessing that fat 40 pj is the reason it takes 10 minutes to start the motor too.

Got a stock motored 03 w/ FMF Fatty's, FMF S/A silencers and K&N pods. TORS is also removed. I'll be riding the Oregon Dunes this weekend (sea level, 70F and low humidity). I was thinking about running 300 MJ's, 25 PJ's and 1.5 turns on the air screw (and adjust as necessary). Does this sound like a winner based on my setup? Also, I just got back from the dealer to get some 27.5 pj's. I removed what I assume is the PJ from the carb and bring it with me. He tells me it is not the PJ and that Mikuni's use a fat-head style PJ. I told him that the PJ I brought with me was removed from the recessed shaft right next to the main, just like where it has been on every other 2 stroke carb I've touched. This picture shows 3 different PJ's that I received with the bike. The one on the far left is a 25 w/ no Mikuni logo. The middle on is a 40 w/ the Mikuni logo (this is also the jet that was in the carb when I got it) and the right one is a 160 (Yes, a 160) and the cavity is 4x the size of the 40. Sorry for the long post, but I'm fucking confused and dont want carburation issues. Is my dealer the stupidest man alive? Are these pilot jets? Why the hell do they have different thread patterns (look at the left one compared to the rest). Lastly, I'm not comfortable using that 25 since it doesn't have the Mikuni logo on it. Is it some cheap knock-off or is that the stocker? Thanks!

My 03 does not like to start when cold. Once I finally get it warmed up it'll fire first kick, but that first start of the day sucks! FMF fatties. K&N pods and TORS removed. Otherwise stock. When its cold I'll choke it and kick, it'll idle very weakly for about 2-3 seconds and then die. I have to do this about 10-15 times until there's a little heat and then I can fire it, turn off the choke, give some throttle and then she'll run. Once warm... it's all gravy.... fires 1st kick. I cannot give the bike any throttle until warmed or it'll flame out 120L/125R compression 330mj 27.5pj I only ride coastal dunes. Sea level, 60-80f The previous owner did not install idle screws (is this the issue?). I recently bought some, but have yet to install them. I just recently bought this bike and this is the only issue I'm having. Any advice is appreciated.

This is actually for my wifes 250 raptor. I know the blaster and lil raptor have interchangeable filters and I wanted to put a gauze type filter on for the sand, but didn't want to drop $50 for the K&N when the Vito's is $25. I do appreciate your advice though.