BayBanshee Posted March 1, 2005 Report Share Posted March 1, 2005 I bought a new set of 28mm pwks about 4 months ago. My banshee is running like it is trying to foul a plug and sputtering once in a while and it feels like there is a deadspot on bottom end when I am going slow, my banshee almost shuts off. The local motorcycle shop here in Ohio that flatslide carbs have a deadspot on bottem end? They said that these should of came jetted right, so I should not have to mess with the jetting. I was told that if I bought these carbs I would notice a big difference, but mine just seems to run worse. I was wondering if you guys had any ideas or mods I could do to make these carbs run better. I did put new superstock pistons and rings in before I put my new carbs on and I put new carb boots on, because one side was cracked around the boost bottle. I have fmf fattys, powercore 2 silencers, k&n filter, and the timing is advanced 3 degrees. Thanks, Quote Link to comment Share on other sites More sharing options...
scotts96fast Posted March 1, 2005 Report Share Posted March 1, 2005 What size jets do you have in the carb now? Does it run like crap only on the bottom?or through out the powerband.... Quote Link to comment Share on other sites More sharing options...
BayBanshee Posted March 2, 2005 Author Report Share Posted March 2, 2005 The carbs came with 140's and I have not changed them. It runs good sometimes, except for the deadspot on the bottom end. I have only ridden it a couple of times, but sometimes it feels like I am running out of gas or fouling a plug. Quote Link to comment Share on other sites More sharing options...
FIRST BANSHEE Posted March 2, 2005 Report Share Posted March 2, 2005 You need to jet those carbs, prejetted carbs are only to get you in the ball park. does it ilde fine, a flat spot on the bottom is probably a to small pilot. how do your plugs look,does it backfire at all at wot...if it does you my need to jet up. did you install new plugs with the new carbs. Quote Link to comment Share on other sites More sharing options...
hamuel Posted March 2, 2005 Report Share Posted March 2, 2005 have yah checked the plugs? Yah sound way lean on top. and probly lean on bottem would suggest trying a 42-48 pilot 162ish main.. yah just sound way lean. ALl ways jet your bike after yah change something Quote Link to comment Share on other sites More sharing options...
BayBanshee Posted March 2, 2005 Author Report Share Posted March 2, 2005 Yeah I changed the plugs when I put the new carbs on. It idles fine, but it is much harder to start. I don's know anything about carbs? Is the pilot jet the long skinny part the main jet screws into? Quote Link to comment Share on other sites More sharing options...
hamuel Posted March 2, 2005 Report Share Posted March 2, 2005 nope. that's complete different. ignore that at the min. off to the side of it yah see a another small screw thats a flat had head thats the pilot. if it's hard to start your lean on the bottom as well. Quote Link to comment Share on other sites More sharing options...
SuperChris Posted March 2, 2005 Report Share Posted March 2, 2005 First off, if you had your motor apart to put in new pistons, you need to leak check it. Intake gaskets are prone to leaking. An air leak will make tuning impossible and in worst cases ruin your new pistons. If you have a tight motor, then it's lean. I'm at 168's on my 28MM PWK's. Runs awesome. Quote Link to comment Share on other sites More sharing options...
BayBanshee Posted March 2, 2005 Author Report Share Posted March 2, 2005 Thanks for all the replies, you guys are great! I don't think I have any airleaks, but you never know. What places do you usually get air leaking and what is the best way to check for leaks? Quote Link to comment Share on other sites More sharing options...
SuperChris Posted March 2, 2005 Report Share Posted March 2, 2005 Here's my recipe. Get one of those blood pressure checker kits from Bi-Mart or wherever(If you have a medical supply place near you just get the bulb and some surgical tubing). Get couple of rubber soft plugs from the local hardware shop(ask for them, they will know what you are talking about) and a 0-15 psi guage. You will need 2 soft plugs for the intakes, and 2 for the exhaust. Get a fitting that will allow you to make a T out of your surgical tubing, and get a fitting that will allow you to attatch one end of the tubing to your new guage. Take the ceramic off of one of your old spark plugs and stretch a piece of surgical tubing around it with the other end attatched to the bulb at a good distance(foot and a half is what I used). Put all your soft plugs in and screw a good spark plug in one side and your makeshift pressure checker in the other side. Find a good place to cut the tubing now and put in your T and guage. That's it. Pump it up untill the guage reads 6 psi and see if it holds. If not, spray soapy water around all the gasket areas and wherever it bubbles it is leaking. I have checked a lot of good running motors and every one of them so far has had leaks. Quote Link to comment Share on other sites More sharing options...
RBD Posted March 2, 2005 Report Share Posted March 2, 2005 BayBanshee ] Are you using the stock intake manifolds? Also, you did plug the fitting on the carb next the the intake boots didn't you? Or at least put a hose from one carb to the other. Quote Link to comment Share on other sites More sharing options...
SuperChris Posted March 2, 2005 Report Share Posted March 2, 2005 Shit dude, I'm sorry for not being more clear about it. Take the carbs off. I use stock boots. You don't need aftermarket boots until you get into much bigger carbs. Keep the crossover tube or boost bottle on. There is a chance I'll get to take a picture maybee tomorrow. I have to drive 200 miles to get to my Banshee and tester, but it would be a good excuse to go home for a couple days. Quote Link to comment Share on other sites More sharing options...
BayBanshee Posted March 2, 2005 Author Report Share Posted March 2, 2005 Thanks SuperChris, pictures would help alot. I bought the aluminum manifold for my k&n to bolt onto. I am using the stock carb boots and a boost bottle. I don't think my carbs have a fitting next to the intake boot for a hose to hook them together like my stock carbs have? Does anyone elses 28pwks have this? Quote Link to comment Share on other sites More sharing options...
RBD Posted March 3, 2005 Report Share Posted March 3, 2005 If your carbs are genuine Keihin PWK 28 carbs they will have a brass hose fitting on the top of the spigot next to the choke assy. as seen in the attached pic. The genuine Keihin PWK's also fit a little lose in the stock manifolds and the stock clamps don't always tighten enough the seal the carbs (air leak). If your carb are PWK copies they may not have the little brass tube and I don't know about the fit on them either. Ron Quote Link to comment Share on other sites More sharing options...
rocketboy Posted March 3, 2005 Report Share Posted March 3, 2005 i have pwks first off your she is running like shizzel because your probably no where near correct on the jetting ,i have 55 pilots and 155 mains now and shes lovin it. your pilots are probably way too lean ,do the choke trick its starving for fuel ,i spent many hours dialing in mine they(28/30mm d slides) suck to jet ! but you should be around a 50 pilot and a 150-160 main jet. your bottom sucks because your she is running on air instead of fuel! your mechanic who told you that all pwks have a flat spot is a raging crack head ,these carbs are much better than stock from my experiance Quote Link to comment Share on other sites More sharing options...
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