slowpokebanshee Posted September 13, 2006 Report Share Posted September 13, 2006 hey, my buddy, just built this bike with 4mm stroker, stock bore, drag port, v-force 3, CPI inframes, 34 mm flat slide Mikuni Carbs clamp on filters 7 degrees advance 19 cc domes, coolhead....where is a good starting point for the jetting? thanks, oh yeah 5,000 feet 80 degrees Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 13, 2006 Author Report Share Posted September 13, 2006 I find it hard to believe no one is running this type setup, or close, just looking for ballpark, how 'bout sea-level? anyone running same carbs w/different setup? Quote Link to comment Share on other sites More sharing options...
sredish Posted September 13, 2006 Report Share Posted September 13, 2006 I find it hard to believe no one is running this type setup, or close, just looking for ballpark, how 'bout sea-level? anyone running same carbs w/different setup? thing is, portwork varies A LOT. also, the "same" portwork on different machines can still vary the jetting A LOT. When porting comes into play, all bets are off because that DIRECTLY affects airflow, vacuum and velocity. He could be at 340's but then he could be at 380's, just depends on how much vacuum that motor is seeing. Best thing to do is to start high, 370's or so and work down. No, the BEST thing to do is get it on a dyno with an air/fuel meter and dial it in that way, that's the BEST way. Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 13, 2006 Author Report Share Posted September 13, 2006 okay, we ran it w/270 mains, and it was blubberin bad, thinking maybe 250? what do you think? heard there is a lot of differnt needle options w/these carbs Quote Link to comment Share on other sites More sharing options...
sredish Posted September 13, 2006 Report Share Posted September 13, 2006 okay, we ran it w/270 mains, and it was blubberin bad, thinking maybe 250? what do you think? heard there is a lot of differnt needle options w/these carbs yea, come to think of it, with the 34's your going to be a lot smaller sized. Try a 250 and see if that works. Sounds like your on to a good start. Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 13, 2006 Author Report Share Posted September 13, 2006 mains are usually hit or miss, but fairly easy to see results....any ideas on pilots, needles (brand, style, clip etc.)thanks we're getting there just so damn slowly Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 14, 2006 Author Report Share Posted September 14, 2006 oh yeah, more info, it has 170 psi at 5000 feet, so if you do the math: a whole lot+ sea-level = a whole lot more psi 200? maybe thanks for any help.... Quote Link to comment Share on other sites More sharing options...
Ducman Posted September 14, 2006 Report Share Posted September 14, 2006 Ha Ha Ha, I had a hell of a time figuring out these carbs at first too. I got luckey and got some decent advice on the selection of the correct needle jet orafice for these carbs to run on a banshee. I think the way these carbs come out of the box they are supposed to be for a RM 250 or something but they are way off for a banshee. If he bought those carbs new they come with a Q-2 (2 steps richer than P-8) needle jet orafice wich is waaay to rich. It will run crappy on anything more than 1/8th throttle. You can never get the main dialed in because there is soo much fuel in the jugs/crank from part throttle needle jet circuit that you can almost never get it cleared out to get a decent plug read on the mains. Some people are more familiar with refering to the needle jet orafice as the "dump tubes". On Kehins you change the needle to go richer/leaner, on Mikunis you change the dump tube. On my +4mm cub motor with rocket pipes (very similar to CPI jetting) I run a P-8 needle jet orafice and my needle on the top clip (leanest position), with my previous +4 stroker I ran the needle on the second clip from the top. I'd say most motors would probably run on a P-6 (= one step leaner than P-8) or P-8. There are only a couple of needle selections (different tapers) unlike Kehins but the ones that come new in the TM Mikunis I think will work fine for most banshee applications. I run 35 pilots (air screws 1.5 tunrs out) and 360 mains on my cub motor ( a little on the rich side). My previous +4 stroker (dune port with tripple exhaust port) ran on 35 pilots and 310 mains and I had this setup dyno tuned with the 02 sensor hooked up and it was right on the money for warmer weather, a hair lean for below 60 deg. In my experience you can roughly ball park figure out what your settings would be on stock carbs and subtract 4 sizes from the main and add 2 sizes to the pilot to get the corresponding sizes on the TM 34 Mikuni's. Anyway, my recommendation would be try 32.5 or 35 pilots air screws 1.5 turns out, P-6 needle jet orafice with the needle on the middle clip or my settings; P-8 needle jet orafice w/clip on the top or second to the top clip and a 330 main. There's now way you could be as low as a 250 main with a drag port and CPI's from my experience (wich may not be worth a hole heck of a lot) with these carbs and the setup you mentioned. This should at least get you pointed in the right direction. Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 15, 2006 Author Report Share Posted September 15, 2006 thanks sounds like you really know what you are talking about, these dump valves, can I get them at my local Yamaha dealer or is there a website or something? for needles and jets? and stuff? Quote Link to comment Share on other sites More sharing options...
dajogejr Posted September 15, 2006 Report Share Posted September 15, 2006 carbparts.com or sudco.com ducman...don't forget...he's at 5000 feet. So...whatever your jetting is going to have to be leaned out for his high ele....but you more than steered him in the right direction!!! Quote Link to comment Share on other sites More sharing options...
Ducman Posted September 17, 2006 Report Share Posted September 17, 2006 Being that you are 5000' elev, I'd probably go with 32.5 pilots, P-6 dump tubes, and about a 320 main and see how she runs and try out a couple needle clip settings, start at the middle clip. Heres some info on the dump tubes and sizes. Sudco - needle jet orafice You can get the dump tubes at either of these two places: http://www.sudco.com http://www.pro-flo.com/ thanks sounds like you really know what you are talking about, these dump valves, can I get them at my local Yamaha dealer or is there a website or something? for needles and jets? and stuff? Quote Link to comment Share on other sites More sharing options...
rocketboy Posted September 17, 2006 Report Share Posted September 17, 2006 do you know theres like only 4 people in the world who can actually jet those carbs .id get pwk keihins like everyone runs .tell hi m to ebay those pieces of shit mikunis ..just my 2 cents Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 19, 2006 Author Report Share Posted September 19, 2006 great info, parts are coming, I will keep you posted, anyone else think we should junk the Mikunis (sell on E-bay) and buy some Keihn air stryker 35mmm carbs? Quote Link to comment Share on other sites More sharing options...
slowpokebanshee Posted September 25, 2006 Author Report Share Posted September 25, 2006 okay pwks are in the mail, anyone looking for some mikunis? Quote Link to comment Share on other sites More sharing options...
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