SDD Posted April 10, 2004 Report Share Posted April 10, 2004 Banchetta have you tried different pipes and different needles in the carbs. Sometimes you can jet a dip out of a dyno graph and other times you can't. To get the most out of your motor I believe you should look into having custom pipes made for your setup. Off the shelf pipes just don't work as well for custom built motors. Quote Link to comment Share on other sites More sharing options...
fixitrod Posted April 10, 2004 Report Share Posted April 10, 2004 Update: I talked to my builder, he ported it w/ 35 degrees blowdown, widened the exhaust w/ slight raise, 196 degrees exhaust, and 116 degrees intake...What does this mean to you Jim? He also put 1/4" booster ports on each side of the intake by the reeds.....Next, we went to the dyno w/ v-force reeds and prodesign intake and tried those.......Walla!!!!!! We gained 5hp and 4lbs of torque w/ stock carbs....The ported stock cages gained 2hp, and the v-force w/ intakes gained 5 more over the ported stock....WE then went to 35mmPWK carbs and tried them. Gained another 2hp and 2 more lbs of torque.......Now we're talking...The shee is pulling 63hp now w/ 41lbs of torque @8200rpms....The stock carbs pulled nicely, but the 35's pulled extremely harder (about 4-5hp) between 1-6000rpms, then stayed the same until 7500rpms and pulled harder by 2hp on top......So much for the theory of larger carbs have no low end....... I'm happier w/ my motor now, but I still have a nasty dip at 5500 rpms....any ideas??? Remember that post where I said I gained and didn't loose from the bigger carbs? Walla !!!! I wasn't crazy Quote Link to comment Share on other sites More sharing options...
Blue Duece Posted April 10, 2004 Report Share Posted April 10, 2004 (edited) id try a different pipe also, im sure youd be able to at least rule out the turners as the culprit, my pro circuits work well with jims motor i am probally just lucky and am sure something like a cpi would give me more gains as well, i have a buddy that was running turners on his stock jugs and his bike ran great, then he had rudy kurtz do his motor and now runs sst's with great results id like to borrow his ptr's and see how they run on my bike Edited April 11, 2004 by Blue Duece Quote Link to comment Share on other sites More sharing options...
Ducman Posted April 10, 2004 Report Share Posted April 10, 2004 Maybe the flat spot is due to sonic waves in the intake are out of phase with the exhaust. Possibly reed spacers or something to lengthen the intake tract cound push the flat spot lower in the RPM's and/or lessen the effect of the flatspot? Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 11, 2004 Report Share Posted April 11, 2004 I think your right on Ducman. The intake and exhaust aren't working together..I thought the same thing, but got tired of dynoing after 4 nights in a row and taking the carbs on and off about 30 times between different size carbs and rejetting...I put the pro design intake on and no change in the curve. The spacers caused a dip w/ my stock cylinders so they might actually help this time since the curve is at a different rpm...I took my shee out tonight for the first time since the dyno.... It is insane!!! Almost beyond control....I never thought I'd say that....As soon as I do a wheelie its hard to maintain, at 1/8 throttle the power just comes on so damn hard. Now I know why Duece is running such a high gear.....This thing needs to be calmed down....Time for a 16/39 gear... As far as pipes and needles, I'll try the needles and some more fine tuning in the fields. I have access to some T3's and some sst's....I want to fine tune the turners first, then go from there... Quote Link to comment Share on other sites More sharing options...
H300F Posted April 11, 2004 Report Share Posted April 11, 2004 I run the paul turner mids on mine and she runs great. althought i would like to see what a set of fattys etc would do. what kind of air filter setup do you have? what jets were you running in the 30s? i had 50 pilots, clip up from richest, and 170-180s. i didnt know if the mid pipes would respond well to big carbs so i stuck to the smaller side, plus i didnt want to loose an ounce of lowend, so i went with 30s. this talk about bigger carbs is killing me, if only i would have known from the start before i bought 30s. oh well though shes fast enough for me the way it is. keep on going, your getting her straightened right out. did you ever try on the dyno plugging up the intakes? i have plugs here next time out if i remember im going to throw them in. Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 11, 2004 Report Share Posted April 11, 2004 I run the paul turner mids on mine and she runs great. althought i would like to see what a set of fattys etc would do. what kind of air filter setup do you have? what jets were you running in the 30s? i had 50 pilots, clip up from richest, and 170-180s. i didnt know if the mid pipes would respond well to big carbs so i stuck to the smaller side, plus i didnt want to loose an ounce of lowend, so i went with 30s. this talk about bigger carbs is killing me, if only i would have known from the start before i bought 30s. oh well though shes fast enough for me the way it is. keep on going, your getting her straightened right out. did you ever try on the dyno plugging up the intakes? i have plugs here next time out if i remember im going to throw them in. I was running 380, 25, needles all the way down on the stock carbs I ran a 160, 42, needles 2nd clip from the taper on the 30's I ran a 160, ?, needles in the 2nd clip on the 33's Now I"m running 155, ?, needles all the way down on the 35's w/ the prodesign intake and v-force reeds.... The larger carbs make a huge difference on low end and response..They are doing the opposite of what you'd think..The stroker loves to breathe...I'm running the 35's w/ the stock air box and single K&N. I figured a way to get it to work nicely. You just have to pull the box to get the carbs off.....If your still running the stock intakes, then you have no idea how much hidden power you have waiting.... Quote Link to comment Share on other sites More sharing options...
Ducman Posted April 11, 2004 Report Share Posted April 11, 2004 This is all excellent info for anybody looking to do a +4 stroker in the future, so pay attension kids! R&D like this is priceless. Hmmm Pro design intake makes a big difference eh? I'm dieng to know what pipes are going to make the nicest power curve. More info! Quote Link to comment Share on other sites More sharing options...
PassionRE Posted April 11, 2004 Report Share Posted April 11, 2004 Update: I talked to my builder, he ported it w/ 35 degrees blowdown, widened the exhaust w/ slight raise, 196 degrees exhaust, and 116 degrees intake...What does this mean to you Jim? Banchetta that translates into ex. timing opening at 82 degrees ATDC, transfer opening at 117 degees ATDC, and 126 degrees transfer duration. A great running engine that still has a potential of an extra 15 hp if you desire....Jim Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 11, 2004 Report Share Posted April 11, 2004 (edited) 15 more!!!! This thing is insane right now.....My main concern right now is the dip....What do you think, I want the curve I had before.....Timing settings didn't change the dip at all...The only thing I haven't tried is the reed spacers....Will the 15hp hurt my lower end or torque? Hmmm... bad pic I guess. The stroker is pulling 63hp w/ the larger carbs, the old curve is my setup last year and the smoothness was insane....I love the power of the 4 mil, but my motor bogs down when I'm at the dip or rpm...I can feel it in the field. Drives me nuts when I need the throttle and it bogs out at that rpm..... Edited April 11, 2004 by Banchetta Quote Link to comment Share on other sites More sharing options...
PassionRE Posted April 12, 2004 Report Share Posted April 12, 2004 MMMMMMMMM..first guess, needles. If you have them try a thinner needle, your engine may be leaning out in the mid and then recovering. If your running the stock airbox, you might try longer runners between the box and carbs. I reccomend 3.5 inch runners on the back of my engines and usually dont have to change the needles on PJ34's. BUT, you will have to move the box back to run it this way..Ive had great luck with it and hesitation is a rare complaint....Jim Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 12, 2004 Report Share Posted April 12, 2004 (edited) The stock air box can't go back unless your suggesting to move the coolant bottle?? I've dyno tested w/ the air box at first and got tired of trying to remove the carbs, so we then tested w/o the air box completely and run the carbs w/ no filter for the dyno...We still got the same curve.....I ran 28pwk taper bored to 30's w/ custom needles, 33mm carbs (not sure what kind of needle), 35mm carbs w/ DE? cant remember, and stock carbs w/ stock needles....All four carbs produced the same exact curve.....I doubt all these carbs have the same needles, but I'll check tomorrow and let you know what all the needles are....Here is the carb graphs... Edited April 12, 2004 by Banchetta Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 12, 2004 Report Share Posted April 12, 2004 (edited) I believe the 5000rpm range is running rich...A few different dyno runs would break up and spit and sputter when I got into that rpm range. So its running rich, I'm thinking the porting isn't matching my pipe......????? Think reed spacers would help w/ the crankcase pressure and eliminate that dip?? Here is a graph from last year in comparison of the spacers on the stock ports.... Edited April 12, 2004 by Banchetta Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 12, 2004 Report Share Posted April 12, 2004 (edited) Here's a close up graph at lower rpms... Edited April 12, 2004 by Banchetta Quote Link to comment Share on other sites More sharing options...
cb67rs1 Posted April 12, 2004 Report Share Posted April 12, 2004 are you running v force reeds when the dip is present? just wondering cause when i went to the dyno the other day , i dynoed at 72.3 hp and it didnt have a dip, and the guy up there was amazed cause he said EVERY banshee he ever dynoed with v force reeds had a dip in the band. just something to think about Quote Link to comment Share on other sites More sharing options...
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