Wildcardracing Posted January 21, 2010 Report Share Posted January 21, 2010 Snop, do you think the 35's are overkill in my situation? If so, why? I wouldn't go any larger on your setup. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted January 21, 2010 Report Share Posted January 21, 2010 Yeah, its pretty nuts when you see some of these guys with 35mm pwk's on dune bikes that are ported pulling like 9,900 peak rpm. Way Overkill! I ran 38's on my old 4mil duner with shearers and a dune-port. Wasn't overkill at all. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted January 21, 2010 Report Share Posted January 21, 2010 (edited) Snop, do you think the 35's are overkill in my situation? If so, why? Where are your durations set, what kind of rpm did the thing pull on the dyno? You can also tell by looking at the end of the dyno curve usually. Edited January 21, 2010 by Snopczynski Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted January 21, 2010 Report Share Posted January 21, 2010 (edited) I'm quite sure the engine described in this thread will make more "impressive" numbers on a crank dyno at 700' with 180psi compression as compared to his pump gas 5000' rear wheel pull. Apples to oranges. Im not sure it would be different numbers, thats why I am not too impressed. I think the back down to near sea level elevation would up the hp. However, the correction factor program between the Dynojet and the crank dyno would knock it back down to a real hp reading. So I think that motor would dyno at about the same hp on a crank dyno at sea level, as it did on a dynojet at 5,000 ft. Edited January 21, 2010 by Snopczynski Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted January 21, 2010 Report Share Posted January 21, 2010 thats great numbers brother im here in kansas 1300 ft above sea level and i have a 4 miil cub and i made 72 hp with stock carbs and reeds with pc pipes Not sure why you would run a 4mil cub with stock carbs though.You have esentially cut your Hp by 20 on a race design cylinder. Props for using stock carbs^^ So many think you NEED bigger carbs^^. On his cylinder he needs bigger carbs.It is a race design cylinder not a stock cylinder! Yeah, its pretty nuts when you see some of these guys with 35mm pwk's on dune bikes that are ported pulling like 9,900 peak rpm. Way Overkill! Snop for tight tree shoots and trails in OR I would agree but for open dune areas small carbs on a 4mil or even a good port does not cut it. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted January 21, 2010 Report Share Posted January 21, 2010 (edited) I used to run 32mm lectrons on a stock cylinder drag ported bike I had. It would hand a lot of "Open Dune Bikes" their ass with those so called "TOO SMALL CARBS" on it. We still have drag strips in Oregon. Edited January 21, 2010 by Snopczynski Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted January 21, 2010 Report Share Posted January 21, 2010 I used to run 32mm lectrons on a stock cylinder drag ported bike I had. It would hand a lot of "Open Dune Bikes" their ass with those so called "TOO SMALL CARBS" on it. We still have drag strips in Oregon. A 32mm lectron is not a small carb.. You are comparing a drag port to a dune port,I would hope you would beat them. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted January 21, 2010 Report Share Posted January 21, 2010 (edited) Im trying to understand your reasoning here. Everyone and their brother puts 35mm pwks on dune bikes. So if a Drag ported stock cylinder bike is running 32mm carbs, why would a bike with just a dune port on stock cylinders need 35mm carbs on it? I beat other drag bikes, as well as other peoples play bikes. So whats the reasoning if we dyno test a bike and it does better with 32mm carbs? Why do people who obtain less max rpm, have lower durations, and less peak rpm feel the need to run 35mm carbs? If 32mm's is not small, why does everyone and their brother run a 35mm pwk? Why do we have guys on here running 38mm pwk's on stock cylinder bikes? Why did my buddies trinity bike that he bought have a set of 38mm pwk's on it when he has a stock cylinder stage IV port job, with Stage IV pipes? Edited January 21, 2010 by Snopczynski Quote Link to comment Share on other sites More sharing options...
SonOfSand Posted January 21, 2010 Report Share Posted January 21, 2010 Where are your durations set, what kind of rpm did the thing pull on the dyno? You can also tell by looking at the end of the dyno curve usually. Snop, can you explain "durations" to me? I have yet to dyno my banshee, so no help there. I will say this, I was expecting more of an increase when I put the 35's on, I cant even say I felt a noticeable increase. Thanks. Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted January 21, 2010 Report Share Posted January 21, 2010 Im trying to understand your reasoning here. Everyone and their brother puts 35mm pwks on dune bikes. So if a Drag ported stock cylinder bike is running 32mm carbs, why would a bike with just a dune port on stock cylinders need 35mm carbs on it? I beat other drag bikes, as well as other peoples play bikes. So whats the reasoning if we dyno test a bike and it does better with 32mm carbs? Why do people who obtain less max rpm, have lower durations, and less peak rpm feel the need to run 35mm carbs? If 32mm's is not small, why does everyone and their brother run a 35mm pwk? Why do we have guys on here running 38mm pwk's on stock cylinder bikes? Why did my buddies trinity bike that he bought have a set of 38mm pwk's on it when he has a stock cylinder stage IV port job, with Stage IV pipes? I'm not saying they need 35mm carbs,If you look back at my origanal quote the guy had stock carbs on a 4mil cub cylinder,That is my example of needing to run bigger carbs.Smaller carbs IE 26-28 and even 30mm carbs are fine for stock cylinder with a dune port and running bigger just defeats the purpose of being able to have a good power band in the mid rpm range.I think people put 35's on because they are fairly affordable and easy to tune(lectrons are bad A$$ carbs but alot more then pwk 35's) As for me I run 35's on my 4mil stock cylinder because where I run is wide open fast dunes and I like having the hp in the high mid and high rpm range it works perfect for my aplication.If I was running in tight trees and trail dunes then I would have 28's and some fmf pipes not cpi's. I cant awnser for the other examples you used on those combo's because I see know reason to run 38's on a stage 4 set-up. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted January 21, 2010 Report Share Posted January 21, 2010 (edited) Duration is the height of the ports in your cylinder sleeves. My 32mm Lectrons were $432.00 for both when I bought them 5 years ago. Some guys just dont get, that you pick carbs based on porting, pipes, compression, etc...... Carbs dont determine where your power will be. Carbs are the last thing you pick, because they are based off everything else you did. Your not supposed to say, I am gonna run 35mm carbs cause I want to. Your supposed to say, I have 198 degree duration, drag pipes, 160 psi compression, 4 degrees advanced timing, the motor revs to 11,500 rpm on the dyno (or looks like that the rpm it will achieve), well I think we should probably run a set of 35mm carbs. For Example: Dune Port, Sheares SB inframes, Stock type cylinder. This setup doesn't mean, that if you buy a 35mm carb, your power will be mid-top. The porting and the pipes already determined where the power will be. The carbs need to be picked out, to allow the cylinder to be fed enough, but provide the maximum velocity it can achieve to properly feed the a/f charge as fast as it can. You may only need a 33mm carb because of the peak rpm your motor is going to be pulling. Anything over that potential 33mm mark, can actually make the bike slower. I dont run 28mm carbs because I ride my bike in tight trails or trees. I run 28mm carbs because the bike is built for low-mid power and doesn't rev much past 8,750 rpm. Edited January 21, 2010 by Snopczynski Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted January 22, 2010 Report Share Posted January 22, 2010 My 32mm Lectrons were $432.00 for both when I bought them 5 years ago. Some guys just dont get, that you pick carbs based on porting, pipes, compression, etc...... Carbs dont determine where your power will be. Carbs are the last thing you pick, because they are based off everything else you did. Your not supposed to say, I am gonna run 35mm carbs cause I want to. Your supposed to say, I have 198 degree duration, drag pipes, 160 psi compression, 4 degrees advanced timing, the motor revs to 11,500 rpm on the dyno (or looks like that the rpm it will achieve), well I think we should probably run a set of 35mm carbs. For Example: Dune Port, Sheares SB inframes, Stock type cylinder. This setup doesn't mean, that if you buy a 35mm carb, your power will be mid-top. The porting and the pipes already determined where the power will be. The carbs need to be picked out, to allow the cylinder to be fed enough, but provide the maximum velocity it can achieve to properly feed the a/f charge as fast as it can. You may only need a 33mm carb because of the peak rpm your motor is going to be pulling. Anything over that potential 33mm mark, can actually make the bike slower. I dont run 28mm carbs because I ride my bike in tight trails or trees. I run 28mm carbs because the bike is built for low-mid power and doesn't rev much past 8,750 rpm. I understand duration I understand carbs dont make where the power is at.My point was (because we both understand porting and pipes dictate where the power is at)that 28's would be the more proper carb for a tight trails or tree shoots because that is what the port duration is for a lower rpm range setup if it is ported to said low end-mid duration.For the one guys 4mil cub that I origanaly quoted about stock carbs are not correct for his duration. I mentioned I run 35's because of where my port duration is and 35's equall the correct volocity for my set up. Snop check out my dyno runs on my 05 4 mil stock cylinder,You will notice that where the HP and torque are from roughly 6k rpm to 9500 rpm exactly where I need it to be for the dunes I ride.Here is the link for you.It is the run with 74.6hp not the 91.6hp sheet. http://bansheehq.com/forums/index.php?showtopic=122838&st=0&p=1064287&fromsearch=1entry1064287 Quote Link to comment Share on other sites More sharing options...
Badasshee Posted January 22, 2010 Author Report Share Posted January 22, 2010 haha im going to stay out of this! ill just sit back and read. lol Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted January 22, 2010 Report Share Posted January 22, 2010 I would say by the looks of those charts your way over carbed on both those bikes also. I would have 35mm's on the cub, and at the most 33mm's on the stock cylinder bike. Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted January 22, 2010 Report Share Posted January 22, 2010 LOL ok you are intittled to your opinion.I have done extensive tests on these engines and the #'s don't lie.It is possable that at sea level smaller carbs would work do to the air pressure differance but here actually running them in the real world(IE making passes and runs)These are the correct carbs for these applications. Quote Link to comment Share on other sites More sharing options...
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