SlowMoe Posted August 31, 2017 Report Share Posted August 31, 2017 I don't have a shitload of experience with different banshee pipes. T-5's, Paul turner hi revs, Pro circuit platinums and now CPI. Each one of these pipes had something the CPI pipes seem to be missing; overrev. When the CPI's hit, it's a very hard midrange hit that pulls decent RPM's, but prefer to be short shifted, unlike the aforementioned pipes, which don't mind revving to the moon before hitting the next gear. I guess my question is, is this typical of a CPI pipe, and if not I was wondering if my porting has something to do with. My numbers are 196 exhaust 124 transfer. The exhaust port is very wide, probably 75% of bore.The intake ports were not opened up much. No boyesen ports. Is there anything I can do porting wise to improve my overrev? Do boyesen ports help any? Will more transfer timing help it rev out further? Or is this just the nature of the pipes? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted August 31, 2017 Report Share Posted August 31, 2017 I have zero problems with CPI overrevving. My guess would be porting or domes, timing. Looking at your dyno numbers your missing roughly 10-15 hp with those same durations. Some builders consider those durations to be drag porting. What configuration of domes are you running and what size ? Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted August 31, 2017 Report Share Posted August 31, 2017 It could be fighting itself up top with the wrong dome configuration. What's your squish at? compression? did you end up doing anything out of the ordinary with motor set up ? Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted August 31, 2017 Author Report Share Posted August 31, 2017 I'm trying to get the dome info from my builder. I don't think anything else is out of the ordinary.-Cool head pump gas domes-vf4-34mm PJ-porting-+4mm crank-+4 timingIt could be domes but my builder is pretty reputable around here and I doubt he would have totally dropped the ball on that. So. Sleeper, you've seen my dyno chart. Does it look to you like the power is falling off faster than normal on the top end? Maybe it's all in my head because the midrange is so strong Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted August 31, 2017 Author Report Share Posted August 31, 2017 795 series 21cc noss domesSent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted August 31, 2017 Author Report Share Posted August 31, 2017 Not sure on squishSent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted August 31, 2017 Author Report Share Posted August 31, 2017 I'm not hearing any signs of detonation. How can I know for sure though?Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted August 31, 2017 Author Report Share Posted August 31, 2017 Looking at your dyno numbers your missing roughly 10-15 hp with those same durations.The guy that built and dynoed my bike said that his dyno reads AT LEAST 5-6 hp lower than any other dyno he knows of. So 68 HP is conservative, not to mention my clutch was slipping Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted August 31, 2017 Report Share Posted August 31, 2017 What you have rite there my friend is a time bomb on your hands. What size pistons? Usually under 65 you can get away with 23cc domes, over that go with 24s sometimes 25. Like said above your detonating that motor, hear it or not but it's fighting itself. What's your static compression like Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted September 1, 2017 Report Share Posted September 1, 2017 Anything Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted September 1, 2017 Author Report Share Posted September 1, 2017 I'm gonna buy a compression gauge and see where I'm at. 65.5 mm Pistons. Are you saying I should be running 50/50 race gas?Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted September 1, 2017 Author Report Share Posted September 1, 2017 I never believe when someone says their dyno reads low, normally a bullshit excuse. But looking at the curve, your engine peaks around 9400 with CPI. This one peaked around 10K with CPI[/url] This one after some jetting peaked around 10K with CPI http://www.bansheehq.com/forums/index.php?/topic/183834-4-mil-stock-cylinder/ Since PB sucks now, hard to look at old charts. But the 9400 peak just seems low for CPI. I remember seeing them peak aroud 9800-10200.[/url] Sent from my iPhone using Tapatalk Maybe the motors shown have higher exhaust port durations, that will move the peak up higher in the rpm range if I remember correctly Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted September 1, 2017 Report Share Posted September 1, 2017 I run alky with that set up on asphalt, I would use straight race fuel if your running any timing Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted September 1, 2017 Author Report Share Posted September 1, 2017 Ok. How much timing do you recommend if I jump to race fuel? Would avgas work too?Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted September 1, 2017 Report Share Posted September 1, 2017 I have little to no experience with av gas . The experience I had wasn't a good one either.you need to give us an idea on static compression . You also need to squish test that bitch. Report back Quote Link to comment Share on other sites More sharing options...
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