Jdawg82 Posted May 24, 2005 Report Share Posted May 24, 2005 I recently bought some ported cylinders for my banshee. I was running 290 main jets with toomey t5s, and a removed airbox lid. I decided to jet up to a 330 and go from there. The bike was way too rich and flooded the bike with gas would barely run and was very hard to get started. The bike would also rev have the rpms it would before the cylinders. I popped in the 290 jet and the bike revved much quicker. My question is can porting actually make your jetting go down? My bike still isnt running quite right and I think I am going to try a 270 or 280 main jet. Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted May 24, 2005 Report Share Posted May 24, 2005 Nope. Porting opens up your intake and exhaust, allowing more air and fuel to pass through, resulting in more horsepower. Are you 100% sure those cylinders you bought are ported? I've never heard of anyone going down on jetting with ported cylinders. Quote Link to comment Share on other sites More sharing options...
Jdawg82 Posted May 24, 2005 Author Report Share Posted May 24, 2005 Nope. Porting opens up your intake and exhaust, allowing more air and fuel to pass through, resulting in more horsepower. Are you 100% sure those cylinders you bought are ported? I've never heard of anyone going down on jetting with ported cylinders. 373218[/snapback] Yea I am 100% sure they are ported. They are all silver and polished and the divider between the intakes is a lot thinner than stock. I am very confused as well. All though I definetly know that the 330 jets were drowning it with fuel as were the 310s. I haven't gotten a chance to ride it yet since the rebuild so I dont know if I gained any power. I elminated an over oiled filter because took the carb boots off for a few seconds just to see if it would change anything which it didnt. Quote Link to comment Share on other sites More sharing options...
Big Blue Posted May 24, 2005 Report Share Posted May 24, 2005 you may also take into consideration the motor is pulling more air in which will allso pull more fuel in as well. Quote Link to comment Share on other sites More sharing options...
01bansheeke Posted May 24, 2005 Report Share Posted May 24, 2005 something isn't right somewhere else if you can't run a 330 main with some porting. stock carbs correct? I ran 360's in myne and it was spot on when i had t5's and stock carbs with porting. Maybe check for airleaks etc. Quote Link to comment Share on other sites More sharing options...
Jdawg82 Posted May 24, 2005 Author Report Share Posted May 24, 2005 something isn't right somewhere else if you can't run a 330 main with some porting. stock carbs correct? I ran 360's in myne and it was spot on when i had t5's and stock carbs with porting. Maybe check for airleaks etc. 373226[/snapback] Wouldnt air leaks allow me to run bigger than neccassary jets? Since the air leak would lean out the mixture? I know it doesnt sound right because my buddy ran 310s with just pipes and a filter. I am running the stock carbs. I also switched carbs with my buddy and it did the same thing so its not a carb problem. It is also not a spark issue because I switched cdi boxes with my buddy as well. I am running 100 octane fuel without advancing my timing. Could that effect anything? Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted May 24, 2005 Report Share Posted May 24, 2005 Wouldnt air leaks allow me to run bigger than neccassary jets? Quote Link to comment Share on other sites More sharing options...
Jdawg82 Posted May 24, 2005 Author Report Share Posted May 24, 2005 That's what I'm thinking...if you had an air leak, it would run better with bigger jets (theoretically) OK, let's take this down to square one. What setup were you running when it last ran good? What was changed to make it run crappy? Does it overheat? Your problem is not your timing, however, if you advanced it by 4 degrees it will improve performance. 373259[/snapback] Well I threw a rod and messed up my cylinders, pistons and one of the rods. I then purchased a welded crank off ebay and these ported cylinders and pistons. The only thing I changed was the cylinders, crank and pistons. The guy I bought these off of was running 270 mains with dmc alien pipes and holes in the airbox lid. Thanks for all your help Quote Link to comment Share on other sites More sharing options...
sredish Posted May 24, 2005 Report Share Posted May 24, 2005 My question is can porting actually make your jetting go down? My bike still isnt running quite right and I think I am going to try a 270 or 280 main jet. 373122[/snapback] Is it actually "ported" or just cleaned up? In theory, it is possible, because, as Big Blue said, the faster airflow will produce more vacuum, allowing the possibility for more fuel with the same jet. If it was just cleaned up, then it's possible that it's not really flowing much more air, but it's much faster, hence the need to back the main off. I have actually heard of porting causing the main to go down, but only with small portjobs and cleanups, but it's very rare that I've heard it. Scott Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted May 24, 2005 Report Share Posted May 24, 2005 Well I threw a rod and messed up my cylinders, pistons and one of the rods. I then purchased a welded crank off ebay and these ported cylinders and pistons. The only thing I changed was the cylinders, crank and pistons. The guy I bought these off of was running 270 mains with dmc alien pipes and holes in the airbox lid. Thanks for all your help 373281[/snapback] OK; I remember you saying that with the 290 main that it revved quicker, but did you ride it? If so, how did it ride? Were you able to do a plug chop? The port you have may be a clean-up port job...if that is the case, then Big Blue's and sredish's theories make the most sense in this situation. If I were you, I would put whatever jets in it that make it run right. No matter what other people's engines run off of (jet sizes); every engine is different to some degree. As long as the plugs tell you you're getting a sufficient amount of gas then you should have nothing to worry about. Quote Link to comment Share on other sites More sharing options...
Jdawg82 Posted May 24, 2005 Author Report Share Posted May 24, 2005 OK; I remember you saying that with the 290 main that it revved quicker, but did you ride it? If so, how did it ride? Were you able to do a plug chop? The port you have may be a clean-up port job...if that is the case, then Big Blue's and sredish's theories make the most sense in this situation. If I were you, I would put whatever jets in it that make it run right. No matter what other people's engines run off of (jet sizes); every engine is different to some degree. As long as the plugs tell you you're getting a sufficient amount of gas then you should have nothing to worry about. 373305[/snapback] I just rode it with the 290 jet in there and it bogs and I can barely get it over 5 mph at wot. I am going to jet down and see what happens. The machine is real easy to start. First kick no choke even when cold. There is a slight amount of oil coming from the silencers which I believe is telling me its too rich. Quote Link to comment Share on other sites More sharing options...
sredish Posted May 24, 2005 Report Share Posted May 24, 2005 Three words: Read your plugs. If it's bogging and all, kill it right then and check your plugs for oil and such. Don't just keep throwing mains in there just to "try out". You need to get a bearing on what you've got going on. Take it for a ride, even if it's at 5mph and kill it when your doing everything you can, then read the plugs. Sure it's not the TORS acting up? The "first kick starting" is the pilot and has nothing to do with the main, so the two don't even relate. Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted May 24, 2005 Report Share Posted May 24, 2005 I just rode it with the 290 jet in there and it bogs and I can barely get it over 5 mph at wot. Quote Link to comment Share on other sites More sharing options...
sredish Posted May 24, 2005 Report Share Posted May 24, 2005 JDawg, what elevation are you at, where are you man?? Quote Link to comment Share on other sites More sharing options...
lincster Posted May 24, 2005 Report Share Posted May 24, 2005 Your going the wrong way. Starting has to do with pilots, not mains. Easy to start means you have the right pilots and/or air mixture screws adjust right. Are your filters/filter dirty? Do you have fresh gas? Quote Link to comment Share on other sites More sharing options...
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