Banshee0028 Posted June 18, 2004 Report Share Posted June 18, 2004 Ok, with biger mains, you get more fuel in the engine......up to some limit of course.......And with bigger carbs, you get the same... So my question is, when would you need/or benefit from bigger carbs rather than going higher on the mains Quote Link to comment Share on other sites More sharing options...
Toomey Banshee Posted June 18, 2004 Report Share Posted June 18, 2004 Depends on the mods. The stockers actually out flow the stock motor. The 26's are actually a very good carb, when properly tuned. When you get into porting/polishing, higher compression and the like is when you want to start to look at bigger carbs. Quote Link to comment Share on other sites More sharing options...
Banshee0028 Posted June 18, 2004 Author Report Share Posted June 18, 2004 Well i have mild MX porting, FMF sst's, cool head, 18cc domes, getting ready to put in Delta VF 2's, and eventually some more stuff...Right now its Great for buttom/midrange...Just trying to get more top end pull.....I think I need to go higher on the mains, but was just asking about the carbs.....I am still at 260...Would I be safe if I had to go up to 300 with stock carbs with this setup? Quote Link to comment Share on other sites More sharing options...
Meat_Head Posted June 18, 2004 Report Share Posted June 18, 2004 So my question is, when would you need/or benefit from bigger carbs rather than going higher on the mains Ok bigger carbs do not provide more fuel they provide more air so you need bigger carbs once the ones you are using cant meet the engine demand in air.In essence you dont want to choke your engine by using carburators that cant provide the air needed for your engine to reach its full potential.On the other hand if you over carb your engine,you kill the velocity at wich the air is drawn into your engine, not much better... When do you benefit from bigger carbs? Size of the engine,porting specs,pipes,the type of riding/racing you plan on doing, etc. will pretty much dictate if you will benefit or not from bigger carbs. Quote Link to comment Share on other sites More sharing options...
geaux 4 it Posted June 19, 2004 Report Share Posted June 19, 2004 You might be able to go up to 280 or 290 mains.If the bike is running great on the 260's,not popping or falling off the other end.I don't think bigger carbs going to help you. Quote Link to comment Share on other sites More sharing options...
Banshee0028 Posted June 19, 2004 Author Report Share Posted June 19, 2004 What would be the difference between going up one or two sizes of main jets, vs going one position higher for the needle? They both will allow more fuel and run richer, correct? The needle is easier so should that be the first position to test? Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted June 19, 2004 Report Share Posted June 19, 2004 yea go on up with the main. have you checked the plug? you may be too lean. im running 320 mains in stock cars with some mild portwork. it fuckin screams. i bet youre too lean, id run it WOT and then check the plugs. then check back here with your results. Quote Link to comment Share on other sites More sharing options...
sredish Posted June 19, 2004 Report Share Posted June 19, 2004 (edited) What would be the difference between going up one or two sizes of main jets, vs going one position higher for the needle?They both will allow more fuel and run richer, correct? The needle is easier so should that be the first position to test? throttle position. the main is a wot adjustment. the needle is responsible for the transition from the pilot to the main, and it controls this transition with the clip, the taper, and the diameter. Going up one on the clip will affect 1/4 to 1/2 throttle, where the main mostly (like 99.9%) affects WOT. If you have a problem with WOT, then you need to address it that way, not change the needle cause it's easier. Just something to think about. Figure out where in the throttle position, your problem is and go at it with that in mind. Edited June 19, 2004 by sredish Quote Link to comment Share on other sites More sharing options...
Banshee0028 Posted June 20, 2004 Author Report Share Posted June 20, 2004 Well with all thse tips, that about wraps it up for now...........I am getting a pkg of jets...I m gonna start around 300 and depending on how that works, prob go up or down from there....I will reanalyze and make sure the problem is from 3/4 to WOT.....IF lower, I will start with the clip....I will keep everyone posted on the results later this week. THANKS Quote Link to comment Share on other sites More sharing options...
. Posted June 21, 2004 Report Share Posted June 21, 2004 good idea on going up on the mains, and that is an awesome diagram sredish. You have an aftermarket airfilter in there? Running with the airbox lid/snorkel on? You might be alright on the mains if you have the lid/snorkel on, but still could probably go up a little bit. I've run the pro flo foam dual stage filter with the airbox mod thingy and no lid for the life of the shee basically and I've had water over my seat a few times. I leave the plug hole open (cut the very bottom off the plastic piece so its not really far open) and my airbox drains really quick if it gets some water in it. I keep the filter well oiled and it repels water rather well. I run 320 mains/30 pilots on stock porting and my shee is dead on. I cant wait to go to some good play porting and get some taperbored 30's to throw on my bike. Quote Link to comment Share on other sites More sharing options...
Banshee0028 Posted June 21, 2004 Author Report Share Posted June 21, 2004 Yes, I am running a K&N with outerwears, full airbox with "modified cutout lid"....However I am soon thinking of removing the lid altogether and/or modifying the air box itself...I gues this WILL also change the jetting....I guess I should get things on par first then make those changes... Quote Link to comment Share on other sites More sharing options...
sredish Posted June 21, 2004 Report Share Posted June 21, 2004 Make all the changes that you feel you want to make, then jet it all at one time. If you jet it then take the lid off and/or more airbox mods, you'll probably have to rejet. Double the work. Make the changes you want and only jet it once. My opinion. Good luck and let us know how it goes. Quote Link to comment Share on other sites More sharing options...
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