290 mains for a k&n ?

[stockridinshee]

i have a completely stock banshee and i put a k&n on it and took the lid and snorkle off. i was told a while back that i only needed to go up one or 2 sizes on my main im up to 290's now and still needing bigger. is this a problem or am i just getting alot of air in that box? thanks for any help

 

 

also it seems like if i open the throttle all the way its fine but when i get into high rpms it has no power. its not the throttle position its the rpms.

Edited July 19, 2005 by stockridinshee

[Rare Scottish Tree Badger]

The following are some guidelines for your situation taken from an old FAQ of BenBB:

 

Remove snorkel:1-2 sizes larger on the mains, adjust airscrews

Remove airbox lid:1-2 sizes larger on the mains, adjust airscrews

Add K&N air filter:4-6 sizes larger on the mains, adjust airscrews, add one size on pilots if necessary.

 

Those figures say anywhere between 6 and 10 sizes (260/270 -300/310). ... Without pipes, you'd be around 260 at the most IMO. Do a plug chop and see what your plugs tell you.

 

I would think that it's your stock pipe that's restricting your higher RPM/ power. ... You've opened up all the intake side of things to get more air in, but it just can't get out. Get yourself some aftermarket pipes to suit your riding style, and your bike will be massively improved! (Remember to jet up again ).

 

Rare.

[sredish]

i have a completely stock banshee and i put a k&n on it and took the lid and snorkle off. i was told a while back that i only needed to go up one or 2 sizes on my main im up to 290's now and still needing bigger.

 

that kind of sounds strange. going up to 290s with just stock pipes and everything minus the lid and snorkle just doesn't sound right. I'd start looking for an air leak. Check the boots where you take the carbs out on the motor side of the carbs. Spray WD40 or Carb Cleaner or use propane gas (unlit) or something around there to see if you can find it. You should be around 230 or 240 maybe, but 300s doesn't sound right to me.

[decon]

if your taking the lid off might want to go up on the pilot also.

[80overShee]

290's sounds high, 260 at the most unless you are in Antarctica. Im with the 'check for leaks' suggestion. That or make sure you really know what your plugs are supposed to look like. I am at a 320 and thats with pod filters, T5 pipes, advanced timing and Boyesen reeds.

 

It sounds more to me like you are looking for power from jetting instead of looking for correct performance but I may be wrong.

[Banshee~]

290's sounds high, 260 at the most unless you are in Antarctica.  Im with the 'check for leaks' suggestion.  That or make sure you really know what your plugs are supposed to look like.  I am at a 320 and thats with pod filters, T5 pipes, advanced timing and Boyesen reeds.

 

It sounds more to me like you are looking for power from jetting instead of looking for correct performance but I may be wrong.

394697[/snapback]

Im with him, I dident even rejet for my K&N filter, but went up about 4 main jet sizes when I took my snorkel and lid off.

[2strokesmoke]

im at 240 with k&n filter and motofast 2 in to 1 pipe

[stockridinshee]

i checked for an air leak and nothing . i took starting fluid, cause thats all i had, and sprayed everything infront and behind the carbs and nothing just idled normally. from what you guys are saying i almost definatly have an airleak so what should i do next? any help at all is appreciated.i wanna ride it but i dont wanna blow it up.

[Rare Scottish Tree Badger]

How are you reading your plugs? Have you done a plug chop at any stage of trying different jets? What size jets did you try - all sizes upto 290? Are they B8ES/ BR8ES plugs that you're using?

 

Since you don't have an air leak (at the only places you've worked on, i.e. carbs and boots), and most of the guys have suggested that around 240 mains is about where you should be; I think a fresh set of plugs, 240 mains and a plug chop run are in order. ... Look for a clear white porcelain color, like new but not grainy/ porous and a 1mm ring of carbon at the base of the porcelain where it joins the shell of the plug. This is seen the best by cutting the threads off the plug - hence 'plug chop'.

 

Rare.

[Banshee~]

How are you reading your plugs? Have you done a plug chop at any stage of trying different jets? What size jets did you try - all sizes upto 290? Are they B8ES/ BR8ES plugs that you're using?

 

Since you don't have an air leak (at the only places you've worked on, i.e. carbs and boots), and most of the guys have suggested that around 240 mains is about where you should be; I think a fresh set of plugs, 240 mains and a plug chop run are in order. ... Look for a clear white porcelain color, like new but not grainy/ porous and a 1mm ring of carbon at the base of the porcelain where it joins the shell of the plug. This is seen the best by cutting the threads off the plug - hence 'plug chop'.

 

Rare.

395029[/snapback]

Im not a big fan of the plug chop deal. I just throw in new plugs and run in threw all the gears and hold it WOT for about 6 seconds, pull in the clutch and kill it with the throttle pinned. Then take out the plugs and they should be papersack brown. On the plug chop I think the ring should be 2mm thick and brown also. IMO you should jet buy feel and a plug check.

[crbanshee]

i have a completely stock banshee and i put a k&n on it and took the lid and snorkle off. i was told a while back that i only needed to go up one or 2 sizes on my main im up to 290's now and still needing bigger. is this a problem or am i just getting alot of air in that box? thanks for any help

also it seems like if i open the throttle all the way its fine but when i get into high rpms it has no power. its not the throttle position its the rpms.

394570[/snapback]

i just went through this..i had to put the lid back on and run a 300 main..shee runs great now

[Rare Scottish Tree Badger]

i just went through this..i had to put the lid back on and run a 300 main..shee runs great now

395110[/snapback]

You've got pipes tho'. ... His bike's got stock pipes.

 

Banshee~, this is a quote from Streppe about reading the plugs:

 

"You won't find any soot out near the insulator nose, on a plug that's running hot enough to keep itself from fouling, because temperatures there are too high to let soot collect. But the insulator is much cooler deep inside the plug body, and coolest where it contacts the metal shell, which is precisely where you "read" mixture strength. Look far inside a plug, where its insulator joins its shell, and what you'll see there if your engine's mixture is too rich is a ring of soot. If this ring continues outward along the insulator to a width of even a millimeter you can be sure the mixture is rich enough to be safe, and too rich for maximum output. In most engines best performance is achieved when the mixture contains only enough excess fuel to make just a wisp of a "mixture ring" on the plug insulator."

 

Rare.

[stockridinshee]

ill try the plug chop in the morning but my understanding is if i have 290 mains in and i open the throttle all the way it should bog if its to rich correct? and it will rev high and fast if its lean? if so i need to still go up on the mains and every time i go up on the main its gets better and better. so i dont understand whats wrong. but ill deff. try the plug chop tomarrow and get back with you guys. thanks for all the help!

[sredish]

ill try the plug chop in the morning but my understanding is if i have 290 mains in and i open the throttle all the way it should bog if its to rich correct? and it will rev high and fast if its lean? if so i need to still go up on the mains and every time i go up on the main its gets better and better. so i dont understand whats wrong. but ill deff. try the plug chop tomarrow and get back with you guys. thanks for all the help!

395235[/snapback]

 

depending on the level of lean/rich, it will act differently. Slightly lean will let it rev easier, but if it's definitely lean, it will often bog, no sputtering bog, just flat no power bog. If it's rich and it bogs, it's usually a wet sputtery bog unless it's really rich, then it'll bog somewhat flat but still kinda wet. If it bogs, kill it and check the plug. if it bogged because it's rich, the plug will be wet, if it's lean, it'll be really dry and clean.

 

Scott

[Rare Scottish Tree Badger]

ill try the plug chop in the morning but my understanding is if i have 290 mains in and i open the throttle all the way it should bog if its to rich correct? and it will rev high and fast if its lean? if so i need to still go up on the mains and every time i go up on the main its gets better and better. so i dont understand whats wrong. but ill deff. try the plug chop tomarrow and get back with you guys. thanks for all the help!

395235[/snapback]

What you've said there, in theory, is correct. ... What premix ratio are you using?

 

EDIT: Scott's given you the 'in practice' situation in the thread above. ... Good info.

 

Rare.