Bonneville America Forums Forums Technical Forums Performance Mods K&N pod's

am currently running 142&45 jets in the carb's on a 04 speedy
removed the airbox and fitted the pod's ok i know i'll be needing to tune the carbs to suit the pod's took it for a ride befor tuneing the air/mixture screws
alls good till about 50mph in top,went to throttle on and the bike was dead so to speak ok fair enough since i havent tune the carbs to suit yet
turn the screws in till they seat to get a refence point 3/4 of a turn is all they went (thats what the mechanic set them at the last time it was in for a service)
set em at 2 turns as a reference as stated by the repair manual what a difference it made big improvement in the midrange power mind you i've lost a little of the low end performance so my question is.....
do i put a shim under the needle and screw the mixture in a little to return performance in the lower rev range or is their something else i should be looking at??

BTW i'm at sea level and am running cocktail shakers with a slip in baffle

well folks priced a pair of tbs needles from bikebandit $16 a pair fair enough i thought went to place the order,got a shock when i noticed the postage charge of $80 to send them here to OZ i'll give the local stealership a call in the morning hope fully it wont take as long to get them in as they did when i orded the cush drive 5 weeks to get it

I'm thinking you need to up your mains for better overall performance. The TBS needles will help everywhere but the top end when the main jets are on their own to supply the fuel. You are correct in thinking that a shim under the needle will help lower throttle performance with your current set up and since it's such an easy test why not?

thanks Ed
at the moment the concern is the midrange as for the top end of the rev range thats been fine all along any thing over 5 grand is great
i'll try i shim or 2 till i can get hold of a pair of tbs needles

Man, if you've already go the top end dialed in it's a cakewalk to get the midrange set; all of that work is done from the top and it's quick to test different ideas. The shims will show you how the TBS needles will work at lower throttle input but since the TBS taper is "faster" it won't give you an exact picture of how much better they might be. I found the Thrux needles were good for my set up; I still need to up my mains, I just haven't because I rarely get that far up the throttle (okay, maybe I'm lazy when the weather's good cause I'd rather ride than wrench).

I didn't like the TBS and think that the stock needles work better in our bikes, I'm sure others will disagree. I put them in and messed with it for a while and didn't get the same or better results than stock needles. I had better results playing with the jet sizes until I had it dialed in.

As to the mix/jetting question at the end of your first post. I would do a correct mixture screw adjustment before making any changes and see what happens.Not just set them at arbitrary settings. Set your idle so you can disconnect 1 cyl. and have it stay running then adjust the cyl. still connected. Turn you mixture screw in until the engine starts to tun rough then back out until it starts to run rough and split the difference between the two points. Do the same for the other cyl. this will be your correct idle mixture setting. They may or may not be the same on each carb. If you end up much more than 3 turns out you should increase your pilot jet size.

i think stock needles with shims is the way to go, thats how i did mine and tonys bike when he had it and both ran great

Frank

thanks guys a lot of stuff their to go thru
Ian with regards to the mixture screws thats how i was planing to do it as i've read from you the thing is tho with either cylinder disconnected adjusting the screw on the cylinder which is still connected didnt seem to make any difference maybe i had to idle to high?
weather i screw ed then all the way in or 4 turns out their wasnt a noticeable difference to the ear

It is very possible the idle was too high and the engine was just running off the main at idle. Try starting with the pilot out about 2 turns and turn the idle up just far enough for it to run on the 1 cyl.. It is also possible you may have a leak somewhere like bad O rings on the pilots allowing air in there thus diminishing the effects of the screws. Clogged pilot circuit could another reason. Pilot size could be another but I doubt that one if turning the screw all the way in didn't effect your idle. That last one leads me to believe you had it running off of the main.

thanks Ian it'll have to wait till tomorrow now as were off to a wedding this arvo all the best for the weekend for you and the rest will update tomorrow arvo my time

Brendan, you can have my tbs needles if you are really interested for $20, which will help cover my postage costs to get up to your way.

BTW, my daughter just bought a half acre block on Bribie. It's at one of the new estates opening up there.

Hey Benny,
How was the wedding, went for that ride yesterday to Beaudesert - Boonah back to the Peak Crossing pub & then back to the Royal Mail at Goodna , could have kept on going - the best day for riding in about 6 months

Thanks Staffo i'll have them i'll pm you a postal address if you'll be kind enough to pm me your details i'll do a transfer
Dave you lucky basstard if was a great afternoon for a ride glad to hear you enjoyed it
as for the wedding the bride was lovely the groom was nervous poor bugger lol all went well and good a great afternoon all round

well after buggering around with shims and mixture setting
said stuff it and pulled the carb's off tonight result is i think i may have found out why i could'nt get her to perform propertly 127.5 mains???? so much for our local dyne guru telling me she's now got 145 mains and 48 pilots you'll notice the difference now with a big grin on his face
so off to chase down some 142's or should it be 145's tomorrow at least i'll know whats in their from now on and while i'm at it i'll drop the pilots down to 45's as well as per Pat's calculator

ok folks now i'm confussed
the 145 mains are in set the mixture as per Dog's method, tried 1 shim nah still dead
2 shims thats a little better
3 shims wow anything over 4grand she goes like a cut snake
below 4 grand tho she is a little sluggish
any thoughts?

Pull the shims and increase the main a size.

What Dog said. My best estimate is going to be a 150 or 152 main jet will do it for you. You may or may not need a shim once you get the main dialed in.

ok i may be foolish some of the time
goin by your past post's and advice you have given which seem's to be right
i'll take your advice and off to the shop to get some 150's and we'll see how they go

Ian 150's are in and while they were apart i went with a pair of 48 piolet's as well much nicer bike to ride
weather ther 48's had anything to do with it or not while setting the mixture screws their was a noticeable difference when turning then this time which i was'nt able to do befor
left side 2 turns she picked up rev's so backed it out a 1/4 right side 1&1/4 turns then backed it out a 1/4 good throttle responce no popping on decell
thanks guy's for the help