jetting new pistons

[banshee tuner]

I have been running stock pistons with toomey t5's, boyesen reeds, ported cages, dual k&n pods at sea level for a couple of years with my bike running perfect. My jetting was 280 mains, 30 pilots, needle clip next to the last bottom groove. With my new vito's super stock .20 over pistons and tdr reeds I am running lean. I had hard starts so I jumped to a 32.5 pilot jet and solved my starting problem and smoothed out idle. My top end screamed but plugs looked lean so I jumped to a 320 main. Now I'm having trouble trying to get the mid range right but I've been raising the needle clip. Do I need to go down a size on my mains to get mid range right. Sorry about the long post just trying to give all the details.

[brock_fuzzy_69]

well as a general rule

 

do not mess with jetting till the fresh top end is broken in

 

the plugs wont really look right until the rings have been seated so that you get good compression

and i am sure that when you assembled the motor you added some extra oil to the crank and top end when you assembled it

 

i have heard of nightmares where a guy started to mess with the jetting ona completely fresh motor and blew it sky high from the plug readings being off

 

i would jsut take it easy ont eh bike and run 5 gals or so of gas through it before i mess with any jetting changes

[banshee tuner]

I went and run about 5 gallons of gas through it on sunday and that is when it was hard starting and bottom end was real rough, mid range was off but would run decent and top end was great. I checked my plugs after my my ride and my plugs showed lean condition.

[Wallrat]

I'd recommend dyno tuning to anybody that has a place nearby and can afford it. Even the guys that are shit-hot with jetting (which I ain't) will only get it perfect 75% of the time. I've got a place near my house here in SoCal that'll do it for $150 flat - regardless of how long it takes. Plus they've got all the jets and needles so you don't have to buy $50 worth of stuff just to figure out what you need.

[banshee tuner]

I would do that but the only place local that does dyno is motorcycle only, one of those harlie type of shops.

[banshee tuner]

So if I move the needle clip all the way up and still rich on mid range should I go down on the main jet. When I pull the choke out half way it does run worse.

[Banchetta]

The main won't affect the midrange, unless your way off, then your powerband won't even kick in....your pilot on the other hand will affect the needle....so where your running so rich on the pilot, then your midrange is probably too rich....your settings don't sound right...new pistons won't change your jetting. Reeds cages could a little, just reeds could change the needle one clip...Did you make sure the choke tube was in place when you put the carbs back together??? Slides in backwards?? Swapped the carb bowls?? These will all affect how the shee will start. If one of these aren't right. Then your jetting will be way off...

[banshee tuner]

The choke tube is hooked up, I got it starting and idling good now just cant get it running right in the midrange. Once I get to top end it screams. I went from stock pistons to .20 over vito's super stocks. The intake ports on the pistons are larger than what I had.

[Banchetta]

The choke tube is hooked up, I got it starting and idling good now just cant get it running right in the midrange. Once I get to top end it screams. I went from stock pistons to .20 over vito's super stocks. The intake ports on the pistons are larger than what I had.

447835[/snapback]

Super stocks........I jetted a shee w/ those and still ran best w/ the stock pilot.....Just having a hard time believing the 32 pilots are what you need...how does it start when its warm? Do you have to hold the throttle open a little? Or will it start up w/ no throttle and idle?

[banshee tuner]

With the 32 pilots it starts up first kick and idles real good, with the 30 pilots you have to crack the throttle and it will not idle by itself. With the stock pistons I set it up exactly by yhe toomey instructions and it ran great without any tuning required.

[FIRST BANSHEE]

have you tried cleaning your carbs,make sure all your passeges are clear. I use brake clean and then blow them out with air.

something in your carb circuits aren't working together. your pilot seems to big. good luck

[Banchetta]

What exactly are the symptoms in the midrange??? Is it hesitating before powerband or does it break up like the choke is on?? Also are you running toomey needles or stock? What clip positions have you tried?

[banshee tuner]

I'm running stock needles and can move the clip up 1 more and will be at the top. I dropped the main to a 300 and it improved. The main problem is between idle and getting into the power band. Once in the power band it runs well. If I pull the choke out halfway it runs worse.

[ogre03]

Just a thought, but could he have screwed up his idle, and then when it didn't like to start or idle he went the the huge pilot to compensate, which is now making him run rich in his mid range?

[Banchetta]

Just a thought, but could he have screwed up his idle, and then when it didn't like to start or idle he went the the huge pilot to compensate, which is now making him run rich in his mid range?

448323[/snapback]

It will have an effect, but the needle at the lowest position should be able to compensate.....