what size main jet?

[thunder1295]

The more I read and there is so much to read on here about carb's and tuning, I just rebuilt my carbs on my 1988 1200, be an 89 in the states and it turned out pretty good but the bike is lacking that punch in the mid and high rpms, I know its got more in it, just want to bring it out.

I took off the stock air breather and put on 4 single pods, have all stock jets and the needle is in the middle, 3 from top or 3 from bottom, stock mufflers.

What jets should I go with and where would you suggest I set the needle to.
I want this bike running like the beast it is.

Thxs
jim

[thunder1295]

Don't seem to be getting any reply's so this may help, the carb's have 110 main jets and the needles on the 3rd groove,
as I mentioned before I put pods on the carb's and I'm thinking of getting the Delkevic 9" slip on's

So if I drop the needles drown a groove and move up to 112.5 or 115 main jets will that be pretty close to being right on with the carb's

Hoped that helped.

http://www.delkevic.us/?section=shop&product_category=exhaust_s7rhj&sub_category=silencers_yamaha_9nw3x&product=yamaha_ss70_stainless_steel_mufflers__silencers_9andquot_225mm&variant=yamaha_fj1200_19861992&start=0&search_term=&order_by=

[racerrad8]

If you are having a bogging in the mid range, you would want to raise the needles because it is lean. The setting you have them set to is the stock setting and 90% of people raise or shim the needle up.

You should also add some pilot jet to 40.0 and the main jet up to 112.5-115 which make the wide open throttle run properly.

You also need to keep those pod filters oiled. The camshaft overlap will consistently wash the oil from the filter and render it basically useless.

Randy - RPM

[thunder1295]

Hi Randy, I have to say its not really bogging anywhere, I just don't think it has that kick in the ass get up and go, when I hit 7 grand it just keeps pulling but not like my 87 did where it would seem to hit warp speed to redline.
there are #42.5 Fuel Pilot Jet
             #155 Air Pilot Jet
             #110 Main Jet
So should I move to the next size on the fuel pilot jet ?  and I will try the 112.5 first and see what kind of diff they make, plus move the needle up one spot, once I get the slip on's
The pods are the cone type, 4 separate ones thought you didn't use oil on those kind since they have paper filters in them ??

I'll hold off a bit and see if you get any news on your pipes this week, what ever way I go thanks for the help.

Jim

[racerrad8]

Well, the pilot might be a little big depending on your altitude & weather conditions.

The main jet is too small and the needle might need to be raised.

You need to check the vacuum line to the ignition box and make sure it is good. You might also test the advance on the ignition system and see if it changes with vacuum applied.

The paper filters are a single layer media and require oil for filtering. Unless it is a new design of paper media filter I have not seen before, then the need to be oiled. You will need to be oiling the regularly as the fuel mist will wash the oil from the filters.

There has been many posts regarding the difference of air filters and why the dual element foam pod filters work better.

Randy - RPM

[RichBaker]

The stock paper filter does NOT need oil..... Just like a car filter. Oil will make it more restrictive.

[HARTLESS]

The stock paper filter does NOT need oil..... Just like a car filter. Oil will make it more restrictive.

Negative ghost rider. Any cone airfilter in a car needs oil, don't know where you got that from. Paper particles have microscopic gaps which can let crap in, hence the oil to keep them moist and close the gaps. Dry paper=uh oh!

[Pat Conlon]

Oh for fucks sake, I see now why DavidR needed a break from this chaos.....

[HARTLESS]

Oh for fucks sake, I see now why DavidR needed a break from this chaos.....

Wasn't meant to be offensive .....if that's what you are saying

[fj11.5]

Think rich may have missed the bit about paper cone filters, and not the stock paper filter

[ribbert]

Negative ghost rider. Any cone airfilter in a car needs oil, don't know where you got that from. Paper particles have microscopic gaps which can let crap in, hence the oil to keep them moist and close the gaps. Dry paper=uh oh!

I would answer this but I'm not entirely sure you are being serious.

[HARTLESS]

Think rich may have missed the bit about paper cone filters, and not the stock paper filter
[/quote
Think I missed the part where he said stock paper filter.  my bad!

[fj11.5]

Just a minor break in ccommunicatttion 

[ribbert]

Negative ghost rider. Any cone airfilter in a car needs oil, don't know where you got that from. Paper particles have microscopic gaps which can let crap in, hence the oil to keep them moist and close the gaps. Dry paper=uh oh!

So you close up the gaps with oil, how does the air get in?

You don't oil ANY paper filter.

[fj11.5]

Most of the cone type filters, eg k&n are a material ,gauze weave type of thing,  that need oil,  they are not paper filters