Quote from: dgyverThe longer the valves are opened with the high lift cams will increase the amount of fuel supplied.

I wish I still had access to CFD software.

That will mean higher lift and higher curation. Duration is to make the thing run well at higher rpm inspite of fuel loss due to over lap. High lift fills the chamber better by effectively not letting the valve itself obstruct flow. Just high lift will not significantly alter vacuum or velocity in the carb throat ... I think ... honestly you can only fill a certain volume of chamber with so much material ... the duration the thing is open if it goes up with an increase in the overlap ends up losing mix into the exhaust ... there by it is like filling a larger chamber ... so if he got high duration cams it may need a smaller main jet ... I think ... also there is that element of having the re-atomisation thing ... you want to sorta compensate for it too ...
My guess then is ... high duration = smaller mains ... the rest all are insignificant ... Happy now ...
Cool.
Srinath.

Makes sense.

Still wish I had CFD to model it.

What is CFD - computational flow diagram Computerised ... whatever ... I studied flu mech, and some of this crap was what stuck ... Yea ... scary ...
Cool.
Srinath.

CFD =  Computational Fluid Dynamics

i now have 140, 142.5 145, 150 and 155 mains with #40 pilots i will let you know what i find.  first set up the #40 and start about 145 and will take it out runn full throttle and kill the engine check the plugs and tell you what i find.  if i have to go leaner i will, richer i will.  will also re-read that link to see about the cold vs hot running so see if it correlates to what the plugs show.  I was debating on velocity stacks for it as well as they do wonders for the tls i was hoping they would do the same here.  will let you guys now what i find as i find it.

ok at what point are plugs no good anymore?  i think i have 2 bad sets now and forgive me by i am going to run lean to rich.  sorry but not in the mood to buy a gross of plugs for this job.  i cannot even get this thing to idle correctly.  i have the 40 jet with 135 mains and it is blow black moke out the rear.  

I have a question because it is different from stock but is the pilot jet supposed to have small holes drilled into the body?  my 37.5 stock jet did not and it ran a little lean but my 40 has holes in the body and it runs extremely rich.  is this my problem for idle?  
i think i am going back to 37.5 pilot with new plugs and setting up the mains,  then buying #40 pilots without holes and setting up the idle.  then i'll tinker with the midrange as i feel like it.  should i be looking at different heat range plugs?  i am lost here the bike ran OK but never this bad i am just disgusted with it right now.

The pre-2001 used "non-bleed" pilots and the 2001 and later used "bleed" type pilots.  Bleed Type run much richer than non-bleed type in the GS.  So, a 40 bleed type acts like a 42.5 or 45 non bleed.  That is WAY too rich at idle.

That said, if you are jetting by the trial and error method, you always start with the main jet - get that right and the rest is much easier.  Get that wrong, and there is nothing you can do to figure out the mid-range and off-idle.

Your list of jets is conspicuously lacking the 147.5.

Way back in the thread you mentioned that your needles were equivilent to 3 washers and you have a 122.5 main.  Are you using an aftermarket kit that came with needles?  If so, are the 122.5 their jets too? If so, most of the advice on jet sizes is wrong - it is based on stock needles and standard Mikuni jets.  Different kettle of finny things if you have Dynojet needles the Mikuni jets will be way richer than the Dynojet jets.

thanks for the pilot jet info.  all the main jets i just bought are mikuni jets not dyno jets.  the pilot jets are bleed type with the holes which explains alot.  i am gong back to my 37.5 stock pilots and then a 145 main.  right now i cannot even get the bike to idle correctly so i might as well go back to stock and order the non-bleeder type pilots in a #40 IF it is still running rich after i go back to stock (it should be)  that way i can atleast test the main jets to see if they are the correct size and work back wards a little after i get the #40's in.  if anything it will run a little more rich which is not a bad thing.

I am still learning about these carbs just wish i did not spend money on what is now junk.

Yea 40 non bleeds ... Parts unlimited number is 42-7130. Need 2 in that pack of 4, sell the rest to someone else ...
Now plugs ... stock plugs - NGK - DPR8ea-9 whatever = total junk. Somehting has happened to NGK of late, and they seem to have made their plugs a lot colder in heat range ... they plugs foul out easy and just are total BS. I went to Champion 809's for a well jetted GS, so you're rich and that makes the plugs choke up and die ... please get champions ... autolites are black on black on black ... and hence un readable ... 809's baby.
Cool.
Srinath.

much appreciated.  little update i had the entire stage 3 dynojet kit so i figures i would install it.  The bike runs perfectly off idle, pulls well to red line but same as before it does not seem like it has power in 5th and 6th above 8k BUT tat is above 90MPH and not a concern for me right now so the bike runs well i am leaving it alone and will pull plugs after running to make sure it is OK.