Just to get something clear. To meet pollution guidelines I have assumed
factory settings are on the lean side With the 182.5 jet stock on the 1700 there seem to be a lot of settings ending up on the rich side when changing out the stock air filter . Are the needles different in the kits pms settings etc I am a little fuzzy on exactly why we are getting rich condtions when adding aftermarket exhaust and air kits which should in my mind be creating leaner conditions from supposedly lean factory settings?

I tried to run my roadstar with the stock jetting and the speedstar intake / filter... she didn't run (to lean) so I had to rejet... the big difference is mostly the needles in the jet kits... the 1600 roadstar had a 165 mikuni jet, teh 1700 roadstar has the 182.5 mikuni jet (gigantic difference) the needle respectively for the 1700 is also HUGE... and by rejetting you go to a much smaller needle... and most people will tell you that the aftermarket needles have a better taper and allow finer control over the jetting process... now I don't know how big the speedstar needle is for yamaha, but I got the impression when I was deciding which to go with that they use the same needle for the speedstar 1600 and 1700 and just have you jet downward on the main jet for the 1700 and upward for the 1600, I believe that most people like baron's jet kit (uses mikuni jets and a custom needle)... because of ease of use, I chose to use their kit...
Now as far as roadstars running rich, I think a lot of mechanic will go rich on the mix because the roadstar will run great rich, but we are learning that even though we don't see an immediate problem, we're getting carbon build up on the exhaust valves and this is causing the sticky valve problem... I admit in setting up my star I went really rich, a 172 to start with, and the bike ran GREAT, but never being satisfied, and knowing that our bikes won't run real lean, but will have long term problems running rich I slowly dialed back the mix until it's just a little lean... I'm now running a 167.5 on the 3rd slot (or 4th CRS) with my PMS about 1 & 1/4 out... she still runs great with good gas milage ~Guido

Thanks Guido ...different size needles explains a lot... Then I could be going from lean to leaner or no change at all just by changing the exhaust ..in my settup... without touching the air intake Seems to run good though and I suspect no change
Cobra has different jet set for the 1600 and the 1700 ..two different part numbers anyway... and this confused me more...not knowing what was in the sets..same needle different jets or different needles different jets etc
I see that the kit is the same for both the 1600 and 1700 speedstar so the needle must be the same. and yes and a different needle in each stock set up would explain a lot
That clears up my confusion a lot again thanks!!!! <br><br>Post edited by: Pop Rivet, at: 2006/04/23 10:37

I believe the stock 1700 is jetted richer thus you can rejet to a Mikuni 172.5 when you change to a free-flowing filter.

Counter-intuitive

On the other hand, the 1600 needs a bigger main (165 to 170) when adding a free-flowing filter.

Although all the circuits interact, a main jet which is one or two sizes smaller than optimal isn't very important unless you're riding at very high speeds and/or frequently using sustained throttle settings more than 3/4 WFO. Having a main which is too small is rarely critical unless it's excessively small.

I believe the needle is probably more important. If you have the chance, compare the stock and aftermarket needles side by side. It's a little more than just the addition of 'grooves' in the needle. Aftermarket needles are generally thinner (and tapered differently which I believe allows much richer settings with the same jets than possible with the stock needle. The needle is important in the mid-range but affects both the pilot and main.

Doc

How does removal of the AIS effect all of this? I removed mine right away. When I put on aftermarket pipes, Hard Krome 3&quot; big straights, I did not have to re-jet at all. My mechanic uses an exhaust analyzer and after initially re-jetting went back to the stock set up. I am now adding the Speedstar air filter and the ported and polished manifold and he requested that I order the Speedstar jet kit as he said he preferred it over the Dyno kit for this set up. Any thoughts?

the ais only injects air into the exhaust manifold to futher reduce hydrocarbon emmisions It is not a factor in setting up your fuel/air mixture ....its removal does however eliminate popping in the exhaust which was made worse by the addition of the aftermarket exhaust<br><br>Post edited by: Pop Rivet, at: 2006/04/24 12:52