so what are the readings now?

D0T-C0M said:

Well, I haven't ridden it yet, I do very little riding in the summer here.
I will post up the results as soon as the weather cooperates and I can go for a ride,

It was a little lower temp outside today about 95 degrees and thought I would go for a short ride to get some more readings...
after adjusting the fuel screw (pre-ride) I was still getting about 11.4AFR so I adjusted it some more and ran out of adjustment...still reading about 11.9 so definitely need a smaller pilot jet which was already assumed, I just got the confirmation from the O2 sensor...

I put on about 27 miles and by the end of the ride I was reading about,
13.3AFR 1/4 throttle,
11.7AFR 1/2 throttle,
11.7AFR 3/4 throttle,
11.9AFR bouncing down to 10 something WOT,(AFR bouncing quite a bit)

so smaller main jet (also assumed-thanks for your input people:worthy:) needed as well...

It would be nice If my local dealer had a jet exchange program so I wouldn't have to buy all these damn jets, I've already spent almost $30 on jets and only If I get lucky need to buy at least two more jets and possibly a new needle...cripes...

jjast said:

What needle are you running?

jjast what is your AFR at idle? I concur with your readings seem still to be slightly rich.

pwrpapa said:

still the one that came with the carb-OCEMR-I'm not getting into the needle until I get the idle sorted and possibly a bit closer on the main?-not sure, seeing how the needle will affect the main through the mid range.
I was looking at jets-R-us for a selection of needles but I couldn't find any NCVT,NCVS,or NCVR?

D0T-C0M said:

at idle with the fuel screw turned all the way in I'm still reading about 11.9AFR.
so what pilot jet size should I try next?

The reason why I recommend the needle be changed now is because the needle circuit overlaps the pilot jet and MJ circuits (see pic below). In this case the NCVR and OCEMR needle have the same straight ® diameter so the PJ circuit should in theory not be affected (or very slightly) but the MJ circuit WILL be affected to a some extent although your definitely in the ballpark with your latest change. Maybe your goal isn't to get a perfectly linear AFR slope from 0% to 100% WOT but rather to get your bike working well. That's alright too because your bike will work well with the OCEMR needle when properly tuned as many attest to here. I'm anal and always try to strive for perfection, that's why I bought an o2 gauge LOL. If this is your goal too then I suggest to pop a NCVR needle in and fine tune to your hearts content. I think you'll be pleasantly surprised. So far your jetting changes are improving your AFR nicely but I'm just trying to save you some time in the long run.

jjast said:

I don't want to say I told you so but I told you what jets to get since almost day 1, LOL :) :). You can always resell the unused ones on ebay.

jjast said:

I gave you the Yamaha part numbers for all those needles. They cost about $12 each. The quickest would be to just go to the dealer and order them and get the NCVR one in 3 to 5 days or go to babbitts online and order it there if you don't might waiting 10 or so days for them to get the needle and then ship them to you. Also get a 40 and 42 PJ while your at it and your done IMO.

Quote

D0T-C0M said:

I was just hoping that I could order a needle through jets-r-us along with my pilot jets I'll be ordering in the hopes of saving some time and money,
I really got set behind on all the jetting because of the initial problem I was having with the carb in the first place but after it being sent back to the manufacturer and back to me I had already bought all those jets trying to fix a initial problem that now doesn't exist, had there been no problem out of the box I would have just followed your recommendations strait out,
I am getting close now as you said and appreciate all the help, hopefully I can get this dialed in to where I'm happy enough before my riding season gets going.

here is a link to the calibration chart (and other stuff) that goes with this carb-keep in mind there is no throttle valve cut away on my carb. -> http://www.keihin-us...slide_valve.pdf

ordered a new needle 8/31/11 from local dealer, gave him the part number, told him it was a NCVR, he confirmed it was a NCVR, ordered the part, it came in yesterday 9/6/11, I went to pick it up today...got the needle in my hand, looked at the needle-(reading) N-C-V-Q... um...:bonk: (sigh) they are RE-ordering the correct needle now...so another week...:banghead:

they are going to hang on to that other needle for a couple weeks is what the guy at the shop said so it should be available for a bit still just in case I need to go that route.

jjast said:

It probably would have worked, though the 0 to 1/4 throttle would have been slightly richer.

Mike in Fresno said:

That is not what I learned after spending many hours tuning my FCR-MX with a wideband. Changing the main jet would only change the AFR at WOT. Changing the AFR from 1/4 to 3/4 throttle was only accomplished by the needle taper and clip position regardless of main jet size. I found that if you need to change 1 number in your AFR reading that equals 10 number sizes in jet size. ex., 12.2 to 13.2 would be exchanging a 165 with a 155. I wasted a lot of money buying jets that did nothing because there was not enough difference between (for example) a 160 and 158. Jet the main first and forget about it.

Jet the pilot next. Forget about the wideband for now, it will run much better if you tune the pilot circuit by ear. Do the 'highest idle' technique. What you really want is when you whack the throttle the engine will return to idle almost immediately. If it stays up its too lean, if its rich it will not be crisp. If you have the idle mixture correct but the idle screw is out more than 2.5 turns then get a larger pilot jet, or the reverse is also true, in more than 3/4 turn out you need a smaller pilot jet. You may also have an air screw, regardless, the idea is the same, select a jet that gets the screw the average 1.5 turns out.

Once those two are correct then look at the three parts to the needle, the diameter, length and taper angle. Though you only need the base diameter and taper angle changes to effect AFR. The length dimension is really only changed so when it runs perfect the clip is in the middle position, that way you can change it one clip position for changes in temp or elevation. In other words you don't want it correct being on the very top or bottom clip position, there's no room for fine tuning.

Now it should run great at any throttle position. If it bogs off a whack then you need to figure whether its getting too much or too little from the pump. BTW I didn't read through the whole thread so I'm sure I just repeated something, not trying to be a smartypants just want you to get it right, its really worth the effort. Good luck.

Mike in Fresno said:

flatfender-2009 said:

the needle meters/controls the fuel through the main jet so there should be a measurable effect with changes in the main jet.

my bike came stock with a very straight needle taper and 168 main jet...

...after installing a OCEMP needle the main jet was reduced to a 158.

tunning top-down or bottom-up is debatable but most find get'n the pilot dialed in for ease of starting, good idle and being able to crack the throttle w/o stumbling the easiest. :thumbsup:

also when get'n the timing and duration of the pumper squirt dialed in it's important to do that under load...wack'n the throttle in the garage doesn't tell u a whole lot. :smirk:

:cheers:

Kenzo said:

I think the needle meters fuel flow using the needle jet. Even the smallest main jet will feed the needle/needle jet more fuel than necessary during 1/4 to 3/4 throttle. When the needle is allowing 100% flow then the flow is determined by the main jet size.

The main jet does affect the needle and vise versa. James Dean's graphs also denote this overlap

flatfender-2009 said:

More good advice,
keep your inputs coming in, I like to hear all opinions.
I tend to believe the above statement and was thinking this same way seeing how I have gone from a 162 to a 155 and am still getting the same AFR at WOT.

I'm getting tired of buying jets as well and the smallest main I have is the 155 and the smallest pilot I have is the 50...so more jets are needed.:banghead:

D0T-C0M said:

I agree, I think I read something as a suggestion you change the main to effect middle, instead of change the needle. I'm probably wrong though. I just dropped by to get some fork advice, I probably should have stayed out.

post if it kicks ass when your done

flatfender-2009 said:

remove the main jet...then remove the main jet holder...the the "needle jet" can now be removed(will fall out)...

...it's one straight path, that's why I say "the needle meters/controls the fuel through the main jet" :smirk:

the "needle jet" is really the "needle seat" it has maybe a 2mm opening...the needle seat and needle act as a valve controlling the the flow through the main jet. :thumbsup::thumbsup:

:cheers:

Picked up the correct ordered needle on the 16th and for the heck of it I asked If they wanted to give me a deal on the wrong ordered needle and so they knocked 15% off, It's probably going to be a waste of money for me but it might not...guess we will see, so I now have a NCVR and a NCVQ needle to play with,
aaaaaaand on to getting more mains and pilot jets,

flatfender-2009 said:

This is my first post... however I have been a lurker for awile...

I just installed my new FCR 41 from sudco. I also installed the innovate AFR guage. As others have posted as installed

170 Main
50 Pilot
EMP#4 clip

Sea level to 900' average outside temp 70 deg F


Way too rich according to AFR I installed the 168 Main and 48 Pilot which came with the kit running now

11.8 idle 11.5 WOT also lean 15.5 around 1/4 throttle.

Based on the above reading since I want to change amost 1 AFR point the 158 Main and 40 Pilot should bring it closer to home, Im also assuming the NCVR needle will fix the lean bump.

What clip position should the NCVR be at to start?
Does the MAJ or PAJ need to be changed? I think they come #200 from sudco.

As others have said it takes quite a bit of time to pull or even rotate the carb to make changes so I want to get it closer first time out.

Also if the jetting discussed on this thread seems to be the common solution across the board why is the sudco "pre jettings" so far out? Has anyone communicated with sudco to see if they could swap out all the wrong size jets for ones closer to reality?

Thank you

Paul