Blakes K&N Project Update!!!

[Blake]

Hey everyone.


First of all i want to say a big THANK YOU to everyone who helped me out with my electrical problem. ?that thing was such a hassle for being something so menial and simple (dumb).


But to update.. ?when i fixed the wiring, and everything was running good i decided "hmm..theres still daylight..and i know my current jetting wont let me go past 6k rpm. ?so i changed the jetting too.


If you havent been following all of my "adventures". ? I put K&N filters on a few months ago, and bought a pretty high-tech AFR (air-fuel ratio) meter that i hook up to my laptop to get precision-shop quality measurements. ?The went to the local bike shop around august and ordered some jets.

The jetting i had with the first k&n test: ?135 main jet, 127.5 air jet, 60(i believe thats it..the biggest you can get) pilot jet. ?the bike ran, i tuned the idle screws to make it run correct at idle. ?Like i said earlier, the bike pulled, but wouldnt really let me go past 7,000rpm (WAY too learn).


but today. ?I put in a 150main jet, and put a 135into the air jet. and kept the 60 pilot jet. ?didnt adjust the idle screws, didnt change pilot jet. ?so then i took it out for a test ride.

HOLY CRAP! ? Now, this jetting is still a ways off from being dead on, and theres other issues to sort out, but Holy crap this is a FAR cry from what i had. ?I've seriously never had this bike pull this hard before. ?When i got onto the highway and ran through the gears, i literally almost thought the front end was going to come off (maybe just my excitement.) ?but this sucker REALLY pulls. ?i was flying through the gears!

but now for the nitty gritty details.

-I dont have my YICS on. I took it off a few years ago, but have recently decided i need to put it back on. ?That will go on shortly to hopefully help improve performance.

-I havent adjusted the idle mixture screws since last jetting. ?I had to turn them out pretty far to compensate for the lean mixture. ?So now its rich, and with the choke on at idle you can smell a strong gas odor coming out of the exhaust. ?So those are definately too rich and need to be adjusted.

-There is a medium (somewhere between a .5 hesitation when you wack open the throttle and it slightly dies, and a slight gurgle) hesitation between 3-6k rpm. ?if your slowly rolling on its ?worse around 3-4k. ?if your around there and want to accelerate faster and open the throttle faster, the medium hesitation comes in around 5-6. ?But after that the bike just screams straight to redline. ? So my first guess is that the pilot jet system is way too lean (too much from idle, and too much from main, and waytoo much from idle jet itself). ?So that needs to be leaned outl

-I havent synced my carbs in over a year, way before i started screwing with k&n's. ?when the bike was warm you could hear it hunting around, much like unsynced carbs would do. ?I need to get that done.

-I still have the front carb top on that has a vaccum port on it to open the airbox flapper. ?I need to switch that out with one without a port because its a possible airleak (even though its before the carb. ?I just have some electrical tape ziptied around it now. ?

-I dont have any filters on my breather tubes. ?not sure if this is doing anything to performance, but i definately am going to go buy some clamp on filters now to make sure no crap gets into the engine.

-When the engine warmed up the idles went lower. ?(Symptom of overly rich idle mixture? ?when cold it was around 1,600. ?when warm it went down to around 1,000. so i kicked it up just to be safe. ?need to figure that out.

-I have a custom made race exhaust. 2 into 1 for each cylinder. ?the pipes for each cylinder run independant, but are equal legnth. ? Because of this my mixture with k&n's probabaly wouldnt be the same as with a stock exhaust (its a free flowing exhaust). ?This probabaly also helps my performance since it is free flowing (more air in, more air out). ?


How the bike is running now is far from being perfect, as my jet selection was literally pulled outta the air..i need to get the meter on it to try and get it dead on. ?But this is a huge leap. ?There actually isnt that much of a problem with the free flowing filters when you want to go fast, but the problems i have now im pretty sure will go away with jetting changes.

But just thought you all would like to hear about how close i am to getting a k&n conversion down perfect.


Rick G- ? thanks a lot for the 83 footpegs! ?i havent put them on yet, but the next sunny day i plan on doing it, and cant wait to try them out.

and Wayne - I got the fairing in the mail today. ?Looks good! ?thanks a lot!


Thats all for now. ? just thought id let you all know.


Blake

[Lead_Deficiency]

I would love to see what kind of readings you get on your meter before and after you install a yikes. Someway to test if that thing really does something. :-/

[silicon_toad2000]

what are your afr readings around the time of the stumble?
Don't forget there are three fuel circuts on the bike, idle, prgression/intermediate and main.
Idle mixture controlled by the idle mix screw
progression by the pilot/idle jet
and main by the main (duh)
then there is the timing of when each circut comes in...

[jasonm.]

YOUR PILOT AIR IS LIKELY CLOSE. MOST RUN 135 AIR'S ON AN '82. ANY BIKE THAT THE IDLE DROPS AS THE ENGINE WARMS IS TOO RICH.BUT NOW YOU ARE ALSO LIKELY TOO RICH ON THE MAINS. THESE ARE LITTLE CYLINDERS, 132.5 IS AS BIG AS I WOULD GO. BUT GO IN SMALL STEPS 005 PER TEST. THE BOGGING IS A RESULT OF TOO RICH OR TOO LEAN AT THE TRANSITION TO THE MAINS 5500+RPM. YOU MUST ALSO HAVE A GOOD YICS. NO YICS INCREASES THE RICH CONDTION. I KNOW WHAT I AM TALKING ABOUT> WHAT IS HAPPENING TO YOU HAPPENED TO ME. YOU CHANGED 2 THINGS, INTAKE AND EXHAUST. SO YOUR WORK TO FIX THIS IS TWICE AS DIFFICULT.

[Blake]

Hey everyone!

quick update.

Today the weather was about 45 this morning when i rode the bike the 5 minutes (2 miles) to school.

When i was puling onto the road i turned off the choke and started rolling on the throttle and noticed a stumble, and then quickly flipped on the choke and got power again.  Got me thinknig that maybe im still lean on everything.

Fast forward to 4 this afternoon.  Went and got some 1/4" line from the autoparts store and put back on my YICS (good one from my parts bike) then hooked up my AFR meter to the front cylinder to adjust the idle mixture.

As it was, the fornt cylinder was at about 19:1 (VERY lean, at idle you want about 13:1-slightly on the right side).  so i turned out the screw some and got it down to 13:1

Then did the rear cylinder.  I was amazed.  As it was the rear cylinder was idling at 23:1!!! (glad i havent riden the bike too many times since changing jets...)  so after some fiddling around with trying to get a screw driver into the akward idle screw hole, the rear cylinder is down to 13:1 too.  

I noticed when the front cylinder was at 13:1 and the rear hadnt been adjusted yet, the revs went up.  but when i adjusted the rear mixture to be richer, the rpms  went up slightly as it got richer and then went slightly lower, but definately sounded like a better combustion.


I really assume all of this is because i put 135 air jets in (which seem to increase the airflow throughout the entire spectrum.  But this is good information because now when i check the other RPM ranges, if the mid range mixture is too lean, ill decrease the air jet because im already at the max idle jet (60) without changing types (ours doesnt have holes in the sides, but there are two other kinds with 3 and 4 holes in the side. i might try those)


But tomorrow i'll syncronize the carbs and hopefully get a run or two in before classes at noon ;D.


but everythings defiantely looking promising.  havent riden the bike yet with the idle jet change, but defiantely will later this afternoon.


I'll keep you all updated.


Blake

[Blake]

Hey everyone,

update once again.

today i slapped in 160 main jets and left everything else alone.  And also i hooked up the AFR meter (just the real time, didnt tag along the laptop because it looked like it was going to rain any minute.

Anyway,  Idle is beautiful.  nice powerful sound.  Idles around 13-12.5 when hot(running temperature).

Mid section is again the problem, BUT, its getting better.  doing 4k in 4th (about 35-40 i think) it cruises around 15:1.  slightly too lean.

Around 6k (60 in 5th), it's doing about 15-16:1.  even leaner.  HOWEVER,  the very exciting part, past 6,000 i gunned the throttle, and accelerating all the way to 80 i got about 10:1 (slightly dipped to 9:1 which is still good, but got back to around 10:1.  ;D    VERY nice for power.  could possible be a jet size smaller to get it around 11-12:1

But from messing with the main jet, and air jets, this seems to be what i need to do:

Go down a size (or a few), on the air jet. the air jet appears to affect the entire range.  I can adjust the idle mixture fine, and the main jetting, but the idle jet is at its max now and is still slightly lean.  So i figure if i cut back slightly on the air, itll richen up everything a little, (i'll compensate by adjusting the idle and main jet (going down a few on main to correspond with air jet change), but hopefully going down on the air jet will get the midrange down to a good level (im going to shoot for 12-13:1).

bike definately sounds like its running better/stronger(?) than with the stock airbox.  Even with my one-off exhaust, theres a noticible difference with the exhaust noise.  

but Im definately getting closer :).   However this might be the last time i get to tinker with the bike until mid-may, as my parents are coming to bring the bike back to DC this weekend (im at school now in SW VA).  :(  it'll be sad, but i can work a lot faster and better at home with a garage and proper tools.


Blake

[silicon_toad2000]

the air jet affects higher revs more than it affects lower revs, or more simply it has a greater affect as the revs rise.
So if you go down a size in the air jet while keeping the main the same, it will be a little richer at lower revs and a lot richer at higher revs.

[jasonm.]

What most folks don't know is that all the circuits work together. They don't shut off past a certain rpm. The low speeds are always working. The air jet is ALWAYS pulling as you have noticed. Blake, from what you have shown(good mixture to 6k), ONLY the main jet needs to be dropped down a size or 2. If you are running the 150 still. THAT IS WAY TOO BIG for these little cylinders. Remember these have accel -pumps, YES they will richen up when you roll on the throttle. That's what is suppose to happen. Also there are only 6 and 8 side hole pilots. These holes make no difference in our bikes due to the carb design. I have 6 hole 52.5 piots in my '83. The 8 hole type should not be used because the sized part is at the opposite end of the jet. You need to see them side by side to understand.

[Glyn Pickering]

Blake - sounds like you're having fun on your jetting project. I had the same issues with my weber carb. Took me ages to sort out the jetting. Don't give up.  I prob spent as much on jets as I did on the carb. My carb has a very low restrictive K&N type filter also. The induction note when accelerating and decellarating is lovely. I've got a very slight lag, almost none exsistant and only when I whack the throttle open really hard. Apart from that it's a clean tansmission right up to the red zone. I never bothered to really test mixtures etc. A good road test will show up any deficiencies. I use my bike everyday (now) so it has to be a good runner in all traffic types. Jets are the same for front and rear pot and no YICS.

All the best.

Glyn.

[silicon_toad2000]

150 may not be way to big for these cylinders. The size of the optimal jet is determined more by the vacuum in the carb than by the size of the motor. since you have the K&N's there may be bugger all vacuum in the carb so 150 may not be too big.