Topic: Ping Pops911. Need jetting help

[dragracer]

Richard, can you p >:(rivate message me your phone number. I need some assistance with flatslide jetting. I'M fighting a serious lean condition. Seeking your expert advice.

[POPS 911]

FRANK: We ran FBG carbs w/power jets...... simple turn needle LEFT for lean or turn needle RIGHT for RICH , AFTER YOU PUSH NEEDLE UP TO TURN.  Down load the RACE PACK to get readings on run and up or down on power jet [ with super skinny screw driver ] to screw out and in these jets.  Flat slides are best set a little fat , forget the power and save the pistons. I used a EGR reading from the bung welded into my collector, you do not need a 2-4 thousand dollar one like someone on here said they have !! a single wire system from a e-bay seller or JEGS will give you a reading after a short warm up of the motor running = remember the tool story $$$$$ my PREDICTOR box reads DA'S and temps and shows me track changes. I got the K&L JET KIT BOX w/4 jets  in many sizes $$$$$. Best tool you can have is a scale SO STEP UP ON IT as since the last race YOU put on 10-15 lbs....... and you though the motor was slowing down !!!!!
A quick check can be had with a hand held temp gauge and putting that red dot on each header pipe close to the head, pipes should all be close in readings, when I bought this TOOL years ago it cost $75 but now a days HARBOR FREIGHT sells one for $25 just as good. Old school bikes need tools to tune, modern FI bikes need a dyno and a lap top, watch NASCAR and all the lap tops laying all over those race cars = the day of a carb tuner are about over as their brain BOX is between their EARS.

[johno]

Early days for me yet Frank but I agree with pops re power jets.
With my Mikuni TM 32mm they just leaned out quickly at the top end and I went from 115 up to 140 in stages until the leaness stopped but it was very rich low down then from 3,000 rpm to 7,000 at around 10 : 1 then higher RPM was around 13 : 1where it should be.
Mikuni OZ said that that was normal for the TM flat slide series and recomended small main jet back to 115 to take care of the lower RPM mixture but install power valves  to take care of the engine "coming on the pipe"   just like 2 stroke engines require.   Sounds like good plan so I ordered the power jets from ebay this week.

It will be many months  before I know the result but will let you know.
cheers johno

[dragracer]

Bike is loosing a tenth and a half or more as the temperature drops. Its got 130's in it now. I've got 132.5 and 135's on the way. Hoping not to need to be more aggressive. I do have a simple AFR meter I bought from Jegs. Won't be able to set it up before the Cup race but I'll get it on later.

thanks Pops and Johno.

[PeWe]

I'm going the other way with my Mikuni TMR32 also flatslides on my streetbike.
836, ported K head w 34mm in valves, megacycle 125-20 cam. I rev up to 9500rpm max. std rods.
Tested yesterday 140, 135 too rich. Will try 132.5 today. Pilots 25, mix fuel screw 1 turn out
I have a bunch of main jets when they are same as for VM29.

[POPS 911]

FLAT or ROUND SLIDES : Think about where the needle is on a drag bike and a street ridden bike    Drag bike w/two step all the way up [ or no two step will be up and not pulling you thru the beams W/CLUTCH IN  ], street bike ridden = up and down with the clutch action ....... those jets will be different ...... and with the FLAT SLIDES rod taken out on a drag bike setup "SO YOUR NOT FAT" w/a bog off the line. And you wonder why most drag racers run FBG carbs a simple fix, but not for street ridden bikes... without a weather station for the DA'S and other information on the screen tuning for flat or round slides on a 2-3 day meet you will be guessing [ like I said the tools to tune are not cheap, but the rewards are that win ticket at the end of 1320'.] I don't take a bike trailer to the track, but a tool shed on wheels full to haul the bike.

[dragracer]

Thanks for the data PeWe. You need to go down on jet sizing, I need to go up.

I'm going to try the 135's first and then back to the 132.5's. I talked to a shop not far away and he can give me a dyno pull with logged AFR and RWHP for $50. I'm going to schedule an appointment for next week. I need to see on paper whats going on with my AFR through a full run. Its not something I've done before but its another tool- like Pops mentioned.

[PeWe]

Tried 132.5 today. 
Bike will still accelerate quickly up to the green area after the dangerous red line on tacho. Especially 2.nd, 3:rd a little bit slower on 4.th but too bad responce on 5:th gear.
I booked time at my local tuner on their dyno with total setup of the carbs. It might need more main jet and lower needles.
I have to wait until end of this month to know the result with dyno chart.

[POPS 911]

FRANK: A fellow who went to THE OHIO STATE UNIVERSITY to be a engineer made two things that made him rich$$$$ = LEAK PROOF SEALS and DIAL A JETS and I went to his farm 30 minutes from my home to buy both [ he gave me a school on how and why these work ]. Dial A Jet is a simple add on that gave the LEAN BUILT BIKES OF THE 80's a fuel boost with the turn of a flat blade screw driver, I bought 5 sets for 4 cyl. bikes at DIXIE INTERNATIONAL  in my hometown of Columbus, Ohio.  THUNDER PRODUCTS are now the name and used on many snow mobiles in racing for more or less fuel without the hassle of a jet change. Look up on the web about this tool that you can change the jetting on 4 carbs in two minutes. Next time I see you I will bring the boxes for the different set ups 750-900-1000-1100 cc motors. Some sets are sold on e-bay and I have the list of part numbers for the different CC motors.

[dusterdude]

Thunder jets are found on a lot of harleys too