tuning the fcr37mm

[Venom]

Got the carb mounted 3 days very tight fit almost touches the tank.
Got the bike running but having issues with idle.
Running the same jets as Mvvette97.
But 45pilot is still lean... i have no intake booth leaks, the hot start is conected and off( it leanes out the mix). 2.5 turns on fuel screw ( beyond that it bogs on accel) idle screw on minimum (dosen t touches the cam) and i still have high idle and red exhaust header... maybe #47.5 or should i jump to #50.
i also have no bog on acell (thanks to mvvette97)

larger cc bikes get a way with 42 or 45 pilots why do i need to go bigger with only 350cc?

 

[geeessfore]

Your cable may be adjusted incorrect at thumb throttle. If it pushing on it, it will rev idle high

 

[Venom]

i ve check that the slider sits on the botton fully closed

 

[geeessfore]

Damn there goes my help

 

[Venom]

Got a 48 pilot... idle solved!!!
Now revind the engine lots of backfire through exaust needle is an obeks in top noch should i lower the needdle or is it idle circuit related ?
I HAVE BOG!!!!!! Cant blip the throttle it dies... #40 leak jet , # 68 starter jet
help?

 

[Gen1Pat]

What size is your main, and what notch is that needle on exactly?

 

[Venom]

i have a 165 main, obeks needle in last notch (leanest setting)

 

[Gen1Pat]

So your needle clip is at the very top? You are too lean. Lower the clip to raise that needle. I don't know how many notches that needle has. The 39mm has 7 notches, and several different needles to choose from. Also, you should get LOTS more mains and jump that sucker up really big (like a 190 main). It SHOULD finally be rich, then you just back the main down till it's just right. We've all had to do this on the 39mm. None of us expected to have to go that big.

 

[Venom]

my needle has 7 notches going to put it in the midle one , i have an 175 main going to try that one. I used mvvete jetting as a base line and he ended with an 170 main...(his build is the same that i have) i saw your main an thought wow thats big, why ?? the drz400 crowd go with 162 and 165 mains...
Anyway timed the Ap and improved the bog but not cure it, the bog is off load going to ride it tomorrow and check

 

[Gen1Pat]

I don't know what to tell you about why the main in mine has to be so big. But, it's what the engine wants.

 

[fknboss]

Yea if you have certain areas where your lean and with that same setup you have a rich bog its a needle issue. Put it in the middle. You might need to rechange jets.

 

[fknboss]

And like pat said when your trying to find a perfect jet you start at the top and carb at stock settings and move smaller til the rich bog is gone.

 

[Venom]

First run today, just around the block. The low and mid range torque is insane!! but the top is a bit lacking...
I have no bog on or off load i folowed gen1pat advice and put the needle on middle notch
But the main work is done:
idles great
no bog
runs good but there is room for improvement.
mid range is very good but going to start plug chops to work out the jetting

 

[fknboss]

Try moving the clip one more notch down moving needle up see what it does

 

[Gen1Pat]

Did you ever increase the main jet size?

 

[Venom]

Did you ever increase the main jet size?

No i didn didnt have the time... but took it to work about 4km mountain road ran great but at night start poping and backfiring... the temperature at the afternon was 15 but now is 1or2 to degrees + do you think is ambient temp related?
Ive got to check also the intake booth because is a bit skechty...could be an air leak.
Going to try that also fnkboss but just for the fun because low and mid are very good.
also going to see my plug color tomorrow

 

[fknboss]

Mine is doing the same thing. Temp today was 23 and it was popping letting off the throttle. You prolly need a bigger pilot jet.

 

[Gen1Pat]

Yes, temp has a lot to do with that problem. But, until you plug chop it at idle (for several minutes), chop it at mid range, chop it at full throttle; you are only guessing and throwing jets at it.

 

[Venom]

it was the intake booth...gona make another intake i used an oem flange but like Pat said in another post it doesnt have enough meat...