jetting questions

[WOLFYMAN]

I'm getting a bog when I crack the thotel heres my jetting.

155
42
2 1/2 turns
2nd groove on the clip
ride in kansas 1000 ft

any sugestions

[canyncarvr]

2 1/2 turns? You have a modified carb?

What's '2nd groove' mean?

What needle?

It falls flat on its face..or just hesitates?

OEM final drive?

I could go looking...don't recall...but this is a 200 I hope (with those jets anyway).

While you're at it...what's 'crack the throttle' mean?


I don't have any answers...I just like axing questions.....

Pretty much no 2T is going to respond well from an off-idle to an instant WOT flick.

[WOLFYMAN]

ITS A STOCK CARB
GNARLY PIPE
POWERCORE 2 SLIENCER
2ND GROOVE ON THE CARB NEEDLE
STOCK DRIVE
QUICK TWIST OF THE THOOTLE (CRACK)
DOES FALL FLAT ON FACE TO WHERE IF YOU DONT LET OFF IT WILL DIE
YES ITS A 200
SORRY I WAS IN A HURRY YESTERDAY

[canyncarvr]

If it's not a modified carb, the 'general rule of thumb' regarding pilots and air screw applies. Basically: If you're over 2 out on the air screw, your pilot is too rich. If you're less than 3/4 out, your pilot is too lean.

That said...you have adjusted your air screw to 2 1/2 based on throttle response? That's where it's the best? You are familiar with the procedure to get TO the 'best' air screw position?

Sorry, '2ND GROOVE ON THE CARB NEEDLE' isn't what I was after. Some folks don't know from which end the slot numbers start. That was the point of my question.

'GNARLY' means the pipe is made out of 18ga metal. It has nothing to do with the pipe profile, as both the so-called 'rev' and 'torque' pipes are 'GNARLY'. The rev profile takes a richer jetset than does the torque.

Adjust your air screw according to established procedure, for starters.

With a rev pipe, stock reeds, stock carb and 13/47 drive, you will have a hard time getting to ZERO hesitation from off-idle on a throttle snap.

Your jetting numbers don't seem too far off. With a rev...a 40/152 would be worth a shot. You're kind'a wandering around in the dark with the 117X needle, too.

If you're running the 'stock' -ES plug, you will be doing yourself a favor changing to some flavor of 'thin' wire, like an -EG.

Don't waste your time doing any carb tuning without a clean air filter and a spark plug in decent shape.

[WOLFYMAN]

thanks will try the small jets

[canyncarvr]

Re: 'Adjust your air screw according to established procedure, for starters.'

155/42 may well be just fine depending on humidity and such. 'Specially with a -30 pipe.

A plug chop is the way to get a solid handle on where you sit main-jet wise.

[WOLFYMAN]

TRIED A 40 PILOT EVERYTHING ELSE THE SAME. PUTTNG AROUND THE YARD IN FIRST CRACK THE THOTTLE AND IT STILL BOGGS BAD. BIKE WAS WARMED UP, WHAT DO YOU MEAN BY A CHOP

[Indawoods]

That BOG could be a lean bog!

[canyncarvr]

It could be indeed a lean situation. The two are pretty similar in off-idle/throttle response effect.

Does 'bogs bad' mean it's different, the same, worse, recovers differently...what?

Third or fourth time around for this matter: ...you have adjusted your air screw to 2 1/2 based on throttle response?

And....Adjust your air screw according to established procedure, for starters.

How did you get to 2 1/2? And don't say, 'By turning the air screw OUT.'

[WOLFYMAN]

GOT 2 1/2 BY LISTENUNG TO PEOPLE TELL ME WHAT THEY THINK IS WRONG. I GUESS I DIDNT KNOW THERE WERE TWO DIFFERENT KINDS OF BOG I'M NEW TO THE TUNNING PART SO ANY HELP IS GREATLY NEEDED THANK U

[canyncarvr]

Re: ' BY LISTENUNG TO PEOPLE TELL ME WHAT THEY THINK IS WRONG.'

That's a problem..a basic problem that can't be fixed by anyone 'cept you.

The only reasonable way someone can tell you what they think is wrong is if they ride your bike. 'Jet By Mail' (email even) is largely a frutile* exercise that won't end particularly well. Yes. I realize that's what is being attempted here.

There is no replacement, no substitute for the rider understanding what's going on and why.

For starters...I don't mind at all answering your questions, but if there is no response to my questions..then there is no point in continuing the conversation. I ask the questions I do for a reason, in the sequence I ask them for a reason.

I don't know what needle you're running (I've asked), I don't know what clip # you're on (I've asked about four times), I don't know what pipe you have..except that it's made out of 18ga metal. Saying 'clip #2' I'm afraid means nothing to me unless you can tell me exactly how you came up with that number.

Set your air screw using the proper procedure. That method involves testing throttle response from off-idle (not a completely slack throttle cable), from a slow (walking) speed, one gear up (2nd gear) with the engine under load (uphill, drag a brake). You are looking for the best throttle response to a flick of the throttle to 3/8- 1/2 open or so. Each time you make an air screw adjustment, ride the bike for a minute or two to 'settle' your new setting. Test throttle response again using the same sequence as noted above. Make only small changes to the air screw (1/8 turn at most). Bracket those changes on either side of a given point until you know what direction is making your response better: Test at 1 1/2..set 1/8 in..reset the bike..test again. Turn out 1/4 (now you're 1/8 out from where you started)..reset the bike..test again.

If your pilot jet is close to the correct size, you will feel a difference and know which direction you need to go to further improve your response test.

A procedure you can use to get you started is a basic 'lean roll' setting. The 'lean roll' method has been used to set low speed carb circuits for decades. It consists of slowly (small increments, not a sweeping movement) adjusting the air screw out and listening to the bike's idle to respond to the change. When you reach the point the idle speed just reaches the highest point, turn the air screw IN from that point 1/8 or a bit less.

THEN run the throttle response sequence noted above..from that baseline.

At the end, you will either have a bike that responds well (other things being in fairly good order...air filter, correct pilot size, decent plug, properly serviced S/A, reeds, compression...etc etc), or you will know it tends to work better farther out than the air screw should be..or farther IN than it should be. THAT information will indicate the pilot jet change you need (already noted which way means what).

You asked about plug chops. That's a main jet indicator. Basically..bike at operating temp, new spark plug, WOT run under load( for as long as you can hold it WOT, probably..30 seconds is plenty, less will do), then, shut the bike down hard: Chop the throttle (drop it..hard), pull the clutch, hit the kill switch. Remove the plug, cut away the threads to plainly show the insulator. Look for a dark ring at the base of the insulator. The richer the bike is running, the thicker the ring will be. Likewise, the leaner, the thinner. A 2mm thick ring is safe (slightly rich), a 1mm thick ring is the gnat's ass, but gives you no room for 'error'. A temp drop of 25º with that jetting and a WOT run may well get you a stuck piston. The plug pictured below is about perfect (it's NOT the result of a plug chop test..but you can very easily see the RING I'm talking about):




*frutile: Morph of 'fruitless' and 'futile'

[WOLFYMAN]

THANKS AGIN WILL TRY SOME OF YOUR TIPS. ITS THE STOCK NEEDLE AND WHEN I SAY 2ND GROVE I MEAN 2ND GROVE FROM THE TOP OF THE NEEDLE. I GUESS YOUR CALLING IT A CLIP NUMBER I SAY GROVE CAUSE IT LOOKS LIKE A GROOVE FOR THE CLIP TO SLIDE INTO. SORRY FOR MISUNDERSTANDING

[lemmy]

And do you know if you have the Rev or Torque pipe?

[WOLFYMAN]

believe it or not went back to a 46 pilot and no bog I guess that would a lean bog. Not for sure but thanks for all the help.

[Indawoods]

Cooler weather = Fatter jetting