Hey all!

My 89 has a bad bog when whiped open (3/4 to WOT) at lower RPMs. Not real low in the power band either, anywhere from idle to 4 or 5k. Sometimes it will chug out of the bog after a second, but that usually doesn't happen.

I have to either close the throttle and open it a bit until high rpms or grab the clutch. Both a PITA!

To try and get rid of this I cleaned the whole carb REALLY good, made a decent difference but only helped down low power. Didn't do too much for the bog.

So then I messed with the air screw, and found that 2.25 - 2.5 turns out gives the least bog....but the bogs still there.

Heres what I'm running:
Stock needle at 3rd clip position (i think, can't remember exactly)
Stock silencer with a few holes drilled in baffles
PC pipe-all banged up though
158 main
48 pilot
And all testing done at sea level

I am thinking the main could be too fat, or the needle needs to go down (clip up). My plug always has a bit of spooge on the threads, but none on the electrode-it is a dark brown color.

Any suggestions as to what's causing this?

Alittle off topic but whats a good aftermarket needle to run? I really don't know a whole bunch on the PWK.

Thanks to all...again!!!

I assume you have checked if the power valves are working? Use [search] key above for how.

Check Simple stuff first, like replace airfilter if a bit old. Spark plug & plug cap (perhaps if at low revs spark a bit feeble).

Check there are no airleaks & the reeds are worth a look to see they’re not damaged.

& the ugly bit is the carb slide is probably worn a groove in it making jetting a bit hit & miss. Replacing mine helped a lot but they are not cheap.

Uh....all of the above?

Well lets see...I just changed the air filter, new plug, spark is good, reeds checked out good, the slide DOES have a grove on it and the power valves probably DO need to be cleaned. But when I take off that cover on the left side (says KIPS) the inside does have fresh "carbon stuff" on it, soo....I dunno.

I checked the carb boots no air leaks I could see of.

How much would a new slide soak me?

I didn't think that the kips being clogged up would make it bog so hard though. It is really bad! I have to be VERY gentil on the throttle when the bike is just getting warmed up or it will stall. Sounds like a deep muffled tone when it bogs.

---

Well probably about $90 of your capitalist greenbacks.

Yeah I know.

While you are rooting around perhaps you have a look under the LHS cover & look for oil, the crank seal may be sucking air.

I would at least measure that plugcap, a good spark in the open air means little under load. Perhaps your stator may be a little weak? Just throwing suggestions out there.

90 BUCKS!!!! Geebus that's expensive!

Well I'll inspect a bit more tommorra and maybe try a smaller main (155 sounds to my likings).

Thanks alot David and Jason! Any other suggestions are welcome. :confused:

WOWman, try your clutch, it'll slip at low rpm and cause the bog your talking about. Even a simple adjustment up at the perch will liven up your beast. My old zinger would bog at take off and I fiddled with the carb thinking it was a fuel problem. I then read a post on here about free play in the cluth lever and noticed mine was a little too loose, 3 turns on the perch and "Sorry didn't mean to Roost Ya!"

Drop the needle way down is the fastest and easy thing to try. Next to top or top ring on needle. Sounds like jetting is way too rich.

If you're in the market for a slide, talk to ron @ RB designs:

rblack66@attbi.com

His website: http://www.rb-designs.com/

I ordered one from my local parts place $75...got two of 'em...both the wrong size. Ron sent me one in a couple days for $40. AND it was the right one!

The bog you are describing is exactly what you get with a mis-jetted bike. Yeah...could be a spark problem, and air filter problem..a number of other things.

Which needle? A 'C' (1.5º taper) series is a good wakeup for the kdx...a CEJ or so 3-4 clip.

A lot of good advice!

A bog usually indicates a lean condition.

I would check to make sure the main is clean and if so try one size larger main based on your description of where the bog is occuring