KDXRIDER.NET

1989 200.
FMF Gold Pipe
48 pilot
158 main
stock needle in middle clip

Bike starts, runs, accelerates great!

When closing the throttle after a hard acceleration, the engine chugs or stutters. Kind of sounds like someone is downshifting without the clutch.
It's as if the engine can't keep up with the momentum of the bike. Is this a backfire? It is a deep, chugging sound, coming from the entire engine, not the "pop pop" sound.

Just wondering if this is a jetting issue or something else.

Well... you jetting is extremely FAT !

Like Rosie O'Donell!

Give 155/45 a shot. Generally a good start for a 200.

I have an 89 200. I have been messing with the jets for a couple weeks now(trial and error) My bike is all stock and i am running 152/42

That'll be pretty darn close there Smokey!

Indawoods wrote:That'll be pretty darn close there Smokey!

I got an A+ on the error side of things. I went off into the woods for a good 12 hrs yesterday/night. btw the Acerbis DHH hooked up to the stock stator with one bulb, worked great! I was using 155/45. I rode around for an hour or so messing with the air screw. I got it going nice, but it was still out too much. Well, i noticed the bike had a little more in the higher part of the tthrottle. So i was going to try turning the screw a little eensy weensy bit more and..... somebody stole my air screw I drove it for awhile like that unknowingly and it was going good.. That tells me it's def too rich :supz:I just went ahead and ordered RB's air screw and got the bowl screws while i was at it.

It was recommended to use a CGK needle 2nd clip from top, 42 pilot and 152 +/- main. You have a pipe which i do not have. I'm not sure what you would have to adjust for it.

Battery, you are running the stock jetting.

89 and 90 kdx200 came from the factory with 158 / 48
91 to 94 kdx200 came from the factory whit 150 / 48

Did you tried to raise the needle clip ?

Well I think your problem is not the jetting. Very strange Ah...could it be the float level? Maybe the float level is not good and after a good acceleration the bike running lean for a moment?? hmm I just try to find a solution

Re: 'When closing the throttle after a hard acceleration, the engine chugs or stutters.'

Is this something you feel, or hear? Offhand, it doesn't sound like something to worry about. It may be the rear tire skipping, a misfire due to the overrich condition you get when you chop the throttle, or the chain.

What shape is your chain/sprocket set in? What's the slack with the bike on the sidestand measured on the swingarm at the back end of the slipper (like the manual says). How far does the chain move when pulled away from the rear sprocket?



Re: ' btw the Acerbis DHH hooked up to the stock stator with one bulb, worked great!'

In another thread you indicated you tapped off the CDI for that.

Which is it?

Re: 'When closing the throttle after a hard acceleration, the engine chugs or stutters.'

Is this something you feel, or hear? Offhand, it doesn't sound like something to worry about. It may be the rear tire skipping, a misfire due to the overrich condition you get when you chop the throttle, or the chain.

Its both a hear and feel. It's a physical "jerk" you can feel, like a "reverse lugging" or a rythmic stutter, almost like the wheel is overdriving the engine.

The closest sound I would compare it to is if you were full throttle in 5th, then closed the throttle and shifted down to 4th, 3rd, and 2nd without the clutch. (not as dramatic, but the same type of sounds)

It's a cheap chain and sprockets, but they're fairly new. I adjusted per the manual (50-60 mm? I think)

kdxquebec wrote:Battery, you are running the stock jetting.

89 and 90 kdx200 came from the factory with 158 / 48
91 to 94 kdx200 came from the factory whit 150 / 48

Did you tried to raise the needle clip ?

Well I think your problem is not the jetting. Very strange Ah...could it be the float level? Maybe the float level is not good and after a good acceleration the bike running lean for a moment?? hmm I just try to find a solution

My 1990 was pretty much stock when I bought it, even had the airbox lid. It had 150/48. This 89 has a pipe and seems to run pretty good, so I figured the 158 was probably put in with the new pipe.

Seems weird to me that the same engine with arguably the same stock pipe would be shipped with such a difference in jet size from one year to another.

Maybe they realised the main jet was too BIG