is this a jetting problem?

Got questions? We got answers....
Post Reply
battery
Member
Posts: 27
Joined: 09:51 am Mar 13 2007
Country:
Location: Twin Cities, USA

is this a jetting problem?

Post by battery »

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.
1989 KDX200
2000 ZR7 750
2005 DRZ400
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Well... you jetting is extremely FAT !
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
2001kdx
Supporting Member I
Supporting Member I
Posts: 1522
Joined: 08:36 am Sep 23 2006
Country:
Location: Town of Montgomery, NY

Post by 2001kdx »

Like Rosie O'Donell!

Give 155/45 a shot. Generally a good start for a 200.
AwfulSmokey
Member
Posts: 95
Joined: 07:11 pm Oct 16 2007
Country:
Location: Ft Myers, FL

Post by AwfulSmokey »

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
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

That'll be pretty darn close there Smokey! :mrgreen:
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
AwfulSmokey
Member
Posts: 95
Joined: 07:11 pm Oct 16 2007
Country:
Location: Ft Myers, FL

Post by AwfulSmokey »

>|<>QBB<
Indawoods wrote:That'll be pretty darn close there Smokey! :mrgreen:
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 :roll: 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.
User avatar
kdxquebec
Supporting Member II
Supporting Member II
Posts: 1255
Joined: 07:18 am Nov 24 2004
Country:
Location: Québec:North Pole
Contact:

Post by kdxquebec »

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 :roll:
'89 KDX 198cc '03 Gasgas Ec250 '13 Husaberg Te300
*CANADA* LEADING THE WORLD IN BEING JUST NORTH OF THE UNITED STATES.
Image
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

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?

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
battery
Member
Posts: 27
Joined: 09:51 am Mar 13 2007
Country:
Location: Twin Cities, USA

Post by battery »

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)
1989 KDX200
2000 ZR7 750
2005 DRZ400
battery
Member
Posts: 27
Joined: 09:51 am Mar 13 2007
Country:
Location: Twin Cities, USA

Post by battery »

>|<>QBB<
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 :roll:
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. :?
1989 KDX200
2000 ZR7 750
2005 DRZ400
User avatar
kdxquebec
Supporting Member II
Supporting Member II
Posts: 1255
Joined: 07:18 am Nov 24 2004
Country:
Location: Québec:North Pole
Contact:

Post by kdxquebec »

Maybe they realised the main jet was too BIG
'89 KDX 198cc '03 Gasgas Ec250 '13 Husaberg Te300
*CANADA* LEADING THE WORLD IN BEING JUST NORTH OF THE UNITED STATES.
Image
Post Reply