Engine Compatibility - KDX 200- 1986-7-8

O

omrik88

Member

Dec 5, 2009

58

0

• Aug 12, 2010

• #1

Hi, need some help ...
I have a KDX 200 c3 1988 .
I'm considering buying a used cylinder jug which might be from a 1986 or 1987 model.
The questions are- will it fit and work?
what adjustments will i have to make?
what are the things i should watch out for?
*is there a way i could check before buying ,which model did this come off?
*are the Cylinders in these years (86-88) phisically different in any way?

Thank you very much :)
Have a great day!

 

Dirtdame

Member

Apr 10, 2010

146

0

• Aug 12, 2010

• #2

The 88 had different porting/carb than the 87 and 86.

 

O

omrik88

Member

Dec 5, 2009

58

0

• Aug 12, 2010

• Thread starter
• #3

Thanks Dirtdame!

Could you please explain what do you mean -
different porting?
I know the Carbs were different.

Can the 86-87 cylinder fit&work with the bottom end of the 88? can it be fitted with the 88 carb? (with a different boot),
or are the measurments of the carb mounts and ports are just not the same?


If anyone else has more information that would be
very helpful !
Thank you :nod:

 

Dirtdame

Member

Apr 10, 2010

146

0

• Aug 12, 2010

• #4

The cylinder will fit on the cases and the intake manifold will bolt to the cylinder. The porting is just more dynamic to match the flow characteristics and jetting of the Keihin. You will probably have to tinker around with jetting on the carb to get it to run the best with the milder porting of the older cylinder. You will probably have a milder power output as well.

Just have the 88 cylinder recoated.

 

G

glad2ride

Member

Jul 4, 2005

1,071

1

• Aug 12, 2010

• #5

The length of the boots is a bit of an issue, as they are not the same.

Dirtdame, thanks for the 1986 - 1988 information!

 

O

omrik88

Member

Dec 5, 2009

58

0

• Aug 13, 2010

• Thread starter
• #6

Thanks again!

What is the length difference in the boots? and are there good solutions? and what about the Air boot, is it the same in all 3 models ?

is it worth trying to work with the oval PJ/Pwk keihin carbs
on the 86-87 cylinder(for better performance) , or should i just stick to the STOCK carb?

Are the Bore&Stroke exactly the same in 86-87-88 models?
and what about the Ignition timing?
Any differences in the power valve operation?
I know that opening Timing/Amount in the powervalve&resonator/governor is controled from the bottom end - (Right?) - so if install an 86-87 cyllinder on an 88 bottom end - will i have problems with that?

Thanks!

 

Last edited: Aug 13, 2010

J

Johnson45

Member

Jan 30, 2022

1

0

• Jan 30, 2022

• #7

Dirtdame said:

The 88 had different porting/carb than the 87 and 86.

Click to expand...

Will a cdi box off a 86 kdx 200 work on a 87 model

 

Okiewan

Admin

Dec 31, 1969

29,550

2,238

Texas

• Jan 30, 2022

• #8

Will a cdi box off a 86 kdx 200 work on a 87 model

Click to expand...

86,87,88 all work.