Engine Compatibility - KDX 200- 1986-7-8

[omrik88]

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]

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

 

[omrik88]

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]

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.

 

[glad2ride]

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

Dirtdame, thanks for the 1986 - 1988 information!

 

[omrik88]

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!

 

[Johnson45]

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

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

 

[Okiewan]

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

86,87,88 all work.