Engine differences between 1993 model and 2001

[legendboy]

Engine differences 1993 & 2001 [CR/KDX Hybrid related matter]

Speaking specifically about the 200.

I have an issue with my CR/KDX200 hybrid bike. The pipe.

The only pipes I have been able to get used and at a reasonable price are from late model bikes, stock pipe and silencer. They fit with minor modifications

The motor in my hybrid is a 93.

I modified a late model 220 pipe when i built the bike. The bike runs ok but is majorly lacking top end.

I have done some reasearch and have found that once the 220 was introduced in 1997, it acutally uses the same pipe as the 200.

So I am not sure if there are engine differences in the later model bikes when compairing to the older versions (1993) that could be causing my trouble.

On the flip side to that, it could be my modifications to the expansion chamber that caused the lack in top end.

So i have a fresh pipe to work with and was thinking of cutting it completely apart and removing the inner baffle and insulation.


I have no idea if a larger expansion chamber will help top end or low end.

Do you guys have any ideas for me?

PS. I originally tried to use a modified CR125 pro circuit pipe. It fit like a dream but the bike did not run correctly at all.

 

[Frankenschwinn]

Seen this?
http://dirtoverstock.com/searchresult.aspx?categoryid=132

 

[sr5bidder]

want to know why and how 2t pipes work start reading
2stroke pipe designer
http://www.mh-aerotools.de/airfoils/javapipe_main_en.htm


this link will download you a copy of Graham bells performance 2 stroke ..about 3mb pdf. good reading
http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf

 

[julien_d]

You'll want to use an aftermarket pipe for 95+ kdx200/220, preferably an FMF Gnarly Desert pipe. The stock 95+ pipe is good for a boat anchor, but not much else. Trying to fit a stock E series pipe (89-94) will be a nightmare, since it's a high pipe. If you had to add an extension to the head pipe to meet the cylinder, the longer header section will reduce top end power.

 

[helio lucas]

sr5bidder,
that book is still copyrighted. i have the original second version and is a great starter book.


legendboy,
removing all the internal baffles usually gives you more punch out of the turns, midrange. but like any 2 stroke tuned pipe, it could do a lot of things including not desirable ressonances. suck it and see i think :think:
on the cr 125 pipe do you jetted the engine after fitting? usually mx pipes work very well on the power band with road\enduro engines :cool:

 

[sr5bidder]

copywrited...does that mean I can get in trouble for linking someone to it?

it is a very interesting read, though it is old, the theories and principles still apply

 

[helio lucas]

copywrited...does that mean I can get in trouble for linking someone to it?

yes, copywrited :|

i guess the main problem is my conscience keeps telling me that if the men has worked to write the book, then i should pay to have it. actually the last version is pretty inexpensive through amazon.
http://www.amazon.com/Two-Stroke-Performance-Tuning-Bell/dp/1859606199/ref=pd_sim_b_12
despite the fact that book is based on the gordon jennings book ( he is the real man!!!) is a very good one. i´ve read it more than 30 times i guess.

 

[julien_d]

sr5bidder,
that book is still copyrighted. i have the original second version and is a great starter book.


legendboy,
removing all the internal baffles usually gives you more punch out of the turns, midrange. but like any 2 stroke tuned pipe, it could do a lot of things including not desirable ressonances. suck it and see i think :think:
on the cr 125 pipe do you jetted the engine after fitting? usually mx pipes work very well on the power band with road\enduro engines :cool:

a 125 pipe is not gonna be near enough pipe for a KDX.

The stock 89-94 pipe is a decent performer if it's cut open and the double wall taken out before welding it back together. This is NOT the same as removing baffles from the silencer. I would never recommend that to anyone.

 

[legendboy]

thanks for the input guys.

i might have to bite the bullet and buy a new aftermarket pipe, cut it up and hope for the best.