surging idle please help

[Y2Z]

I have had this bike for about 1 year(92 KDX 200) and ever since the idle has a really bad surge to it, the bike runs fine once im riding, about 1/4 throttle and up. I tried playing with the airscrew and changing the needle pos. in the carb, moving the pin helped a little but not enough.
im horrible with tuning carbs and have been trying to read others posts but still no luck.
thanks in advance for the replies!

 

[David Trustrum]

Ok well a few things first. Pull your LHS engine side cover & see if there is any oil in there. Note the position of the ignition & pull it off with a puller (std jap puller only a few $)). The 3 indentations around the oil seal leak. Clean with meths or brake clean & fill with JB weld or some epoxy.

Right now pull the carb slide out. I suspect there will be a groove wore in it in near closed position. Replacement mandatory if so. Sorry they aren’t cheap.
Now look at the airbox & all the boots that they seal properly. May be best to take the box out, clean it up & check that the ring that seals the box near the filter seals properly, which they never do. Pull the reed block out & check the reeds.

OK now you are ready to start fiddling with the airscrew & pilot jet. Until you do the above you are working with a variable airleak which can’t be tuned out, but they can be fixed & carburate(sp) real well.

 

[Y2Z]

thanks for the help david, i will check those things when i go to my dads shop again(i keep my bike there). when i did a rebuild in spring part of the reed looked as if it had melted or somthing, do you know off-hand how much the stock reeds are for it? my local kawasaki dealer is rarely open so i cant call to find out.

 

[David Trustrum]

Ahh well the reeds will certainly make it run inconsistently if it is damaged. Boyseens (the garden variety type) are fairly cheap but not sure exact $, try surf mail order

 

[speedyts49]

You should consider the Boyesen 607 reeds mail order or local dealer. I think I paid around $26 for mine. Do a search to learn more about them.
tom
93&96 kdx 200s

 

[wibby]

I reccomend the 607 reeds :thumb:

I recently installed 'em on my bike, I have amazing bottom end now. It runs very 4 stroke like. I'm finding myself being able to lug it in the tight stuff in 3rd or 4th where before I would have had to been in 1st or 2nd. It's really cool to be able to lug it so low but still be able to crack it open when you need it.

 

[G. Gearloose]

I've experienced surge at idle when I lost coolant and/or had air trapped in the head.

 

[Y2Z]

26$ for reeds?, sorry i meant to say that the reed cage was damaged, looks as though the material inside of it got too hot or somthing and melted a bit. im going to see if i can make some time today to go work on it and get some pics of the reed cage.

 

[Y2Z]

ok i went to their site, its about 150$ american for a new rad valve! im not exactly sure what that comes out to in canadian but, will i be getting my moneys worth? im going to sell it this winter/spring and i know i wont get my 250/300$ back when i sell it. i was just hoping to get it running good so i will have no trouble selling it.
thanks

 

[beefking]

Kawasaki part # 12021-1067, includes everything (reed cage/stops/pedals/screws). Ronayers.com has it for less than $60. (Click for RonAyers link) :thumb:

 

[David Trustrum]

The important part is that the reed seals on the rubber block properly. I’ve seen burnt reeds before but never the plastic flow block. Perhaps in the past the reeds were real burnt & run like that for a long while, bit odd though.

IF the reedblock & reeds are ok I wouldn’t worry about it.

 

[Y2Z]

i think i found the problem, on the left side of bottom of the head there look like therer is a big of oil penetrating through, its very little but i think it would be enough to cause this. Another reason i think its this is because when i start the bike(first time when cold) it will idle perfect and as the bike warms up it will start surging, probably somthing to to with the expansion...
my question is could i just re-touque it or should i buy a new gasket and torque it. i dont know why its doing this because we torqued it properly in the spring.
thanks

 

[David Trustrum]

Well if the head gsk is leaking (not that uncommon on an old bike, mine was) then the head gasket will only take up so much slack. Pull the head & make sure it is flat, -a light skim, you can carefully use a flat (new) fine oil stone in figure 8 if not too bad.

Then a new head gasket & file the head stay holes a little looser. They pull on the head as an older frame flexes causing head sealing problems.

 

[Y2Z]

well i tightened up the head(it was REALY loose) and it still does it, im starting to hate this stupid bike, thank god i got my new bike(brand new 02yz125). Its not even really rideable because its just so inconsistant and gives me a headache ridiing it. if anyone has anymore suggestions about what it might be i need to sell this thing soon. should i put a new gasket on it, i dont think thats the problem though because we put a new one on early this year.

thanks