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Author Topic: 1987 kx 250  (Read 28790 times)

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Offline Oblivious Maximus

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Re: 1987 kx 250
« Reply #45 on: April 21, 2014, 01:26:17 PM »
I have a Keihin PWM on my 87 and it works quite well. I was told it was from a late 90's Suzuki but I don't know that for sure.

Motopunk will have the information you need.
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Offline bens87braap

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Re: 1987 kx 250
« Reply #46 on: April 21, 2014, 09:33:06 PM »
Another thing,  If my motor was rebuilt 10 years ago then stored in the shed will the crank seals be perished?  iv done maybe 25 hours on her and still fouling plugs every so often.   It just doesnt seem to be running at 100 %

Hiawatha ride we put 14 hours on my mates bike so i must have done same and i went through 3 plugs..

Plug comes out oily and black sort of wet..

Since that long ride bike has not been happy,  Tonight i read lots from here and something I read got me thinking,  I pull off my "stator"  cover the plastic one on left side,  out comes the water :(  im assuming the pressure cleaner got a bit close or the water spray from the back of my car may had something to do with it.

I pulled off "flywheel"   not sure if im talking right as i said previously i can work on cars but doing 2 stroke bike for first time lol..  Now im sure those magnets on the inside shouldnt have rust on them??  what should i do im lost without the smell of 2 stroke it really hurts :(

i could get spark but im sure it used to be more spark and easy to start but not so easy any more ......
   
« Last Edit: April 22, 2014, 07:41:27 PM by bens87braap »
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Offline bens87braap

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Re: 1987 kx 250
« Reply #47 on: April 22, 2014, 07:43:05 PM »
I will post pics of the magnets if that helps but its dark now down under and the lights are blown in the shed so have to wait till tomoz

looks alot older and rusty then the ones i see on you tube
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Offline bens87braap

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Re: 1987 kx 250
« Reply #48 on: July 20, 2014, 12:43:30 PM »
Finally done,  well as much done as it needs to be for me,  Final touches are done and have a complete set of plastics now with OEM stickers,  The bike is ridden almost daily so i  not putting them on stickers are in pack i will keep them incase i sell the bike,  New pegs landed, Showa forks from a Red bike,  New brakes, tires, chain, sprockets, jets, the list goes on but finally DONE to my liking




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Offline motopunk

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Re: 1987 kx 250
« Reply #49 on: July 22, 2014, 06:54:20 AM »
Quote from: bens87braap on April 21, 2014, 01:00:33 PM
OK so now im stuck in a hole again I think i need a complete new carby.  The low jet will not come out have tried everything is their another carbie that will fit the 87 kx 250 or do i have to run that exact carb??  MIKUNI? is the one i have on bike but so many other things are different could also be wrong one.

to the carb..
 i run at the moment the 39mm keihin pwk carb from a 1990 kx250.  pilotjet 48, mainjet 175, needle n85c (stock in 88-91 kx250 ) airscrew 1,75 turns out... runs great ... 

next upgrade for my bike is this one:

 caught this fresh rebuild 88 kx500 motor for a real good price...  :evil:
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big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

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Offline bens87braap

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Re: 1987 kx 250
« Reply #50 on: July 22, 2014, 06:08:41 PM »
Carb fixed I used Spiral Flute Screw Extractors to remove pilot jet then bought all stock jets and started tuning from their         Main Jet 320
Pilot Jet  35
2 turns out air screw
2nd top clip on stock needle

 Bike is running awesome with no power valves the only issue i can see is the snap from nothing into band now is so more aggressive those power valves really did smooth out the band,  u notice it heaps after removing them lol
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Offline motopunk

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Re: 1987 kx 250
« Reply #51 on: July 23, 2014, 07:24:04 AM »
the feeling without powervalves is similar to the older kx250 from 84 and older...  little bit like modern 125.. first decent power and with the right rpm: woohoo ... 8-) ...

 you should try to find good used powervalves maybe 85 to 87 could be very similar ... 
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big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

---  www.der-motopunk.de.tl  ---

Offline bens87braap

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Re: 1987 kx 250
« Reply #52 on: July 24, 2014, 11:37:52 AM »
87 is a one off year for power valves i have been looking as i only need one side.  I even bought some tecate 87 ones but they are bigger and i dont want to machine the cylinder to make it fit.  Bike does everything i want it too,  I dont race it just mainly take it camping and ride on my farm 
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Offline motopunk

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Re: 1987 kx 250
« Reply #53 on: July 27, 2014, 05:53:39 AM »
the 88-92 power valves are also discontinued ...  :-)

you could only try to find good used ones or a complete 87 cylinder or engine...   at the moment i am thinking of reproduce them , but thats not so easy as it looks... 
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big 2 stroke bikes are weapons for real men, who don´t fear death or devil. ;O)
´83 kx250, ´87 kx250 (with 360 big bore), 87 kx500, ´93 kx500 sfc

---  www.der-motopunk.de.tl  ---

Offline bens87braap

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Re: 1987 kx 250
« Reply #54 on: August 25, 2014, 08:30:19 PM »
Iv Done it finally a brown plug not a dripping black plug the Bike is lifting in top gear,  and I was just getting used to it now its a different bike so much more power went down to a 310 main on 2nd from top clip.  2 turns out on air screw check this out
 :mrgreen:
https://www.youtube.com/watch?v=8kj-7zWJELQ&feature=youtu.be
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Offline sandblaster

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Re: 1987 kx 250
« Reply #55 on: August 26, 2014, 02:18:51 AM »
Looks and sounds great!
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The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline bens87braap

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Re: 1987 kx 250
« Reply #56 on: August 26, 2014, 12:02:45 PM »
I changed jetting while the bike was warm and everything was fine.

Today I started the bike (Usually first second kick)  5 kicks to fire (I never used the choke it always starts without it?).

It was revving really high so i pulled the choke on and it killed the revs. 

I now need to warm the bike up with the choke on for about a min or it revs high when i turn the choke off.

any idea why the changes i made it jetting and air mix screw has done this? 

thanx for any help.   Ben
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Offline bens87braap

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Re: 1987 kx 250
« Reply #57 on: August 27, 2014, 09:00:38 PM »
got it sussed i just start the bike from cold with no throttle and choke on and it fires straight away.   The idle is still a little erratic sometimes it climbs a bit higher for 2 secs or so? hopefully im not hurting anything i did a plug test in forth at full revs and the plug is dark brown now not black
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