KX Riders
Maintenance & Technical => KX250 / KX125 => Topic started by: chipped tooth on April 17, 2014, 09:55:08 AM
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I just bought a 93 250 that needs some tlc.
It has the usual Kx skipping kick starter, low compression and many other small issues.
While I'm in the process of dismantling and restore, modify what should I do?
I have herd a 94 expansion chamber is a good upgrade.
Not looking to spend a ton on it just cheap or free mods.
One more thing, I run my own machine shop so any engine work I can do myself other than replate cylinders.
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it really all depends on how reliable of a bike you want...period.
do you want to ride worry free...or pray you make it back to the truck/home each and every ride?
your kick start issue is more than likely just a ratchet spring...$6 part
your low compression is telling you complete top-end, re-plate included...either side of $500 by the time you're done...gaskets included.
we don't know what the bottom end is like, but I'd put money on it needing attention in some way...which could run you another $1000..."could".
not sure what the "other small issues" are...but you can rack up some serious cash...really fast.
when I buy any used bike...I go into it knowing and expecting to spend between $1500-$2000...just to start...that doesn't include all the little nick knacks along the way.
the more you spend, the less worry you'll have.
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I'm just looking to make the usual upgrades, not gonna spend a ton on it.
I can do everything to the bike minus replate the cylinder.
I'm a engine builder/Machinest, I have my own business.
I herd the 94 pipe was a good cheap upgrade for the 92,93 bikes.
I can't seem to look at the link here for Kx250 racing files at the top.
It shows there is supposed to be a attachment but nothing showes up.
Am I doing something wrong? I'm on my Droid one.
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I have a 94 FMF nickel Fatty that I have no use for if you're interested....you can have it if you want, just send me a couple bucks for shipping.
I never heard of the 94 pipe being a good upgrade, but hey, maybe you can verify it for us. :-)
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I did a little sniffing on the net and only found one about the 94 pipe on a 93, might be a load of bs LOL
I will send a Pm Foxx
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alright...here's a couple pics...I just got off the phone with FMF to verify that it is indeed a 94 pipe. The numbers on it are "K-27 070896".
I'll get you a shipping price by tomorrow.
(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/HPIM0876_zpsf4fe9b3d.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/HPIM0876_zpsf4fe9b3d.jpg.html)
(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/HPIM0875_zpsd409bb7b.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/HPIM0875_zpsd409bb7b.jpg.html)
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i had a smart modified 98 oem-pipe on a 93 kx250 engine ... it gave little bit more bottom power and lots of riding fun...
you can also change the complete cylinder. 93-2004 has the same base... that would be a real power-update to the engine... :wink:
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I'm just looking to make the usual upgrades, not gonna spend a ton on it.
here's a few NOS items...
http://www.ebay.com/sch/i.html?_trksid=p3984.m570.l1313.TR0.TRC0.H0.Xnos+93+kx250&_nkw=nos+93+kx250&_sacat=0&_from=R40
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The 93 (J2 Model) is THE KX250 motor in my opinion, it can be made for bottom end or top end power with just a few changes. If you are after top, keep the stock pipe as it pulls harder up top than any other pipe & I tried them all. If you are looking for more bottom & mid go with the FMF, but it takes away a lot of top & over rev.
The FMF pipe for the 93 (92 model also) is the K24, the K27 is for the 94 model as Fox has stated & the mounting for it is for the "New" style frame of 94, but it is the last of the "Big" exhaust port pipes.
I think there is an extra stock 93 model pipe at my shop as I am using the later style frames now, i will check if interested, but it is a "Top End" style pipe.
If you would like more info on the 93 motor, let us know what type of power you are looking for & sure we can help.
DoldGuy
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The 93 (J2 Model) is THE KX250 motor in my opinion, it can be made for bottom end or top end power with just a few changes. If you are after top, keep the stock pipe as it pulls harder up top than any other pipe & I tried them all. If you are looking for more bottom & mid go with the FMF, but it takes away a lot of top & over rev.
The FMF pipe for the 93 (92 model also) is the K24, the K27 is for the 94 model as Fox has stated & the mounting for it is for the "New" style frame of 94, but it is the last of the "Big" exhaust port pipes.
I think there is an extra stock 93 model pipe at my shop as I am using the later style frames now, i will check if interested, but it is a "Top End" style pipe.
If you would like more info on the 93 motor, let us know what type of power you are looking for & sure we can help.
DoldGuy
all agreed.. but the last fullsize exhaust port was in 95... in 96 came the smaller one (for more torque and bottom end power)... thats important to know for all guys, that want to make a big bore with 300cc or more...
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I have a 94 FMF nickel Fatty that I have no use for if you're interested....you can have it if you want, just send me a couple bucks for shipping.
I never heard of the 94 pipe being a good upgrade, but hey, maybe you can verify it for us. :-)
beaver have yous got a l/h kip in gud nick for myne :lol:
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no, sorry Staffy...the only reason I had this pipe was because the hack teenaged kid that had my 2000 250 before me, had strapped on the 94 pipe and only had it held on there by the springs...or I should say spring, because one of the spring loops on the cylinder was broken off...probably due to no bolts holding the pipe on.
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aww mann neegood budd,ya wouldn't happen to know where I coulf get some purple handlebars by anychance ther lookin impossible to find ,ive been out on the menace today it ran great loads of power an rm rider fell off tryin to keep up :lol:
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not sure how good they are...kinda look more like ATV bars....pretty slim pickens :|
http://www.ebay.com/itm/MOTOCROSS-TRAIL-DIRT-BIKE-7-8-BRACED-BARS-PURPLE-ALUMINIUM-HANDLEBAR-ECspares-/360892482219?pt=Motorcycles_Parts_Accessories&hash=item5406de42ab&vxp=mtr
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here's a few more sets...just gotta search...
http://www.ebay.com/itm/EMGO-ALUM-HANDLEBAR-MED-BEND-7-8-PURPLE-W-BLK-PAD-/360159018831?pt=Motorcycles_Parts_Accessories&hash=item53db267f4f&vxp=mtr
http://www.ebay.com/itm/NOS-PRO-SPORT-DUAL-FLEX-SYSTEM-PURPLE-FORGED-ALUMINUM-MX-HANDLEBAR-RM-BEND-7-8-/331159441973?pt=Motorcycles_Parts_Accessories&hash=item4d1aa41235&vxp=mtr
http://www.ebay.com/itm/Bike-It-Purple-Low-Braced-Handle-Bars-7-8-22-2mm-/191117707535?pt=Motorcycles_Parts_Accessories&hash=item2c7f80c90f&vxp=mtr
http://www.ebay.com/itm/NOS-EMGO-Yamaha-YZ-Bend-PURPLE-Dirt-Bike-Carbon-Steel-Handlebars-7-8-/231204966184?pt=Motorcycles_Parts_Accessories&hash=item35d4e3cf28&vxp=mtr
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cheers they don't make them anymore so ther hard to come by ,amazing how much of a difference repackin your silencer makes like,dont think people realise ,al repack myne every few months now a think keep that nice clean power :lol:
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Well this is what I have done so far.
Fresh bore to 68.50mm one of the previous owners had a sleeve installed.
I cleaned up the exhaust port and matched the sleeve to ports that I could reach, raised exhaust port 1mm and widened it 2mm.
Intake side I matched the ports to sleeve and opened up the lower intake ports quite a bit
Smoothed everything out also, not polished though.
I couldn't get tho transfer port openings cause all my porting stuff is for automotive app.
I have a carb on the way from a 91 KX500 PWK 39mm or 39.5 it's not here yet.
I could use some jetting advice if anyone has ran a bigger carb on one.
The stock pipe has a few small dents but otherwise in decent shape, probably gonna use air pressure and heat to remove the dents.
Any known tricks for the stock silencer? Mine the guy attempted to repack it but it all blew apart.
I think with a next size up tap and some new screws and thread lock it should work again.
What's a good set of reads for my app? Mine have a chip and hang open all the time, they look like a dual stage set.... Boysen? Idk
Foxx let me know what shipping is, I would like to see the difference between the pipes.
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ive got an 94 stock silence on myne but havin trouble tryin to get it to fit my fmf gold series like,oils sprayin out the joint in the middle.tried wrappin some ali around but still been coimin out,dont wanna change it to new one like cos I prefer some oldskool stuff esp my silcencer think the oldskool ones look better
(http://i1067.photobucket.com/albums/u424/staffy32/DSCF0793_zps224049cf.jpg) (http://s1067.photobucket.com/user/staffy32/media/DSCF0793_zps224049cf.jpg.html)
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Mine has original pipe and silencer but silencer is in poor shape.
I like the look of the little elbow sticking out of silencer so I might try and find a new one or aftermarket one of similar design.
Once Foxx gets back to me on the 94 fatty I will do a back to back test on the 93 with stock vs aftermarket.
Right now compared to my 82 RM250 it's midrange is crazy, I need more seat time though. Terrain was really wet grass and mud, been raining for 2 days now.
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class I love myne like,i wanna keep it oldskool asmuch as I can,might go for vintage graphics next year after ive worn the menace ones out but thatl take awhile lol ,ive got a few jobs to do on myne before nxt race,need new pads nd hoses etc..wer you been riding like chipped tooth anywhere good .
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I have just been riding around my place, mostly trails and such.
Really wet and soft with the snow melting. The old D752 still works good though.
I wonder if the D952 works as good as the old D752?
I'm gonna wait till it gets a bit warmer out and just spend a day jetting LOL
I haven't herd much even on Thumper forum.