KX Riders

Maintenance & Technical => KX250 / KX125 => Topic started by: sportracer07 on February 12, 2014, 02:42:25 PM

Title: A few questions 85 kx 250
Post by: sportracer07 on February 12, 2014, 02:42:25 PM
Hey guys im new to this forum, i just bought an 85 kx 250 and have a few questions. First one is that the kickstarter on my bike slips, i have heard that this is a cmmon issue, but kind find any info on what is actually wrong. Does anybody have any ideas?  Second thing is that i got a set of inverted forks off of a 91 model i think, they came with triple trees and all. So my question is can i swap these out, just triple trees and all, and will my front brake and axle assembly work with the inverted forks?
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 12, 2014, 09:54:24 PM
Since this is your 1st post...Welcome to the site!

Being a nearly 30 year old bike...more than likely the Ratchet Spring is really weak and worn out causing the kicker to slip...or the Ratchet itself is shot. You won't know for sure until you take off the engine cover and get a "good" look in there and be sure there's no other issues.
Unfortunately there aren't many parts available for the 85, but the Ratchet Spring is...

Part# for the Ratchet Spring...92081-122...$5.16 through Rocky Mountain..3 In Stock.

As for the fork swap, anything is possible...I'm sure there's someone on here that can give you better info about that than I can....there's been several guys on here that have up-graded to newer forks on various years of bikes.

Title: Re: A few questions 85 kx 250
Post by: Goat on February 13, 2014, 07:20:58 AM
Welcome to the forum.

As Foxx4beaver said the spring is probably weak. As far as the ratchet assembly the teeth will look perfectly fine sometimes but still wont hold. I usually take a dremel and fine tune each tooth 90* angle is generally fine but I usually go a little farther and angle them so they lock into each other a little more.

Upgrading to newer forks is always a great idea. I haven't done this exact swap on that old of a machine but I have done many others. More than likely the front brakes, axle, and hub are way different. If you have decent fabrication skills they could be made to work with the new forks. Triple tree should fit but not 100%. If you have the parts it's worth tearing the front end off and see if you can put it together with the newer parts.

There are a lot of knowledgeable people on here that will go out of their way to help someone out. We also like a good challenge. Post pics, ask questions, and dig around. There is a crazy amount of info on this site.
Cheers
Title: Re: A few questions 85 kx 250
Post by: motopunk on February 13, 2014, 08:09:09 AM
the 91-forks will fit without any problems to the 85-frame. i have the 1990-forks in my 87 kx250 ...  you´ll need also the complete brake assembly of 90-93 .
the 85 brake caliper could not fitted to the usd-fork . and trust in me, the 90-93 nissin (double piston) brake caliper works much better than the 83-86 (single piston) tokico brake... 
Title: Re: A few questions 85 kx 250
Post by: sportracer07 on February 14, 2014, 03:01:40 PM
Thanks for the quick replies everyone.   I have a few more questions, i need a piston and a carb, Any ideas what years will work for either one? And what size carb.
Title: Re: A few questions 85 kx 250
Post by: splime738 on February 14, 2014, 09:43:52 PM
I am just rebuilding an 85 250 as well, I got a Wossner piston but Wiseco do them as well, 78 up to 86 are the same piston, I am looking to get a pipe once its running if any one knows who still offers one, thinking of putting a flat slide Keihin on it as well
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 14, 2014, 10:21:26 PM
as far as I know, no one makes a pipe for the 85 anymore...but that doesn't mean you couldn't find a custom pipe shop and have a really nice one made for it :-D.
there used to be a big list of American custom pipe builders on here...I'll post it if I come across it.

give these guys a call if you're seriously considering buying a new flat slide...
http://www.sudco.com/Carburetor01.html
you don't have to buy specifically from them, but let them know what your plans are...what type of riding you're doing...etc, and they'll give you good advice which one to get.
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 14, 2014, 10:34:00 PM
I got a Wossner piston

good choice...stick with them over wiseco whenever possible!...far superior craftsmanship. :wink:
Title: Re: A few questions 85 kx 250
Post by: motopunk on February 15, 2014, 12:11:24 AM
i have also an wössner piston in my 83 kx 250 ..wiseco was not available at this time so i took the wössner and runs great with it..

the stock carb on the 85 kx250 is the 40mm mikuni roundslide but i think a 38/39 keihin pj or pwk would also work perfectly with the right setup... 

to the pipe: fmf and pro circuit offering still pipes for the 88-89 kx250. this pipes are still very similar to the 85-87 pipes . thats the only alternative that you would have, if you find no good used pipe for your bike.
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 15, 2014, 12:40:58 AM
I am looking to get a pipe once its running if any one knows who still offers one.

here's the list of custom pipe builders....I'm sure if you did some research, you could find some where you're at too, and then you could have a very nice new one :wink:

http://www.kxriders.com/forums/index.php/topic,8164.0.html

Another option, which I know some members on here have done...is buy the computer software and you can design and make your own pipe from scratch.
I can't remember which member it was, but he had posted some really nice pics of a pipe he built/designed from scratch.

Use the "search" option on here, lots of good info about it.


Title: Re: A few questions 85 kx 250
Post by: splime738 on February 15, 2014, 02:10:24 AM
Cheers for the info, I have had a nice pipe made in the past for my 125 A5, was hoping for a quick fix if one was available, just tried to put up a picture, how do you attach them on this site
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 15, 2014, 02:14:01 AM
you need a host to post pics...like this one...

http://www.kxriders.com/forums/index.php/topic,10040.0.html

there's other sites you can use also....
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 15, 2014, 02:26:30 AM
Cheers for the info, I have had a nice pipe made in the past for my 125 A5, was hoping for a quick fix if one was available, just tried to put up a picture, how do you attach them on this site

Here is Splime738's 125 pic.....very nice 125 too by the way!!!

(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/tn_zpse2256209.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/tn_zpse2256209.jpg.html)
Title: Re: A few questions 85 kx 250
Post by: splime738 on February 15, 2014, 02:38:42 AM
A company in the UK made the pipe, silencer is from Holly Equip in Japan. Hey Foxx tried to send you a pm but it came up as blocked
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 15, 2014, 02:48:55 AM
here's Splime738's 250s...more excellent resto work!!

(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/tn2_zps523d8f78.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/tn2_zps523d8f78.jpg.html)

(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/tn4_zps2b544651.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/tn4_zps2b544651.jpg.html)
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 15, 2014, 02:51:54 AM
A company in the UK made the pipe, silencer is from Holly Equip in Japan. Hey Foxx tried to send you a pm but it came up as blocked

you can send me PMs now.
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 16, 2014, 07:42:15 AM

I had a nice pipe made in the past for my 125 A5.

who did you have build that pipe on the 125?...if you don't mind sharing that info.
Title: Re: A few questions 85 kx 250
Post by: splime738 on February 16, 2014, 09:28:54 PM
A small company in the UK who use to specialise in drag racing scooters called TDR scooters, they made all sorts of pipes for road, dirt but I can't find there web site so not sure if they still trade
Title: Re: A few questions 85 kx 250
Post by: Foxx4Beaver on February 16, 2014, 09:54:39 PM
ahhh...is this them?

http://tdr-racing.com/blog/

they seem to specialize in tuning bikes/scooters in general.
Title: Re: A few questions 85 kx 250
Post by: splime738 on February 21, 2014, 04:32:40 AM
Just got my cylinder back from re-plating and assembling power valve, should it snap shut just with the spring after re-assembling or does it need the governor to help as mine feels rough even though everything is cleaned up and I have used a silicon spray to lube.
Title: Re: A few questions 85 kx 250
Post by: motopunk on February 21, 2014, 05:43:54 AM
Just got my cylinder back from re-plating and assembling power valve, should it snap shut just with the spring after re-assembling or does it need the governor to help as mine feels rough even though everything is cleaned up and I have used a silicon spray to lube.

better use wd40 or little bit 2stroke oil for assembling... i think you will feel the diference...  :wink:
Title: Re: A few questions 85 kx 250
Post by: Goat on February 21, 2014, 06:35:55 AM
I use Bel-Ray moly assembly lube when I put them together. Seems to work good.
Title: Re: A few questions 85 kx 250
Post by: motopunk on February 21, 2014, 07:51:15 PM
I use Bel-Ray moly assembly lube when I put them together. Seems to work good.



any lube would work there, except silicon-sprays, that works better on plastic and rubber parts.

i personally prefer to use 2stroke oil for assembling crank, piston and cylinder-parts for the right pre-lubing, because it would be the same oil that works there when the engine is running ...  :-)
Title: Re: A few questions 85 kx 250
Post by: splime738 on February 22, 2014, 04:26:39 AM
Cheers for that, I will clean it out and try some 2 stroke, I have been riding the old 75 & 79 that long I forgot all about power valves.