85 KLR250 D2 Electrical Questions

Introduce yourself, what you ride, post pics, seek or offer help, general chit-chat.
Post Reply
User avatar
Site Admin
Posts: 1217
Joined: May 02, 2016

85 KLR250 D2 Electrical Questions

Post by 4Strokes » Sat May 21, 2016 5:59 pm

Topic: 85 KLR250 D2 wiring question
Author: johnmw
Posted: 01/31/2009 8:40:22 PM

I just picked up another project, a 1985 KL250 ( KLR ? ). The person who had it before me made one heck of a mess out of the wiring, so I am trying to put things back to stock. One item has me kinda lost.

What the heck does the DIODE do and is it a necessary item ?

There are 3 wires in and 3 out, all 3 wires going out appear to go to the CDI box. The 3 going into the Diode, one comes from the clutch switch, one from the kickstand switch and the other comes from the nuetral light circuit.

Can anyone explain the diode to me ? and why no power seems to be feeding thru it to the CDI box ?.

Thanks for your time. Link: pics of the project (dead link) John

Reply by b_king on 02/01/2009 10:32:55 AM
It seems to control the safey switches to stop spark being produced from the CDI when one of the switches is engaged, say for example the side stand is down, no spark. The electrical definition of a diode is a one way gate, converting AC to DC. Diode's are found in modern voltage rectifiers to control the voltage from the stator/alternator to the battery or electrical system. Where is the "Diode" located on the wiring harness?

Reply by johnmw on 02/01/2009 11:52:26 AM
At this moment, it isn't in the wiring harness. If I follow the wiring diagram, it goes between Clutch switch, kickstand switch and the neutral light and the CDI box. As in all three items in to the diode and then all 3 out and they tie together and into the CDI box.

This is what has me concerned. the 2 switches and grounding switches and the neutral light circuit is a positive 12 volt lead.

At Least that is what I am getting out of the factory diagram in the manual. I can put a scan of the diagram up somewhere ( probably illegal ). It may be that I'm just stupid, also. This has been suggested, and that I just put things together like the manual shows and stop complicating my own life.

I dunno I just want to see a spark outta this thing. At this point, it aint happenin!!! John

Reply by Admin on 02/01/2009 12:30:07 PM
Yes, definitely post a pic of the wiring. The link you posted above only points to one pic. Try posting a link to your entire album.

Reply by johnmw on 02/02/2009 11:06:32 AM
We gave up ..... there was a complete wiring harness on that E-gay place for a good buy it now price, so I jumped on it. Just wasnt up to playing around with this chopped-up, hacked-up harness. Sorry for taking up your time. Thank you for the help. A few more pics at Link: pics of the project (dead link)

Reply by b_king on 02/02/2009 5:05:10 PM
Hopefully you get it running, let us know how it works out for ya.

Reply by Sanosuke on 02/04/2009 12:17:20 AM
johnmw, A Diode is simply just that -- an one-way electrical flow gate -- it just allows electrical current through it but not allow electrical current to flow the other way. If the diode is in-line with everything, it should be fairly easy to find it. But you did mention getting a new wiring harness off e-bay. Let us know how the progress is in getting everything going again. Sanosuke!

Reply by johnmw on 02/14/2009 11:05:47 AM
OK, installed the wiring harness. It came with a diode already installed and even had the voltage regulator/rectifier. I am still not getting any spark. I mean there is a stray spark that shows up every once in awhile ( with the switch off ?? ), but it wont start. Is there a way to test the CDI unit beyond the resistance checking in the service manual ?? Thanks John

Reply by Admin on 02/14/2009 11:26:10 AM
Did you see this: Testing for a Suspected CDI Problem

Reply by johnmw on 02/15/2009 01:26:21 AM
Just read that, Thank You, it was informative. Finaly managed to come up with a decent spark. It still wont start !! I get a BLAST out the tailpipe every 5 or 6 kicks. I don't feel much compression when kicking. I can actualy lean over the seat and grab the kicker by hand and ram it thru a full stroke with not much effort. Valves are set properly,Cam timing is right and it has new rings. Is that compression release any sort of trouble maker ? Yeah, I'm trying to learn at you guys expense. Thanks John

Reply by b_king on 02/15/2009 09:58:46 AM
This may be a stupid question but did you check the coil? I'd do a quick compression test, and if that leads to nasty results, do a leakdown to pinpoint your problem. You said you put new rings in it, did you do anything to the valves while you put the rings in? Hope this helps! Robb

Reply by johnmw on 02/15/2009 10:47:11 AM
The coil checked out fine, even swaped in a known good one. The head was cleaned and decarboned. The valves looked good, so they were lapped and a batch of Viton valve seals were installed and put everything back together. I dunno, I may have missed something. It does sound like there is leakage past an exhaust valve. Something aint right !!! A friend wants his dad to come in from the reservation and do some sort of cleansing. Man I hate the smell of burning sage and feathers John

Reply by b_king on 02/18/2009 7:17:52 PM
Hm...your mention of "leaking past an exhaust valve" leads me to question whether there is some sort of decompressor system and if it is adjusted and functioning correctly. If it is cable actuated, then there could be an adjustment off. Have you double checked the valve clearances? If there is an auto decompressor it is impossible to get an accurate reading out of doing a compression test, even considering a compression test is pretty much useless. I'd go straight to the leak down. Have you checked the CDI yet?

Reply by johnmw on 02/18/2009 8:36:15 PM
Yes, the CDI checked out just fine............ I swaped in the Voltage regulator/Rectifier that came with the eBay harness, Got spark......... go figure. Still doesnt have the compression I was expecting. Pulled the head and cylinder this afternoon. Still checking if I screwed up or what. Thanks John

Reply by b_king on 02/19/2009 10:27:27 PM
How did the cylinder and piston measure out when you had it apart? Did you have the cylinder deglazed or honed before installing new rings?

Reply by johnmw on 02/23/2009 7:43:19 PM
The piston and cylinder measured well within the specs in the manual, lightly honed the bore with a medium shone set. At the moment I am lost........ I took the head and jug off again, everything looked good. Put it all back together just like before. Suddenly there is compression up the wazoo ( I think it was my wazoo ? ). 2 kicks and it came to life and sounds down right healthy. So I went thru the motor and it wont run, take it apart and put it back together the same way with the same parts and it runs ??? WHO CARES !!! It runs.. Thanks for all the help and ideas. John

Original URL: 4strokes.com/forums/topic.asp?TOPIC_ID=30654 © 2016 4Strokes.com

Post Reply