still no spark

[1984RM250]

I know I posted a message a while ago but I am still stumped. Right now there is no voltage coming out of the CDI box... I bought it with a hole burnt in the top of the piston which i figured was due to the 210 main jet instead of the 270 stock one. After I got a new piston I installed the 270 main, but the bike ran like crap and had absoltely no mid or top end power. I tried many different sized jets without success. My brother suggested that I check the stator and flywheel and clean them and mess around with timing. Finally after many trials, i found out that the stator had to be adjusted all the way advanced for it to run right. This seemed a little funny to me but i just rode it anyways.
Every once in a while the bike would just shut down, especially when I was riding while it was wet. When I pulled the flywheel cover off, everything inside was wet. There was a small piece of the cover broken off and that was letting water in. I took the stator off and cleaned it and the flywheel off. That worked good, but each time it got wet inside, the bike seemed to run worse and worse. There are exposed wires on the coils that were soldered there. I'm wondering if the coils could have gone bad. One coil is producing about 30 volts AC and the other is producing about 3 volts AC. This seems too low to me.
Another thing that bothers me is that the CDI box is not the right one. I saw a box for an 84 250 on ebay and it looked like it was black plastic. This one is metal and has the numbers CU1169 32900-41321. I was told this is not the right box. Should this matter? Would the wrong box make it a need to advance the timing all the way?
I dont have my owners manual so I dont know what voltage and resistance my system should have for testing stuff like this. Any help would be greatly appreciated.

Thanks,
Shawn

 

[tedkxkdx]

I can impart some wisdom. 

1. Get a new flywheel cover.

2. The coils are probably shot.  http://www.electrexusa.com is a place where you can buy a new set.  The resistance is the key to the coils not what they put out.  There is a resistance guide for their coils. Maybe yours are similar.  With all the water you talk about it would not be suprising to see them shorted out some.

3. The CDI unit your bike is suppose to have is an analog and not digital curve.  Next is compliments of ERIC GORR This means that at idle it is firing at 6 BTDC then advances to 20 BTDC at the rpm of peak torque.  At high rpm the time changes back to a retarded position of 6 BTDC. This retarding reduces the heat in the cylinder.  This curve is controlled by the CDI.  The voltage generated by the stator coils determines where the CDI curve should be.  So testing just output is not good.  Also the hole in the piston you had is a sign of the CDI advancing the ignition too far.  The engine was detonating under acceleration and thus caused the damage.  This also accounts for your having to move the stator farther than it should be moved.

4. So now you see that you need to replace your CDI and since there is only one item left in the electrical system, the spark coil, you might replace that as well.  I just installed and have ridden with the Electrex HTCDI.  A combo black box that houses the CDI and sparking coil.  It is easy to hook up and tidy under the tank.  The only problem is Electrex USA does not sell this, and their web site in England shows that exact part for replacement on your 84 RM 250.  I have already emailed them and asked about carrying this part for all the years of kdx.  You should ask for one on your RM.

Once the electrical situation is cured, you can start on the carb issue if there is one.

Ted

 

[tedkxkdx]

The htCDI looks like this.
http://www.electrexworld.co.uk/PROD-DETAILS/ht-pulse/HTCDI.htm

 

[1984RM250]

Thanks, I'll have to look into those Coils and CDI's. Would you suggest these coils over ones from Moose? They are listed in Dennis Kirk for $85.

With my piston, I dont know why the hole was burned in the top of it. When I got the bike the stator was adjusted to TDC, i dont know if the previous owner messed with it.

If I get new coils should I replace the CDI and spark coil. I'm trying to save $$ but I dont want it to go to crap again and dump more money in later on.

Thanks again,
Shawn

 

[sjmaster]

If you want to save some money, we can rewind those coils for you for roughly half the cost of new. We have been doing all types of jetski coils for years, these appear to be very simular and should not be a problem. Check us out at www.jetskisolutions.com The contact info is there. Thanks

 

[tedkxkdx]

It is your choice of brand of coil to go with. I was just pointing out an alternative to OEM. Get a manual and check the resistance tests on the other parts.