Author Topic: Need help with ignition issue (Read 4208 times)

c_williamson007 · « **on:** March 15, 2015, 12:58:37 AM »

I just put a pwk 38mm on my R. I did it because I was trying to solve a running problem that caused the engine to break up at higher rpm and felt like a fouling spark plug or the first few seconds after starting with the choke when the engine is clearing out.

The problem was still there with the new carb. After messing around with spark plugs I tried gapping at .018 and boom problem solved.

So my conclusion is one or more parts of the almost 30 year old ignition are getting weak.

My questions are,
Has any one experienced this problem and do you have a resolution.
If the CDI needs to be replaced what is the difference between the 86,87 and the 88,89 box.
And I would apreciat any other input any one has on this topic.

Thanks in advance

Jimbo45 · « **Reply #1 on:** March 15, 2015, 01:29:38 AM »

I am no expert, but just went through all this with an electrical gremlin. Assuming your jetting is close enough to rule that out, Here is the order I addressed it:

-test coil
-test stator
-test pickup coil
-check and clean ALL electrical connections (I ended up just making an almost entirely new harness with new connectors), and put NOalox or similar on connectors.

My next step was to try swapping out the CDI unit, and while waiting on it to arrive, I pulled the stator cover for an inspection......well I noticed that the stator was a little loose,and rocked back a forth a few degrees! I then pulled the flywheel and simply tightened the 3 phillips screws that hold the stator together. Boom, top end break up and popping and power loss solved! I also cleaned everything up in the stator cover while I was in there.

On your cdi question......after all the reading I did, it seems that most say you can use either part number and that only the timing curves are a little bit different. Then, some say that the wiring and or connectors may be different between the two model year groups. So, take that for what its worth, but I think you can use either, honestly. Hopefully someone will be along to answer that part for sure.

c_williamson007 · « **Reply #2 on:** March 15, 2015, 01:47:36 AM »

Thanks for the information jimbo. I read through your thread befor I posted this one. My parts physically look good but I have not tested resistance yet. I worked out the jetting as soon as I closed up the spark plug gap. The coil is new cuz the old one the plug wire was rotten. I know the wiring and connectors are in order cuz I went through it all when I put lights back on.

The engine is running top notch now but if I open up the plug gap past .018 it starts breaking up.

Jimbo45 · « **Reply #3 on:** March 15, 2015, 01:53:30 AM »

Quote from: c_williamson007;51612

Thanks for the information jimbo. I read through your thread befor I posted this one. My parts physically look good but I have not tested resistance yet. I worked out the jetting as soon as I closed up the spark plug gap. The coil is new cuz the old one the plug wire was rotten. I know the wiring and connectors are in order cuz I went through it all when I put lights back on.

The engine is running top notch now but if I open up the plug gap past .018 it starts breaking up.

Hmmm. Not sure about that. The stator is grounded under the flywheel....you check that ground too? I would check that ground and the check the resistances on the coil, stator, and pick up coil

fearlessfred · « **Reply #4 on:** March 15, 2015, 01:38:34 PM »

Most motor builders suggest going to 18 because of the age of the component's

Rupp250 · « **Reply #5 on:** March 15, 2015, 05:29:03 PM »

First off check the flywheel. take it off and shake it. Does it sound like there is gravel inside? Other than that I have every component you need. More than welcome to try them out.

c_williamson007 · « **Reply #6 on:** March 15, 2015, 05:49:41 PM »

It will be a while befor I get out again. I was planning a trip on the 20th but it has been canceled. Thank you Rupp for the loaner parts offer and sorry I never got back to you on the fender support. I am still wondering is it worth replacing the stator and/or the CDI? Or should I just run with the small plug gap

hontrx265r · « **Reply #7 on:** March 15, 2015, 07:28:55 PM »

I just had my motor ported by Jerry Hall. My first trip out i experienced exactly the issue you are having. With the same solution. Previous to the cylinder and headwork, i had no issues. Jerry told me he recommended running .018-020 on his motors. Im not saying a better ignition would not help. This is why i am now going to try a vortex and prob an msd. The bike is running great, but i also want to see if a better ignition would help.

fearlessfred · « **Reply #8 on:** March 15, 2015, 07:51:37 PM »

I hope I'm not wrong in saying this ,but a motor that has been massaged to have a much greater output can also have more turbulence which can actually blow the spark out. A motor with more turbulence helps reduce detonation. Hopefully Jerry will correct me if I'm wrong

c_williamson007 · « **Reply #9 on:** March 15, 2015, 09:08:07 PM »

Quote from: hontrx265r;51641

I just had my motor ported by Jerry Hall. My first trip out i experienced exactly the issue you are having. With the same solution. Previous to the cylinder and headwork, i had no issues. Jerry told me he recommended running .018-020 on his motors. Im not saying a better ignition would not help. This is why i am now going to try a vortex and prob an msd. The bike is running great, but i also want to see if a better ignition would help.

This problem existed on a recent ride befor I did a little work (.010 head gasket, pwk 38mm carb, and 100 octane fuel) but after the work the problem became major. I think the issue became bigger because of the increase in compression. I am interested to know more about MSD ignitions because I have used them on V8 and 4cyl turbo applications and have been very happy with the performance.

c_williamson007 · « **Reply #10 on:** March 16, 2015, 12:09:16 AM »

I checked out the MSD offering. It looks really cool and I'm sure it would pack the punch I'm looking for BUT.... It looks like it needs a battery and the timing curve needs to be programmed. Two things I don't care to deal with on this project.

hontrx265r · « **Reply #11 on:** March 16, 2015, 12:36:17 AM »

I was planning to try the msd with a capacitor as i believe it would be sufficent. And yes having to start from scratch on the ignition is a downfall, however there is sufficent data out there to have a damn good starting point.

c_williamson007 · « **Reply #12 on:** March 19, 2015, 10:56:08 AM »

After checking out the MSD and the Vortex I think they are way cool but also way more than my project needs. I also saw a box made by dynatech. Has any one used it or has any spec on how it changes the powere curve?

Again thanks for all the input so far.