Today I got my new Spark Plug Cap. Measured a solid 4.7K. Put it together and now the coil is measuring 9.7K from spade to plug wire. SO, I've eliminated that possible problem/breakdown.

8 hours at DurhamTown and alls very well! The pilot ran good. Funny thing; fuel is. Shes very thirsty down 1/4 to 1/2 throttle and so I ended up with EEF needle in the middle clip. That one actually ran best. Idle dropped to 1000 with that needle, but since my idle stop screw is in a more 'tame' position given the #7 slide, I was able to easily turn up the idle to 1200. Idle down after a pull works quickly and a quick blip only has a very slight richness hesitation (I may drop from a 48>45 pilot jet to clean the very bottom initial throttle crack), A quick blip and she's got nuts off the line and fantastic power in the middle end.

My top end still needs a bit of a solution however. 185 main was a bit too lean on a plug chop. 190 felt -ok- but not perfect. I lost my 195 in the mud somewhere lol, and a 200 main jet would not clear out. I ended up running a 190 main jet for the whole day and kept a nice watch of the EGT.

Plug chop with the 185 main jet measured 1.85mm BR8ES

Fun thing on the EGT gauge is, at about 1/2 throttle the temp gets up to 1100F - this is where the Engine seems to be very very happy, but then at more than 1/2 throttle the temp drops to 1000F and the Engine isn't able to produce a whole lot more output. I thought for sure with a PWK39 the top end would nail harder.


Heres the problem though - I don't think its carb or jetting. Its that I cannot get this dang Engine to rev past 7200 RPM still! Its like a solid wall and I mean - my tiny tach should be able to display RPM in increments of 10. So whats up here? Fixing the spark plug cap didn't fix anything. I modified this CDI (Capacitor Discharge Ignition) back on page 2~4 to have no rev limiter but still the stock rev limiter should be more like 7400. I'm thinking or reverting the rev limit modification and test again. I also thought I could remove the belt for a second so that in gear I could see how far the Engine can free-rev.

So I'm thinking it might be mis-firing by way of some kind of ignition limitation. Any help is appreciated. Could my driven be opening wide and bogging the motor (( Internal Combustion Engine ? ))? I removed primary weights on my powerblock - that seemed to assist with bottom/mid delivery.

FYI - This is the for sale section and you might get more input if you place your posts in the correct section. I'm not being an ass, just trying to help. My money is on the CDI (Capacitor Discharge Ignition) and your mod may not have been done correctly or the CDI (Capacitor Discharge Ignition) is not working correctly. Do you have a spare that you can swap and test?

I tried asking Hoser to move this thread over. In fact now I’ve got two threads like this in the FS section. If there are any mods please move this thread.

No I do not have another CDI (Capacitor Discharge Ignition) but know it could be suspect. Does anyone have a spare I could try and rule out? Buy?

I saw hoser logged on yesterday so I sent him a PM. He didn't answer it so I just deleted it. He rarely shows now and does not comment. Also seen some very very long time members (10-15 yrs) log on after years away and they don't comment either even if you send them a PM.
Keep this thread rolling here otherwise stuff will be spread out all over the place.

I have several with the no rev mod already done and they all have been tested.
$200 each, if your interested.

I also don't mind lending you an old CDI (Capacitor Discharge Ignition) that still has the rev limiter so you can test to see what the issue is. Please just pay shipping there and back:)

I once had a bad stator that worked perfectly fine until higher rpms. A member here was going to csi it but that was a year ago and never heard from him again.

That was/is me - So far nothing to report. I need to find a better way to test it. If I ever get any info worth posting I will start a thread.

Pilot bird, Do you have any stators you could lend/sell? Chasing expensive electrical items....

Sorry sir, I do not, I only have complete engines

Without a rev limiter, should a pilot Engine be able to free-rev in neutral unobstructed? Mine only sees 6200 rpm with my old CDI (Capacitor Discharge Ignition), and 6500 with the test CDI (Capacitor Discharge Ignition) from Pilot Bird.

The only way I could tell when the rev limiter kicked in, is when I was out in the desert or dunes and had the Engine under load while driving. I couldn't tell if the pilot was parked or even driving it in the street.

Ok because just on the trailer it acts like it’s loading up at full throttle and can’t get past those figures. I guess when moving it gets tons more load and airflow. Everything else on this pilot is solid. Btw I live in an area where I need to keep the pilot on the trailer. I can’t run it around unfortunately have to drive a good distance to stretch her legs. Next test I will hook up a timing light and see if it stops flashing or something.

I won’t be going riding until end of this month.

On the trailer without load reving the Engine I’m surprised that you can’t get anywhere near full throttle. Every Engine I’ve reved without load nearly maxed out reving with the throttle just cracked (not that I make a habit of it).
The belt off it should zing to max revs. Just MO.
Keep on it, the answer can’t be far.

Thanks go ody. Yea same here. Even lawn mower engines can easily tap out. I can literally hold the throttle at 1/4, 1/2 or wide open and it’ll only see ~6500 rpm on the trailer. Hell I remember my old fl350r was able to wing out 9,000 easily while unloaded. I don’t condone doing this but there’s an underlying problem here.

Anyone got a stator to sale?

What about this $150 option?
https://www.regulatorrectifier.com/cata ... lot-stator

Good morning, been a while super busy and had some lake time. Skimes through your progress. I must say you have done very well suppling information and results. It a mountain of valuble info.
Any way to issue.
The first thing I thought when I read last few pages was ummmmm. Sorry but I had to laugh for a minute even though it's not a laughing matter sorry.
Not laughing at you rather my self for a similar nissue back in the day. I can lead in a direction from a past statement on tunning a new design for an Engine. The statement was regulate the RPM with Gap. Or snuff the flame for top end power dialing in timing, fuel etc.
So let's look at the Engine:
12 to 13 to 1 cr
Fuel
Port timming
All these known, what is not known is area at (T). No big deal.
Back to basics.
Higher cr,fuel not gasoline greater quanity.= Less gap
In a way the Engine is supercharged more pressure requires less gap for a fixed coil power. Or the flame snuffes at a given rpm. Hench Engine rpm control. One can set this even for a gasoline Engine design when at deto limit with a given main jet. You did change needle and bigger on main Hench increase in fuel quanity. The Engine ask for more not you have to ignite it. The pipes timing changes due to egt posted so does the supercharger pressure effect. Food for thought
This may or may not be taken place however should be considered or a higher voltage coil will be required If this is an issue.
Next would be tiny tack. Time for a better tach. Your baseing your decisions off of this, has to be accurate. Hope you took good notes. If the right change in clutch had no effect measured via the drive and driven via black marker with no rpm measured change on guage I would go umm. First check drive run out , black line and measure with given number of disk. Check driven at same time to formulate a given gear ratio. Then look at RPM . May have weak driven spring. Shim into place or replace. You should feel a two disc change easy.
I see your at eef and around a 200 sounds about right. A 190 should bring it pipe temp and increase top end pressure, reduce gap. This if course if area for (T) is good.
Your port timing was set up for what RPM again. So this could be a result of area at T. You may need to raise it up a touch more and increase area at new T. This will bring your port open diff more in line.if I remember correctly it was off by two degrees or three. With fuel thought it was ok.

Any way check gap and do a cheap expermint.
For other Google it. Info should be out there. Go Co go.
Time for work.
Again thanks for sharing.
Adnoh

Yes Adnoh I know that was a shot ---
and I have done a lot of digging on using a high output auto coil. I did have a thread on it somewhere.
Interesting thoughts there Adnoh -- I didn't think about a clutch issue or the flame snuffing issue.
Good ones.

EDIT: Silly thought here but are you sure that tiny tach is accurate ??

I think it is. I’ll run a few other electrical checks when I get the chance. Grounds and voltages to see if anything looks funny. I’ll also try reducing plug gap as a quick check. I’ve been using this same tiny tach for years and it’s helped tune and diag a few machines but sure it’s just a cheap little thing.

One more idea and now that I recall, upon initial disassembly I had found a load of water inside the front cover mixing with oil due to a failed oil seal, waterpump mechanical seal, and Someone had RTV’d the weep hole. Antifreeze and oil we’re mixing both ways. It was all sludgy inside the cover and I don’t think the P.O. even used antifreeze- looked like straight water mixed w oil. It’s quite a possibility the stator May have been subjected to corrosive water and was partially lost. No longer does this Engine mix fluids after full rebuild

Tonight I ordered a new stator and pickup trigger coil from that regulatorrectifier place. This is with stators; I’ve always found them to fail slowly rather than abruptly. Sure I’ll run some more peak voltage tests before I pull and replace it. I’ll also try and see if I can somehow adjust the trigger pickup gap to a tighter flywheel clearance which may help. If anything the charging coil could be bad or low output, or the trigger coil could also be weak. I figure when I break it all down why not have an on hand spare or at least pitch the old one in the bin.

Pilot bird; have not forgotten about you. You’ll be the first to know based on the CDI (Capacitor Discharge Ignition) you trusted to me.

OK! Now that my FL350r is rebuilt and ready for a go, its back on the trail of figuring out this Pilot ignition problem, where on the trailer I only see about 6200 rpm peak while in N, and on the trail its like a hard rev limitation at 7200 as indicated on my tiny tach.

So, Pilot Bird let me borrow another CDI (Capacitor Discharge Ignition). It didn't seem to make any difference on the trailer and so I bought a stator from a place called regulatorrectifier.com. It came with a pulse/trigger coil.

The new pulse/trigger coil is measuring 65k ohms and so I think its dead out of the box :( and I've emailed Regulatorrectifier.com. By comparison, my stock pulse/trigger coil is measuring 360 ohms which is correct.... but the old stator as a whole is still a suspect.

So tonight I decided to run some peak/hold AC voltage checks on the stator with using the Engine's pull start. I got ~5vAC on each of the 3(4) Yellow wires coming from the stator - 3 go to the rectifier, and the 4th which I believe is just T-ed into one of the other three wires goes to the CDI (Capacitor Discharge Ignition). The trigger coil is measuring about .4vAC

Pullstart test referencing ground:
Stator yellow wires: ~5vAC
Stator trigger/pulse coil: ~0.4vAC

So this made me wonder about something. The FL350 stator is quite different - It has a lighting coil, charging coil, and a trigger. FL350 charging coil can reach 70vAC. The FL400 stator/CDI (Capacitor Discharge Ignition)/regulator setup is quite different. Instead of a charging coil, its using the lighting coil - aka alternator coil - for both the charge AND the lighting hence why the voltage is so low at 5vAC compared to the FL350. Next I thought to check the FL400 wiring diagram to see how the CDI (Capacitor Discharge Ignition) connects to the alternator, and the battery - and sure enough the 400 CDI (Capacitor Discharge Ignition) gets a direct reference to +12vDC from the battery (Through the ignition and the off/run/off switch). Because of this, the CDI (Capacitor Discharge Ignition)'s sensory of +12vDC is also carrying whatever the alternator is being converted to at the rectifier. [edit] It is possible this type of CDI (Capacitor Discharge Ignition) is depending on direct +12vDC from the battery in order to charge for ignition spark. If any of the ignition/switches are slightly dirty then a loss of amperage/voltage through this wiring could prevent the CDI (Capacitor Discharge Ignition) from charging. Not sure if the CDI (Capacitor Discharge Ignition) charges through the yellow wire or through +12vDC as it could actually be from either. I know not enough about the FL400 CDI (Capacitor Discharge Ignition) to be sure.

This got me thinking. I've seen small vehicle rectifiers fail in the past... unfortunately its not very straight forward testing the rectifiers directly. Instead, you can measure what a rectifier can do rather than what it's numbers are with a direct probe. What I mean is - measure it's output in action. It should be putting out about 12 to 15 vDC at the battery, and NO AC. Batteries tend to not like AC - in fact they struggle with AC voltage which a battery will actually convert to DC. If a battery sees too much AC voltage for too long, the battery wills tart to over-heat and fail, but until then a battery does a strong job of being the 'rock' in a DC voltage system - at keeping DC going and AC at bay.

Three ways one can rule-out the rectifier:
1 - unhook it at both plugs. This will disconnect the alternator from the whole system; except the CDI (Capacitor Discharge Ignition) will still get fed one of the legs for it's charge. Will the Engine continue to run? I don't know for sure, but I think it should while the battery still supplies +12vDC. I'm going to test what the maximum RPM is while the rectifier is disconnected to see if its any different, ad if not...

2 - unhook the battery at the negative terminal. Pull start the Engine. This is a bit more dangerous and detrimental to the electronics. If the rectifier happens to be bad, the possibility of it passing AC voltage across it's output instead of DC could mean some fried parts in the test. I recommend getting the meter probes onto ground and +12v and get ready to check both the DC AND AC output at the disconnected battery terminals. There should be no significant AC across the battery terminals. Probably 0.1vAC would be ok, but anything over that would cause me to question.

3. Swap the rectifier with another unit. No-can-do. I don't have a spare.


At the end of the day, my final thought is if the rectifier has gone south, then the voltage supplied to the CDI (Capacitor Discharge Ignition) which referencing +12vDC could be interfering with what the CDI (Capacitor Discharge Ignition) needs to do - IE produce output to the coil at any given non-limited RPM.

If I find the rectifier tests didn't help or conclude anything at all, then I've got to have a bad stator.

But, one more test. Now that I have a nice running FL350r - I'm going to try swapping-in the 350's ignition coil into the pilot as they look to be very similar parts.

I ran and bench tested the rectifier today - and I think mine may be bad. While not 100% positive, the rectifier not only failed ohm tests 80% of the time, it also passed vAC to the battery terminals.

-If I disconnect the battery and pull start the Engine, I noticed right away something wasn't right. The Engine came to life as normal, but I noticed indicator lights, Neutral, Brake, Fuel, etc, started flickering badly above the steering wheel - like a Christmas tree on/off/on/off. When I probed the battery + and - wires, again with the battery disconnected, I measures both AC and DC voltage across the leads - that's 5.5vAC and 10vDC. Again at idle. When I revved up the Engine the AC voltage reduced but the DC voltage stayed the same at about 10vDC.

What this is telling me is - one of the 3 legs of diodes inside my rectifier may be shorted (Because each of the three legs regulates about 5vAC/DC, and I'm getting 10vDC and 5vAC), this is why charging voltage is supposed to be about ~15vDC, and I'm only seeing 10vDC).

Second test - removing the regulator from the circuit. Unfortunately the Engine fails to start on the battery unless the regulator is connected on both connectors - so that test gets ruled as inconclusive and not testable. The CDI (Capacitor Discharge Ignition) depends on the regulator across the Black and likely yellow wires.

Again and so, what I know is - vAC is being passed to the battery by my regulator. This... should just not happen. Its one reason why I also toasted one battery after about ~5 hours of run time. Lead acid batteries cannot take vAC for very long.


Question:

1. Can someone please try disconnecting their Pilot's main battery and then start it with the pull start? Do your indicator lights flicker on/off/on/off at idle when you do this?
2. Does anyone have a spare regulator I can try swapping in for test?

Thank you

I'm really getting my hands dirty over here. Last night I re-tested the rectifier on the bench and it actually tested -OK- with my Fluke meter, and so I decided since I purchased and received a new stator - to just go ahead and replace it. It was a big deal, but I was able to get the old stator out in a couple hours. This old stator initially looked to be -ok-, but it smells burnt. I took a whiff and was like, that's weird. Smells like burnt semiconductors. The new stator doesn't smell.

The replacement stator came to me with wires and a couple of heat shrinks. It needed to be hard-wired into the factory harness. I took my time and care cutting the old stator out, and that's when I noticed the old stator may have had a broken winding. Not sure if it was because of me servicing it, or if it was actually broken when last run in the pilot. The broken lead was one shared by the CDI (Capacitor Discharge Ignition) and rectifier - so that's a bad/good sign. Needless to say the old stator is done for at this point.

The new stator is slightly different in that the green ground wire does not have a place to mount. When I put it all back together I'll have to tie this ground wire to somewhere else under the front cover. I don't think that should be much of a big deal as ground is ground and its all connected... hopefully.

New heat shrinking, soldered joints, new loom, and all taped up. This new stator is ready to be re-installed into the front cover.

I also ordered a used Rectifier from eBay last night as well. At least I'll have a spare and one to test. I'm still un-easy about the flickering lights and so the rectifier could still be at fault anyways.

Pics next post

pics

Last pic is with new stator

God I get a headache reading this. I so hate electrical and am glad its not mine.