Starting problem

[HuskerChop]

Great to see this site back up and running. Ive got a long standing prob needing some outside influence on. Been fighting a starting issue for some time. I decked my cylinders to zero deck, added 600 Tman cam couple yrs ago along with adjustable Thunderheart ignition. All was great. On hwy, bike started intermittently just cutting off. Cycle key and would mostly restart. Troubleshot and found once ign box got hotter, would cutout. Removed, sent to Thunderheart and they heated up unit, and duplicated problem. Sent me new box. Installed and since then been fighting very hard starting. Actually kills starter rotation and drops battery voltage to 6-8 then starts rolling and starts. Ive changed all pos and neg batt cables, triple checked attach points, installed 2 new batteries, function checked comp releases (pulled them and bench checked, and installed and verified actuation), changed starters. I even pulled spark plug wires so NO spark at start up. Still, every time, hit start button and its like it hydraulic locks, then starts spinning. I cannot figure this out. Im an aircraft mechanic and feel confident that I have covered everything minus something internally. I did all motor work myself. Also when i rolled hard on throttle, motor sounds like it is pinging terribly. Does not matter where ignition module is set, minimal advance or max, bike sounds as if pinging. However, runs a timed 1/4 mile at 12.3 @ 121 mph. Im lost. Runs great after getting started, and pinging. I did have one comp release(rear) that the shaft start coming out of is swedging internally. It had bout 7/16 travel versus approx 3/16. Replaced. I know this is long, just wanting to explain all i have done. Nothing done with crank sensor however, possibility maybe??? Thank you in advance for patience of this long post

 

[HuskerChop]

Add another item, i installed Wire Plus EHC eliminator as well. Im not for sure on the amount of degrees between cylinders as far as piston movement. Could i possibly have somehow in ign swaps, switch the front and rear cyl coil trigger wires around? Im playing that scenario in my head to see if that would even be possible. I believe there is 8 degrees between front n rear cylinder piston relationships. So if timing was at 32 degrees advanced, and i swapped inadvertently, the coil trigger wires, could front cylinder be retarded to 24 adv and rear cylinder be at 40 degrees adv? Im starting to overthink this whole debacle

 

[Sven]

High comp is ping... Use an octane booster to stop the ping.
Remove spark plugs... This tells you if the comp slowed the starter, overrode the starter and the momentum starts in. But the initial first comp is the stopper. By removing the plugs, zero compression to spin against, where is that action vs. plugs in and working against a higher compression?

 

[HuskerChop]

Everything was perfect starting, no ping, until first ignition box went bad. This current box Has been sent back to Thunderheart and was tested good. This all started after ign box was installed. That made me question crank sensor, etc. thank u for the reply Sven! With spark plugs removed. Spins fine. It starts like it has 50 degrees of adv. i even have the Thunderheart set to let eng 'roll' 2 revolutions before ignition starts. Tried 0, 1 and 2 revs. No difference

 

[Sven]

Im not for sure on the amount of degrees between cylinders as far as piston movement.

Think about this. I can swap pistons and cylinders and where are my degree differences to the ignition? Make sense? My cyl is no diff, my piston wrist pin has not dropped/raised to compensate for two different ignition curves.

I believe there is 8 degrees between front n rear cylinder piston relationships.

Lets look at our ign tone wheel or the one window cut in an old harley electronic ign with VOES. The ign is not sequential. Sequential means it fries only once and this now eliminates the wasted spark at the exhaust on the other cylinder. However, we revert back to the old VOES setup, this comes with one window cut or a tone wheel with on collapse of the pickup coil or crank sensor... same part or say the same function is the crank sensor or the cup passing the pickup and then the window opening collapses the current, calls the spark to occur at both plugs... or here is the wasted spark or I forget the opposite of sequential vs. wasted spark... don't get old.

So if timing was at 32 degrees advanced, and i swapped inadvertently, the coil trigger wires, could front cylinder be retarded to 24 adv and rear cylinder be at 40 degrees adv? Im starting to overthink this whole debacle

No. You reverse wires and it backfires. That means if you Reverse at the coil wires this is out of timing to valve open/close postion. Reverse at the spark plug leads, this acts the same way as if you swapped the coil wires. So, I am going to assume no [individual] advance curve for both cylinders, but the same curve for both cylinders. Make sense?

 

[HuskerChop]

Yip, makes sense. I didnt think all way thru that there are 2 cut outs on flywheel to trigger collapse of field. Duh, my bad. Again, overthinking. I wanna blame all on ignition box, kinda KISS method as all was good before second box. Im really relying on what Thunderheart told me from benchtest they did. I have stock ign box, need to install it and simply eliminate the entire box theory. If it all is corrected with stock ign, tells me problem.

 

[Sven]

Everything was perfect starting, no ping, until first ignition box went bad.

A hint!?

This all started after ign box was installed.

Well, that sounds like two different ign curves out of each ign box? Can't blame compression.

That made me question crank sensor, etc. thank u for the reply Sven!

You're welcome, Husker. Crank sensor is a pulse maker. Sends in more AC current that can be measured or when the crank spins faster, more electricity made, but it's going to be sent to ground for spark eventually. So I could cut off the degrees when it starts out at 0v to ??v. I should wire into the sensor and see how much AC it does put out... curiosity only.

With spark plugs removed. Spins fine. It starts like it has 50 degrees of adv.

Yeah, without a difference, might be that ign curve to begin with. VOES has 3 curves. I think the first is 10° for starting and up to 2,000 rpm. 40° is mid rpm, then full advance is at 55°. So the hotrod feel or the faster response one feels without-VOES, the curve is 10 degrees and after 2,000 rpm, she locks into 55 degrees for that seat of the pants response one feels.

I can't believe the ign is locked at 50° to start? Has to be at least 10 degrees if I follow VOES. Only other option is to find the older ign box to use?

 

[FrankBDPS]

I am not a super mechanic by any means and learn something new every day. Why would you want an engine to turn over a revolution or two before the ignition sets off a spark? I always thought a well tuned engine should start on the first rev or two especially with such a small starter and battery trying to crank over a relatively large displacement and high compression beast.

 

[Sven]

It goes something like this... Fuel burn lag. So what Husker is trying to do is not start the bike at 50 degrees for starting? The piston is so low down there, it could literally cause the engine to reverse fire or since the piston is that low, spark occurs, the flame front, the compression trying to push the piston back down, add those combos and it runs backwards.

But there was no mention of this occurring. I just wish I had taken a video of that evo engine I timed. It was so on the raggedge of starting, it would seem to stop at TDC and BAM, she'd start faster than any harley I've come across.

I think now that I would move the ign plate were it would start easier, not mess with the toggled ing curves? Run the least degree for starting, see if the bike heats up being too retarded, Husk.

 

[FrankBDPS]

I see what you are talking about. I am new to the V twin thing and forget about the cylinder being sparked during the power or exhaust stroke. Lesson learned,thanks.

Now another stupid question, I therory shouldn't the engine stop with one cylinder close to the top of the compression stroke? Of course I realize that the compression could be lost between starts.

I used to have trucks with 2 stroke detroit diesels in them. They were know to roll over and start running backwards especially on cold mornings with weak batteries and a good snort of starting fluid.

 

[HuskerChop]

Swen, maybe i misunderstood ur last response but to clarify, i currently have the ign curve set to start at 10 degrees advance, it stays at 10 degrees to 900 rpm, at that point it increases to 26 degrees advance then on up to 34 degrees thru the rpm range. This ign is completely crank triggered, no cam plate. I have tried unsuccessfully to use my advance timing light to actually see what timing is. I was unable to use a clear timing plug as oil quickly covered flywheel timing marks and clear plug. I am left with completely relying on a laptop and graph as to where timing is actually at

 

[HuskerChop]

One more addition, with the cr's removed and hole open, motor still starts very hard. Rear cyl has very little air escaping open port while idling while front cyl has a ton of air escaping. The rear cyl was the cr that had the internal pin work its way outta its internal swedge internally. The end on cr plunger appears to have been contacting inside of cyl port everytime it actuated. Could this have hammer shut the hole in the alum casting possibly. Once again, reaching for peoples thoughts

 

[HuskerChop]

Sorry to keep responding, just want to give all the info i have and can think of. When i say it acts like it starts with 50 degrees advance, im not saying it HAS 50 degrees, it just simply acts like it has a ton of advance. Only thing I can say it does have is what the software and laptop tell me. I had a 360 methanol sprint car that each week we would have to add 3-4 degrees advance back in when cheecking mag timing. Instrad of troubleshooting we simply retimed and went on. The crank fire MSD crank mark was slipping each week on its shaft, telling us it was retarded when in fact it was fine. One night finally i detonated a piston and found we were at 52degrees adv. this bike starts like that motor did, HARD

 

[FrankBDPS]

Do you have a bore scope that you could use to look down into the compression release bore to see if it is damaged?

 

[HuskerChop]

I do have a borescope that i use on turbine engines, 3mm that can bend 90 degrees. I will try it tomorrow and see what i can come up with.

 

[Sven]

I used to have trucks with 2 stroke detroit diesels in them. They were know to roll over and start running backwards especially on cold mornings with weak batteries and a good snort of starting fluid.

Yep, makes perfect sense to me now that I think about it. A diesel runs on high compression to make a lot of kinetic light the oil off. The glow plug turns off once running, right? The starting fluid lights off faster [in the cold ambient] than gas or burns faster, the weak battery fighting that kind of compression and boom, it runs up just enough compression, boy, is that flame front is now burning that whole combo; way before TDC... I can see it happening that way is my guess?

I'm going to time the bike my way or how I address that shitty timing window design. Move the bike outside in the street. Wrap your arm with cling-wrap plastic. Wrap the timing light with plastic wrap. Find a clear piece of sheet, preferably a large window pane. Remove timing plug. The glass pane is up to your face, the timing light is now finished off with cling-wrap, wrapped around your bare hands and again over the timing light handle; is now an oil free hand/arm/gun/glass pane>(I added a layer over it).

Start the bike and as the oil flings out of the hole, you have to be fast on the throttle blip to see if the ( I ) mark is in the middle of the timing hole. Want less advance, move the plate so the ( I) is now to the right of the hole as you look at the hole straight on, but keep the mark shown in the window. That's a guess of, I don't know, say 2 or 3 at the most [degrees] from the middle is the retard?

This next thing is how you watch the timing mark. Can you watch it make it curve up to and stop? Or does it pop right into the window past this 900 rpm threshold? I can't see how it could pop into, or maybe I can.

I think it should curve in and out, not here it is; having that VOES disabled hit to it. See watt I'm getting at?

 

[HuskerChop]

Ok i borescoped cylinders, port hole on both open to cr chamber hole. Both ports leading into exhaust port from open as well. Load checked my battery cuz with a Snap On 800 amp booster pack motor starts fine. My tell tale sign all along has been scorpio alarm chirps at start up cuz battery voltage is drawn so low. The alarm picks up battery drain like battery is disconnected and chirps. With boost pack, no alarm chirp or starter stoppage. This is third battery, this is a Braislle (sp?). Every single second bike is not ridden, batteries are on a desulfidizer style tender. Battery showed 52% capacity. Checked Drag Specialties battery that I replaced with the Braislle, it was 77%. Aircraft we fail batteries lower than 85%. Also, gonna ask a question in next post for feedback...

 

[HuskerChop]

On rear CR, the one that the pin internally had pulled loose and was allowing the seat to travel almost 1/2". I could tell with borescope that the plunger was hitting the bottom of the machined well inside head. If i look at how far the plunger came off seat, it allowed the cutout part of the cr shaft, the part that allows gases to transfer from comb port, thru the cr port and exit the cr into the exhaust port, to travel fast the cutout part. This travel actually brought the large diameter of the cr pin past cr holes where compression pressure would escape into exhaust port, thus closing off ports on cr and stopping any bleed off of cyl pressure. I hope i somewhat expalined this. Will try and take some pics and post showing this entire debacle

 

[FrankBDPS]

No surprise about the battery. Lots and lots of post on the forum about bad batteries. I installed a Drag Specialities a year and a half ago. It won't hold a charge already. Going to install a glass mat battery next.

Good luck!

 

[HuskerChop]

This is failed cr, rear cyl, this is actuated and amount of travel that was ocurring when actuated