DG Rider
Member: Triple Clutch Club
Lifetime Member
Unrelated to the issue, but What brand of filter did you buy? I've never seen one with those options?
Can you post a video of the spark/cranking going on? The engine should have a distinct rhythm when cranking, and the spark should match that. Doesn't really sound like the issue, but I'd like to hear and see it.
Glock21user
" Nothing succeeds like excess "
Lifetime Member
Opinion vary and there are many, I will offer mine as well I reckon.
1st - Valve Adjustment
2nd - fuel pump
3rd - ignition switch.
Turn the key forward but not to start and you should hear the fuel pump spin up and pressurize the system.
If not verify power to the pump from the relay, if the relay isn't sending power then verify the relay is getting power hence the ignition switch.
Those few steps will determine where to check and how to proceed.
It will show itself quickly I hope.
Good luck.
1st - Valve Adjustment
2nd - fuel pump
3rd - ignition switch.
Turn the key forward but not to start and you should hear the fuel pump spin up and pressurize the system.
If not verify power to the pump from the relay, if the relay isn't sending power then verify the relay is getting power hence the ignition switch.
Those few steps will determine where to check and how to proceed.
It will show itself quickly I hope.
Good luck.
M
I figured they should fire simultaneously. I just thought they would fire a heck of a lot more than 1 spark per second.
I assumed the compression was fine because when it runs, it sounds perfect and has tons of power. Is that a safe assumption? I’ll grab a shot of the old plugs this evening. I intended to hit the intake with a shot of ether this morning but, of course, it started ...did turn over a while, but did start right up and purred like a kitten.
M
Here is a pic of the old plugs. Look decent to me. White-ish tip. A bit brown at the end of the insulator. Don’t know how long they were in there.
M
Interesting find on taking 3 minutes to clean out my spark arrestor (you never know). Does not look like the Honda manual I just purchased. See pics. The screen is large and stays inside the tailpipe. The only thing that comes out after removing the (3) 8mm bolts is a short piece of pipe. Nothing came out for me to clean. Sorry, no torque spec listed. Default to 8mm bolt torque
DG Rider
Member: Triple Clutch Club
Lifetime Member
The spark arrestor screen is missing. It's a tube of wire mesh about the diameter of that metal the gasket is around...Like the pic in the manual.
M
M
The pre-oiled air filter was purchased from my local Honda Powersports dealer. The packaging was just a clear plastic bag - no labels.
attaching a video of the spark plugs in action. Prior to this, I followed DG Riders excellent post and adjusted the valve clearance. Surprisingly, none of the four were out any more than a whisker. The video shows the spark pattern which now appears to be sparking about 3 times faster than before. Not sure why. Also, shot ether in the airbox- not even a bark. Can’t understand how I clearly have spark, throw ether in — and nothing at all. Sorry guys, tried to load the :36 video clip but the site said the file is too large.
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M
Talked with my brother in law - bit of a motor guy. Had me throw a shot of ether in the top plug, throw in the plug and wire, and turn it over — nothing. Not even a bark. I then took another member’s advice and compression tested. Only 50psi (both plugs gave same reading). Read manual and said to test at WOT — result was 52psi. My brother in law told me to put a teaspoon of motor oil in the plug hole and re-try. I did so, put in the tester and found the pressure jumped to 70psi. The service manual said 80 is normal. So now what???? Starting to want to run my new toy right off a cliff.
DG Rider
Member: Triple Clutch Club
Lifetime Member
Load the video to youtube and post the link.
A lot of things go into actual compression psi. Altitude and cranking speed have an effect as well. Honestly, my experience with ether is that it will start an engine with too low compression, but thanks to EPA screwing with stuff, maybe that's not true anymore. Maybe try ether again with throttle open? (You did remove the filter, right?)
50 at WFO throttle at NORMAL cranking speed is low, as you observed. Are you way up high in Colorado some where? You did have the other plug in, correct? (Yes it's obvious, but I have to ask)
Are you sure you checked the valves right?
A lot of things go into actual compression psi. Altitude and cranking speed have an effect as well. Honestly, my experience with ether is that it will start an engine with too low compression, but thanks to EPA screwing with stuff, maybe that's not true anymore. Maybe try ether again with throttle open? (You did remove the filter, right?)
50 at WFO throttle at NORMAL cranking speed is low, as you observed. Are you way up high in Colorado some where? You did have the other plug in, correct? (Yes it's obvious, but I have to ask)
Are you sure you checked the valves right?
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DG Rider
Member: Triple Clutch Club
Lifetime Member
Here...
My 2020 lower plug. Your 2016 should be the same.
It looks like it is fired 2 times per 4 cycle event for the 1st few cycles, and then reverts back to the once per cycle event you'd expect.
This may have actually answered a question I've had for a few years, and that's how does Honda know when to fire the injector and spark without a camshaft position sensor (remember that the crank position sensor would pass 2 times per 4 cycle event). My guess: maybe sensing vacuum pulses in the map sensor, and until it gets that sync, it simply fires at both crank signals? I'd bet the injector does the same thing (or maybe not???)...and I'd bet this is why these things always take a few seconds to start? And are grumpy cold weather starters.
My 2020 lower plug. Your 2016 should be the same.
It looks like it is fired 2 times per 4 cycle event for the 1st few cycles, and then reverts back to the once per cycle event you'd expect.
This may have actually answered a question I've had for a few years, and that's how does Honda know when to fire the injector and spark without a camshaft position sensor (remember that the crank position sensor would pass 2 times per 4 cycle event). My guess: maybe sensing vacuum pulses in the map sensor, and until it gets that sync, it simply fires at both crank signals? I'd bet the injector does the same thing (or maybe not???)...and I'd bet this is why these things always take a few seconds to start? And are grumpy cold weather starters.
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CID
Well-Known Member
Lifetime Member
Supporting Member
My DR650 dual sport motorcycle has a lost spark ignition as do many others - they fire at every TDC. It wouldn't surprise me to learn the SxS do it too. I am curious about the change in frequency though, it obviously gets cut in half. 🤔 Thanks for the video, learning every day.
DG Rider
Member: Triple Clutch Club
Lifetime Member
Lots of older autos use "waste spark" systems. Same coil fires 2 plugs: the plug at tdc compression and the "opposite" cylinder which is at tdc exhaust, where there is no harm in it at all.
Maybe it doesn't fire the injector all until it gets that sync (again, no harm firing the plug every time). I've had my suspicions, but figured it'd be hard to illustrate without a lab scope. The point where the spark cuts in half is probably the point where the ecm finally determines which tdc it needs to use.
@HondaTech, any input?
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M
Ha ha. Yes. I did remove the air filter and sprayed the either right up the tube. Tried with both no throttle and WOT. No difference. I was really surprised that I didn’t get a bark when I sprayed it right into the cylinder itself and didn’t even get a bark. Yes. I did have the other plug installed, plugging the hole, with the wire disconnected from it.
I’m in the western part of NY - farmland - not the city! Can’t understand how there is a spark and fuel and not even a bark.
H
HondaTech
Guest
The dual plug 700 engine is for emissions reason im gonna guess, not sure if they fire both or one as main and other as waste.
I cant locate it, but i want to say their was an article about thr Map sensor being used in place of a camshaft positions sensor to help determine firing, atleast on the atvs.
DG Rider
Member: Triple Clutch Club
Lifetime Member
Both on the same coil and only 2 wires, so they have to fire together. I believe the second plug was done for emissions. Suzuki did the same thing in the king quad around the same time.
Thanks for the confirmation about the map sensor. If you come across that article, I'd love to see it.
M
M
In Comparison with the post of the 700 spark, I believe mine is sparking properly. I posted a YouTube video of mine. this leads me to considering 1. The fuel system or 2. Low compression. As my compression is only 50, I suspect it an issue, though it does run very strong when running — no apparent loss of power.I’d like to best understand how to chase back a fuel issue.
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