Dealing with spark plugs

[Junkie]

changing the oil isn't going to make it start

 

[ST Guy]

No, I can hear the starter turning. Wouldn't happen with kill switch on.

Depends upon the bike. Some bikes will crank over with the kill switch activated. Don't know about the bike in question.

And interesting that some SV's have dual plug heads. 'Did not know that.

 

[afm199]

Ok, it's an SV. It has plugs and the coils are mounted on the frame. It's 12 frkkn years old if I read right. The plug wires screw onto threaded posts in the coil and in the plug cap ( the snap on cap that snaps on the plug.)

The SV is notorious for loosening at the coil and mostly at the plug. The solution can be as simple as turning the plug cable one more turn into the coil, and turning the plug cap one more turn onto the plug cable. Or removing the cable from the coil and cutting off a 1/4" and threading it back on, and doing the same at the plug. It's harder at the plug because of the right angle.

That's not always a cure but often is. The low voltage wires often fall off the coils as well.

The fact that it was running says that it should run. Deconstruct the process. You removed the plug caps from the plugs and replaced the plugs. What changes? The biggest variable is that the plug caps got put back on wrong ( not on an SV, they are front and back not side by side) or, as Robert mentioned, you simply did not push the plug cap back on hard enough. Do that FIRST. Push the plug cap down HARD on the plug. It will probably go click click click. You also may have tugged the plug cable out of the coil, that happens as well. The week point on the SV is also that the front plug cable is riding in free air and wobbles every second you ride the bike, as it is horizontal not vertical. It loosens the connection in the plug cap, as I mentioned in the previous paragraph. So check these first. The oil change won't do shit. You changed something when you changed the plugs. Find out what. Also, if the plug cap does not go click click click but simply slides on, the plug cap is shot. Get a new one. Let me know, I have some Gen 2 wires and coils sitting around gathering dust for ten years.

If that doesn't do it, then it's time to start using a meter. The SV regulators are always weak, the Gen 2 better than Gen one but both are pieces of shit.

 

[Lukich]

My friend has an 05 SV650. Would sometimes just not start. Crank but no fire. After chasing our tails we looked at the "green plug" under the tank. From the outside it looked fine. Unplugged it and found the connectors burned and melted. Hard wired the connections and no problems since.

Mad

I guess I'm checking for that, too. I've never heard about it until now, but apparently it's very common. You live, you learn. Thanks!

 

[afm199]

Depends upon the bike. Some bikes will crank over with the kill switch activated. Don't know about the bike in question.

And interesting that some SV's have dual plug heads. 'Did not know that.

POS heads make less HP and torque with two plugs than one. Race bikes we stick on the gen one heads, lol.

 

[Junkie]

POS heads make less HP and torque with two plugs than one. Race bikes we stick on the gen one heads, lol.

I didn't realize that there were any differences between gen1 and gen2 heads (before dual plug)

 

[295566]

I didn't realize that there were any differences between gen1 and gen2 heads (before dual plug)

Gen 2 had different cams. Common swap is to put the gen 2 intake cams on gen 1 head, and swap the gen 1 intake cam on the exhaust side.

Might be other differences but that's what I know!

 

[dmfdmf]

Recently, I experienced a problem with my bike. As I was riding, I felt it started losing power in the lower range, and soon after it just died and refused to start back up. I had it towed home and when I tried to start it up a couple of days later, the bike started up without any issues.

As someone else mentioned, [air/fuel, spark, compression] is the key to a no-start situation. The symptoms are a bit vague but I'm guessing an electrical issue cutting off the spark or fuel. If the fuel pump was bad or some kind of clogged filter, line or injector the higher range usually loses power not lower range. With only 25K miles (on a bulletproof SV motor) I'd assume the compression is fine until you rule everything else out.

Before taking it for test runs to see if dies again, I decided to do a couple of pieces of maintenance that were due (bike's at around 25000 miles). One of them is spark plugs. I bought new spark plugs and installed them as per the shop manual/youtube videos - I have magnetic spark plug socket to guide it in properly and once in place, I torqued them to spec with a torque wrench.

You did the plug swap fine, should not be an issue. I always measured the gap on new plugs and they have always been to spec out of the box. The only caveat is banging the electrode gap closed on the way into its hole but sounds like you were careful but won't hurt to pull it, check the gap and for spark.

However, when I tried to start the bike, it just didn't. The starter is turning, but plugs don't seem to be firing. Did I miss some standard step in installing them? The only thing I can think of is that I didn't do anything to the gap between the electrodes on the plug, assuming it to be correct since the plug came straight from the box. Was this an incorrect assumption? What else can it be in your experience?

I'd skip the oil change for now and focus on getting it running. You want the oil warmed up to change it anyway and by doing unnecessary service you might confound the problem by knocking a wire loose or something thus making troubleshooting that much harder.

Others have given good advice on how to proceed so my 2c would be to make sure to keep your battery charged up on a charger if you are going to be doing a lot of cranking without running. If it is an electrical problem then suspect number one is always a bad battery, so test that first. If it is anywhere near 4-5 years old I'd just replace it and check the ground wire to the motor as they sometimes corrode and cause weird issues.

 

[Junkie]

Gen 2 had different cams. Common swap is to put the gen 2 intake cams on gen 1 head, and swap the gen 1 intake cam on the exhaust side.

Might be other differences but that's what I know!

Yes, but there's a big difference between a cam swap (which I did on mine) and a head swap

 

[afm199]

I didn't realize that there were any differences between gen1 and gen2 heads (before dual plug)

Not really. Slightly different intake ports due to the FI, basically the same head. The truth is that the Gen one motor is superior in every way. The Gen one crank is much stronger, the Gen one rods are much stronger, and the clutch setup is easier to work on. Racers who build motors always use Gen one cranks and rods if available. However, if you are running flatties get the gen one heads.

If you want to have some fun, pull your barrels, send them out, and have them cut down 10 thou, then run a two layer head gasket. Or just use a one layer head gasket. Take the stock head gasket and peel out one of the stressed steel sides. But in order to do that, you have to pull the pistons and cut 2-3 thousandth of an inch of the top. Easy to do with emery paper and a flat surface. Good for several HP, don't even have to degree the cams.

 

[Junkie]

if I still had a 650 I'd consider it

on the 1000 I'd still like to do some things to the engine to go along with what I've done to the bike as a whole (suspension/brakes/wheels/upright bars/exhaust) but it's a whole different engine

 

[afm199]

if I still had a 650 I'd consider it

on the 1000 I'd still like to do some things to the engine to go along with what I've done to the bike as a whole (suspension/brakes/wheels/upright bars/exhaust) but it's a whole different engine

Just cut 20 pounds off that flywheel!

 

[Lukich]

Good day. Here are my findings so far:

I recharged the battery and tested it with voltmeter - I got about 12.9V in a regular state with voltage dropping to 10V when starting up, which seems pretty good.

I swapped the spark plugs back to the old set and used one of the new ones for a spark test - it gave me a pretty consistent blue spark. Manual says to look for a fat spark, not sure if it was fat or not since I don't have anything to compare it to.

I can definitely smell gas when I'm cranking it, so it seems like EFI is working.

I installed a new air filter

If I see a blue spark on startup, is it safe to assume that coils are in good state?

Thank you!
Luka

 

[295566]

"dropping to 10V when starting up" does that mean when cranking over? Presumably the bike is still not running? Does it cough at all?

 

[Lukich]

"dropping to 10V when starting up" does that mean when cranking over? Presumably the bike is still not running? Does it cough at all?

Yes, when cranking over. The bike is not starting. It's not catching at all.

 

[Biga]

Have you checked the clutch lever safety switch and the one down the kick stand?

 

[295566]

Have you checked the clutch lever safety switch and the one down the kick stand?

Presumably if those were faulty it wouldn't be sparking.

 

[Biga]

Presumably if those were faulty it wouldn't be sparking.

That's is correct Sir

 

[295566]

10V is a little low, but should likely be enough, especially if you're seeing blue spark at both cylinders.

Just to confirm: did you check for spark on both plugs, or just one? If you have spark on both cylinders, we'll assume you still have compression (less likely that something catastrophic happened to cause complete compression loss), and that leaves us with fuel. Check for kinked fuel lines that would cause the engine to not get fuel.

 

[Maddevill]

I think 10 V means you have a bed cell in the battery.

Mad