Dies on Revving - Suggestions welcome

[williamturner1]

Hi Guys PLEASE HELP SV650 K4 Pointy

My beloved SV was on a long weekend ride and suddenly started spluttering and was unable to rev any more than 2,000rpm ish. I just managed to limp her home.

PLEASE tell me what to investigate
I have a friend with quite a few tools + multimeter, etc
Just need to be pointed in the right direction

YOUTUBE VIDEO of her running
I've made a short vid for you with vacuum gauges attached.
(https://youtu.be/YFvAEKWKsH4). - 1st run is trying to rev her hard, she cuts out. (https://youtu.be/YFvAEKWKsH4)
. - 2nd run is very gently throttle twist and again she cuts. (https://youtu.be/YFvAEKWKsH4)

https://www.youtube.com/upload_thumbnail?v=YFvAEKWKsH4&t=1 (https://youtu.be/YFvAEKWKsH4)


Fuel Pressure
I'll get my hands on a fuel pressure kit and check she's getting 43psi (ish)

Fuel Filter + Crap in Tank
I've had the fuel pump out and cleaned the tank (pretty clean).
With fuel pump out of tank, I cleaned fuel-pump-mesh-filter
and used a hand pump to gently back flow petrol through the pump to clean the fuel-pump-high-pressure-filter, black flowing petrol until it got much cleaner.
Sooooo much fine sediment!!

She's had regular oil + oil filter + spark plug changes. Only Castrol + Suzuki Oil Filter + NGKs.

[Craig380]

Although I can hear the fuel pump whining, the way the engine slowly dies implies that it's not getting enough fuel. Could the pump be shot?

[Bibio]

could be the injector mantles are clogged. i notice that one of the cylinders is a bit lazy on the vacuum on the uptake which would suggest a blockage somewhere.

things to try for free. spark plugs tight? battery terminals tight? water in the front cylinder spark plug?

[nutzboutbikes]

My father and college (yes many years ago!) both told me the first things you need to check on an engine that either wont start or run are the three main things an engine needs.
1, fuel
2, air
3, spark.
If you can eliminate all three your stuffed! lol.

[joe_f59]

Try the Ignition leads to the sparks, if they go bad they arc into the frame and kill the ignition, is this happening more when it's warm?

[williamturner1]

FANTASTIC. Thank you very much for getting back SOO quickly. You guys are the best.
I'll test what you've suggested tonight and post back.

[SV650Racer]

I would replace the fuel pump filter. Clogged filters dont clean so well and a pump that has run with a clogged filter can also be easily damaged. We have changed so many of these on various bikes over the past few years. Common issue.

[williamturner1]

Ok test results in.
She's getting harder and harder to start and barely runs.
When she does run it sounds like the vid above (https://youtu.be/YFvAEKWKsH4)
and there is lots of fumes pumped out the PAIR, leaving a slight blue hue to the air.
.
Any suggestions / further test ideas welcome:
So far:
--- Dealer Mode Error Codes = C00 (with Airbox connected)
--- Battery 12.8v, 14v when idle
.
--- Fuel dumped, replaced with 10ltrs 98octane. Fuel tank cleaned + pump strainer
--- Fuel high-pressure-filter gently back-flowed with petrol (hand pump) to flush it clean
--- Fuel Pressure - Priming = 41psi (spec=43)
--- Fuel Pressure - Cranking = 39-41psi (good idea Craig380 (https://forums.sv650.org/showpost.php?p=3017495&postcount=2))
--- Fuel Flow - 360ml in 9secs so 40ml/sec (spec=minimum 16.8ml/sec)
.
--- Both Injectors swapped (using spares I brought a few months ago) no difference = (
--- Both injectors + mantles lovingly cleaned out in naive hope (good idea Bibio (https://forums.sv650.org/showpost.php?p=3017506&postcount=3))
.
--- Spark Plug - out + grounded to frame = Front+Rear sparking on crank (idea Nutzboutbikes (https://forums.sv650.org/showpost.php?p=3017515&postcount=4))
--- Spark Plug water vents clear, and she hasn't run in rain for weeks before her sudden symptoms came on during the [dry] ride.
.
--- Ignition Coil Resistance - RearCylinder (BelowRegulator) Primary 3.7Ω (spec 2-5Ω)
--- Ignition Coil Resistance - RearCylinder (BelowRegulator) Secondary 27.6kΩ (spec 24-37 kΩ)
. (good idea joe_f59 (https://forums.sv650.org/showpost.php?p=3017526&postcount=5))
--- Ignition Coil Resistance - FrontCylinder (BelowCoolant) Primary 3.6Ω (spec 2-5Ω)
--- Ignition Coil Resistance - FrontCylinder (BelowCoolant) Secondary 28.5kΩ (spec 24-37 kΩ)
However, initial readings for the front secondary was all over the place, the multimeter kept swinging between 50-75 kΩ for as long as I tested
Due to the consant varying of values, I reconnected the ignition coil lead to the spark plug, cranked, then removed and re-tested and it was rock solid on 28.56 kΩ
.
Any test suggestions welcomed

[Sir Trev]

You've measured fuel flow but have you tried leaving the tank filler ajar to see if the vents are blocked? If you have the second key try opening the filler when it starts to bog down.

[williamturner1]

SirTrev. Just tried with fuel-tank-filler open and sadly no difference, and no difference made to in-line fuel pressure gauge. Sits on 39-41psi.

[Bibio]

do you have an alarm fitted?

have you run the bike low on oil?

[williamturner1]

No alarm fitted.
She is v high mileage. It is possible she has run on low oil. What would that do, what signs should I look for?

cylinder compression test?

[Bibio]

49k miles is not high.

if its not run low on oil recently then all should be well.

safety cut out switches?
green ignition connector?
how new are the spark plugs?

the vid you posted sounds like its running on 1 cylinder with the other cutting in and out.

[nutzboutbikes]

49k miles is not high.

if its not run low on oil recently then all should be well.

safety cut out switches?
green ignition connector?
how new are the spark plugs?

the vid you posted sounds like its running on 1 cylinder with the other cutting in and out.



Agree, sounds like its on one cylinder so its probably an electrical problem.

[Corny Gizmo]

Another vote for it running on one cylinder, sounds rough

[williamturner1]

Thank you ALL for replies! You make this forum awesome + very informative.

Okay ... played with the borescope (thank you china) and took some pretty pics (will upload tomoz)
Cranked her but just won't start now.
Spark plugs black and oiley.


Starting to suspect
--1. valve stem seals were old + extra leaky
--2. long motorway ride heated oil and burnt off water + fuel contamination
so "oil" level dropped rappildy on ride home.

--3. She had sat for 5months before resuming regular use
so potential rust on inlet or exhaust valve depending on engine orientation during rest. I'll poke about with borescope more to see if spots of rust have got into cylinder and scratched wall or damaged ring.

Possible cause of dying on ride = excess oil coming from leaky valve seals?
Thinking back to that night, limping her home, she was belching dark clouds from her exhaust.
Yesterday, when running for that video for you guys, she was belching clouds and there was blue haze in air.

And possibly her now not starting at all despite "air, spark, fuel" (+black plugs) = a now oil-flooded engine??
Does this logic make any sense or am I off on a wild goose chase?

Measurements + Checks = info
so ideas welcomed! I'll measure or photo anything ... within reason ;-)

Tomorrow I'll check valve clearances - as haven't been done in 8k mi, info can't hurt
I'll try to get an air compressor and do a leakdown listen and assume I'll be ripping heads off soon.

If heads come off (to replace valve seals):
What is parts list?
2x replacement head gaskets + 8x Valve Seals?

What are leakdown test listening areas? Are these right?
- if can hear air in crankcase vents = piston rings damaged
- if can hear air in coolant passages = cylinder wall damage puncturing water jacket or head gasket leak
- if can hear air in exhaust = exhaust valves
- if can hear air in ???? = inlet valves

[Bibio]

first thing i would do is replace the spark plugs then empty enough oil from the bike to put a can of oil flush in. run the bike till nice and warm revving up to 6000 rpm every 5 min or so then dump the oil, change the filter and put nice fresh oil in.

could be a case of gummed up rings. if it works then yipee if not then its a head strip down for the stem seals. if you do have to change the stem seals at least the engine is going to be nice and clean inside.

[williamturner1]

Quick update - Head gaskets + valve stem oil seals ordered.
I'll take the heads off, replace the valve stem oil seals
I've got some time off in 3wks, so I'll upload photos in 3wks
Thanks all