running issue on my SV650

[Finesse]

thought I'd post here for your guys' wise input .. esp since some of you have SVs. calling on @Jono and... I forget who else...

anyway, I've got a small problem. when the bike is hot (over 180F) and I pull the clutch in from 4k+ rpm, the bike cuts out at above normal idle speed and will not restart. I only lose the motor, no electronics. it doesn't stumble, it just dies quick. usually at 2k rpms. if I baby it and let the rpms down slowly I dont have an issue and it will idle normally. after it dies it does not want to restart until at a cooler temperature, around 170 it seems fine. it ONLY happens when hot, and ONLY happens when I let the rpms fall (I dont think it has anything to do with the clutch other than it's the easiest way to let the rpms fall fast).

it's a 2003 fuel injected with a yosh slip on and no pc but ecu flashed for 10% more fuel at mid and top range. I just did a throttle body sync yesterday. 14,6xx miles. fresh oil fresh coolant stock air filter. below is a video of what happens..

Link to original page on YouTube.

here are some theories:

-vacuum leak
-vapor locking/gas cap breather clogged
-tight valve (gonna do the valve check saturday but I doubt its out of spec)
-bad spark plugs
-bad ignition coils
-coil arcing to cylinder head
-crankshaft position sensor
-throttle position sensor
-clutch/sidestand safety switch

it's worth noting that I've bypassed the clutch safety switch by permanently securing the pin in the 'clutch in' position and zip tied it next to my dirtbike MSR clutch perch/lever but I dont think it is this issue since it only happens when hot..

other theories that I dont hold much stock in include faulty ignition timing, bad fuel map, bad battery and/or charging system, bad fuel pump, clogged injectors, faulty thermostat, overheating, secondary throttle valve

what do you guys think? I will figure this out for sure, bike shall not outsmart me... I don't have any tools at my house today to check and I dont go back to the shop til tomorrow so I got some time to think about it before I start fiddling

[cuong-nutz]

My guess it sounds fuel/fuel pump related. I had a similar experience with the zzr600 where the fuel pump would crap out which ended up being a solder to the pump had broke off from the vibrations.

Do you have a inline fuel filter? Can you hear your pump prime?

[Finesse]

the pump primes every time it should, it's loud but it's always been loud and especially loud the lower the fuel level goes. somehow I dont think its a fuel issue because the temperature of the motor shouldn't affect the flow of fuel from the pump. I can check the fuel output but since it revs up just fine and runs normal when cooler.. hm. I'm off to get some spark plugs and see what I can see...

[csmith12]

My money is on fuel pump and/or screen. Easy fix, but kinda common when the engine is pretty warm.

[choneofakind]

180 reliably and repeatably or just about 180? If it's reliable and repeatable, the temp sensor could be faulty, telling the ECU that the engine is one temp, adjusting the fuel to an amount that the engine doesn't run on at the temp it actually is.

Is there a way to check error codes or anything? I'm not super familiar with factory EFI systems on bikes.

Also, what's the timeline look like with the ECU mapping relative to the problems you're experiencing?

[Motofool]

Originally Posted by Finesse

thought I'd post here for your guys' wise input .. esp since some of you have SVs.......

You have a real challenge to troubleshoot !!!

Do you have a way to temporarily increase the idle rpm some, in order to by-pass the problem and make your street riding less dangerous?

When you suddenly close the throttle, only air goes in, which lowers the minimum temperature to sustain internal combustion.
If fuel injection is coming back a little too late (or it supplies insufficient or excessive fuel) when the crankshaft reaches normal idle rpm's, the combustion stops.

Why not re-starting right away?
Try starting hot with the throttle open some.

Your spark plugs can tell you how the overall air-fuel mix is.

If the oil pressure is insufficient, the pistons may be sliding too tight into the cylinders to start.

[Finesse]

Originally Posted by choneofakind

180 reliably and repeatably or just about 180? If it's reliable and repeatable, the temp sensor could be faulty, telling the ECU that the engine is one temp, adjusting the fuel to an amount that the engine doesn't run on at the temp it actually is.

Is there a way to check error codes or anything? I'm not super familiar with factory EFI systems on bikes.

Also, what's the timeline look like with the ECU mapping relative to the problems you're experiencing?

Seemed to be anything above 180. Didn't happen below 180. There are no lights or error codes on my dash. But there is a way to check them, you just have to ground a wire and it will flash the code, if there is one. But there isn't, so...

Originally Posted by Motofool

Do you have a way to temporarily increase the idle rpm some, in order to by-pass the problem and make your street riding less dangerous?

Even increasing the idle won't do it, it was dying above 2000 rpms and I'm not jacking the idle up to 3k. But yes the idle is adjustable.

Originally Posted by Motofool

Why not re-starting right away?
Try starting hot with the throttle open some.

It will rev right up but will still die and not idle if you let the rpms fall.

Originally Posted by Motofool

Your spark plugs can tell you how the overall air-fuel mix is.

If the oil pressure is insufficient, the pistons may be sliding too tight into the cylinders to start.
__________________________________________________

Front spark plug was black, rear was black and a little bit wet. Changed the oil less than 1,000 miles ago with Motul 7100 10w40 full synthetic and have no reason to believe there is anything wrong with the oil pressure.



I cleaned both spark plugs, put them back in, and could not get the bike to die again. The idle is a little bit low, around 1100 instead of the normal 1250 but doing what I was doing before which caused the bike to die, does not cause it to die anymore.

Will throw in brand new plugs and check back in... Could just be that simple. The air filter is a little bit dirty...

[alex.s]

it's a suzuki so i think you need to put on that fancy full yoshi and do trumpets instead of airbox. powercommander yo. also put beads in your tire. also paint it a different color. and do some more wheelies.

[dcj13]

-vacuum leak? I'd guess not.
-vapor locking/gas cap breather clogged? Naah.
-tight valve (gonna do the valve check Saturday but I doubt its out of spec)? Naah.
-bad spark plugs? Naah
-bad ignition coils. Not if there's more than one.
-coil arcing to cylinder head? Wouldn't think so.
-crankshaft position sensor? Maybe.
-throttle position sensor? Maybe.
-clutch/sidestand safety switch? Naah.

Seems heat-related. If it won't run at all, then it's not likely something you have two of.

I like crankshaft position sensor (hall-effect?), TPS, temperature sensor. Also fuel pump relay (if the SV has one).

Use a hot air gun to heat suspects if the bike's cold. Use compressed air to cool suspected parts if it's hot and won't run.

[choneofakind]

Yeah, if it's only heat related as in problem happens at one temp vs doesn't happen at another and not heat related as in does this sorta at one temp and worse at another temp, I'm standing by my thoughts that it's electrical and not mechanical.

No idea why you don't have codes, but start heating/cooling parts as oldguyDave has mentioned and see what happens.

You work at a shop, pick your coworkers brains.

[Finesse]

Being heat related and being something going wrong with two of something are definitely not mutually exclusive.

I can't get it to die after simply cleaning the spark plugs. I'll replace with new NGK tomorrow and see how it holds up.

opinions like buttholes....... everyone has one. lmao

[Finesse]

I think I figured out my problem. the motor ants have died on my rear plug. does anyone know where I can get new motor ants???

[kdogg2077]

Well at least it turned out to be a cheap fix.

That engine sounds good to me!

[Finesse]

Yeah I'm sure it's not a problem with the actual motor. Sounds healthy.

I'll keep an eye out. It could be the air filter being dirty is causing the bike to run a little rich and foul the plugs after a long time of riding. this would account for my 5-mile commutes not being an issue, and only having trouble after riding around for a long time. idk though.I'll keep you posted...

[jkv45]

I think it's running too rich, there may be fuel-related issues, and the injectors may be slightly dirty. It doesn't need the 10% additional fuel it's getting.

How old is the gas? Ethanol-free 87? Has the tank been sitting at a low level?

If the gas could be old or the level has been low, the first thing I would do is drain the tank, get some fresh gas (87 w/o ethanol), and add 1 oz per gal of Techron Concentrate.

[Finesse]

filled up to the top yesterday with 87.

[Finesse]

it's really hard if not impossible to find gas without ethanol here

[MrAtom]

Originally Posted by Finesse

I think I figured out my problem. the motor ants have died on my rear plug. does anyone know where I can get new motor ants???

One time I was hanging out with my brother and he had an ant crawling on his arm, and he was just watching it. I told him it was gonna eventually bite him and he looks at me, says "No it won't!" and looks down to find an ant burrowing into his flesh. I'm sure the ant is still living happily inside of him several years later. I could extract it for you and send it your way if you'd like.

True story, btw.

[jkv45]

Originally Posted by Finesse

filled up to the top yesterday with 87.

The issue is what was in the tank before filling. If there was significant condensation, or the gas was bad, adding new gas will not fix the problem.

That's why I suggested completely draining the tank, then filling with 87. Adding a strong fuel system cleaner like Techron Concentrate once a season is a good idea with a F.I. engine. 1oz per gal is usually sufficient.

Is there ethanol-free available in any grade in your area? I will only move up in octane to get away from ethanol.

[choneofakind]

So was it doing this plug fouling trick before the ECU was reflashed?

[Finesse]

Originally Posted by jkv45

The issue is what was in the tank before filling. If there was significant condensation, or the gas was bad, adding new gas will not fix the problem.

That's why I suggested completely draining the tank, then filling with 87. Adding a strong fuel system cleaner like Techron Concentrate once a season is a good idea with a F.I. engine. 1oz per gal is usually sufficient.

Is there ethanol-free available in any grade in your area? I will only move up in octane to get away from ethanol.

I always use 87 and always fill to the top, I fill the tank at least once a week, I do probably 100-170 miles per week.

Originally Posted by choneofakind

So was it doing this plug fouling trick before the ECU was reflashed?

dunno.


today I checked the valves and my right rear intake valve was tight by 1 thousandth of an inch so I adjusted it to back within spec. no big deal, only 3 hours, I love shim under bucket. -_- bike runs flawless now though. new spark plugs and new cam cover gaskets/cam cover bolt o-rings. and the motor sounds so nice and quiet and healthy. cams look great.

but I will go on another long ride this weekend and see how it holds up..

after I cleaned/replaced the spark plugs, before the valve adjust, the idle was a little weird when hot, it would rev fine and drop down to 1,000 rpm, and barely creep up to maybe 1100-1200. normally it was idling steady at 1300. after I adjusted the valve, the idle stopped hanging after revving and it's closer to 1400 now (I bumped it up yesterday but it was still only around 1200)

anyway I don't think it was just bad gas, I shook the **** out of the bike which usually mixes it up good enough to see if that's the problem, and it wouldn't make sense that it would only act up from bad gas/water when the bike was hot and would be fine for awhile and then all of a sudden die when the rpms fell.

I think its a combination of the tight intake valve, ******/old spark plugs, a slightly dirty air filter, and more fuel at higher rev ranges. or it could be none of those things, who knows.

I'll keep ya posted and we'll see how it does on a longer ride.

[jkv45]

I'd still add 1oz per gal of a strong fuel system cleaner like Techron Concentrate to a full tank.

Even minor deposits on the injectors can give you odd intermittent problems.

[Jono]

Sorry for not being around to help. Sounds like you got it figured out? I am just as perplexed as you but I would have started with spark as well.

[Finesse]

I'm taking it on a long-ish ride tomorrow, we'll see how it does. My commute is only 5 miles so it's not really enough time to test things out even though the bike does get up to normal hot running temp. Ill keep ya posted. seems good thus far

[Finesse]

soooo... after the valve adjustment it got better... threw a k&n filter on it.. runs like 95% but occasionally, maybe twice in each ride depending on the length, it'll drop rpms at idle to around 1000 and stumble a little, it died once today but i was trying to kill it by revving it and then pulling in the clutch. restarted fine with some throttle after that and was good for the rest of my ride... I put 93 gas in it today just on the off chance it'll make a difference, I normally use 87. dont think it has anything to do with vapor locking or vacuum leaks. I'm kinda stumped and it's not enough of a noticeable problem for me to be able to investigate a whole lot.

[choneofakind]

So... it wasn't the spark plugs?

I'd offer my asshole, errr, my opinion, but you seem to have your mind made up already.

[jkv45]

Add any Techron yet?

93 octane won't help the SV, unless you need to use it to get away from ethanol. The SV makes the most power and gets the best mileage on 87 without ethanol.

Can you back-down (lean) the mixture?

[Finesse]

I had checked the vents from the tank but I hadn't checked the vent on the gas cap actually

I rode another sv today that did the exact same thing as my bike but had a worse case of it and there was all kinds of **** in his gas cap vent. blew it out and his bike was fine. blew mine out and my bike seemed great on the way home.

I will be so happy if it's this simple of a fix!

[Finesse]

okay. so I seemed to have fixed it. and then yesterday it was dropping idle and died on me a couple of times with not too much fuss to restart it but I kept the idle up at stops so it wouldn't die again. Blew out the gas cap AGAIN and checked all the vents. all good. today it sat in the pissing rain for hours after i rode it to work (in said pissing rain) and just as I was getting back to my house from my 5 mile commute, where it normally displays the coolant temp, it says CHEC but there is no FI light and I checked for codes, and there are none.

what the F**K. I'm at a loss. some people on svrider said it's a random issue, my boss thinks it's water problems but I checked the connector to the ECM and it seems fine. the service manual just says check the ignition fuse and wires from the speedometer gauges to the ECM. the only other thing is that one of the letters that normally displays a number of the clock on the gauges wasn't going off even with the bike turned off. like the LCD panel was off but you could still see that one side of the letter.

I'm going ****ing nuts over here.

[Finesse]

replaced the ignition fuse and it was fine.

sviz you're killing me over here.....

[MrAtom]

Originally Posted by choneofakind

I'd offer my asshole...

sign me up!

Originally Posted by choneofakind

...errr, my opinion, but you seem to have your mind made up already.

...damnit...