'01 SV650s cutting out when blipping throttle and backfiring

[DarkLord]

Hi,

I recently had the carburetors re-jetted on my '01 SV650s with a Dynajet kit - it runs quite a lot leaner than before with the jetkit and tends to reach a lot in the lower gears, which is not really a bad thing as I get awesome fuel economy out of it and it doesn't surge anymore like it used to.

It was quite a cold morning this morning and I noticed it running quite rough on idle while I was warming it up. I rode about 30ks to work (my usual morning commute) and when I went to blip the throttle as I was slowing right down to take my turnoff it was like the whole engine just kind of cut out - the red oil light went on and the rear wheel locked up although fortunately I know how to get myself out of skids.

It came back on after a few seconds and I kept going at 50kmph and it started backfiring like crazy - I've never heard it backfire that loudly before. By the time I got into my parking space the engine had already stalled before I could turn the key off.

I don't get it - it ran fine yesterday although it has done this in the past, although never to this extent. Last time I had the plugs checked it seemed ok and it was given a thorough check over last week but no luck.

Any thoughts/suggestions as I can't have the rear wheel locking up like this on me again once I try to blip the throttle!!!

Cheers
DarkLord

[CookMySock]

Continuous detonation is the term, I believe. Way too lean. Get it fixed - don't ride it, or at least don't ride it hard.

Hopefully you haven't done any long term harm.

Steve

[AllanB]

I'd say it is too lean - a quick plug check should show this.

There is a thread about blipping too.

[DarkLord]

I had the plugs checked not long after the carbs were re-jetted and they looked ok...

Just had a chat with the mechanic on the phone who did the re-jet and he thinks it might be water in the fuel? Would running some meths through the tank help, perhaps?

[Warr]

I had the plugs checked not long after the carbs were re-jetted and they looked ok...

Just had a chat with the mechanic on the phone who did the re-jet and he thinks it might be water in the fuel? Would running some meths through the tank help, perhaps?
Yes put a cup of meths into a kind-of-fill tank. If you are doing that sort of commute each day, it will be all gone in a couple of days.

I dont know where "Mordhaus" is but the problem could be the carbs icing up. This can be overcome by fitting carb heaters :)

[AllanB]

Throw in a cup of meths (to a full tank) - works wonders with moisture in petrol.

[DarkLord]

Hehe..... yeah I should put my proper location in huh :P I'm in Taupo and we are just getting into winter so it is getting REAL cold. It was freezing this morning!!

Where do you get carb heaters and how much? I may need them considering my location. What I did think was a bit odd was that it only happened towards the end of a 30k ride... I would have thought it'd be warm enough after that?

[slofox]

I'd still check it's not too lean - sounds like it to me from the symptoms...

[DarkLord]

I poured about a quarter of a bottle of meths into the old girl and let it sit for a few hours before commuting home. No issues whatsoever coming home even though it wasn't much warmer than it was this morning - bike purred along beautifully. One thing that it has been doing is when I have been going to blip the throttle, over the last few weeks it has made kind of a clunking noise while doing it. This didn't happen at all on the way home and the revs seemed a lot better on the whole.

Still going to catch up with the mechanic tomorrow morning though and maybe check the plugs, also I might see if they can adjust it to make it run a little richer to adjust to the cold.

Will keep you posted.

[marty]

Hehe..... yeah I should put my proper location in huh :P I'm in Taupo and we are just getting into winter so it is getting REAL cold. It was freezing this morning!!

Where do you get carb heaters and how much? I may need them considering my location. What I did think was a bit odd was that it only happened towards the end of a 30k ride... I would have thought it'd be warm enough after that?

actually, the colder it is the less likely you are to get carb icing. i would be picking it's plug temp rating - when I got it my RS250 had plugs that were too cold in it - they would be fine one day and shit the next.

[DarkLord]

Got it checked over this morning. Heaps of water in the fuel. Apparently putting meths into the tank is not a good idea anymore either, from what I was told.

Oh well, it runs fine now so I guess that's the main thing. Also checked the plugs and it's definitely not running lean.

[Warr]

putting meths into the tank is not a good idea anymore
Is that like a, more service work for the shop, type quote or is there something changed with fuel these days ?

Regardless hope you all sorted now .. keep us updated :)

[DarkLord]

Is that like a, more service work for the shop, type quote or is there something changed with fuel these days ?

Regardless hope you all sorted now .. keep us updated :)

Apparently it's not good to do anymore as newer meths is loaded with a whole lot of crap the carbies etc don't like, unlike older meths.

Yep the old girl runs fine now.... she took me out to work and back yesterday and today with no complaints.

Only thing I don't get is how the water got in there to begin with. Just hope it doesn't happen again... not fun locking up the rear wheel at 100kmph!!

[TimeOut]

Apparently it's not good to do anymore as newer meths is loaded with a whole lot of crap the carbies etc don't like, unlike older meths.

Yep the old girl runs fine now.... she took me out to work and back yesterday and today with no complaints.

Only thing I don't get is how the water got in there to begin with. Just hope it doesn't happen again... not fun locking up the rear wheel at 100kmph!!

I use fuel set to remove water, I throw some in every now and then just as a preventative.

Small amounts of water can come from condensation formed in the tank and can build up over time.
A large amount of water in a short time is more likely to be the fuel source

[DarkLord]

FFS. It happened again this morning. I pull the clutch in, give it a little rev and the whole bike completely stalls and I end up coming to a standstill in the middle of the road. It was at least 20 odd k's into my commute as well so the motor should be warm enough by then. I am wondering if water is leaking in through the fuel cap or something. Straight to the mechanic tomorrow morning to have it checked out. No problems on the way home fortunately besides an odd clunk when I blipped the throttle.

TimeOut - what is fuel set and where do you get it?

[davebullet]

Are you running with an empty tank or near empty tank? Taupo is cold and the moisture in a near empty tank could condense on the inside, (or even icing) then defrost, goes into fuel and presto. Try running with a full tank for a while to minimise condensation from the inside.

Other option is are you parking it in the rain and is the water seeping in through the cap or surround somehow?

[DarkLord]

I usually just run it continually until the fuel light goes on, however that Fuel Set stuff mentioned by TimeOut seems like a good idea too, meths is apparently useless when it comes to removing water. I will have a chat with the mechanic tomorrow morning and see what he thinks. I do wonder if it is condensation or something as it is frickin freezing round here at the moment and these problems have only started recently.

It lives in the garage at night but it is outside during work hours and it was raining last week so that could be an issue as well. However I've ridden it in the rain before and this hasn't happened so I have a feeling it is probably to do with either moisture in the air or dodgy fuel. The last time this happened, I filled up at Gull previously and my most recent fill up was also at Gull. Needless to say I will have to go elsewhere from now on!!

[DarkLord]

Had it checked out this morning - sure enough, the fuel tank was full of water. I reckon probably close to about 100ml in total. The tank was drained, thoroughly cleaned out and airblasted and the bike has run fine ever since. Could well have been that when it was last cleaned out, not all of the water was removed, however it is impossible to tell. Hopefully that is the last of it and it was just a dodgy bit of fuel and not any leakage on the bike itself. Many thanks to Katman for his time this morning (it wasn't him who cleaned it out the last time this happened).

[BigOne]

Had it checked out this morning - sure enough, the fuel tank was full of water. I reckon probably close to about 100ml in total. The tank was drained, thoroughly cleaned out and airblasted and the bike has run fine ever since. Could well have been that when it was last cleaned out, not all of the water was removed, however it is impossible to tell. Hopefully that is the last of it and it was just a dodgy bit of fuel and not any leakage on the bike itself. Many thanks to Katman for his time this morning (it wasn't him who cleaned it out the last time this happened).

I had a SV650K2, and it suffered from carb icing in winter conditions anytime the temperature went below about 4deg, when it was misty or a little foggy as well. Usually on very cold foggy evenings, or mornings. Symptoms were engine cutting out or running on one cylinder briefly, esp. if I changed throttle setting, such as changing down. When really bad, the engine would die, and only re-start after 2-3min.
The water gets in the tank from parking in rain, or washing the bike, around the fuel cap. Look, and you will see there is a drain tube down thru the tank, from the deep dish below the gas cap. It exits to an external tube at the rear under the tank.
If the long drain hose gets kinked or whatever from raising the tank, or removing the tank and not re-installing the hose properly, the hose does not drain the cavity below the gas cap, and it fills with water.
The water runs into the tank when you raise the cap. The answer is simple, route the drain hose carefully from the outlet stub at the tail end of the tank.
Carb heaters were available as an option for some European models, but I could not find any in NZ. It won't be Mr. Gulls fault.
I just lived with the carbs icing sometimes. Water in the fuel certainly won't help. You can get additives for fuel that help prevent icing, (ice from atmospheric conditions, rather than in the fuel) they are added to fuel for some aircraft that run on pump petrol, such as home-builts with car engines. Have a look on pilot or constructors forums, perhaps.
I only ever suffered icing in cold Hi-humidity conditions, as above.
good luck.

I still have some SV650 bling, PM me if you are interested.

[kevie]

[QUOTE=DarkLord;1129785220] I am wondering if water is leaking in through the fuel cap or something. QUOTE]

Are you fueling up at the same service station all the time? the water may be comming from their tanks, common in some of the smaller stations that havent had new tanks installed yet. One of the Marton service stations is notorious for water in the petrol.

[scroter]

have I seen you in the mornings sometimes on a silver sv heading to lake taupo christian camp?

[DarkLord]

Yup that would be me..... I'm usually leaving Taupo about 8am.

I haven't filled up at the Gull station since and the bike has been out in the rain as well as ridden in the rain, yet I have had no problems whatsoever with water in the fuel, despite the fact we have had some atrocious weather recently.

Me thinks I shall stick with BP etc from now on.