'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?