MIsfire / Bogging down

[pedro187]

DEar All i have a 2000 model SV650S , has been rely reliable and recently serviced ( well within the last 6 months ) has been extremly reliable untill last night.

I had been running out of fuel and began to notice the bikes rev counter dropping and then picking back up with the sensation that the bike was goling to run our of fuel. Anyway i pulled in to a fuel station fille dup and merrel went on my way, the issue has appeared to have gone.

This morning all way fine untill i hit the motorway and the issue started again and now has become much worse and feels almost like it only running on one cylinder. i have listed my thoughts as to the problem would like some feed back thought if anyone has any ideas.


Bad plugs
HT leads
Carb has sucked somethign in fromt he bottom of the tank
cracked inlet manifold
lose Battery terminals
Currently there is no back fire so i think the mixture is still good so may not be the inlet manifold , feels more like ignition to me or fuel starvation.

Any thought would be greatly appreciated

[Owenski]

My guess is a good carb clean, if the tank was drained its possible some crud came though but Im no expert, This sounds like a job for one of our "tech crew" one will be along shortly, you may need to post something in a bit to bring the thread to thier attention before it drops off the bottom of the screen.

Welcome to the Org BTW. :)

[ophic]

I'd agree with Owenski - the fact that it coincided with low fuel indicates crap in a carb, or possibly crap in the fuel filter. Of course this doesn't rule out other problems, but it's the first thing I'd check. Does anyone know of an effective carb cleaning fuel additive that might help? Just might be worth a try before taking things apart.

I'm not one of the "tech crew" but hey it's a free bump ;)

[yorkie_chris]

When you say the tacho was dropping, was it dropping below your actual rpm? Like all the way back to zero when you were obviously still moving?

[pedro187]

HI guys

thanks for the reply i might give the carb cleaner a go , go to try and get home first though as am currently 50 miles from home :(

The RPM counter was dropping to 0 while i was doing around 75 - 80 MPH

[yorkie_chris]

Well it's not a carb issue then, it's electrical.

Check your battery leads are tight, main fuse is not corroded etc.

[pedro187]

I will see if i can go out an check it now , fingers crossed guys , thank you so much.

I hope i can get this sorted other wise it will be a recovery truck for the way home me thinks :(

[pedro187]

I have now checked the battery and the + terminal look like the inside of an old kettle , will take it off and clean it up also will apply some WD40 to it , i hope this works

[pedro187]

issue is till there , i think it must be a coil pack as it only seem to happen under load :( maybe i should replace them both ?

[yorkie_chris]

That can't give you the tacho problem

[pedro187]

well i cleaned everything up on the dodgy battery terminal applied a small amont of WD40 , put it all back together went up the road and tit is fine a low revs.

As soon as i came to open it up around mid 3rd gear to 4th gear it started feeling like it was running out of fuel with the rev conter dropping to 0 maybe the battery itself requires replacement ?

[ophic]

bad connection initiated by vibrations?

[pedro187]

what bad connections? where do you think i should look? I hate electrical problems , i can fix pretty much most mechanical problems i hate dam electrics lol

[ophic]

Electrics are a nightmare. Was trying to apply some logic to the fact that it only happened when you opened it up.

Can you reproduce it at a standstill?

I wouldn't expect it to be the battery - they generally don't exhibit on/off behaviour like that. Did you check the main fuse?

[yorkie_chris]

The tacho reads off the front coil, have a look around there. It can also be affected by the +ve feed from battery. Check around the starter relay and main fuse too :)

[pedro187]

I cannot reproduce it at low revs , it only seem to happen when i open it up.

where is the main fuse? is it on the side as per most bikes , i am at work at the moment so it is really difficult to test it but i have to get the bike home 50 miles away :( dont really want to see it on the recovery truck lol

[pedro187]

thank for the suggestions guys , you are heros , this forum is really good and active . when i had my blade i was on a fireblade forum that was useless all they talked about was getting their knee down.

Rather than actual riding and maitanance of motocycles :)

[ophic]

Can you reproduce it at a standstill?

I cannot reproduce it at low revs , it only seem to happen when i open it up.
So what happens if you rev it up in neutral?

[pedro187]

good point i have not reved it up in neautral other than when the bike is stationary and appears to rev through the range without any issue , it only appear to happen under load

[monkey]

Little Chris had a problem in the Alps with his curvy. At about 7-8K revs in (mostly) 6th gear the engine would cut out completely and re-start after slowing a bit with a bang if the throttle was left open. It was some very rev specific vibes causing the side stand to slightly lower and the switch to cut off the ignition.

[pedro187]

am going to order the fronmt cooil pack + HT lead etc from evil bay and see what that does. This is the first twin i have owed have had over 10 bike and all in line fours.

Am a little concerned about getting to everything as my brother has a race spec VFR 400 Honda and constanyl tells me that V's are a pain to work on

[pedro187]

HI all

Striped the bike down over the weekend and it does appear to be realted to the front coil pack , have got one on order and will let everyone know what the outcome is.

Thanks again all

KInd REgards

Peter

[pedro187]

issue all resolved guys , thank to everyone that sent a post did the work over the weekend and she is now pulling hard again :)