Pointy fuel/engine issue

I've done a search for "pointy fuel issue" and found nothing so posting this thread... If you know of a thread with the information I'm after please post a link below.

I've recently had a brand new TPS fitted to my bike because my K3 pointy was dumping wads of fuel through and causing catastrophic bangs at random revs that made me sh!t bricks . As well as spitting flames out the back there was a stench of petrol. We'd fiddled with fuel mix and done a few other bits and bobs before changing the TPS. The guy who fitted the TPS calibrated it and all was well (only occasional pops and bangs in 3rd gear at approx. 4k). I was also told to run Redex for Petrol Injectors which I did and noticed a small drop in the amount of pops and bangs.

New problems... Occasionally below 5k the bike doesn't put fuel through and if it wasn't for moving, the engine would cut out. It also hesitates to accelerate sometimes at low revs before putting lots of fuel in which then causes a big bang next time the bike drops below 4k. I happen to know that my exhaust packing needs replacing as there isn't much in the can and I have no baffle in the end either.... But surely this isn't going to cause the problems I'm getting?!

Power commander or other varieties are not an option as I don't want to be spending more than £100 on it. I have outgrown the bike and am not in to throwing all my money at it to make it the bike I want it to be. I will be selling it once I'm 19 and can afford to insure a 600/750 s/s but want this bike to be running as sweet as I can make it.

Thanks for any help

You thought about giving it an ECU tune? Usually run at about £80-90 and should sort the fueling out for you. It is almost as good as a PCIII & tune on the SV.

Sounds good although permanent. Is there any danger involved with this?

None. It's a common way of tuning them. You see they come with a stock map, this is ok, but every bike will be slightly different so tuning this way will make it the way it should have been from the factory if they were to set each individual bike up properly!

Incidentally have you checked the calibration of the TPS? He may have moved it very slightly when doing everything up. I would check this first before doing anything else as it's free!

Instructions can be found here: http://forums.sv650.org/showthread.p...=ignition+live

Good shout.. will check the calibration. The mechanic is a mate so will get him to check it... "this rounds on me !!".

Am I right in thinking it's perminant? Also, will this increase my fuel consumption?

Thanks guys !!

The tune is permanent but as I said, it is how they should come from the factory but manufacturers do not have the time or finances to set each bike up individually so a compromise is met and a general map is put into the ECU's. It should actually improve performance AND fuel consumption so it's a no brainer really!

Regards

[mikerj]

The symptoms the OP has indicates an underlying problem that will not be cured by a custom remap or power commanders. Problems like this are most always down to a sensor or wiring/connector fault, though I'd also a check on the fuel pump and relay.

This is true, it may be that the TPS was a misdiagnosis and that just calibrating it properly has lessened the initial problem, though I wouldn't immediately point to wiring/sensor/connector fault. It could be any part of the ignition, ecu or fuelling circuits!

Oh yay... sounds like it could be a variety of things. Any suggestions where I should start looking?

Start with the TPS as that has just been fitted. Check it is correctly calibrated then we'll take it from there.

Are you sure there is something up with the bike? Are your cables adjusted properly? What about tick-over, is that set correctly?

V twins can also be a little snatchy/juddery at low revs and if you are new to bike riding it could be a lack of finesse in throttle control. In line 4's are much easier to accelerate smoothly. This won't be helped if your cables (throttle and clutch) aren't adjusted properly.

Most SV's with aftermarket exhausts pop and bang, it's one of the best things my bike does. After a decent run when I drop down to second, accelerate to around 4-4.5k thousand revs from 2-3k revs, back off...Bang!

So I guess I'm saying make sure everything is adjusted properly and then make sure you are applying the throttle smoothly and see how everything is then.

It may also be worth getting someone used to the SV (maybe a forum member) who is local have a little ride of it to see if there are any obvious issues.

Regards