Calling all mechanically minded

Got an alarm/imobiliser fitted; not unknown for them to give misfire at high revs

Originally Posted by Blue_SV650S

I bet you a shiny penny it is a spark plug breaking down/problem

Had exactly the same symptom on my SV ... it was a dodgy plug ... sometimes it'd rev fine, other times it just felt like it wasn't pulling as hard as it should ... but not as if it was totally down onto just one ...

If you think about it if one (or more) cylinder is under performing, not only is that not giving much power out, but the others are then fighting it staking the power away from them ...

As you have identified, it could be something more s3xy like the power valve or valves themselves, but I'd go for the plugs first

Not thought about the spark plugs. I do tend to use a jet wash and stick it behind the faring to claen the engine block. I wonder if some water had ingressed into one of the plugs or i have lossened a cap on them with it??

but wouldent it have dreid out by now??

Originally Posted by yorkie_chris

Lambda sensors have the potential to muck up the fuelling, as do the spark plugs as blue says, as does a sticky EXUP valve. (wouldn't expect carbon deposits on such a new machine though)

Basically it's a complicated EFI system, if it's showing no fault code then there's no real way to know whats fubarred, also your dyno run could show up perfectly healthy as you've got an intermittent problem

Have a check over for loose connectors and stuff, that's a distinct possibility too.

yeah this is what is frustrating is got sensors everywhere there is no fault code at all, i suppose the dyno will show up a lamba sensor error in the fuel/air mix read out. As if its running far to lean the power will be down a fair bit??

Originally Posted by John Burt

Got an alarm/imobiliser fitted; not unknown for them to give misfire at high revs

only a factory standard Kawasaki igniton imobiliser.

[yorkie_chris]

Aaaarrrghhh jet washing! Don't do it!

Have you tried taking the HT caps off and letting them dry out? Same with all the electrical system connectors.

Originally Posted by yorkie_chris

Aaaarrrghhh jet washing! Don't do it!

Have you tried taking the HT caps off and letting them dry out? Same with all the electrical system connectors.

yeah i know, but it makes it very shiney!!

not yet i will tonight as well, might explain why it splutters and stalls on first start up after a wash, and i do wash it a lot.

Originally Posted by neio79

Not thought about the spark plugs. I do tend to use a jet wash and stick it behind the faring to claen the engine block. I wonder if some water had ingressed into one of the plugs or i have lossened a cap on them with it??

but wouldent it have dreid out by now??

Mine was an actually faulty plug ... i.e. the plug itself must have started breaking down (nothing to do with water in the plug cap etc).

Do you have some old 'known' plugs you could pop in??

As I said, the symptoms are identical ... so it has to be worth a try before getting heavy/expensive ... a new set of plugs would do it no harm anyway will it

Or you might have indeed just loosened a cap

i dont have any good plugs but after checking all other easy posibles i will change them just to rule them out.

Originally Posted by Blue_SV650S

Mine was an actually faulty plug ... i.e. the plug itself must have started breaking down (nothing to do with water in the plug cap etc).

was it easy to see that the plug was knackered?

Originally Posted by neio79

was it easy to see that the plug was knackered?

No visible signs no. It wasn't completely shot remember, just intermittently breaking down (I assume internally). The bike would start, idle and run fine, just sometimes, it lacked 'spunk'!! ... changed the plug (had to be worth a try) and hey-presto

well after checking basics like connectors are dry inside and all tubes ect are unblocked and where they should be, new plugs will be my next port of call.

Although it did have this problem before and after the first 600 mile service where they are changed arent they??

[SoulKiss]

Originally Posted by neio79

well after checking basics like connectors are dry inside and all tubes ect are unblocked and where they should be, new plugs will be my next port of call.

Although it did have this problem before and after the first 600 mile service where they are changed arent they??

nope not changed until 8k I believe and then ecery 8k thereafter - doesnt have an interval based on time.

Thats for my Z750 anyways - woiuld have thought you would be about the same