Sv650 coil voltage problems

Trying to see if the rear coil was sparking yesterday, it wasn’tLwhen the ignitions on there’s 12v onthe black/yellow and orange/white wires on the front coil. And only 6 – 7v on the white and orange/whitewires that power the rear coil, having a look it seems they only have a shortrun from the ecu (icu) which I’ve mounted on the rear subframe.

I’ve given them aclean up using contact cleaner but that makes no difference. They’ve all got continuityfrom the ecu plug end to the coils but somehow the rear white one’s droppingvoltage…

Is there any sort ofsensor I could have not plugged in?

Should I strip the cover of the loom?

Could the wire be split somewhere and still show contiuity?

There’s a 3 pin plug next to the rear stand switch wiringthat’s not got anything plugged in atm…

To explain the history of the bike

This is my trackbike, I’ve taken the engine out and had theframe coated and am in the process of getting it ready for a trip to spain atthe end of the month.


So far I’ve:

Taken the clutch switch off and spliced the two wirestogether.

Taken the stand switch off and spliced the two wirestogether.

Taken from the front loom the wires to connect up anaftermarket kill switch.

On the dash that I’ve made I’ve got oil light, neutral lightand tacho, all of these wires have been taken from the front loom.

The bike was running fine before I took it apart last year withall these things apart from taking the kill switch wiring and the oil lightwiring I haven’t changed anything, could there be something I’ve missedconnecting back up?

[Bibio]

year of bike might help

[Sid Squid]

Seeing as the coil negative goes through the ECU, you can't necessarily ascertain voltage via the pair on the coil, test between the coil positive and a suitable negative - ideally battery neg - to get a true picture of coil supply voltage/

Yeah my bad! It's a 1999 sx model...

Great I'll try the voltage with a proper earth, venturing down to the garage shortly so I'll let you know how I get on.

Attached is a diagram of the said circuit, its all kinda chinese too me but a good friend mentioned earlier trying the resistance over the coils which I'll give a go...

[yorkie_chris]

when not running you got zero current through coil so should be 12v as no power loss to pull it down.

sounds like faulty coil at first guess.


fyi, orange white is main live doing all supply of everything... white(r) nd black/yeller(f) are the coil -ve wires .... ecu allows current to flow to charge the coil then cuts this current off when the little jap inside shouts "fire"

She's running!

Thanks for the info chaps, after trying the battery negative as earth both were showing 12.7v so all good, both coils were at the top of the resistance range 5.7ohms each. Pulled the rear lead off which sparked, put the tank on and she fired but only on one, with aloada smoke! the rear cylinder was hot so front was down.. Doh

Unfortunately I'd already chucked some antifreeze in, so that had to come out along with the rad so I could get the front plug out which turned out to be fine...

It was weird cos I was getting what felt like back pressure from the cam cover, having changed the cams over for injected ones when the engine was out, Hoping to hell I hadn't timed it wrong!

Low and behold, I'd forgotten to attach the front carb to the cylinder properly and all the pressure was blowing out down the engine hense the air over the cam cover. With that attached she runs a beaut.

hopefully have a chance to warm her up on the weekend to keep the neighbors happy! Plus the bloody exhaust wrap smokes to high heaven! I'll post up tomoro some pics of it...

See attached pictures of bike! Ignore the messy garage!

[Sid Squid]

Looks good! Messy garages are good it means stuff is happening, check out all the tidy garages - that's where tools go to die from disuse.