Author Topic: misfire (Read 5289 times)

philthecoal · « **on:** March 03, 2018, 19:58:12 »

Went for a spin last sunday and after about 20 miles the bike stopped firing on one cylinder( the rear one). Ilimped home for a few miles but the left hand exhaust became red hot so called a mate with a van. I haven't had a look yet so where do I start? Thanks Phil

greywolf · « **Reply #1 on:** March 03, 2018, 20:28:40 »

Check for spark. If no spark, you could have a fouled spark plug, bad HT lead open low current connection to the coil or a bad coil.

If you have spark, sometimes the crimp connector in the wiring loom that feeds the fuel injectors can corrode. You can add an external jumper wire to make sure the yellow/red wire from the ECU to each injector has a complete circuit. I think that's unlikely as a load of unburned fuel has made it to the catalytic converter. You may have a completely clogged catalytic converter now though.

philthecoal · « **Reply #2 on:** March 03, 2018, 20:54:00 »

Thanks Greywolf I'll have a look once the weather warms up a bit.

kwackboy · « **Reply #3 on:** March 03, 2018, 23:30:56 »

Yes, as stated , check for spark on rear cylinder and go from there. Could be something as simple as faulty plug.
Electrics are not the best but an injection issue would be a rare fault

hookie · « **Reply #4 on:** March 04, 2018, 05:48:26 »

If the electrics check out OK, then a blocked catalyst in the silencer looks likely. Remove the silencer and see if the bike runs. I don't think blockages can be cleared, so new/used one will be needed or a pair of nice after market cans.

tallpaul · « **Reply #5 on:** March 04, 2018, 09:27:12 »

Vee K8? Did they have a catalyst? I'm sure I remember from the dim and distant past that some people had coil failure that lead to similar symptoms to the ones described. I could be wrong though...

kwackboy · « **Reply #6 on:** March 04, 2018, 09:40:53 »

If I remember rightly the standard silencers had drain holes at thier lowest point , you would see fuel dripping out which is doubtful.

greywolf · « **Reply #7 on:** March 04, 2018, 12:40:31 »

The fuel is mostly vaporised so running an engine on one cylinder for a long time can kill a cat. It's happened before. Every stock V-Strom can since it was introduced in 2002 has a cat in every can. It got bigger in 2007 on the 650 but they all had them. There is a connector pipe that will put some heat from the working side into the non working side.

philthecoal · « **Reply #8 on:** April 19, 2018, 21:22:25 »

The tank is off and I've tried another plug with no spark. I've removed the plug cap and still no spark. I assume the coils live under the air box . I've pulled the cover off and removed the filter but there are no obvious fixings. How do I remove the air filter housing?

tallpaul · « **Reply #9 on:** April 19, 2018, 22:19:13 »

You have to undo the clamps that secure the throttle bodies to the air box. They are a pig to find and undo...

TLPower · « **Reply #10 on:** April 20, 2018, 05:42:02 »

When you find the coils swap them round to check if the coil is indeed faulty and not the signal back to the ECU or the permanent live in. It's worth unscrewing the HT leads from the coils and cutting off 10mm and screw them back in, they do have a habit of burning through the 1st few mm's.

If you have a multimeter you should be seeing close to battery voltage with the iginition on, on one of the terminals. The negative is switched by the ECU.

philthecoal · « **Reply #11 on:** May 03, 2018, 21:01:08 »

Thanks I've been trying to find someone local to take the job further but no joy

so I'll be taking the air box off this weekend

. Is it only clamped to the carbs?

philthecoal · « **Reply #12 on:** June 01, 2018, 20:18:16 »

Well pulled air box off after loosening the two jubilee clips on the carb bodies and detaching a couple of pipes. I checked the power to the faulty side and it was good so put the coil from the other cylinder in and had a nice fat spark. Tried the coil from rear cylinder in the other side no spark. Ordered a new coil with JT Morgan in Swansea and two days later was in from Germany

I've fitted the new coil and have a good spark. Putting the air box back on was easy just a bit fiddly with the clips for the pipes. Next stop is tank back on and fire her up.

TLPower · « **Reply #13 on:** June 01, 2018, 20:27:58 »

Excellent result.

I'm genuinely chuffed to bits that you managed to sort it.

philthecoal · « **Reply #14 on:** June 06, 2018, 22:04:21 »

Thanks TL. I usually go no further than oil and filters etc but waited 8 weeks for a mechanic who still hasn't shown up so decided to have a look myself

. To be honest this has given me a lot more confidence to have a go. Thanks for the support

philthecoal · « **Reply #15 on:** June 13, 2018, 21:42:05 »

Petrol tank was replaced today and she was fired up. Started no problem on both cylinders and settled to a nice tickover. I've decided to take the radiator off while the fairing is still off as the paint is mostly gone so will have a clean and a cost of paint. Also will probably fit a radiator guard.

kwackboy · « **Reply #16 on:** June 14, 2018, 06:50:11 »

While you are there check all the block connectors behind the rad for corrosion . It's a known issue .

philthecoal · « **Reply #17 on:** June 16, 2018, 20:22:28 »

Quite a fiddle getting all the connectors loose but they all seen OK. They'll have a clean before going back on. The radiator has been painted and is ready to go back on once I order a stainless radiator guard from Beowulf.☺

Fat Rat · « **Reply #18 on:** June 16, 2018, 20:31:25 »

See our old mate at cymarcbikeparts.co.uk for your Rad guard (and any other stainless bling).

UK_Vstrom650 · « **Reply #19 on:** June 16, 2018, 20:32:32 »

It'd be worth putting ACF50 or something similar in those connector blocks, and potentially placing inner tube over them (cable-tied at the radiator end), to keep the water etc out, whilst you've got access to them.