Honda magna only running on two cyl?

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Any ideas what could be the cause?

It's getting a good spark on all 4 cylinders.

Has really good compression.

If i remove both the front HT leads it makes no difference(still runs like a bag of sh!t)

I removed the plugs and there is definitely fuel getting to them.

I swapped the rear coils with the front (aswell as plugs) and still no difference.

If i remove the plug leads from the rear 2 cylinders it still starts running on the front two but soon as you get on the throttle it dies.
The exhausts on the front 2 cylinders dont get hot either.

So now i have the carbs off (thinking it must be a fueling issue).

Any other things to try?

This all started after i washed the bike.

Thanks
Dave
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DRZ-400sm

[stinkwheel]

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Yup,i usually do that anyway.

It's not much help to the current problem though as it's getting a spark


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DRZ-400sm

[stinkwheel]

I was starting off simple. You washed it, it stopped working immediately after => the washing has something to do with it => some part of the bike was either dislodged or didn't like getting wet => electrical problem until proven otherwise.

I have also worked on bikes for long enough to know that 90% of carburettion problems are electrical and washing your bike isn't going to have done anything to the carbs. People tend to go for the carbs because it is easy to understand and fix them, electrics are more difficult but are invariably at the root of the problem.

It is sparking but that doesn't mean it is necessarily sparking well or at the correct time.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

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[stinkwheel]

I was thinking more along the lines of a duff connection somewhere, most likely in a connector block.

I'd be checking all the wiring between the CDI and the coils with particular attention to any connector blocks.

I'd check the power supply to each coil.

I'd give the sidestand cutout a spray just for good measure.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

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[Robby]

Firing on two sounds like a prime electrical fault, doubly so in a V-4.

You will have a different pickup coil serving those two cylinders, although I doubt that's the problem. Does your bike have a thing to stop it going over 112mph (Jap market speed restriction)? If it does, they work by cutting ignition to two cylinders when the bike is doing 112mph or more.

I'm with Stinkwheel. Carb problems are nearly always electrical, particularly seeing as you haven't been fiddling with them either. Water, Honda electrics, that's asking for trouble.

[loply]

Recent experience with my Mille has confirmed how totally unbelievable electrical problems can be.

Since it will only take 20 minutes to do, I second the idea of spraying all of your electrical connectors with WD40 from point blank range.

Maybe give the spade connectors a wiggle on the coils and stuff too. Also, check the engine earths? I dunno how they are on that bike.

Never rule out daft electrical problems!
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Yamaha SZR660 Caution to the wind, the throttle pinned!

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Finally figured it out

If i knew this bike had two cdi units i would have figured it out a lot quicker

So yeah it has two,and ones flecked.



Just so you know stinkwheel,i wasn't doubting your knowledge of bikes i was just trying to understand how you were coming to the conclusions you did under the circumstances.
Either way you were right

Thanks
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DRZ-400sm