Running on 3 cylinders

**Hiflyer** · 26th January 2011, 11:41

What would be the most common reason(s) that a 4cyl bike would be running on 3cyls after being left for 7 or 8 weeks.

I'm hoping to fix it myself, hence asking for the most common reasons...

I'm thinking, check the plugs and clean the airfilter first, other than that, maybe some blockage somehwre in the fuel line or carb? Sediment settling etc

Guess I shoulda let it idle for a while every few days when I couldn;t ride it ay

!

**slofox** · 26th January 2011, 11:43

I'd check the plugs first.

**Hiflyer** · 26th January 2011, 11:46

Yea will do that tonight. I hope it's something simple like that...

**bogan** · 26th January 2011, 11:51

how long you try it for? mine was missing heavily on one after xmas, bit of a ride (round the block ish) and it came right.

**onearmedbandit** · 26th January 2011, 11:52

Do you know what cylinder isn't running? If not run the bike for 2 minutes, turn it off and with a wet finger briefly touch the headers.

Like slofox says check the plug on that cylinder. Take it out of the head if the lead is firmly on/doesn't look damaged and check it for a spark. Someone who knows better than me can suggest a place to rest the plug against, sometimes the cylinder head isn't suitable.

Are they individual carbs per cylinder? Or shared? If it's shared than it's unlikely to be carb related.

**White trash** · 26th January 2011, 12:01

If you work it out, let me know. My fucken MVX is running on three too. Dunno what the hell to do about it..........

**avgas** · 26th January 2011, 12:15

Originally Posted by White trash

If you work it out, let me know. My fucken MVX is running on three too. Dunno what the hell to do about it..........

Cut one off. Its clear 1 and half times a bike. You shouldn't have that kind of power on the road.

**Hiflyer** · 26th January 2011, 12:16

Originally Posted by bogan

how long you try it for? mine was missing heavily on one after xmas, bit of a ride (round the block ish) and it came right.

yep took it a few times round the block, didn't wanna try too much riding on 3 cyls

Originally Posted by onearmedbandit

Do you know what cylinder isn't running? If not run the bike for 2 minutes, turn it off and with a wet finger briefly touch the headers.

Like slofox says check the plug on that cylinder. Take it out of the head if the lead is firmly on/doesn't look damaged and check it for a spark. Someone who knows better than me can suggest a place to rest the plug against, sometimes the cylinder head isn't suitable.

Are they individual carbs per cylinder? Or shared? If it's shared than it's unlikely to be carb related.

aha! What an excellent way to tell which one isn't working! haha

I'll try that tonight, and yea shared so hope it's just the plugs

**ducatilover** · 26th January 2011, 12:51

Drain the carbs and throw fresh petrol in for a start, check the fuel filter too.

**Hiflyer** · 26th January 2011, 13:00

Originally Posted by ducatilover

Drain the carbs and throw fresh petrol in for a start, check the fuel filter too.

I wish Chaos Rider was here so he could endow his wisdom upon this thread.

**ducatilover** · 26th January 2011, 13:10

Originally Posted by Hiflyer

I wish Chaos Rider was here so he could endow his wisdom upon this thread.

Take the flywheel off and sniff your exhaust?

**Hiflyer** · 26th January 2011, 14:04

Originally Posted by ducatilover

Take the flywheel off and sniff your exhaust?

na I'll just remove the headlight and a couple of other things and it'll save so much weight, the 3 cylinder engine will still feel like a 4cyl due to reduced weight.