Running lumpy ... where to start?

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Sep 15, 2012 | 06:04 PM

#11

Sprock

Administrator, MVN / ROTM NOV 2012

Joined: Aug 2008

Posts: 11,003

Likes: 3

From: Republic of Boon Island

Bleed each fuel bowl on the carbs Shakey .... easy with a long necked flat head !

See where that gets you - sounds like accumulating moisture to me

You might have got one bad load of petrol with shyte in it thats slowly
accumulating in the bowls

Sep 15, 2012 | 07:01 PM

#12

shakey

Thread Starter

Senior Member

Joined: Feb 2010

Posts: 411

Likes: 0

From: Blackpool, Lancashire, UK

I'll try that Sprock ... get back to you when I've done it

Sep 15, 2012 | 09:42 PM

#13

slowpoke

Senior Member

Joined: Aug 2005

Posts: 787

Likes: 0

From: Denver, Colorado

Quote:

Originally Posted by shakey

Well, that's what it feels like .... Like it's only firing on 3 1/2 cylinders ... Very spluttery .... Any ideas where to start looking?

Plug, coils, carbs???

Can hear a definate mis fire in the engine on tickover that goes right up the rev range ....

Cheers all

Quote:

Originally Posted by shakey

Thanks for the replys all ... but I really don't think it's the fuel, as it's been getting worse over the last 2 or 3 weeks ... I've filled up at various places ..... I use the bike every day, so it's never stood for long ...

No, this seems to be a physical problem ... there's quite a bad mis-fire on one cylinder ... I think I'll start by changing the spark plugs and see if that makes any difference ....

Keep the suggestions coming tho ... I need to find the problem

There's no water in the oil
There's no water in the airbox
Fuel filter is good

Cheers all

I know it's old school, but for a misfire up the rev range, the first thing to check is the ignition timing with a timing light. If the timing mark doesn't move, don't bother messing with the carbs until you fix the timing. Timing problems are usually due to a problem with the Pulser Coil(s). If you have the early H or J model, you have two of them. The later models have one.

And if you pull the spark plugs, lay them out in order, take a close-up picture and post it on here.