Bike poorly

[Phil B]

Hi all,
My 2006 cbf1000a has developed a bad misfire and sometimes stops firing at all on cylinder 3, I have taken the plugs out and the plugs from cylinders 1 & 4 are perfect colour, the plug from cylinder 2 is slightly lighter, but the plug from cylinder 3 is very black and sooty, anyone got any idea what the problem could be?.

[jm2]

Probable HT lead failure on #3.
Have you done, or had someone else do, the valve adjustments recently?

Plug failure is possible but unlikely here, even coil 2/3 the same.

- assuming when you pulled the plugs you've seen nothing obviously untoward (like loose connections, plug very loose).

[Phil B]

Thanks jm2,
Have fitted new plugs, just waiting for ht leads and plug caps to arrive and fingers crossed all will be good.

[Phil B]

Update, new plug leads and caps fitted, problem solved running like a dream, most painful thing was the £330 I had to give the stealer for the leads and plug caps.

[Rev Ken]

Originally Posted by Phil B

Update, new plug leads and caps fitted, problem solved running like a dream, most painful thing was the £330 I had to give the stealer for the leads and plug caps.

£330! Gold plated? That sounds morel like the cost of a second hand replacement engine! How can such a rip-off be justified?   I used to make up my own HT leads, just buying plug caps and Iridium spark plugs which lasted 'for ever' which sorted out my starting problems.

[Art]

Ken and I are 'old school' I'd have liked to have pin pointed the failure to either the No3 plug cap or, the No3 HT lead or, the connection between the No3 cap and lead. In the 'old school' tradition of 'if it ain't broke...' I'd have just repaired the connection or replaced the failed part sourced from a motor factor rather than pay Mr Honda's packaging, numbering and stock holding premiums.

That said I do understand that diagnostics, proving parts to be serviceable or failed and sourcing pattern parts is not for everyone. Well done on completing the work yourself and saving a potential additional £150 on workshop labour charges.

Happy days

[Phil B]

Just pleased to have the bike up and running, however I will be keeping well clear of the stealer in future. 

[Scootyman]

I looked into a set of leads and plug caps recently (last year) and was quoted £75.00 ish per plug cap. The problem is that they are so long, there’s nothing much out there deep enough that will fit. The only thing that did work was an extra long straight NGK plug cap with a lead already connected. I put two cable ties around it, one around the plug cap and another inside that one to make something to pull the cap off with but it wasn’t ideal. You could have had water going down the ports due to the shape at the top so I decided against the idea. Instead, I repaired the outer rubber on my number one plug with a piece of thick adhesive lined heat shrink which pulled the split rubber together and stopped the lead tracking across the plug and onto the cylinder head wall.
Daylight robbery those OEM caps and such a captive market too.