Misc: Everything Else Misfire

[David Wardingley]

It’s only a temporary set back, ignition seems to work very well( two sets of Pazon) I think a lot of really rich running is caused by the relatively slow speed of the traffic around, get onto the A1 at 70mph and the forward cylinder is a nice mid brown but the rear is still black . I think that the slide cutaway is a good place to start actually. I’ve not had the carbs apart yet but will investigate and report back at some point.
Cheers
Dave

 

[Bill Thomas]

Dave it's a shame yours is a 1200, Well not really !,
But when I set mine up in the 1970 s , I had a look at what Moto Guzzi and Ducati where using,
Just to give me an idea, Main jets and slides etc, But yours being a 1200 might be tricky .
Good Luck, Bill.

 

[bmetcalf]

The Riders Manual, the Spares List, and the Richardson book are good starters.

https://www.vincentownersclub.co.uk/threads/essential-reading.15203/

 

[Normski]

I had very dry sooty plugs on a Bonneville many years ago - the first time I used a composite head gasket rather than a copper one. The gasket settled with use and the valve clearances closed up, it may be worth checking your tappets?

 

[nigsey]

I had very dry sooty plugs on a Bonneville many years ago - the first time I used a composite head gasket rather than a copper one. The gasket settled with use and the valve clearances closed up, it may be worth checking your tappets?

Thanks for the advice Normski, I’ll certainly check my tappets.

 

[nigsey]

Nigsey, you say you are on a BTH mag. If mag, 30 thou is too wide a gap on the plugs I'd have thought. Be careful with NGKs, they are widely forged by unscrupulous manufacturers. I'd stick with Champions. If you are still on mag, you don't want plugs with an R in the name (=Resistor), nor do you want resistors in the caps. Are you getting any leaking from the carbs? I think you are also not giving it enough fist. I warm mine up for the first 12 miles, but quite often this is at 70mph on a dual carriageway and I'm still running my engine in with new pistons and rings (and bottom end, but that's another story). Bear in mind that in top, 100mph is only about 3500 revs. The other thing I would try is removing the Vokes filters and revert to standard settings on jets etc and see what this does.
Dave, strangely, if my plugs soot up it's usually the other way round the front (no 2) is sooty. I do use quite a lot of choke (up until end of the road). I'm on 32mm Amal Mk1 Concentrics though.

SteveO, I removed the K&N inserts from the Vokes air filters and the improvement is very noticeable, it even started first kick from cold with no choke, which is unheard of. The engine pick up was much improved and no misfire. I did 40 miles today and took her up to 80 very comfortably. Having said this, the clean plugs that I put in at the start are black & sooty again. I still need to check the tappets as has been suggested elsewhere but if they’re ok then do I need to start looking at looking at changing the height of the float needle? I’m also not keen on going without air filters long term.

 

[Martyn Goodwin]

I had very dry sooty plugs on a Bonneville many years ago - the first time I used a composite head gasket rather than a copper one. The gasket settled with use and the valve clearances closed up, it may be worth checking your tappets?

Why did you have a head gasket in a Vincent?

 

[passenger0_0]

Maybe Normski meant the cylinder base gasket rather than head gasket?
I prefer to use only 3 Bond on the cylinder base as I've seen a few instances where the paper is progressively compressed and squeezed out.

 

[Robert Watson]

Or maybe he means what he said



I had very dry sooty plugs on a Bonneville many years ago - the first time I used a composite head gasket rather than a copper one.

 

[Martyn Goodwin]

Or maybe he means what he said



I had very dry sooty plugs on a Bonneville many years ago - the first time I used a composite head gasket rather than a copper one.

silly me - my crap eyes read AT Bonneville....