misfiring

[tattoo]

hiya

can anyone help me with a problem thats accured,after fitting new plugs to my storm it refuses to run properly on the rear cylinder,the gaps right and the plug is tight,it also gives out a small knock or bang from the front cylinder(this isn't all the time tho) before the cylinder goes off...i checked for a spark when this happened and it was good and strong,after refitting it still run rough,like it was misfiring...i also cheked the timing and everything was spot on

any help would be great.

[sirch345]

If you removed the tank did you refit the vacuum pipe on the back of the petrol tap on the horizontal outlet and not the drain outlet at the bottom (16ltr tank models only).

Chris.

[Pete.L]

Also try putting the old one back in and see if the problem disappears.
Some times a plug will spark fine out of the bike but will brake down under load when it's in the engine.
Check your HT leads too. Maybe disturbing them you gave one a problem.

Pete.l

[benny hedges]

Check your HT leads too.
Pete.l

best way to do that is start the bike up in a dark garage - have a look under the tank, subframe etc for arcing,
obviously don't gas yerself lol!
with the tank and seat off, if there's any arcing, you will see like tiny thready pencil lines where it's been sparking.

[tattoo]

HIYA
yes the vacuum pipes on the horizontal outlet,i've got the thing firing now but there's a intermitant knock coming from the front cylinder when it's held at around 2000rpm,it's heavy enough to make the tank jump when it does happens..i've now stripped the front off and checked the front cylinder timing again and it's as it should be,tbh it sounds like it's spitting back through the carbs but very heavy and very loud

any ideas please.

[benny hedges]

it sounds like it's spitting back through the carbs but very heavy and very loud

any ideas please.

are the carbs on proper & inlet rubbers good and tight?
x head screwdriver doesnt get them tight enough imo, try a 8mm socket on a long extension

and are you sure the plug caps are on properly?

[Gerrit]

Replace the spark plug supressor caps with generic NGK caps.

Since I did this my bike has been transformed

Gerrit

[tattoo]

i've found the problem with the knock,took the rear cam cover off and tuned it over by hand and noticed the timing chain is riding up on the cam sprockets,seemed alittle slack but timings spot on,tensoner feels ok too...took it for a little run and found it to be hesatating so new plug caps tomorro and balancing

thanks for all the advise.

[tony.mon]

STOP RIDING IT IMMEDIATELY! Don't even start it.
There's a problem with the CCT, and you're about to have the usual CCT disaster, where the chain slips over two or more teeth on the sprocket and valves meet pistons.

In no way under normal conditions should the chain be anywhere near enough slack to ride up a sprocket, so you have CCT problems, definitely.

I assume that you still have standard CCT's?
If you have manuals fitted, they're not tight enough by a long way.

[tattoo]

i suspected as much tony...i checked the rear one when i did the front exhaust valves when that one went earlier this year and found it to be tight at that time but i have been up and down the a1 to cambridge alot,it's on sorn for the winter now so will change the tensioner and do the timing again...

thanks again tony.mon