Firing on one cylinder

[LutonStorm]

A biker chap a few doors down with a triple thinks the Storm sounded today like it was running on one cylinder as i pulled off the drive.

Now i'm Satan for saying this but as a new owner i'm not 100% sure of the correct sound. I does sometimes sound different if that makes sense? At 2500+ revs it sounds ok and pulls well but it is a little lumpy down in the low revs, a little push/pull jerky??!!. Not sure the cheapest way of finding out? Or are all things like this costly?

Any thoughts?

Cheers boys

[goody]

Start it up don't rev it and feel the exhaust headers to see if the heat up evenly. if one takes longer or doesn't get hot then it's not firing properly. If you've just got the bike then might be worth giving it a service. If it's excessively jerky down below it could be the carbs out of sync (need balancing) slight misfire, tight spot on the chain, knackered cush drive. It is a twin though don't expect it to be silky smooth at low revs.
He's probably jealous because he's got to many cylinders!

[Stratman]

Believe me, if it was firing on just one cylinder you'd know!

I have a fuel injected TDM900 as well. I get my carbs balanced regularly and the Storm is a lot less jerky than the TDM at low speeds and I can trickle along in 1st at low revs with no problems, so its probably just in need of a good service and set up. Go for the obvious first, service, filter, plugs, balance etc then see.

[LutonStorm]

Cheers guys.

Thought i might have been worrying over (nearly) nothing. Being only used to a 125 and 500, the accel from the Storm is incredible so it can't be that ill! looking forward to her being 100%...

Thanks again...

[LutonStorm]

ok, decided it's definately popping and not dugga-dugga-ing, therefore only running on one cylinder. Sometimes comes in but in 3rd it runs out of puff at 70. I only6 get 60 odd miles out of a tank too. Give away huh??

The temperate doesn't ever get above quarter so not up to tempertature

Done an oil and filter change and looked at the plugs. Good news, they were a little grey/black but noting oily or sinister. Haven't replaced the plugs as they look new but need another one to do a spark test (as per Haynes)

The temperature thing worries me as i've had that before in cars and it's been the head gasket.

It ran fine from the dealer so i'm thinking its not terminal. I'll Redex it next fill up to see if that clears anything. Failing that its a full service and pray!!??

Any thoughts? Ideas of price? (nervous grin)

[AMCQ46]

sounds strange, and the 60 miles to a tank could be a big clue.

Reading some of the old workshop posts I saw one which had similar fuel consumption and it turned out the choke was stuck open on one of the carbs.........that could be a similar problem and would lead to one cyl running badly when the bike has warmed up.

As one of the other guys commented, the heat of the exhausts should indicate if they are both running the same. I suggest you use a thermocouple [temp probe] rather than your hand, if you are going to do this once the engine is warmed up.

[yorkylancs]

Yeah could be the choke,mine did it once when the choke lever was not returning to fully seated,it coughed and farted badly.Also not so long back,it didnt seem to want to rev past 7 thou,just hit a brick wall,could not coax it at all.Took carbs off and the front carb choke assembly was not seating properly,the plastic bit that screws into the carb had stripped its thread,only noticed it once i had stripped the carbs down!Anyhow managed to bollock it up reasonably tight,ok now..

[LutonStorm]

oo.. cheers for the Choke idea, might explain the colour of the spark plug too.
Ok, will investigate..

[Stratman]

My temp gauge hardly gets off the C in normal operation (and that's in 9 years of ownership) so I wouldn't worry about that. Choke problem sounds quite possible to me.

[LutonStorm]

That's a relief StratMan.
Cheers for that. I'm always worried when I see vehicles not staying at a regular temperature. Takes a small weight off my mind!

Will look at the choke tomorrow evening. Why is it that I just get comfy under the bike and the heavens open? Is it Sod's law at work???

[LutonStorm]

Blimey!

How is it that removing and replacing the choke cable is so involved! Haynes says...
Remove seat
Remove fuel tank
Remove Carbs
Remove/Drain coolant

just for an itty-bitty cable...... Any workarounds??

[Phil-VTwin]

not really, but once you have done it a few times it doesnt take long, no need to drain coolant if you have some hose clamps.

[Phil-VTwin]

Ohhhhhh i would love to take an SP to bits

[sirch345]

Mike, is the tank support all part of the SP tool kit

Chris.

[tattie]

Luton Storm.
I would think again about the Redex , sort the choke problem if it is that and give it a good run.

Cheers

A.M.