Running rough

[Silver twin]

Hi all, just looking for a bit of extra advice from the knowledgable.

Had a good ride on Sunday, first down to loomies, then down to porchester and then made my way back up to midhurst and onto the A3.
I had been out for about 2 hours and had done about 60 miles since a fill up, when after a bit of spirrited ! riding on the A3 she started to not respond as cleanly to the throttle being opened, this got worse and she started coughing and generally running badly as I slowed to move into the inside lane. Luckily I was near a petrol station and pulled in, but she wouldnt idle and wanted to die. On re stating and holding a constant throttle she would hunt around eratically almost like it would drop to one pot and then back to two again. Had to have her recovered back home as she was un-ridable ( thank god for Carole Nash ).

Got some new plugs on order, and hoping one has failed and thats my problem

I had changed to a new battery before this ride and thought maybe the rectifier had got a shock and began to fail ( will check with a multimeter)

If they dont fix it I'll start looking at fuel, ( are there fuel filters on the storm ? )

Its the 1st time in 10 years if had a problem like this, I'll let you know what fixes it !!

Cheers Dave

[sirch345]

Dave, I'd fit the new plugs and check the voltage at the battery with your multi-meter first as you intend to do (reading should be between 13.5 - 15.5 volts with engine running). If they check out not to be the problem next I would check the vacuum pipe and fuel lines for splits, along with the tap diaphragm. If your bike is the earlier model (16ltr fuel tank) the fuel tap has a drain off spout at the bottom of it. If the tap diaphragm has split fuel will be seeping out of the drain off hole. If the front cylinder has a take off hose fitted for balancing the carbs, check the bung in the end hasn't come out.

If the bike has been laid up for the winter the petrol could have gone off and has left some gunk in the carbs/jets. Other possibilities are one of the HT coils has broken down, plug cap broken down or one of the diaphragms in the carbs have split.

There are (as standard) no fuel line filters fitted. They're only going to be there if a previous owner has fitted them and will be visible with the fuel tank removed.

Chris.

[Silver twin]

Cheers Chris

New Iridium plugs turned up today, so will fit them at the weekend.

Regarding the fuel tap ( my bike is a 98 model ) If the diaphragm has split then I should have a petrol leak from one of the pipes from the tap ?.
I guess this is the only fault that can occur with the tap, I assume if it fails it must effect fuel supply to both carbs not just one.

Will investigate this and other possibles if the plugs dont cure it.

Cheers Dave

[benny hedges]

if you have the tank off, check the state of the air filter as well, it might be choked up.
i couldnt believe the amount of dead flies and dust in mine last summer - more than usual, as though i'd been hoovering up everywhere i rode!

when your new plugs turn up, show us the colour of the old ones...
plug colour is a good indication of engine health & fuelling.

you weren't lugging it in high gear at very low rpm were you? if so that couldve fouled the plugs.
iridium plugs (standard) don't last forever, and you should be changing them at least annually

[Silver twin]

Fitted the new plugs, took her for a spin and all is well again.Didnt have time for a long run, only did about 20 mins of riding, but enough to warm her up and then try a few big handfulls and the running is spot on.

The old plugs didnt look to bad ( will post some photos ) the centre electrode looked more worn than the new NGK iridiums, but the old ones were NGK platinums so it could be that the plug designs differ.

Will have to do a longer run to rule out any chance that its something to do with 80 nto 90 + throttle openings in top, to definateley confirm a sucess.

Dave

[sirch345]

Dave, good to hear it seems a lot better

Chris.