Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Supersports: SS / SuperSport / Supersport 950 > 750ss fire on 1 cylinder!

[paddy]

hi, i am new to this board, and ducati's. i recently got a 750ss(1991) and it has developed an intermitten problem with running, itsomtimes runs ok, and another it becomes erratic, and now its just firing on 1 cylender. any 1 got any ideas what this might be, sorry to sound a little dumb, just that im not to machanically minded, and new to dukes.thanks.paddy

[KeefyB]

Is it firing on one pot all the time now,or only after a short ride?If you switch the engine off for a while does fire up on both cylinders?
Could be carb icing.

[Iconic944ss]

Very hard to check the plugs apparently for risk of blowing some of the ignition components - the Haynes manual recommends a way around this making a little jig.

I've been told the rectifier and ignition amplifers can be weak on the early models - not sure how true this is.

Frank

[Iconic944ss]

ps - Welcome on board

Good to see more 2V Dukes around !!!

Frank

[paddy]

thanks for making me feel welcome here! right, for a week or so, she's been a little tempermental, times it felt like fuel starvation, i brought the bike a month ago, and was told that it had been standing for a while(2-3 months i think),so at first i figuered the fuel was stale, but now the horizontal cylinder is dead! is it safe to take the plug out and turn it over to check spark? the wiring under the tank looks a little suspect too.

[Iconic944ss]

Shes a beauty Paddy - I always did like the White framed SS - nice crash mushrooms as well.

Nope - checking the sparks like that has a high chance of blowing bits

I must search for Haynes as I aint seen it for a while - as I remember you make a wooden block (honest) to accept and insulate a spark plug, then have a moving nail/pin so you can push it up to the outer electrode and then crocodile clip it or bolt it to the frame somewhere to ensure a good circuit.

Throwning some new plugs at it might be an idea.

Can you smell petrol at the exhaust that isnt firing?

Is the petrol tank vent clear / can you hear fuel returning to the tank when the ignition is on (fuel pump running).

The HT leads screw into the outlets of the coils (under the tank) I guess it spossible it could of come undone or the lead is faulty.

My always takes a good while to start after a lay up and I usually end up 'jumping' her off my car rather than burn a battery up - even then she can run on one cylinder for 30 secs or so for some strange reason know only to herself - but always comes good.

Good Luck - Frank

[Cris]

i just had a similar problem. my bike had been standing for about a couple of months, and i thought it was fuel related, i.e. stale, blocked or icing. the bike had only done about a thousand miles since a major service, so i just assumed plugs and filters were ok. anyway, i took the plugs out and found the front plug to be covered in carbon. the haynes manual suggested either the fuel mixture or the air filter. it turned out to be the air filter. clogged up over one side of the carby. quick clean of the plug, new air filter and she's back to normal.

after reading the thread here on k&n air filters, i decided to go for one. i too went to work on my airbox with a cordless drill.

[paddy]

thanks a lot guys, i will have a good poke about today, cheers frank, knowing me i prob would of caught fire to the beast!! lol...and cris, thats inspired me loads knowing that you sorted your problem out so simply! as i said this is my first ducati, and at 38 im no stranger to bikes, i can see me growing to be quite fond of dukes(thats if i get my bu66er going!!!

[paddy]

happy bunny here! cleaned all the conections on the coil, tidyed up the wiring which was very iffy looking, poped in a new set plugs, then "presto"...on the button! runs sweet as a nut! pouring with rain now, so she sits in my kitchen...waiting!(yes kitchen, i havent got a garage you see) not to the amusment of my suffering partner. anyway, happy days, just now anyway!
thought id add a decent piccy of her again, this time with my lad..."dreaming"!

[Iconic944ss]

Well done! - Glad to hear it all worked out OK...just found my Haynes manual in the garage and was going to scan the diags and spark plug 'tool' sections - so you saved me a job

Blimey - those are clean crankcases as well !!!

Regards - Frank

ps - there are some new end cans for sale on ebay i think from....

http://www.spareshack.com