Throttle bodies on a 1200 sport

For a while the 1200 has had difficulty ticking over at lights at much below 2000rpm…given it has the stage 1 kit it always decides to be particularly antisocial in quiet villages on Sunday mornings . As the service was due this Spring, and it wasnt being used much during the winter - I just ignored the problem. Yesterday it went to Motorsport now Dorset Bikes for a service - and I hoped cure of this problem.THeir diagnosis is it needs its throttle bodies removed, cleaned using their ultrasonic cleaner and possible a new jet (though they weren’t sure about that one) - anyway they reckoned that was a days work - you can guess the estimate. It has the stage 1 kit on it and the feeling was that it has sucked all kinds of detritous into the bodies, added to which the additives in petrol now don’t help. The aged Audi had this problem last year, and the garage I take it to, sprayed stuff (brake cleaner??) into them - and the problem went away. Input welcome on:Has anyone else had this problemIs it a days work, to strip them, clean them, reassemble and re tune… I guess “yes” but just checkingAm I likley to be able to do a partial improvement with spraying brake cleaner into the bell mouths, or removing them and doing the same?Any other thoughts?The bike has done around 40000 miles faultlessly (more or less) so maybe its time I paid a big bill other than the service - which with MOT and VAT came to over £400 yesterday Adam

Adam,First thing I’d do, if you’ve not already done so, is run a couple of tankfuls of injector cleaner through the bike and see if that improves things.When I had the problem of the throttle staying wide open in third due to the butterflies sticking in the throttle bodies on the Centauro shortly after I’d got it, (and the associated required change of underpants of course!), I took them off, (TBs that is, not underpants), and gave them a good internal dousing and light brushing in carb cleaner while operating the mechanism.That seemed to remove any gummy residue from fuel due to the bike standing for 6 years or more prior to my ownership and the problem has never surfaced again.If your Stage 1 still has an air filter of sorts then it shouldn’t have any great deal of crap going in that way.If the cost of a can of carb cleaner plus your time to take the bodies off, clean them and refit works, then it’s a win, win surely?BTW. A new ‘jet’? Did they mean an injector maybe? If one of those has gone pop it will give problems all over the rev range, not just at idle.

guzzijack2013-05-09 11:34:31

Hi Zeics
Shame the 1200 sport website isn’t up and running!
I don’t know where the oil breather goes with the stage 1 but on air box sports the throttle bodies would clog if you kept the engine oil too full ( ie on the full mark!) it had a natural settling point about 2/3 full when it wouldn’t chuck out oil.
Anyway I would go with carb cleaner, if you work at the spindles and edges of the butterflies you should be able to clean it enough without resorting to full strip down. Sticking bodies usually sesult in high idle not reluctance to idle at below 2000!
Perhaps stepper motor problem? Or throttle balance?

IF injector cleaner does not work find out if any garage within reasonable distance can do the fuel cleaner Terraclean I believe it sure cleaned out a jag engine far cheaper than taking it all apart.

I had the V11 do the coughing and spluttering thing, some FI cleaner along with tankfulls of the supa unleaded worked well for it

To find local dealer 12:29:16

Thanks Gents -
Am I right in thinking we are talking injection not carbs on the 1200 Sport - the only airfilter is a open mesh bell mouth per cylinder under the seat - I have read somewhere else that these are prone to suck in all kinds of mess.
As for the oil level, it has never been too high, often too low , The motor has always had aspirations to be a two stoke, it gets through oil at an amazing rate.
Re… totally agreed… I wonder if the content is still on an archive somewhere, or lost forever !!

Certainly my thinking mirrrors yours… use cleaners and the expensive petrol for a while to see if we can get it back on song before major surgery at Motorsport.


Yes, injection.Injection cleaner, (petrol version, not the diesel one!), you mix with the fuel in the tank and it helps keep that side of things clean.If that doesn’t improve matters, then a propriety carb cleaner is a good product to remove gummy deposits in the demounted TBs - spray it in and agitate with a brush, then wash off. I’d advise using a soft brush to avoid damaging the orifices and injectors in there.Where’s the oil going? Maybe, as Borderer says, it’s being sucked into the inlet and gunking things up?

guzzijack2013-05-09 13:23:22

OK - thanks Graham

Adam, have you done anything to the air bleed to the stepper motor? This tickover at 2k is a fairly common fault according to Guzzitech posts. Basically the trick is to put a tap in the air intake pipe to the stepper motor and close it when the engine is warm. Needs to be open when cold starting.
Of course this may not be your problem.Brian UK2013-05-09 16:55:34

Cold start without stepper motor is ok it just means you can’t let the throttle go for a minute or two.
Benefits: steady idle, engine braking, les backfiring on overrun.
It is possible that the stepper motor is disconnected on the stage 1 kit as the intake for this is from the air box which I guess is in Zeices garage!

Brian - I have done nothing… I have difficulty holding a wrench let alone getting involved with air bleeds and stepper motors!!!
So I am trusting that Motorsport will have done what they need to on those things.
Borderer is right - there is a large box of stuff in the roof of the garage that was given back to me when the Stage 1 kit was fitted, not just the airbox and pipes.


I wonder where the air bleed pipe is now the air box has been removed. It should have filtered air really.The mod I mentioned is very unlikely to be known about by any dealer. It also does not involve any cold starting without the stepper motor.

I suppose either there is a small filter on the air inlet to the stepper ( best guess) or the stepper has been isolated, the stage 1 has a different ECU( the standard one doesn’t like the stepper being electrically disconnected.) so possibly that is what has been done.
My guess is simply balance problem possibly air bleeds way out of synch or fallen out or the bike has been set up with sticky throttle bodies and is way out on balance.
Still would like to know where oil breather goes