Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > For Ghosty / Kev / anyone DD Mechanic. question

[Gbyte666]

Fired up the DD bike today first time from Mallory. Not sounding right somehow?
I let it warm up then with a wet finger if I touch the rear pipe where it exits the head it is hiss the wet hot. ( you know what I mean )
Now if I touch the Front pipe where it exits the head, well its hot but not enough that it could burn my finger or make the wet on my finger hiss.
Should'nt that be burning hot as well ?

If I remove the front spark plug cap and start it it will tick over fine no revs( all be it on one cylinder ) If I put the front one back in and remove the rear spark cap it will not start unless I give it a little throttle and not tick over on idle but will run on a little throttle ok.

Any clues please or is this all just normal ?
As I say it starts ok and ticks over ok and revs all the way up without any misfires or anything.

Thx

Craig

[Ghost]

Hi Craig, not normal, front pot is not firing correctly.
Firstly swap spark plugs, if it was running ok prior to this then we can rule out compression prob.

The next thing to do then is swap the coils/igniters from cyl to cyl and see if the problem moves to the back cylinder.

I doubt if its fuel unless its been upside down somewhere.

[Gbyte666]

Thx Phil, I forgot to say I put another plug in the front one.
I'll go swap over the coils/igniters

Craig

[Gbyte666]

OK, I swapped over the coils/igniters, Same runs freely on the rear on it own, but not without a bit of revs on the front on its own.
Front header pipe did seem a little hotter ( maybe my imagination ) but still no where near making water boil on contact like the rear one does.

Craig

[Ghost]

Originally Posted by Gbyte666

OK, I swapped over the coils/igniters, Same runs freely on the rear on it own, but not without a bit of revs on the front on its own.
Front header pipe did seem a little hotter ( maybe my imagination ) but still no where near making water boil on contact like the rear one does.

Craig

Mmm, if you have a meter to measure the pickup coils resistance ought to be 95 to 105 Ohms.

Just to check if its fuel with the air filter out put some fuel in a houshold spray bottle, then whilst its running mist some fuel straight into the throat of the front cylinder carb and see if it makes that cylinder run.

[Gbyte666]

Thx again Phil.. I'll measure the resistance now.
Have to empty the Mrs washing liqid somewhere and put some petrol in it. lol
Errr are the pickup coils the two black things with what looks like a solid fuse in the top of each one or the black box's either side with two white connectors into each ? Lol

Craig

[Gbyte666]

Hmm asumming on on the right thing, going against the two connectors on the black bakelite jobys I get about 7ohms on both of them.
I'll upload a pic to make sure im accoss the right thing.

Craig

[Gbyte666]

Sprayed mist of fuel into the top of the carb, no joy. Here is a pic of what I am mesuring at 7 ohms on a digital meter.

[Gbyte666]

Measre this as well, Gives between 115 ohms both sides, turn it over and it changes each time but stays same both sides between 105 ohms and 115ohms.
When I first messured it the gear side gave 130 ohms and the rear brake side gave somthing stupidy high. Untangeled the wires and it gives constant now both sides at 105 ohms but still not heatingup that front pipe out of the header or running on the front on it own on idle.

[Ghost]

OK Craig your first two black things are the ignition coils, across those two terminals you are checking the primary resistance, slightly high, but not enough to be your problem. The last pic are the wires that come from the pickup coils, they look in spec also.

So the misting of fuel has it been tried yet??

Just remembered, did you say at Mallory you had a belt jump? If so compression check is needed and check those belt timings again.