Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > For Ghosty / Kev / anyone DD Mechanic. question 2

[ells]

Just when you think everything is moving foreards you get slapped back down again.

This morninl, I was happy as Mr Happy himself. I had hatched a plan to turn up at Mallory and with some help improve my pace and race craft so I could whoop some arses at Pembrey. So packed light, no spare levers, rear sets, just the bare bones. (Mental not never do this again). Put the stand in the cowshed, place bike on stand, walk away and hear crashing sound. That was the moment when I knew it was going to be one of those days. Clutch lever was usable so carried on. First session and 4-5 laps at a good pace to just warm up and I pull in.

Second session, go like a scalded cat (relatively speeking) hurl round to complete one lap and as I go into Gerards the bike goes down to one cylinder . Bring bike in check plugs, coils, igniters for loose wires etc but all looks ok, revs cleanly on the spot just goes to one cylinder under load. Check and good flow of fuel.

Third session and we left the pits and she went straight into Gerards and straight onto one cylinder, so round and into the pits we go, as I ease off the throttle the other cylinder kicks in.

This is when I realise that it is just going to be one of those days...

Scratching my head I remember Snet Race 2 Part Deux we left the line there on one cylinder also she did pop and bang occasionally. Then we had the Dyno and she ran fine on the Dyno but a tad down on power.

My deductions so far are ....
it only happens under load, sit her on the stand and she will rev happily.
It feels like she is going to one cylinder rather than the two failing (like when there is fuel starvation).
As it is a single cylinder I wonder if plug, lead, coil, igniters are iffy on one side? As it runs ok one the stand I dont know which one it is


All helpfull hints, guidance etc gratefully recieved. With 2 weeks to go going to be a real squeexe for Pembrey

Thanks.

Mark

[ells]

did wonder if it was heat related but after going to one cylinder it would go back to two just ny removing the load?

Could it be timing or is there one feed that does both cylinders?

How can I tell its one cylinder rather than the other??


Many Thanks
M

[Ghost]

Originally Posted by ells

did wonder if it was heat related but after going to one cylinder it would go back to two just ny removing the load?

Could it be timing or is there one feed that does both cylinders?

How can I tell its one cylinder rather than the other??


Many Thanks
M

Carb diaphragm not lifting properly, needle dislodged. You have 2 pickups one for each cylinder.

If its running on two at idle it is difficult to determine which is the offending one when it drops out dynamically. But you could reach down and pull the vertical plug lead off when on the move, when running on one. if it stops then its the front pot that is troublesome. If it keeps going on one then its the vert cylinder.

[skidlids]

Originally Posted by Ghost

But you could ........ pull the vertical plug lead off .... when running on one. if it stops then its the front pot that is troublesome. If it keeps going on one then its the vert cylinder.

Craig is now an expert on this method

[Gbyte666]

Lol Kev...Had my faie share of this.
Mark, sounds very much like I had at the first round at Brands this year. Mine was the wire just about hanging on the ignighter. In the pits its was ok, soon as I gave it some it cut out onto one. IE the loose wire was braking contact. But I would'nt listen to anything I say cause I'm the worlds worst mechanic..lol If you saw my last HELP thread you would see why.

Craig

[Ghost]

Originally Posted by Gbyte666

Lol Kev...Had my faie share of this.
Mark, sounds very much like I had at the first round at Brands this year. Mine was the wire just about hanging on the ignighter. In the pits its was ok, soon as I gave it some it cut out onto one. IE the loose wire was braking contact. But I would'nt listen to anything I say cause I'm the worlds worst mechanic..lol If you saw my last HELP thread you would see why.

Craig

Your bloody spillin is worse than yer mecaniking.

[Gbyte666]

lol, thats because I've been sat at this friggin PC till 4am in the morning every day trying to do V2V's

Grrrrr

[ells]

Originally Posted by Ghost

Carb diaphragm not lifting properly, needle dislodged. You have 2 pickups one for each cylinder.

I did have a sneek peak at the carbs and all appeared well. Will look again.

Will be looking at the wiring again

Many thanks.
M

[ells]

Well,
got some time this morning to have a look

igniters and coild redults seem to match on both sides

Coils (Dyna coils marked 5 ohm 0409 4+)
Coil (gear side) primary is 5.7 ohm
Coil (brake side) primary is 5.9 ohm

Igniters (DP AL9000 release 6.6)
measured on the pins on the igniters not the feed wires
gear side - infinate resistance
brake side - infinate resistance

feed to igniters (the plug that goes on igniters other end is in the engine)
gear side - 97.4 Ohm
brake side - 97.4 Ohm


All above readings were done with ignition off

Carbs.
I have had issues before with diaphrams (no s******ing at the back) on high mileage suzukis where they have deteriated through age and use. So stuck my fingers in the carbs and gently teased each side up and down (no s******ing) and all felt nice and smooth and both reacted the same.

So I started her up and stuck my head down to have a good look, nothing different about either slide both go up and down ok.


Odd things I noticed.
The wire from engine to igniters is clamped tightly at two points to the frame and the yellow and white wires to the brake side igniter looked like they had seen better days. I gave them a good manipulation while they were attached to the multimeter to see if the readings moved when they were wiggled.

As before only seems to have started the issue when warm but seems to be deteriorating as well.

If I get time I wil look at coil leads. It may end up either not going to Wales or going to a shop. As it only occurs when warm and under load its going to be difficult to trace.

Mark

[ells]

Gone to shop now, hoping its nice and easy (cheap). Hey ho. Quick call now for a set of tyres. Now I am understanding why racing aint cheap.