Ducati Monster Forum

recently bought a 1997 600 Monster as a winter project. Before I strip it down I thought I would get it running, which is proving difficult!

It starts, sounds OK, but runs very rough...   and soon as I try to rev it it cuts out! I have done all the usual checks and come to the conclusion that its the CDI units. I know its strange to have two faulty ones, but I dont know the history of the bike, and they may have both been swapped. the bike is stuck on full advance when I check it with the strobe, and seems to advance more as the revs rise and it just cuts out...

So what are my options? seems new ones are £500 ish a pair... is there an alternative?

There are aftermarket ignition units, like this, assuming that's what you found:
http://www.carmoelectronics.co.uk/index.php?main_page=product_info&products_id=681

I've been using an IgniTech on my M750 for 5 years/24k miles, quite nice and better performance than with the OEM style units.

I'm filling in a lot of blanks, but I'm guessing that the bike has been sitting for a while.
So you could have carburetor issues, or who knows what.... bikes often sit due to an unresolved technical issue.

Unless you are loosing spark, this.

My FHE is that CDI's either works or are dead, so your
symptoms sound abit strange.
Bad fuel pump, fuel hoses, carb or battery issues seems plausible.

http://www.ignitech.cz/en/vyrobky/tcip/tcip.htm
Good alternative for ign boxes.

To be honest they are strange....   to eliminate the fuel pump and hoses i have put a test tank high above the bike, so there is fuel to the carbs...  battery is a large car battery, and some thick jump leads

I am going to put my CDI units on a mates bike the weekend and see if that runs, i will report back.

Any other suggestions feel free, this has got me stummped

Wiring all the way to boxes ok?

My experience with ignitor boxes is the same as GM's...good, or bad, with no in between.

Where are you grounding the battery? To the OEM cable?

I'm leaning towards a carb issue, myself.

Thought I would update this with the reason the bike wouldn’t run… it may help others in the future..

I had initially bought the bike as a none runner…  It looked like several people had had a go at repairing it, there were two invoiced in the documents, one for £200  where they failed to find the fault, and one for £350  from 2010 where they had replaced the ignition pickups but the invoice stated the bike needed new carbs.  It has stood since 2010!

On initial investigation I found a hole in the pipe from the manifold to the fuel pump, (see the picture) and initially thought this was the reason it wouldn’t run.  I repaired the pipe and although it now started, it wouldn’t rev at all.  Soon as you gave it any throttle, it cut out completely.
It had a good spark so I initially thought it was the carbs, so I stripped and rebuilt them… still no joy…  I used a spray with petrol in and sprayed neat petrol into the carbs… still cut out.

This is why I thought it was the CDI units.  Today I put the strobe on and looked through the window… no timing marks.  So I took the cover up and started it up (yes I got covered in oil!) and noticed that the timing on BOTH cylinders was way out.  Knowing the pickups had been replaced, I wondered if they had connected the wires back to front.  I took the wires out of the pickup plugs on the coils and swapped them over.  It ran perfectly!

So it looks like the original fault may have been the pipe with a hole in it… but this was miss diagnosed to being the pickups.  Which introduced a new fault on the bike when these were wired incorrectly!

(https://jtccc.files.wordpress.com/2018/08/hole-in-pipe.jpg)

Thank for your help and suggestions guys.

 [thumbsup]

So it would run with the H and V ignition circuits swapped.
That's nutty.

Glad you fixed the concurrent faults. After awhile you become accustomed to fixing other peoples cock ups on old bikes. It causes a few headaches that's for sure.

It wasn't not the H and V wires that was swapped over...  but the two wires that come from each pick up to each CDI unit.   Looks like when somone had put new pickups on they had mixed the wires up.  They probably assumed it was OK, but it must alter the signal in some way, posibly the wave form.  Dificult to check that though without an ocilascope. 

Ah, each pair from each sensor.