Jota series 2 misfire then.....

J

Jota996

Junior member
Location
Northumberland
So it stared with a very occasional misfire, then moved up to a more substantial misfire that felt like the engine was cutting out, then more multiple engine cutting out events until he just stopped, started straight back up mind and got me home....

Series 2 180, with DMC2 ignition, mosfet Reg/Rec, NGK8's with black ngk caps, new Motobat battery.
Ive had the reg/rec tested and even tried another one, Ive redone all the connections, Ive changed the nippoin denso coils for TEK Honda ones

Now he will start ok and sort of run but as soon as teh revs rise to 3k he just shuts down

was running really well before this started

Any thoughts before I beg for a loan of a DCM2 to prove that mine is u/s. and rob a bank to try and buy another one or change the whole thing and only loose a kidney.....

cheers all
 
Long call and short answer, seen DMC exhibit similar symptoms, the main aspect being it starts up again after ignition off and on procedure. Bruce 1200TS has hands on experience also to draw upon in regards to battery volts and DMC as i recall.

Dont mention if it is all three cylinders misfiring, HTH j
 
My symptoms with a Witt were a bit different than yours, mine would just drop one cylinder. But since like you everything else should have been good it pointed to the Witt. And it was. A loaner is your best bet to confirm. Been totally reliable since then. Shit I probably just jinxed myself.
 
Hi Stu,

Is the misfire across all three cylinders, similar to flicking the kill switch off an on?
If so, I had a very similar issue with my DMC2-equipped RGS on my last trip to Breganze.
I finally traced the problem to a cracked wire in the sub-loom (the aftermarket wiring that includes the multi-plug that connects to the DMC2 ignition box).
I sourced a new one from Uwe Witt (20 or 30 Euros), fitted it and it's been fine since 😊

HTH
Alan
 
I agree with Alan's observation. In my case it was very difficult - actually make that impossible - to identify the broken wire, the red 12v supply. Insulation appeared to be intact, but conductor strands had fractured just above the crimped connector.
 
Same with my earth wire broked 50mm back from the battery connection, the cluey blokes on that ride made a complete bypass EI mini loom on the way home and that bypassed the issue and got me the 500ks home, that's an excellent way to check for internal wiring faults hidden under the sheathing. Mine started backfiring and cutting in and out, so frustrating with 10 other blokes watching on. Thankfully those same cluey blokes carried a bunch of wiring bits and pieces and a gass soldering iron plus a multimeter. Bless their cotton socks.
 
DMC2 still operates with the original pickups, right? If so, check the insulation of the pickup-wires and best solder in some new wires (leave 1 cm / 1/2 inch of wire, remove the rest and solder a new wire on, heat-shrink some protection on, re-connect in the right order (!!!) the wires to the DMC and off you go!).

If it's one with the optical sensor, check it's not dirty or oiled!
 
I had an issue with the DMC, sometimes popped and farted for a while before cutting out. Leave it for a while and it would generally start. Untill the last time it made me push the bike home.
Taking the pickup cover off I noticed that there had been an ingress of water for some time. Hmm, what to do? I thought it may be the optical pickup even though it looked ok.
Whilst checking over the rear of the circuit board I noticed that one of the small wires going to the sensor had had part of its insulation worn away and was shorting out on the crank case. painted over the wire with liquid insulation and also painted the cranckase with the same just to be sure.
Filed a small grove into the inner face of the cover to ensure that any water entering gods sanctuary could drain away. 5 years later the bikes still going strong.

The wires running up the back of the circuit board are very thin with minimal protection and the engines vibration soon wears it away.

Good luck.
 
a14rgs said:
Hi Stu,

Is the misfire across all three cylinders, similar to flicking the kill switch off an on?
If so, I had a very similar issue with my DMC2-equipped RGS on my last trip to Breganze.
I finally traced the problem to a cracked wire in the sub-loom (the aftermarket wiring that includes the multi-plug that connects to the DMC2 ignition box).
I sourced a new one from Uwe Witt (20 or 30 Euros), fitted it and it's been fine since 😊

HTH
Alan
Click to expand...
HI Alan
Hope your well....!!
Yep exactly that... just like its being turned off for a second....
Can anyone test the DMC2 box?....

Stu
 
Jota996 said:
HI Alan
Hope your well....!!
Yep exactly that... just like its being turned off for a second....
Can anyone test the DMC2 box?....

Stu
Click to expand...
either a dodgy ignition or kill switch will give the same symptoms: try bypassing the kill switch for starters
 
a14rgs said:
Hi Stu,

Is the misfire across all three cylinders, similar to flicking the kill switch off an on?
If so, I had a very similar issue with my DMC2-equipped RGS on my last trip to Breganze.
I finally traced the problem to a cracked wire in the sub-loom (the aftermarket wiring that includes the multi-plug that connects to the DMC2 ignition box).
I sourced a new one from Uwe Witt (20 or 30 Euros), fitted it and it's been fine since 😊

HTH
Alan
Click to expand...

Blood hell, I closed my eyes, or looked away, every time I saw your nude RGS while you were looking for the issue on route to the 70th. Jacca hotel car park being the first.
 
chrisk said:
Blood hell, I closed my eyes, or looked away, every time I saw your nude RGS while you were looking for the issue on route to the 70th. Jacca hotel car park being the first.
Click to expand...
That's when I pissed off the residents - they didn't appreciate the music of a Laverda triple before 7.00am.....🏍😁🤣
 
Jota996 said:
Can anyone test the DMC2 box?....
Click to expand...
It's extremely unlikely to be the box. There is a test facility (see DMC2 instructions) but of course that doesn't replicate the effects of vibration on the connections & wiring. In my case, the issue only initially appeared on the overrun into the pits after a good thrash around Spa. It took a couple of years for the wire to finally break and leave me stranded on the circuit!
 
Thanks Rob, he does start ok, but then stops about 3k rpm, start straight up again...
Im going to strip out the box and the little loom and bell out all the wiring giving it a good wiggle at the same time to see if i can find anything....
 
Have you checked the fuse-box for the contacts are all tight? We had a similar issue on a 1000 SFC and it turned out to be a "dancing" fuse, that lost contact once in a while due to the contacts were not tight enough... Or look for the wiring coming from the key-switch. Sometimes they tend to develop an intermitted loss of contact.
 
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