Jota problem - got me stumped

[Dellortoman]

Going back to perhaps the obvious faults, you didn't happen to leave a rag in the air box during reassembly?
Wayne

Haven't got an airbox. Pod filters.

Hi Cam have you checked the rev limiter setting?
                                                      Dave

8,600 rpm

I know very little but I would personally take it on to a quiet  road ...

I may yet end up doing pug chops etc, but it might be more useful to do a dyno session.

I'd check battery condition ...

Battery good. Charging system working properly.


Lex also emailed me with a couple of tips about setting up the ignition pickups/rotor. It's beer O'clock now so I'll leave it until tomorrow.

Thanks for your help folks. Much appreciated.

Cam

 

[Grant]

Personally I prefer pork chops, but you are closer to Asia than me I guess.

 

[dja981]

Can't think of anything else to check Cam, looks like your just going to have to accept your Jota has now become a 3CL.

                                                                                                                      dAVE

 

[redax5]

Cam,
On your coil dwell settings, I take it you have it currently set on "Auto" ?
To the right side of the screen you have additional settings, try these settings.
Dwell correction 115%, Dwell addition 20%, Max dwell time 12,500

see if that helps

 

[Dellortoman]

Thanks Red. I'll give those numbers a try. Is that what the Ignitech guys recommend?

Anyway, I think I may have tracked the problem down to poor sparking on the middle cylinder. I could barely see a spark, so stuck my finger on the bare end of the HT led and could only feel a mild shock. Even my lawnmower will give me a good belt if I do that. Spark is much better on the twin output coil.

The coil and HT lead is OK so the problem is somewhere between the pickup and the LV feed to the coil. I'll talk to Lex about diagnosing that side of things.

 

[Grant]

Tried another plug cap?

 

[AndyW]

Anyway, I think I may have tracked the problem down to poor sparking on the middle cylinder. I could barely see a spark,

Aha!?. : :

 

[Davo]

Loose wire/connection at the control box? Had that happen with the LeMons while riding and almost stripped the bike until I wiggled the wires at the control box and one fell out.

 

[Rocket]

Could it be that the mighty all conquering Ignitech ignition system is, unlike the Pope, fallible after all?
Cam,  can I suggest you purchase another black box, plug it in and have another few years of fun trying out all of the different settings.
And with your newly created spare time perhaps you can assist young Tim with his fuel economy issues?
All the best,
Rocket

 

[sfcpiet]

Cam,

Can you swap over the ignition channels, ie middle to L/R and vice versa?  If the problem moves to the other coil, the amplifier in the box might have taken leave...

Had a similar problem when trying to power 3 double coils from the DMC for twin sparks.  The sparks for the centre pot were fine, the outers would simply fall to bits as soon as the engine started making real power.  The DMC amplifier was not up to the job of firing two 3-Ohm double coils, all well with 1.5-Ohm units currently fitted.

piet

 

[Dellortoman]

Could it be that the mighty all conquering Ignitech ignition system is, unlike the Pope, fallible after all?
Cam,  can I suggest you purchase another black box, plug it in and have another few years of fun trying out all of the different settings.
And with your newly created spare time perhaps you can assist young Tim with his fuel economy issues?
All the best,
Rocket

I suppose any ignition system is fallible. I'll do a bit of testing today (swapping channels as Piet's suggestion), checking for loose connectors, etc. If I can't find a simple fix like a dodgy connection, I'll grab the Ignitech box out of the RGS, re-program it for the Jota, and see if that fixes the problem. If it turns out the Jota's box is dodgy, I'll ask the Ignitech guys for some replacement smoke.

Tim's fuelling problem has already been sorted. I gave him the Dellortos off my Jota (which now has Mikunis on it). Fuel economy is back to where it should be and he said the bike is running better. Just out of curiosity I'd like to have a look at his old carbs some time and see if I can work out why it went way too rich all of a sudden. It wasn't choke plungers. We replaced the rubbers in them and made sure they were seating properly, but it didn't fix it.

 

[Dellortoman]

Well, I made some progress today. Tried swapping channels on the Ignitech box but the problem stsyed with the middle cylinder, which confirms that both channels of the ignition box are working (so you'll have to eat your words Rocket  ). I'd already eliminaed the coil as a problem, so the only possibility left was a dodgy (Sachse) pickup.

I didn't know how to check the operation of the Hall pickups, but figured they must produce some kind of voltage. So I poked my voltmeter probe at the pickup wires where they plug into the ignitech box. The working pickup produced around 0.6V when the engine wasn't runing and about 3V with the engine running. The other one showed zero. Aha!

The wire between the ignition unit and pickup board had continuity all the way back to the pickup board, but there was no electrical continuity between wire and the solder joint on the board itself (was jabbing through the insulation with a pin connected to the meter probe). Figured it must be a dry solder joint, so I scraped off the black silicone muck (looks like Sikaflex) that coats the wire junction and re-soldered it. I now have sparks on all cylinders!

Test ride was disappointing though. Bike now pulls like a train at low revs but pops, farts and misfires, and still won't rev out.  It now surges and cuts out like someone flicking the kill switch off-on-off-on at about 1 second frequency. Still won't get past 5,000 but it's a totally different failure mode to what it was before.

So it seems I've fixed one problem only to reveal a different one. Bloody old bikes eh?  :

I've had enough for today so I'll tackle the new problem tomorrow. Will re-check the ignition timing, balance the carbs again, and treat it to a new set of plugs.

 

[AndyW]

try replacing the tacho..

Failing that, you could always refit the Bosch pickups and install that DMC unit you have lying around..

 

[Jod]

Had a similar problem with a GSXR where it would cut out at high revs... Discovered there was a hole in one of the diaphragms in the Mikuni carbies... Therefore the slider wasn't moving up like it should (which was observed by reving the bike standing still).

 

[chrisk]

Bike now pulls like a train at low revs but pops, farts and misfires, and still won't rev out.  It now surges and cuts out like someone flicking the kill switch off-on-off-on at about 1 second frequency. Still won't get past 5,000 but it's a totally different failure mode to what it was before.

Sort of like a rev limiter set to 5,000rpm?

 

[Rocket]

Well, I made some progress today. Tried swapping channels on the Ignitech box but the problem stsyed with the middle cylinder, which confirms that both channels of the ignition box are working (so you'll have to eat your words Rocket  ). I'd already eliminaed the coil as a problem, so the only possibility left was a dodgy (Sachse) pickup.

Cam, I never say never anymore but I have a can of Alphabet Soup ready to go should the Ignitech box prove to be innocent in this affair!

 

[Grant]

Did you replace/inspect the plug caps?
I had an issue once when it revved so far and then went flat. Turned out that the threaded part that screws into the HT lead had separated from the cap and was just floating there. Passed enough smoke at low revs but broke down as revs went up.
But I do think it sounds now like a dodgy ignition unit.

 

[Dellortoman]

Hooray! Finally got the bugger sorted. 

There was another dodgy connection on the same pickup wire. This time at multi-pin connector that plugs into the Ignitech box (one of my soldered joints  :-[).  I re-soldered that connection and she now goes like a proper Jota and pulls my arms out of their sockets right through to the rev limiter.

Strange how a poor electrical connection can be OK at low revs but cause problems when the revs increase. It was a bloody saga trying to track it down too, especialy since there were actually two faults in the same bit of wire, neither of which showed up with a multi-meter test. The meter didn't read any resistance or voltage drop, but I suppose that's at no load. Once there's a bit of current flowing it's evidently a different story.  I've spend days weeks scratching my head over this bloody problem. Maybe I'm just losing the plot.

Now I just want some half-decent weather so I can go for a proper ride. It's blowing a gale and raining here at present.

Maybe now I can put in a bit of time on the track bike project.

 

[Davo]

There was another dodgy connection on the same pickup wire. This time at multi-pin connector that plugs into the Ignitech box (one of my soldered joints  :-[). 

Strange how a poor electrical connection can be OK at low revs but cause problems when the revs increase.

Not saying I suggested this...but 

Connection will change dependent on vibration and resonance at the joint.

 

[chrisk]

Hooray! Finally got the bugger sorted. 

You can say that again Cam  .......... it's been like a Days of our Lives series. And we all new Brook was porking the uncle and her aunty would find out, it just took 15 episodes for it to happen.