Mystery starting and running issue.

[Gibbotvr]

The pods are Ramair and do not obstruct the air holes on the intake.

I had an 84 GPZ750 that if it didn't start on the first push of the button it would soak the plugs. Admittedly it was the original ignition but I put some Iridium plugs in and it never missed a beat there after. Not cheap but I believe they have a lower resistance, smaller contact area and produce a stronger spark. The only issue is that I think they are only available in resistor form and this maybe counter productive with resistor plug caps, maybe??

A possible option for me after I have checked the Boyer setup.

[Al]

The bike will start from cold on choke and then will run off choke sounding quite good and revving.
Then it starts spitting back through the carbs as if its running mega weak. And then revs up unevenly.

Does the ballast resistor get excessively hot at the point you mention above?

AL

[Gibbotvr]

Hi, I haven't checked that as its tucked under the tank. I will check.
I have started it today very quickly and after backing the fuel/air screws off by 3 turns it ran a fair bit better.
I didn't get chance yesterday after moving the coil connections away from the mounts as suggested earlier, but it may have made a difference as my rev counter is now reading correctly which it wasn't before.
Keep picking away.
Thanks for all the suggestion though

[Al]

My understanding is that Iridium plugs were invented to extend the service intervals of modern lean burn car engines. They may be the answer for you but an adequately running J will be more than happy on standard plugs for many thousands of miles with no loss of performance.
Sounds like the 750 may have been flooding or far too rich on the pilot jet system.
See the other thread currently on the subject of resistors in plugs. Resistors in plugs or caps but not both is normally ok but it also depends on other factors whether you can get away without resistors at all. Reading the Boyer installations instructions; you must silence the noise because there is a microchip embedded in the baseplate of youre particular ignition.
I have a Dyna system and have Dyna leads and coils. Not a resistor to be seen anywhere. My neighbours probably hate me

Mine had Ramair filters on it when i got it. Far from the best arrangement but perfectly ok to get it up and running on for now, but performance in some areas will be adversely affected and some will not be able to be fixed with them there.
I, like you, can tell when there is a problem with the coil wiring as it sends my tacho haywire. This also extends to dodgy connections, broken wires and in my case a succession of partially failed fuses and ultimately the fuse board itself. Standard fuse board is highly suspect and i discovered to my cost that modern type blade fuses are not vibration resistant. How dare they. They like to snap the legs inside the plastic top and then make or brake contact as they see fit.
The last settings for my CV's WRT The mixture screws was that they averaged approx 2 1/2 turns out from lightly seated across the set. Range about 2 1/4 to 3 1/4 turns out from seated from memory but its been quite a few years. I didnt find this unusual even though the standard is about 1 1/4 turns out because petrol characteristics are very different from when the bike was new. If you were trying to start it with no spark, no fuel would also be a stumbling block if you see what i mean. You mentioned that plugs looked dry! Mixture screws turn outwards (anticlockwise) to richen the pilot mixture. They are fuel screws unlike some!!

AL

[Gibbotvr]

Run out of time today again and don't feel the urge to piss the neighbours who have just come home from work (remember that!!) plus I need a beer

Job for the weekend, tank off and sort the spaghetti out.

[Gibbotvr]

A glimmer at the end of the tunnel, after insulating the coil wiring and winding the mixture screws out a bit more and we have a starting and running machine (rev counter is reading correctly as well).
A few issues left and then maybe insurance and then mot.
I will just wait for the last couple of bits and I will post some pics.
Thanks for all the advise, sometimes you just need that new direction to look at.

[Adrianbrooksbank]

What main jets are you using? With pod filters main jet should be increased approx 25% percent. Using BS34s on my GPZ1100B2 with dynojet kit on,runs brilliant with standard cdi and coils etc,previously used 160 mains with acceptable performance,as suggested by an old EBC catalogue with pods and jets from the 80,s ,have you checked cam timing and valve clearances due to past fixing nearly ready bikes that just need a bit of talc when in fact everybody and their dog has tried to fix. Have just gone back to basics and check everything. If main jet not big enough will give symptoms you have and floats just need a tap to dislodge and use flat screwdriver against post to ease out pins hope this helps