Upgraded Dyna Coils - New Problems

[sambodie]

On my 81'XS11 SH I installed new coils from Dynatek part number DC1-1 3.0 Ohm. It runs better except from idle up to 2000 RPM If you get on it too hard it stumbles, but if you let it climb to 2K and gun it you better be holding on tight. It seems that the vaccuum advance is chattering now on hard acceleration under 2K RPM. I replaced the hose ( it for sure is going to the tap behind the boot on #2 carb ). Any ideas?

TIA

[Pat Kelly]

Maybe go one size larger on the pilot jets. They advised that you 'might' need to rejet. In my case I didn't need to. I have the Jardine 4 into 2, K & N in stock airbox (not drilled) one size larger main jets, needles in stock position, and using Bosch Platinum plugs. I also had the air/fuel needles set a little on the rich side, my colortune was showing twinges of yellow in the blue flame.
Before all that, make sure the advance plate is moving smoothly. Might be 'hung-up' till vacuum pulls it loose.

[Geezer]

Is there any chance you connected the vac advance hose to the connector on a manifold rather than on carb number 2?

Geezer

[sambodie]

Geezer,
No chance it's goint to the port on #2 carb, not the manifold.

[Geezer]

What happens if you put the stock coils back on? If the problem gets better then it's ignition related, if not it's something else.

Geezer

[Snow]

A couple shots in the dark if you run out of ideas:
Check the plugs on the manifolds, make sure they are in good condition. Make sure the manifolds are on nice and tight, maybe try spraying WD-40 on them to make sure there are no cracks/holes.

Have you done anything to the carbs since around the same time you changed your coils? Any changes to the mixture screws?

[sambodie]

I have made no changes to the bike except the coils, wires and NGK caps. I may be on to something new though, I found the voltage regulator doesn't spec out according to the test listed elsewhere on this site. The stator coils give the proper reading but the green and brown wires from the regulator to the exciter field don't pass the voltage test ( low on the green wire at run ). Battery voltage at idle is just below the voltage with the bike turned off, you have to get above 2K RPM to bring the voltage up above 13, around 4K RPM & up the voltage reads ~ 14.5 I'm thinking that the extra drain of the new coils could be causing the problem due to low voltage at slow RPM. Is this possible? I am also experiencing the tach bounce to dead but this is only occasionaly and just for a few seconds at a time.

[Snow]

Something else to think about, I keep hearing how the electronic ignition on these bikes won't function correctly without a good battery, perhaps the combination of a battery getting on in age and new hotter coils is giving the electronic ignition a problem during low rpms - but then again, I didn't think the generator pumped out much before 4,000rpm?