Coils

[CopperCollar]

Okay, really got some miles on the Travesty but I noticed she missed around the 5500rpm mark and felt either lean or rich, I couldn't tell which.

I wanted to blame the carbs but no way as Mike Nixon rebuilt those puppies and I have all the confidence that they were done right. I was careful to install them right and set the choke cable right. The only adjustment needed was to turn in the pilot screws half a turn. Probably due to my 5800 feet of altitude.

I played with pulling the airbox lid off to see if that affected the performance, scratched my head, tried restricting the airflow, scratched my head then I made an observation.

In the first mile the power is clean and linear, strong pulling. After that I noticed the missing and around 5500 rpms. I did this a few times, allowing the bike to cool down each time. To me this means a coil cutting out when warm and under a load.

I measured the ohms and Primary was 2.6, 2.8 and one at 3.1. Of course they were warm but not performing under a load.

What do you guys think?

Yeah, I would like Dyna inition and coil set but deniro for this project is and has been gone for a while so I need to keep with the stock system and go low budget.

Mike

[daves79x]

Mike:

Can you try some non-ethanol gas? Do you have the stock air filter or a K&N? That's right where some bikes have a lean spot with a K&N. But if it is truely missing and not just surging, then it's electrical. My original '79's coils were bad from the factory. It would run great with new plugs for about 300 miles, then develop a mis-fire above 7500 rpm. Lived with it for years, then had a chance to replace the coils and that fixed it. eBay coils are relatively cheap - you might try replacing the whole set. Seems to me Aris or someone had a misfire a while back and it was a wire grounding out on the head or somewhere - can't remember exactly.

Dave

[tevan]

You have 2 CBX'S don't you? The coil packs comes out fairly easy I would switch with the known good set. Then I would buy a set of used ones to put in. Probly just one of them are acting up. The problem is figuring out which one. The challenge begins!!!

[SteveG]

If you are going to be replacing coils, improve on them and go big. Find yourself some CBR600 F2 coils, and use them (need to get 1 1/2 sets) since our CBX's use three.

It is a known quantity over at CB1100F.net to use these coils as replacements/upgrades. I put the F2 coils on my 81 900F, and they make a huge improvement. Easier starting, pulls better, no more "rev limiter" when hitting 8000 rpm. And methinks the red wires look cool.

The coils are cheap to be had on EBay. The CBX's use the same coils as the 900F (shows same part # 30500-422-013), so go for it!!

Steve

[Kool_Biker]

Mike

Here's the thread Dave was referring to earlier:
viewtopic.php?f=20&t=6970
I remember I had a small breakthrough regarding a most annoying problem, not disimilar to yours but at much lower RPM.
Good luck, Aris

[CopperCollar]

Good Idea on swapping coils, I'll give that a go, hell the Travesty already has my bikes spark units!

I'll check for a short tomorrow, use a grounded wire.

I think I have a pulsar going 10-7.

Mike Nixon had me check the pulsar gap and if it wasn't at .020 then to slot the pulsar mounting holes and set them to that. Guess the PO had already done that as they were slotted and at .020.

Mike

[cbx6ss]

as for the short, I thought I recall hearing that wiping all the plug wires down with something like WD40 is supposed to reduce plug wire arcing. It seems to work for me.
/r
Brad

[ajs350]

Mike
I have a set of coils and a pulsar that I know are good if you want to try them.
Ross

[CopperCollar]

Thanks for the offer Ross.

I have pulsar and CB600F2 coils. When I get off flight duty I'll put them on and see what happens.

Mike