New coils, wires and plugs

[RichV]

Hi everyone from Colorado. We're currently in Denver and I'm having lots of fun riding in the mountains. However, I still have my low RPM problem and it really manifests itself on steep, slow curvy roads (like lookout mountain from Golden). The problem is that until I get to about 3 to 3.5K RPM I have power issues. Once over, all is well. The bike acts sluggish and it's been doing this for a year now (so I can't totally blame the altitude). It is most noticeable going from a dead stop in 1st but exists in any gear.

So I've researched this and have found that replacing the coils seems to help this problem more times than not. I have the original coils on my 81 special and they are old to say the least. They still "check out" okay with an ohm meeter but they are really old. So I've ordered two Dynatek DC1-1 coils andd the matching Dynatek 8mm suppression plug wire set DW-800. Hopefully, this will improve things.

My question is this, what spark plugs should I use? The original or something better. I think I have BP6ES on there but the bike is not here right now so I'm guessing based on an old Amazon order.

Also any suggestions on how to mount the coils might be helpful since I don't have a complete shop anymore.

As always, thanks for the help.

[JeffH]

Howdy Rich,


So Lola is wanting new coils?

For sure, new coils will give her some new spark in her step. But it sounds to me like the pilot jet circuit might be a bit dirty or partially plugged. If Lola starts and runs fine cold & hot then runs good on the mains I'd guess pilot jet crud is the bigger issue.

In CO my xs ran great. Used the 85 octane gas (mostly Shell) and went with the rally group up Pikes Peak and we all did fine. Have fun. Hardware (nuts, bolts, L etc.) to install coils can be gotten at Ace Hardware. No reason to change plugs IMHO. Mine were fine at 5,000 ft or 10,000 feet. First figure out what problem you are chasing be it pilot jet (carb) or coil. Plugs fine unless they somehow fubar. Let's see what the gurus think about your problem. Or carb sync is out of whack.

Hope to see you in NC in Sept.

Jeff

[RichV]

Thanks Jeff,

We're trying to get back to NC in time for the rally but I won't know if I can be there until just before (as usual).

Thanks for the advice on the plugs.

I'm going to change the coils because they're old and may be weak (kind of like the owner). Carb sync is currently in wack and I did clean the jets before but I'll do it again if the coils don't improve things.

[jkorn]

I would look at the Carbs rather than the Coils when you have power band issues. Search for that link.

[motoman]

Rich, as Jeff has stated, I would suspect piot circuit is the issue. Those little pilot jets notoriously will trap foregin material up inside them. Sometimes hard to even blow out with an air compressor. I'd definitely remove piot jets and look closely at them internally with a magifiying glass.

[RichV]

I haven't had a chance to look at the problem yet but plan to later this week. I'll remove the pilot jets and see if there is a problem. I'm still going to change the coils since I have them already.

[RichV]

Okay, I replaced the coils and wires. Plugs looked okay so I left them.

Carb sync was okay just a tweak to #4. The pilot jets do not appear to be plugged. I drew the pilot screws down to their seats and the rpm dropped telling me fuel is moving through the circuit. The screws were adjusted to about 3/4's of a turn from seat.

So I tried to adjust them using the ear method posted online but could not hear the change in RPM so I left them at 2 turns.

I test road the bike and the overall performance improved which a attribute to the new coils. The low RPM improved as well which I attribute to the adjustment of the screws.

I did a fuel mileage test to see if that improved and I went from 105 miles to 120 miles on a tank which is a good increase. The light came on at 100 miles and I switched to reserve at 106 miles.

So I still don't have a smooth run below 3000 rpm but it is much better. About the only thing I can do now is continue to adjust the screws until I hit the sweat spot or just be lazy and ride the bike.

[skids]

Synch the vacuums?

[RichV]

Synch the vacuums?

Yes, they were very close and I only had to tweaked #4 a bit.

[DiverRay]

Adjust the fuel level just a TINY bit and see if that helps. I'd go closer to the base, IE 26mm instead of 27, as a first go at it. IF it makes it worse, go the other way, say to 28 instead of 27.
A little bit on the float height makes a big difference at the low RPM.

[Bonz]

Hi RichV, I live just "down the road" in Palmer Lake from you. I think it's in your low speed circuit, I agree with the others. BP6ES is the correct stock replacement plug, you are good there.

Float height can help richen up or lean things out a little bit overall however typically that controls the richness or leanness when you whack open the throttle more than anything. Lower float height means higher fuel level which gets the gas into the carbs fractionally faster when you roll into it. The opposite for higher foat level.

Seafoam works pretty good to clean out minor build up and may free something up if you run some.

Worst case with Seafoam, if it's no better after a couple tanks pull the carbs and clean the low speed circuit.

[skids]

The pilot jets may look OK, but the pilot circuit terminates at the three tiny holes in the top of the carb throat near the throttle plate when throttle is at rest. Carb spray can be used to make sure the holes are clear. With pilot jets removed spray into the opening where the jet seats.

[HalfCentury]

I recently went over my XJ1100 carbs. I used guitar strings to poke into the various holes. A 12-string guitar set of strings has a variety of sizes. The carbs were already clean but I wanted to probe every opening for a possible blockage while I had the carbs off the bike.

[donebysunday]

Hi everyone from Colorado. We're currently in Denver and I'm having lots of fun riding in the mountains. However, I still have my low RPM problem and it really manifests itself on steep, slow curvy roads (like lookout mountain from Golden).

The problem is that dang mountain, ( I know I've been to the top) try going as fast as you can on the way up, then turn around and see what you can get it up to on the way down.
Be sure and report back please ! Or have a witness take video and post it to the forum.
The pilot circuit is very prone to blockage (pilot jets) the smallest little thing will plug them.
A bread tie wire is a bit less hard than other things you can poke through that pilot jet, don't want to enlarge the orifice. Run the wire through then blow it out, even just lung pressure is enough to clear them.
Some of the crap you may get into your fuel system is like a clear gum and you can see light through it. Hold the jet up to the bright sky and look to see if the hole gets clearer after cleaning, this will tell you if you need to flush the system (whens the last time anyone did this ?).

[Bonz]

What about removing the bowl drain screws, shooting carb cleaner into the bowls with a red straw? That could loosen up some stuff. Did it on the '82 Vision 550 I just fixed up and sold, worked well to clean things out as far as I could tell. Start it up right away to clear the remaining cleaner out and see what happens.

I'm heading up I-70 today, going over to Kremmling to stay at the 2017 Colorado Rally campground and do some riding on the rally roads. Will let you know how well the 80SG does (it does well!).