Lagging cylinder on startup?

[Supercoyote]

After a couple years of tuning and tweaking, I've gotten to the point that my XS360 with a 400 engine runs consistently. The only strange thing remaining is that on startup, and really any RPM below 3000 it seems as though the right cylinder cuts out. I've cleaned and synced the carbs, timed the ignition and set the valves but the problem remains. It runs admirably at higher RPM ( except for a Any suggestions or experiences with a cylinder cutting out at low RPM would be appreciated.

 

[NewHavenMike]

That's funny, because I have the same issue with my 360 with points ignition. It goes away after like 2-3 minutes though. It doesn't happen with the choke on but as soon as I take it off and try to pull away it happens. Im getting it on the left cylinder. It also only really happens below 3000 rpm.

I do have iridium plugs with the correct plug boots but it still happened when I have standard NGKs and boots on.

I cant tell if its a misfire, lack of fuel, or the point firing prematurely. It does go away, its just annoying when I first start it and I want to go. Even on a hot day I still have to let it sit briefly until the engine is warmed up.

 

[NewHavenMike]

After some research, Im going to test both coils. I cant remember if I changed back to the original ones when I removed the Pamco, since I thought my whole ignition setup was fried and I knew the original coils were still good.. I do have a spare set though as well.

I also have to say, over the last year or so, Ive stocked up on so much crap, its hard for me to keep track of what Ive done lol. I have an old Ironhead that Im rebuilding, an MGB that Im messing with, and 3 other bikes that Im gathering parts for. Also forgot my Mk1 Jetta 16v that I have.

I will test the coils and double check my timing and report back.

Anyone know what the average lifespan for points is? or how performance degrades as miles rack up? I have somewhere around 1300 miles on the current setup.

 

[Supercoyote]

Funny you should mention that, because I didn't note that I have the PAMCO kit. So you removed your PAMCO and went back to points? I was starting to think actually, maybe one of the springs on the advancer is significantly weaker than the other, and is going to full advance too quickly. Unfortunately I switched my rotor to a spare one for a EI bike so it doesn't have right side fire points to verify if it's advancing too quickly

 

[NewHavenMike]

When I checked my timing, one side was advanced about halfway. I got both sides as close as I could and Ive ridden it to work the last few days for about 250 miles total.. The side that was advanced, is not the cylinder that is having the issues though..

I had the E-advance Pamco. Well, I still have it but its blown out and thats why Im running points.

The mechanical advancer seemed ok when I re installed it. I guess I should check that too and just do everything over again...

 

[Supercoyote]

Blown out?

 

[NewHavenMike]

I had an over-voltage condition from the mechanical regulator and it blew some capacitors on the pickups.

Well, this is only my guess. The VR on my bike was not responding to adjustment and wouldnt produce a charge. I went through another mechanical regulator before installing the R292 regulator.

I posted a thread/pics of it on here a while back

 

[Supercoyote]

That's too bad. Not a cheap piece of kit to have go.

 

[NewHavenMike]

Lol yea i know and the Pamco made a big difference in performance. I also bought one of the NewTronic optical ignitions and that failed on my first ride... So back to points for me, until i hear back from Pete.

 

[Supercoyote]

To go back to your question about points, I don't think there's a limit on point t life unless they're pitting, chipping unevenly or you have a bad condensor causing arcing. As long as they're wearing normally and you periodically gap them bad to the correct clearance, I don't think points with half their material remaining work any less well than brand news, excluding contamination or one of the above situations. Cue someone about to tell me how the world really works