cold weather start

[locoman1968]

Set up;
1970 XLCH 4200 original miles when stored in1973.
Good compression in both cylinders, points and timing good, no leaks at the intake, Tillotson carburetor
Re-started in 2007 for the first time. Now has 7000+ miles on it.
Engine appears to be all stock but with Autolite 303 spark plugs (I'm still using Autolite cause that's what it had in when I got this bike)
Problem;
When the weather is about 40 degrees or lower the first start up has only the front cylinder firing. I can get the rear cylinder firing if I pull the plug wire off the plug and hold it back so that the terminal is about a half an inch away from the plug. I have to hold it there till the cylinder warms up enough before I can seat the wire back on the plug.
Once its warmed up I have no problem till I let the engine get dead cold again. It even gets ridden into the teens, just first start up is where it has problems.
I have no problem starting the bike any other time.
Im not sure if these are even the right plugs but so far they burn choclate brown but still slightly on the rich side
Don't suggest that I go back to Harley Davidson plugs, I have found them to be unreliable in my other bikes.
I've heard of running different plugs for each cylinder, and I'm willing to try anything or just keep doing what I'm doing.

Loco

[pappyfreebird]

i jus had a jap bike do that..was floodin a cyl when cold start..sumtimes plug would take off sumtimes nawt..holdin cap up off would make her fire..i dont unnerstand that either...1st thing id try is switch the plug wires,,see ifn it reverses the prolem..ifn so its the wire er could be that end of wud i call the coil tower..ive had coils git where would ony fire out one line,,but thats usaully when hot...a hotter plug in rear??? id rather start it usin less fuel n see ifn that helps..

[Lew]

I had this problem.  I'm guessing the plugs are causing this.  The Autolite plugs I've messed with have a short reach and are easily fouled.  Using recommendations from this forum I now use the Champion J12YC plugs in my points fired Ironhead.  They have a longer reach than the Autolite's and have not fouled out.  I've also found that indexing the plugs helps. Champion makes the plugs for Harley Davidson.  I've not used the HD plugs in my Ironhead but have never had a problem running them in my Shovelhead.
Good luck!

Lew   

[locoman1968]

Thanks for the input fellas, I'll do me some testing once it get cold again. We had a cold spell for while but now it's back to normal fall weather.

Loco

[saltcaveminer]

have you checked the point gap on both lobes? also i would suggest you check the push rod adjustment(engine cold).Salty

[locoman1968]

Thanks Salty, I can do those while the weather is cold or warm.
Loco

[Spikesime]

Do what lewy said. Sounds like your real close to fouling the rear spark plug. I've used the "wire held away from plug trick" many times to limp home after fouling rear plug. Seems it's always the rear. Champion J12Y work for me, also, mid 60's small block chevy plug. Always plentifull and reasonably priced. Good luck.
SS

[Pynzo]

Champion J12YC are great plugs- make sure you don't get RJ12YC- the resistor in them sucks for kick only bikes. AC44 and 45 plugs are good also, try a hotter plug in your rear cylinder, and carry spares. Short runs without getting the motor to full temp will be a major cause of fouling no matter what plug you run, I pull my plugs and quick flash the tips with an OxyActeline torch to freshen them up if they foul- it has saved me lots of plugs over the years.

[locoman1968]

Refresh my memory someone...the lower the number the hotter plug??

Pynzo
I lol'ed  when you said short runs. Its more than10 miles to the nearest civilization where I'm at.

Spikesime
Thats funny, I was hard pressed for plugs one time for my 80 XLH (converted to points) and used some for my 66 GMC. They worked so much better never went back.

Salty
Both checked out fine.

Looks like I'm changing plugs and going hotter in the rear for the cold months...all the rest of the year it has no problems, if I'm lazy they will probably stay in all year LOL

[saltcaveminer]

american spark plugs - higher# = hotter lower# = colder.
foreign spark plugs - higher# = colder lower# = hotter. Salty                                                               

[Spikesime]

Loco, what is even funnier, is, I've used big block chevy plugs in my Evo and they work better than HD
SS