Funny Harley story

a neighbor called me up this morning---"I got a likely sale on my '92 Sportster, but it wouldn't start when the guy was here....I told home I'd get it fixed.......can you come help me quick?"

Me: "be right up"

So, good battery, good fuel..... Turning over--but not firing. Pull plugs. Good spark. Starter fluid. Nothing. A bit more. Nothing. Put some in the cyls. Nothing. Try again......single pop. Try again. Big backfire. Pull plugs to see which is dry. Both. Put in a bit more gas. 1 pop and one small backfire from rear Cyl. Spray/squirt again but into the carb throat..... 1 pop, but a loud backfire from front this time.

Friend,"gas isn't getting through the carb....."

Me: "it is, I can see the vapor cloud in front of the carb".

Friend: " let's pull the carb to make sure it's ok.......it's started fine three times during the winter, though....."

Me: "got any new plugs?"

Him: "wouldn't be the plugs, I could see spark........I don't have any, I'd have to get some, and they are Harley plugs, and they're not open now"

Me: "ok, how about running just up to NAPA [5 min away],and just ask them for two of the equivalent ---- I'll go get my tools while you do that".

10 min later........

Put in the plugs, touch the button:

"brumpity-brumpity-brumpity-brump-Brump-brumpty.brumpity........."

Him:"SOB!!! That's all it was?!? hOw'd you figure that one out??"

Me: just a little smirk

 

I think I just learned a bit from that story. I will admit that after seeing spark I would have headed down the path of your buddy, wasting a ton of time. Clean carb though!

 

As a snowmobiler, I can't even count the number of times a plug goes down, but you can see a free-air spark yet when it's in the cyl, it's dead.

So, I will go to new plugs before doing much more, juuuuust in case. Often enough, there's the problem, and it's such a quick fix

 

So why is that? Hot electrical system? Typical plug failure?

 

Increased internal resistance/short in the plug due to age/ manufacturing defect.

 

.... and running hours-on-end at 8,000-10,000rpm----

 

I have seen a YouTube video about testing spark plugs but have never actually done it. Would be interesting to know what is out of spec so a plug could be ruled out.

 

Nothing was out of spec.

You need three things for ignition: spark, air, fuel

Air---that was easy, the engine wa sucking it in
Fuel - that was easy......could see it, smell it, feel it
Spark - you'd THINK its easy......pull the plug and see it spark. BUT-- you can't see it spark in the cylinder. It maybe shorting to the side under compression, or internally when in the cylinder. So, the way to try that is simple---put in new plugs. If it fires right up, you fixed your problem. If it doesn't, you know to keep working.

When we're on a sled and blasting across a field, and all of a sudden you lose power;or you com to a stop, and you just sit there and bog when you try to take off again-----pretty good bet you dropped a plug. That's why we always carry several extras with us.......it's a common occurance

 

At one time I rode an old 1980 Kawasaki Invader 440LTD with dual plug heads. NGK used to send me Christmas cards. When I hit the beach in the summer I looked like a hermit crab, huge upper body development on one side only from pulling that freakin cord so much.

 

That was the two-tone blue sled, right?

 

the LTD was dark green. Twin expansion chambers, each cylinder had 2 transfer ports branching into 3, that's what the 4/6 is all about on the hood. The last sled I had was a 1999 Polaris Indy 500 and I don't think it was any faster. The Kawi was a bullet for sure, ahem, once you got it started!

 

My three favorite sleds I have are:
1994 Polaris Indy 500 liquid - everyday ride
1997 Polaris Indy 700 triple - when I want to ride fast...goes from 0 to bat-out-of-hell in about 3 seconds--or less
1994 Indy 440 SuperSport - light and nimble to throw around

Dave

 

Haha! My older brother had the same sled when I was a kid! I got a kick out of the pop-up headlight. They were all aluminum body, no? To this day my bro maintains that was on of the fastest sleds he ever owned.