HarleyTechTalk

My son's 1000cc Iron XL, with HD, P cams, Wiseco pistons, our heads, S&S E, Dyna 2000i, and a rare R&M 2/1 header he stole from me... runs 65 hp, 63 ft/lbs.
The dyno chart posted looks like a plugged up exhaust system.

I use one of these, with a long piece of 3/8" copper tubing so it goes way up into the pipe by the head.  No bung needed...

https://www.innovatemotorsports.com/xcart/product.php?productid=16141&cat=271&page=1

Indeed I have no idea what the deal is with the MAC exhaust that is on there. Since it's not very loud, I guess that implies that it's restrictive as well. We'll see how the HD/Cycle Shack pipes work out. Just picked them up yesterday from the ceramic coat shop. These were actually meant for a 80-85 sporty, so the provided bracket is not right for my '78. Need to do a little bit of fabrication to mount them.

-JW

A carbed bike can be VERY easily/quickly tuned.

Yes, they can be. Having a AFR sure helps I've found.

Baseline:
45 pilot, 160 main, N65C needle
Daytona WEGO III gave me:
Idle: 14.5
Part throttle: 14.7
Full throttle: 15.0

OK, very lean. Explains a lot about the behavior, i.e. coughing at off idle and no power. (38HP on the dyno with a Super B, now has a 40mm CV)

Jetting changed to:
48 pilot, 185 main, N65C needle
DTT WEGO III gave me:
Idle: 12.5 (readjusted to 13.2)
Part throttle: 13.1
Full throttle: 12.2

Running A HELL of a lot better. Pulls hard at WFO. It now has the 'surge on backing off throttle from WFO', which means still lean on the main jet I think. 12.2 on the meter would seem OK, but this is an Ironhead, with slow burn hemi combustion chamber. So it might want to dip into the 11s at WFO for best power. More tuning tomorrow, but so far much progress.

-JW

Having an AFR gauge on a carb'd bike is a game changer. Glad to see you got it straightened out. With an onboard AFR the only real need for a dyno is for the WOT hp & tq curves. Totally not needed for tuning a carb'd bike.

Yes, handy indeed. There's a bit of skill involved trying to interpret the AFR value jumping around, not sure I've mastered that yet but maybe after a little more time with it.

I replaced the "'88 sporty" N65C needed with an N72S, as it was stumbling a bit when I'd give it the wick at lower RPMs. My suspicion was that having both the "rich" needle and an accelerator pump, it was getting too much juice. The N72S did clear that up, but found that it was reading high 14s/low 15s at steady cruise. I put the N65C back in, cruise went back to around 13.6, but the low RPM acceleration stumble returned. I think the next step is back to the N72S, and start shimming it to get the cruise AFR to 14.0 or lower.

Turbo, a question. What will oil do to the measurement? I noticed after a few hard pulls it was now puffing some white smoke, and back home to the garage, stinks like oil. I think I see a top end in my winter plans...

-JW

I think you are on the right track with shimming that needle. As fo the effect of oil on the AFR reading, not sure as I have never had to tune in that condition. I bet the guys that run dyno's day in and day out could answer that question.

As a responsible dyno operator I would never strap down a bike that was smoking.

Chances are real good that it would eat itself up.

I have not yet blown one up and a smoker would reduce those odds dramatically!

Indeed, not going to waste any more time tuning it until I get the oil control taken care of. No big deal, riding season is starting to wind down anyway.

-JW

will be running leaner if there is oil in the fuel mix
since the quantity of fuel is fixed but the overall volume of the fuel mix is increased with the addition of oil

JW before you get out the wrenches, make sure the oil is not contaminated with fuel.
That will make them smoke and cause tuning headaches.

When I saw the bike on Sunday as JW was on his way home it was just smoking out the rear cylinder at idle.  Not sure if JW saw more oil use after or before that.   Nothing like tearing down the bike for it's 500 mile rebuild 

The O2 bung is on the front cylinder so I suppose if any oil is skewing the AFR it's getting to the front through the intake.

Yes, disappointing. I was at a stoplight and saw some clouds getting blown up in front of me, looked back and could see it puffing out the rear pipe, could not tell if any from the front though. Before that last tuning ride, where I was doing quite a bit of WFO pulls up to redline in 3rd, it was fine. So clearly something went "tink" in the rear cylinder. I personally had actually not had the bottom end apart on this bike, our pal Surfer Bill rebuilt this some 20 years ago. No idea of the pedigree of parts used. And here I was all worried how to keep myself off the streets and out of trouble over the winter. LOL!

Did some surfing last night, does not seem to be a whole lot of options for ironhead pistions these days. Tons of those Superior/Dixie slugs on ebay, but am not  considering those. Twin Power has some moly coated cast pistons, am leaning that way. S&S and Wiseco both have forged 10:1, but they look heavy as hell and I don't like the noise of forged anyway. J&P has "KB 9:1 Hypereutectic", but when I looked at the KB website, it says 8.2:1. I'd actually go the KB route if they really are 9:1, but am skeptical. Will give them a call.

And since it's apart....

Now would be the time to dual plug it. Ironheads are kind of funky to get that right side plug in. This outfit does an interesting job, not so sure I want to notch the rocker boxes though. Wonder if this could be done with a 5/8" "peanut" plug and avoid the notch?

[attach=0]    [attach=1]

-JW

Crazy idea, but have you considered that it might not be piston or ring related? A leak down test will tell all.

Yes, entirely possible. The only symptom currently is some mild smoke out the rear pipe. No unusual noises, and runs quite well. Just from my own past experiences with oil consumption, if it wasn't the pistons/rings, it was a valve stem seal that got knocked loose. Which can't be the case here, as Ironheads don't have valve stem seals, at least from the factory. And the guy that rebuilt these heads didn't install them either. (says he doesn't believe in it)  At any rate, the heads have to come off. Will take it from there.

-JW

I dual plugged mine with a 10mm plug straight down from the top.





Used a CNC, calculated the electrode position and matched it on the left.

You don't have a pic of what the combustion chamber looks like, do ya?

Last set I had done, they went in straight from the side, between the pushrod tubes. Seemed to work OK.

[attach=0]

-JW

Didn't realize you hadn't gone through the engine on this one.  It was only smoking on rear when I saw it.  Scope and leak test it?   Call Ron (panman) about KB options?  Pretty sure a few dudes around here might have ideas, AWS Racing? ( I think off top my head for Sporties).

IMO dual plugging it is a waste of time and money.  Unless you want to kick it up a few notches.  You have stock cam and low compression, it won't benefit much.  Oh wait, "Harley riders are happily getting screwed". :-) never mind. 

The only thing I touched were the heads. Did not tear it down past the cylinders. So who knows what was used or how assembled. Kind of odd that it started smoking after some hard and high rpm pulls. Piston pin C clip come loose? Dunno, leak down would be fun, but at the end of the day, it has to come apart to fix.

The thing I see dual plugs bring to the party is aversion to detonation with the crappy gas we have these days. Mountains of evidence that hemi heads, with zero quench and big mountains on top of the pistons, don't produce a lot of ping-abating swirl. Stock Ironhead, at 9:1 C/R, is not off the chart, but higher than stock Evos, Sporty Evos, and Shovelheads.

What can I say? I don't own a boat. What other black hole am I going to throw money into?


-JW

Your daughters education?  :-D

9:1 is not high compression and depending on the cam, likely lower.  Did the R60 ping?  It's got open hemi heads and at least 9:1 ... yes aluminum vs iron.  How many miles you gonna put on this?  200 a year?   :-D

I forget, what was the oil control issue with the other Ironhead, seals?  Same head dude, same problem??

Quote from: JW113 on November 07, 2019, 07:46:29 PM
The only thing I touched were the heads. Did not tear it down past the cylinders. So who knows what was used or how assembled. Kind of odd that it started smoking after some hard and high rpm pulls. Piston pin C clip come loose? Dunno, leak down would be fun, but at the end of the day, it has to come apart to fix.

The thing I see dual plugs bring to the party is aversion to detonation with the crappy gas we have these days. Mountains of evidence that hemi heads, with zero quench and big mountains on top of the pistons, don't produce a lot of ping-abating swirl. Stock Ironhead, at 9:1 C/R, is not off the chart, but higher than stock Evos, Sporty Evos, and Shovelheads.

What can I say? I don't own a boat. What other black hole am I going to throw money into?


-JW

I think there will be some gains had by dual plugging that ironhead. Even at 9:1 o lower, that is a huge chamber with a lump in the middle. The placement of the plugs would ideally be on opposite sides of the mountain instead of on it's ridgeline. Still, two sparks has to help. Too bad dyno tuning was not a thing back in the ironhead and shovel days. I bet tuners and aftermarket would have developed all sots of stuff that actually increased the power output of these old designs.

JW

My 'new to me' 1978/79 has dual plugs similar to the pic you posted except instead of removing two fins they bored a hole just large enough for the spark plug.  The bike is stashed in a corner of the garage with a workbench built up to the left side and the right side is up against the wall, and a hinged drop down parts holding counter is against the front, can't get it out for a good pic.  I also keep it covered so I won't get distracted from what I am supposed to be doing while I'm out there.  I haven't done anything with it so far except store it until I finish my other projects.   [attach=0]
I can't get the photo to load on here, they centered the spark plug through the top horizontal fin between the push rods with a half moon cut out of the outside vertical fin and the second horizontal fin.  Neat installation.

Sure, airheads are hemi also, but as you said, made of aluminum, hung out in the breeze for better cooling, and it is not uncommon to dual plug those either. Ala my R100/S. And the pistons are narrow dome, similar to shovelhead pistons.

The problem with the Chopster was the crappy mechanic.

It was 4-5/8 stroke, and the dumass didn't go the extra mile to make sure the pistons were not playing tag at the bottom of the stroke. So, collapsed piston skirts. Doh! But it sure ran like a scalded dog.

drifter, I think I know what you mean, and I was thinking the same thing. Cut the hole in the "corner" formed by top horizontal fin and right side vertical fin. I have an old rusty head laying around somewhere, might use that to experiment on a bit.

-JW