Dual Plug Heads

[JW113]

Yes it's a CA bike, I bought from a friend back in 2001. I started several project ideas with it, but never go more than half way only to tear it all apart and stuff it in the shed. I finally figured out what I wanted of it, and thus here it is. I did sort of a build up blog a few years ago while I was putting it together.

https://harleytechtalk.com/htt/index.php/topic,92382.0.html

The AFR was reading on the rich side at steady cruise ~35-40mph, like 12.6:1. I think the last thing I did was pop some shims under needle. I need to take it out a few more times and let it get fully up to temp, then see how it reads. I want to get a few laps on my "break in course" before puttin' the spurs to it. I also pulled about 5 degrees of timing out of it, so still need to get that optimized for the dual plugs.

-JW

[Racepres]

I can't do that Front End on an Ironhead, but... that is strictly Personal... I love an Ironhead... and one day I will Finish my Digger!!!! it also is Not everyone's "cup O tea"

[cheech]

Yes it's a CA bike, I bought from a friend back in 2001. I started several project ideas with it, but never go more than half way only to tear it all apart and stuff it in the shed. I finally figured out what I wanted of it, and thus here it is. I did sort of a build up blog a few years ago while I was putting it together.

-JW

By state I meant did you buy it like it is, "that state of build" so to speak.  Sorry for the confusion. Ill check the linked thread out.

[JW113]

Got it. This is what it looked like when I got it from my pal Surfer Bill. He had bought it from another guy here in San Jose as a complete basket case. He assembled it and got it running, but it was pretty much a cobble job.

-JW

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[Racepres]

Got it. This is what it looked like when I got it from my pal Surfer Bill. He had bought it from another guy here in San Jose as a complete basket case. He assembled it and got it running, but it was pretty much a cobble job.

-JW

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IMHO... the '78 was the Last Great Ironhead... Love the Dual Disks too... the '77 would be great... without that damn Pie slice/cloverleaf front brake....
PS... I really like your "new" exhaust... who made that??? nothing really wrong with the one that was on it... but I Dislike slash cuts and or turnouts.. personally..

[JW113]

Believe it or not, those are HD "performance" pipes before there was a Screamin Eagle. I believe they were made by Cycle Shack. They are actually for 79-85, didn't realize that when I bought them. I had to modify the bracket for the '78 frame. Not ideal, need to make a better one at some point. I also had them powder coated, not a big fan of chrome in general.

-JW

[turboprop]

At some point you have got to get this on the dyno (and possibly some scales) for all us that are watching this.

PS - This thread got me interested in iron heads (again). I just did a quick check on Craigslist and Ebay. Nothing on CL and just a few ratty choppers and over priced XRs on eBay. Wasn't that long that owners of almost stock iron heads could not give them away.

[JW113]

Indeed, that is the plan. I had already taken it in to have it dyno tuned with the Super B on it. The guy did a miserable job, is supposedly a savant at tuning FI, but I learned he'd never even touched a B before. I should have demanded my money back, but the shop owner is my machinist and long time friend. Will take it up to RC Cycles after it's broken in. But this time, I'm going to use the AFR and tune it myself beforehand, then let Bob dial it in the rest of the way. If it needs it...

-JW

[Racepres]

And being Contrary... I don't give nuthin for Dyno runs...
The 1/4 Mile MPH will tell you all you need to Know... leave easy get in High gear and tell me the MPH!!!!

[14Frisco]

Will take it up to RC Cycles after it's broken in.

I had one of my bikes dyno tuned by Bruce @ Horsepower Express in Campbell several years ago.  He closed shop quite a while ago I believe, do you know if someone "took over" his business?

[JW113]

Bruce is long gone and no one took over his business. In fact, there is almost nothing left in the south bay area for HD oriented shops and even parts. Even half the HD dealers are gone now. Dudley Perkins HD is no more.

Drag strips are fine if you happen to live near one I guess. For me that would be Sacramento, 120 miles away. Personally, I find the plots of torque curve and AFR very informative. And not at just WFO.

-JW

[turboprop]

A friend of mine has a DJ250i but he is slightly east of Novato. Knows a thing or two about carbs. Send a PM if you want his contact info.

[Burnout]

Bay Area Performance, Mountain View?

[Racepres]

Bruce is long gone and no one took over his business. In fact, there is almost nothing left in the south bay area for HD oriented shops and even parts. Even half the HD dealers are gone now. Dudley Perkins HD is no more.

Drag strips are fine if you happen to live near one I guess. For me that would be Sacramento, 120 miles away. Personally, I find the plots of torque curve and AFR very informative. And not at just WFO.

-JW

If you have a Dyno Guy that shows stuff outside of WFO... you got a Good one... Most will Not/Can Not

[JW113]

You can use an eddy current dyno to put various loads on the motor at various speeds and throttle settings to get the AFR correct throughout the throttle range, as opposed to just acceleration the drum at WFO to redline, so the bike only runs well at WFO.

Right?

-JW

[Racepres]

You can use an eddy current dyno to put various loads on the motor at various speeds and throttle settings to get the AFR correct throughout the throttle range, as opposed to just acceleration the drum at WFO to redline, so the bike only runs well at WFO.

Right?

-JW

If...and Only If 1] you have an Eddy Current Dyno, 2] If you know how to Run the Thing..
I have been tuning the Old Fashioned way for so very long... I will continue My Way..
Working my way from Idle to finally going to the Track [about 10 Miles] for 1/4 mile MPH at WFO..
Perfect??? Prolly Not, Effective??? Yup... Smooth as a babys butt, on my Test "circuit" around the local Lake!!!
It is Important that she work "smooth and even",  in 3rd gear too!!!!!

[JW113]

Although I do not take my bikes to the track, I've been doing the "butt dyno" also for 45 years. I don't have a problem with throwing a little technology at stuff once in a while. In fact am having fun with this DTT AFR I have hanging off this Ironhead. Not being a drag racer, have no time sheets or trophys for bragging rights. So what the heck, will maybe settle for dyno sheet.


-JW

[JW113]

Well I've got 50-ish miles on it, mostly short little 10-12 mile spins on the freeway loop around San Jose, trying to keep it at a somewhat steady 65mph/3500rpm. Temps are around 70, so not too hot. Was puffing a slight amount of smoke initially when on the side stand, rev it and back off. But that seems to have cleared up so rings appear to be taking a set.

Have a tuning issue to work on, at the end of the run after it's fully warmed up it's picked up a blurbber when slightly backing off the throttle to get on a freeway connector and then back on the throttle. Like it goes lean for a bit. At steady speed, the AFR is on the high side of 14s to low side of 15s. I'm thinking that is probably a bit too lean for an Ironhead? I'll start with throwing some shims under the needle and see what affect that has.

The plugs look clean, white-ish, not burned, no oil or carbon fouling. Both heads read around 330degF after a test ride. Have not really given it much more than 1/4 to 1/3 throttle so far. I want to get 100 miles or so on it, then take out and do the 10 WFO pulls.

-JW

[Burnout]

You didn't give it a full 45° with the dual plugs, did you? I'd start at 36 or so and inch it up from there.
I recommend using a VOES too.

Today's gas doesn't put much color on the plugs and it's easy to get too rich looking for color.
A light grey ash kind of coloring I'd call normal.
I look at the plug threads and check how far the heat comes up the plug (3 threads is my target).
(depends on plug reach too as many use a 1/2" reach plug in a head that takes 7/16" reach)
and watch the ground electrode for blueing.

I'd shoot for mid 14's at cruise but you need like mid 13's if you roll into it. ~12.5 at WFO.

15's would be leaner than a pop corn fart.

[JW113]

I rolled the timing plate back by ~5 degrees (one of the tick marks on the plate) before I started it, and also turned the advance mode switch back to "4" (S&S Hi-4N), so no, it's not at stock timing. By the way, the stock timing for this model is 40degBTDC according to the FSM.

The electrodes do not look like they've been hot, no discolor at all on them. After a quick swipe with a brush they look new. I agree, low/mid 14s is probably where it wants to be, now just how to get it there. I have 48 pilot jet in there now, I think the last time I tried a 50 it blacked the plugs in no time. But certainly could give it a try and see what happens. Since this stumble is happening at part throttle, with gentle feathering, I'm thinking more needle than pilot jet. At any rate, have some tinkering to do.

As interesting as this AFR is, I have to keep reminding myself "what would you do if you didn't have it?". Read the signs and make the adjustments, just like I've done forever. What I'm finding is the AFR is just reconfirming what the motor is telling me.

-JW

[Burnout]

Yep I know what you're saying, Motors talk to me.
Some people don't get it, I ride it and tell them it is too rich, they say it runs great.
Huh? It blubbers when you back out of it, it's too rich....
Or worse yet the opposite, it picks up when you ease out of it.....
Maybe it has to do with seat time or they are too busy looking at their reflection in the windows as they ride by.....   

Any Dyno or gauge based settings have to be verified/approved by the seat of the pants.

Yeah later models backed off the timing to 40°, even that is ridiculously high for a faster burn chamber.
It's amazing how much difference dual plugging makes on these motors.
Less timing, more power, better throttle response, easier starting and more.

Sounds like you have a good grip on it.

[Hossamania]

Yes, dual plugs need much less timing.

[JW113]

Yep. The tricky part though is "how much is much less"? Lot of lore on the 'net that says 5 degrees less, but I don't know what the basis for that is. Just for fun, I looked up the timing specs for a 2000 XL1200S, which has dual plugs from the factory. A stock XL is 40deg, a 1200S is 20deg. Yes, that would be a lot in my book.


So how to optimize on an old relic like this that's been converted to dual plug? I'm thinking put it on a dyno and start playing around with the timing. The limitation will be that playing with the timing by rotating the module affects both max timing, and timing at idle. The Hi-4N allows you to dial back the max timing, but only about 5 or 6 degrees. Dunno. I might have to break down and replace the module with a Dynatek or Ultima, which lets you make your own timing advance curve.

I went for another break in / tune loop, the AFR is now mid 13s to 14. Which is pretty much exactly what the WEGO instructions say to aim for. I have two shims under the N72S needle, seems to be right in the sweet spot now. With three shims it was mid to high 12s. While out riding, the WEGO started displaying Lb, which is low battery. Got it home, and sure enough the charge light is on. It lost the gene or regulator. Oh boy, one more thing to fix.

-JW

[Hossamania]

I remember talking to an old rider (like in his 60's!), a local independent shop owner, he mentioned the old Pans and Shovels needed their timing dialed back quite a bit when running dual plugs, I thought he mentioned by almost half. He was, maybe still is, a trials rider, a former club member, and quite the well known local character.

[JW113]

I remember talking to an old rider (like in his 60's!),

Ouch! Hey I resemble that remark!


-JW