One 36 year old hot rod! - Steve Saunders Goldwing Forums

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post #1 of 21 (permalink) Old 12-17-2014, 10:00 AM Thread Starter
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One 36 year old hot rod!

The old "men" in the GL lineup ('75, '76) are mostly forgotten about and sure seem to be small by today's standards, but you can have a lot of fun playing around and hot-rodding them. Their engine layout just begs for all sorts of hand-made goodies, and the basic boxer layout is ready made for doubling, and even tripling output. My final grade from GM Institute in 1978 was to pick an engine and squeeze 3hp/ci out of it without pressurizing it, and on pump gas. (actually, pump gas included Sunoco 360 and 104 av-gas!)

CaptainMidnite wanted to know about my "single-fire" ignition, so here's the whole story of this project, starting with the ignition.

The goal was 180+hp, but that means lots of fuel/air and higher cylinder pressures, which means much higher spark voltage. I've never been a fan of the usual double-ended coils. First, trying to contain that much voltage in such a small package is just asking for a short lifespan and limited output. Also, If your plug gap on each plug is .050", then the coil is looking at an equivalent of .100". That requires a lot of push to jump. As the rpms climb, so do the spark voltage requirements and those stock coils are just very limited.

My solution was to use the points box as a base for fitting a custom distributor. In this case I used the optic pickup from a Toyota pickup truck, a cap and rotor from a Fiat 850, and an old Heathkit CDI unit driving an Accel coil. Had to machine up adapter rings to mount the pickup, the cap and another adapter to hold the rotor. The slotted rotor from the pickup system only need very little material removed from the inside to press tightly over the stock point cam.

After the rest of the work was done, quite a bit of dyno time was spent tuning the advance using different springs. Ended up ruining several sets of stock springs by heating them slightly to weaken them. That's kind of an art, and I'm no artist! My dealer looked at me kinda weird when I kept coming in for advance springs. He said he had never sold any others to anybody!

I really don't know what a stock 1000 engine is capable of doing with good coils and everything in tune, but mine seemed to stumble starting around 8200rpm. The new ignition was smooth all the way to 10,500 which is where I detected some valve float. And, this is where the rest of the story begins about the other mods to this bike. But, first, just a couple more issues with this distributor before anybody runs out to try this!

Notice the 90 degree plug towers on the cap. Naturally, they had to be to clear the rider's left foot. Still, my foot only cleared them by maybe 1/2". That all worked well under normal conditions, but when you roll the throttle on hard and rpms climb, so does the spark voltage. I lost count how many times I got bit hard not paying attention to that fact! Eventually moved the peg back 1" and shortened my shift lever 1". That was fine, except for riding in rain! Had to hook my foot on the rear peg and be sure I wasn't "on it" when I would slide forward to shift it. Not exactly a rider-friendly setup! Again, eventually I made a mica shield to block my foot from the wires! The Accel coil and higher spark voltages took their toll on the Fiat's cap and coil. A distributor driven off the front of one of the cams and sticking out forward, and having a larger diameter cap would work much better. Even a GM HEI cap/rotor, using just four towers, would be much better, but what did I know back then?

That's the distributor part of this build. More later. BTW, it eventual put out 182hp at the output shaft.





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post #2 of 21 (permalink) Old 12-17-2014, 10:53 AM
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Thank You for posting!
A single-fire solution that appears to be next on my list of upgrades.
I've gotten all that I can get from factory coils and this is the next step in my interests of ignition.

Do not be offended if I duplicate what I see and read of this thread.
It will happen.
I look forward to more..
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post #3 of 21 (permalink) Old 12-17-2014, 12:38 PM Thread Starter
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I don't mind at all. If you have machine and welding skills and equipment available to you, I would suggest, as I did above, to modify a late '70's-late '80's GM HEI distributor. It would handle the abuses of the higher spark voltages better and be easier to find parts for. Ever tried to find a cap and rotor for a Fiat 850? Also, you can cut off four of the eight reluctor points from the pickup's rotor to give you just four firings. Might as well keep the whole thing GM if you can. I wish I had! You will have to figure out how to mount it to the front of one of the timing belt covers, then connect it to the nose of the cam.

Another solution would be to run a toothed belt from the stock points box up to another pulley above the valve cover and face the distributor forward!

But, if you are a glutten for shock therapy, then the pickup assembly I used was out of my 1979 Toyota SR5 work truck. Had to eventually put it back in the truck to keep my boss happy, but once it proved itself I went out and bought a whole new set. You might want to look around for newer, smaller optic pickups. Check the automotive speed supplies. Speedway Motors, Jeg's, etc.

I'm good friends with the guy who bought the bike from me. He sold it long ago, but he might still have the distributor parts laying around. He removed the carbs immediately after I delivered the bike to him and handed them to me. I still have them, too. I could ask him if he has the ignition stuff. Would sure save you a lot of time!
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post #4 of 21 (permalink) Old 12-17-2014, 12:46 PM
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I'm up for it.
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post #5 of 21 (permalink) Old 12-17-2014, 02:30 PM
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How 'bout using the distributor to trigger power transistors located near the coils. All the high voltage stuff will be solid state. That way the spark gap at the distributor will be almost nothing, extending it's life expectancy and keeping the high voltage away from your foot.

Bruce

Current Bikes:
---------------------
74 CB750 K4
77 CB550 K3
82 CM250C
82 GL1100 Interstate w/ Auburn Gemini (doublewide) Sidecar

Past Bikes:
------------------
What?? SELL a bike??

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Can I have a motorcycle when I get old enough?
If you take care of it.
What do you have to do?
Lots of things. You've been watching me.
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post #6 of 21 (permalink) Old 12-17-2014, 03:38 PM Thread Starter
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Quote:
Originally Posted by OldSchool_IsCool View Post
How 'bout using the distributor to trigger power transistors located near the coils. All the high voltage stuff will be solid state. That way the spark gap at the distributor will be almost nothing, extending it's life expectancy and keeping the high voltage away from your foot.
You've sure got my head spinning trying to figure out the system you describe.

"...spark gap at the distributor..."? The cap and rotor determine the non-adjustable spark gap, and with any gap at all they also can't be used to drive power transistors.

"All the high voltage stuff will be solid state." The "...high voltage stuff..." is simply the output from the coil. I must be missing what you are calling high voltage.

"...coils." This system uses just one coil and a cap/rotor to "distribute" the spark, just like "old-school" automotive practice. What I think you are hinting at is using multiple pickup sensors firing multiple coils. The stock GW points box is not large enough to fit four sensors into. It is possible to make a larger box to fit on top of the stock one that will hold multiple sensors. This would require mounting four coils under the "tank", one for each cylinder. Yes, that would move the high voltage away from the foot.

There are several possible modern variations to move the "high voltage" away from the foot, and to eliminate the small, double-ended coils, as well as the cap/rotor type of distribution.
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post #7 of 21 (permalink) Old 12-18-2014, 08:24 AM Thread Starter
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Fighting the worst flu in my life here, so my keyboard time is limited. But, moving on with the bike's description.

Today I'll describe the intake.

Hp increases mean higher fuel/air flows, and the stock carbs can't flow enough for much more than about 110hp, theoretically. So, new carbs were in order. Enter the Weber 40IDF's. A Maseratti V-6 has roughly the same per-cylinder displacement as the GL1000, and Italian makers are notorious for oversizing their carbs, so the 40IDF seemed perfect! It's big enough that I could have even jetted them for alcohol if needed. To start out I ordered them exactly as they come jetted for M engine. Of course it took lots of jet changes to get it dialed in just right. I also hand polished the bores, tapered the edges of the butterflies, contoured the shafts and hand fit the venturis and blended them into the bores. Just a lot of detail work to be sure they were efficient.

The manifolds were fabricated, too. The bases were made from 1/2" aluminum bar-stock and matched to the ports on the heads after the heads were reworked. A one-piece carb base plate was cut out of 1/4" aluminum. Tubes were fit between the bases and carb base plates and welded. Some grinding and rewelding had to be done inside to fill gaps after blending all the joints smoothly. A flow bench test showed a huge air bubble right at the point where these manifolds meet the heads, so a bit more weld buildup and contouring reshaped the stream to cover the port's whole mouth at the head. Perfect! And, all this grinding of aluminum made my hands black! That stuff doesn't just wash off!

Along with the manifolds I made a cross-bar to tie on carb to the other across the engine to help stabilize them and prevent any cracks from vibrations. Welded to that bar is the throttle cable anchors, too. Stock GL1000 cables were used. I did have to fabricate the cable wheels to fit the ends of the throttle shafts, so I made them identical, although the cables just hook to the left one. A 1/4" brass tube with Heim joints on each end connect/sync the two carbs. Air cleaners were a couple of off-the-shelf K&N units. (more about the air cleaners issue later)

OK, now that's the ignition and carburetion. Still gotta cram all that fuel/air into the cylinders to pump out real power. But, that's for another day!
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post #8 of 21 (permalink) Old 12-18-2014, 12:02 PM
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Quote:
Originally Posted by trikebldr View Post
You've sure got my head spinning trying to figure out the system you describe.

"...spark gap at the distributor..."? The cap and rotor determine the non-adjustable spark gap, and with any gap at all they also can't be used to drive power transistors.

"All the high voltage stuff will be solid state." The "...high voltage stuff..." is simply the output from the coil. I must be missing what you are calling high voltage.

"...coils." This system uses just one coil and a cap/rotor to "distribute" the spark, just like "old-school" automotive practice. What I think you are hinting at is using multiple pickup sensors firing multiple coils. The stock GW points box is not large enough to fit four sensors into. It is possible to make a larger box to fit on top of the stock one that will hold multiple sensors. This would require mounting four coils under the "tank", one for each cylinder. Yes, that would move the high voltage away from the foot.

There are several possible modern variations to move the "high voltage" away from the foot, and to eliminate the small, double-ended coils, as well as the cap/rotor type of distribution.
I think you got the jist of what my clumsy description was trying to say.

Spark gap at the distributor:
What I'm referring to here is the gap between the rotor and the tower. When pumping high voltage through this OldSchool (snicker) setup, it's going to arc. That arcing will erode the metals over time. By using a power transistor and low voltage pickups, you can eliminate the arcing and increase the life of the rotor/tower by quite a bit. Let's call it infinite if you use optical pickups instead of metal contacts..

High Voltage is SolidState:
My original statement was quite clumsy on this point! On my CB750 and 550, I have transisterized the primary of the coils, not the secondary. This reduces even the modest voltage (or more accurately, current) at the mechanical points to almost nothing and has pretty much eliminated the need to resurface and adjust my points every friggen weekend! I'm coming from this experience/application for this whole discussion.

Coil(s):
Will there be enough dwell time to generate the massive EMF in the primary to cause the secondary to produce that highly desired phat spark? You may know better than I on this. It seems reasonable as my old Mustang had a single coil. Lower RPMs for sure, but twice as many towers.

Room for Pickups:
If you went with 4 optical pickups, using a slotted disk to make/break the beam, you might be able to cram it all in there. By adjusting the length of the slot, you can adjust dwell time. And adjustable weights on the disk perimeter would give you fine tuning for advance.

Something Not Said:
And a key point that I totally missed is that the rotor/distributor in my scenario would be connected to the primary of the coil(s) and not the primary. This may also require 4 coils, not just one (still thinking on this point). So totally NOT the OldSchool (snicker again) setup you describe.

Just spitballing here. Please continue your explanation, I'm learning much!

Bruce

Current Bikes:
---------------------
74 CB750 K4
77 CB550 K3
82 CM250C
82 GL1100 Interstate w/ Auburn Gemini (doublewide) Sidecar

Past Bikes:
------------------
What?? SELL a bike??

------------------
Can I have a motorcycle when I get old enough?
If you take care of it.
What do you have to do?
Lots of things. You've been watching me.
Will you show me all of them?
Sure.
Is it hard?
Not if you have the right attitudes. Its having the right attitudes that's hard.


PGR since 2011
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post #9 of 21 (permalink) Old 12-18-2014, 03:39 PM Thread Starter
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"Spark gap at the distributor:
What I'm referring to here is the gap between the rotor and the tower. When pumping high voltage through this OldSchool (snicker) setup, it's going to arc. That arcing will erode the metals over time. By using a power transistor and low voltage pickups, you can eliminate the arcing and increase the life of the rotor/tower by quite a bit. Let's call it infinite if you use optical pickups instead of metal contacts.."

This cannot even be responded to since you have mixed up the primary and secondary sections of the ignition system.

"On my CB750 and 550, I have transisterized the primary of the coils, not the secondary. This reduces even the modest voltage (or more accurately, current) at the mechanical points to almost nothing and has pretty much eliminated the need to resurface and adjust my points every friggen weekend! I'm coming from this experience/application for this whole discussion."

OK, now you have made a comment that makes sense and is true! However, there are more modern ways to do this as well as eliminate the need to worry about setting "dwell" with the mechanical points. Small CD drivers (capacitive discharge) eliminate the need for any dwell time. The mechanical points merely tell the CD driver when to fire the coil. The gap on those points can be quite small with no adverse effects, and they will last until the rubbing blocks wear off.

"Will there be enough dwell time to generate the massive EMF in the primary to cause the secondary to produce that highly desired phat spark? You may know better than I on this. It seems reasonable as my old Mustang had a single coil. Lower RPMs for sure, but twice as many towers."

Again, using CD drivers eliminates any concerns for dwell. Wow! You truly ARE OldSchool! A four cylinder engine should have absolutely no problem developing enough dwell, especially since there are only two sets of points in your engines. I'm not going to go into a tutorial about that. You had better know this point gap versus dwell stuff!

"If you went with 4 optical pickups, using a slotted disk to make/break the beam, you might be able to cram it all in there. By adjusting the length of the slot, you can adjust dwell time. And adjustable weights on the disk perimeter would give you fine tuning for advance."

First of all, adding a set of four optic pickups would mean using four separate coils, Then, the "slotted disk" you speak of would simply mount onto the stock point cam, which already has the correct weights and springs for the advance the engine needs. However, where you are lost is that the width of those slots has nothing at all to do with dwell. Each slot simply gives the trigger point for the CD driver to fire it's coil. Forget DWELL! Except in cars made before about 1972, there is no more dwell. CD ignition (which most cars have) has eliminated that term!

"And a key point that I totally missed is that the rotor/distributor in my scenario would be connected to the primary of the coil(s) and not the primary. This may also require 4 coils, not just one (still thinking on this point). So totally NOT the OldSchool (snicker again) setup you describe."

WHAT????????

Could we please keep this thread on the subject of describing the background to a 36 year old hot rod Gold Wing build, and not debunking other mystical ignition systems? Got questions about what I did, or why? I will answer those.
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post #10 of 21 (permalink) Old 12-18-2014, 06:54 PM
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I think today's answer to the ignition issue would be a 4 coil (over plug) set up. You could still fire 2 at a time using the points as a trigger for an electronic control with no ill effects. In fact someone on this forum has done that on an 1100 using the stock electronics.
Interested in knowing what you did to the heads, keep going.

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