Primary Closing Incorrectly

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krakum1967

krakum1967

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Jamestown, ND
I do not remember but I need to check, when you give throttle to my carb, right at the point where the secondary kicks in, the primary slams shut and then re-opens in sync with the secondary. Shouldn't the primary stay open and the secondary is to open independently with the primary staying in one place with the secondary opens?

Just checking my sanity. That and it runs fine without the filter, but is choking out with the filter on
 
primary is never suppose to slam shut and then open again while secondary is coming in .....filter has restriction and hampers air flow ... how much depends of filter set up
 
I figured it out, and I have to wonder how this will or has affected the test runs and nature of the bike.

Here is what was happening. On the throttle like the secondary link exists behind the primary throttle link. There are springs that are supposed to be set on the "hip" of the rod where the parts are to be exactly placed. This coils for the spring behind the assembly right next to the carb, and the spring that sits between the secondary lever and the primary lever. One coil was in the joint between the secondary and primary throttle arms causing the secondary to hang when operating the throttle, So the secondary and the primary were "running together" at low speeds, or when only the primary is supposed to run the show. Both butterfly are opening and the system was being drowned in mixture. When the throttle reaches cammed portion of the accelerator pump arm and the cam for the secondary arm itself. The throttle would hit that spot, and the secondary butterfly would snap shut, and re-open indepently and complete the action at full throttle. In other words through the range of the throttle, the secondary butterfly would snap shut after opening with the primary until it hots the spot where the secondary is supposed to kicn, and re-open again.

Yea, and if I take it easy, no snap and the bike runs great. So I found a coil stuck down in the area of the return springs. Its first coil was being smashed against the primary arm, causing it to open when it was not supposed to. I loosened the bolt, took a jewelers screwdriver and walked the coil out of the area where it was stuck until the entire coil was sitting on the "hip" of the cammed area of the throttle bar. Next I was able too carefully apply roughly 10 to 15 pounds of torque, than locked the nut in place with the special washer....no more snap of the secondary, and this cures the rich low RPM running, hands down. I am off for a test drive when it cools down. And it fixed the issue, I opened the carb 50 times on the bench with no snapping back whatsoever.
 
Exactly Joe, and due to me not checking to see that the springs were in their proper place when remounting my primary throttle arm after I modified it to give more twist on the throttle grip. I caused one coil of one of those springs to drag against the primary link just enough to open the secondary until it reaches the spot where the secondary was supposed to open. When the throttle goes through that spot, especially rapid twists of the throttle, the secondary that was opening alongside the primary would close and re-open as normal, this is why the bike loves high range as much, and why I could kill the bike with the twist of the throttle. Problem is fixed, I laid the springs out properly, and was able to torques the primary in place on the bar, and the secondary sits independently until the cam tells it to open up. The primary opens and then the secondary opens when you hit the sweet spot, and the accelerator pump kicks in after that, so here is the lesson from Kraig's Dumb Mistake number 30078

Check and Double check the position of the coiled springs on the throttle arm if you have made mods. The springs need to be set on their cammed space so they can coil and recoil properly. And have a piece of the spring get caught like mine did gives you both barrels of the carb at once, causing an extremely rich running mixture.
 
And here is the real fun part, it would only catch and ride along with the primary say 50 to 60% of the time. So the bike would rund outstanding in the shop on the center stand on a level surface (the spring would pop out and the secondary would open as expected), but with the spring tension on the throttle, and sitting on the side stand, it would be difficult to start and ran SUPER rich. I will test drive it tonight, but its hot out and I have to finish putting it together for the last time.

And Joe, I built that new adapter block that sits on top of the plenum. I did exactly what you said in a response a few weeks back. I used furniture grade A veneered plywood (not strand board) and mounted the adapter to the board using 1 inch Lag bolts. I did start the bolt holes with a 3/16" drill bit and went halfway into the wood to give the lag bolts room to expand without cracking the wood. I built new gaskets for that joint, and the carb gasket out of my carquest fuel rated gasket material. The lag bolts never even came close to the surfaces, they all torqued down to 30 lbs. And seating the wood on the plenum was awesome as you can see how the wood bites into the plenum. It passed the leak test with flying colors
 
Center Stand Testing is done, runs drastically different. Last night I could barely get it over 5500 rpm, just zero snap to the throttle. Now it feels like a well tuned 1000 cc bike, honestly its the first time I have heard that, "I am in tune" harmonic when everything is just about right on. I heard it today on the stand, now to test it on the slab.
 
All nI have to say is.... wow!

Not a flat spot one from idle to 80 mph. Than a slight dogdown, and then it was gone again.

The bike finally acts like a capable bike, the revs are correct for up and downshift, no struggle with neutral, idle right at 800 to 900 rpm, but its still slightly rough, I need the 45 idle jet in the primary, and it will be spot on, than I need one more 95 main for the secondary. Once I get the two jets in, it will be as follows:

Primary Idle Jet - 45
Primary Main Jet - 95

Secondary Idle Jet - 50
Secondary Main Jet - 95

Dropping the order tonight, should be here by Friday

OMG, that goldwing rides amazing, I mean all I did was swap the 105 in the primary main to the secondary main, and used the 95 main jet from the secondary to the primary jet, no adjustments on the idle side at this point, no changes in air tubes.
 
VACUUM IS SUPREMELY IMPORTANT.... You cannot get these things to tune well unless the vacuum is known to be good, it is 90% of the problems or was on the ones I encountered. The smaller jet helps on take off, and the idle is rich, so that will be the big change here, that and a 105 being removed from the primary main, and a 95 put in its place.
 

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