Running bad then good

[IanDMacDonald]

I was asking if he was sure its really bent. when my advance fell out of the slot, I assumed the bolt holding the plate was bent, as the plate appeared to wobble.

[3Phase]

Dem bones, dem bones, dem dry bones

Hang on a minuet before you waltz away.

It is not possible for the two different types of advance to be physically connected. The two advance assemblies cannot even touch one another or parts would break the instant you hit the Start button.


Mechanical/Centrifugal Advance:
The reluctor is bushed onto the mechanical advance which is doweled and bolted to the end of the crankshaft. They both turn at engine RPM just like the Timing Plate (the plate with the timing marks stamped into it).

Vacuum Advance:
The vacuum advance is connected to the pick-up coil plate. The pick-up coil plate never makes a complete revolution, it just moves back and forth in a small arc in the large ball bearing in the outer timing assembly/housing.

The outer timing assembly/housing is bolted to the engine case and it only turns when you loosen its bolts to adjust the ignition timing.



.

[jjz28]

I just gave up last night, the bike runs really good, just bugs me knowing it can do better. The carbs have been cleaned like 5 times and the advance seems to be working right. The only things I can think of is that float that is not as springy because of that spring on the needle vavle under it isn't as strong as the other 3 and also, when I had the carbs apart last time I noticed one of the outer slides come down a lot faster than the others. I took it apart and looked at the diaphragm for pinholes and found none. It still makes the whoosh noise coming down but its quicker that the other 3. I guess that wouldn't matter if they work on vacuum anyway would it? If it never would have ran so crisp for that little bit of time, I would never had known. It was like running a new fuel injected fjr or Goldwing, but usually its more like a Hot rod sound. I mean the sound even changed and that has to be because every cylinder was perfectly smooth together and made it so crisp. I guess it could still be a carb problem. Its mostly where you slow down in higher gear to make a very slow turn, it will kinda shutter (not miss) when accelerating. When right I could be in higher gear and this would not happen. and when switching the petcocks worked, I think it was because it was changing the fuel flow for a second maybe doing something to the floats. Also, right at the point where it switched from pilot to mains, if you hold it there (I did it on purpose) it will do it, like flutter or whatever its doing. As soon as it hits the mains, its gone. Thanks for everyones help. If its just out of synch, could it run good and then bad? And really bad isn't the word for it, I should say not perfect. If someone were to jump on my bike they would probably never notice it unless it decided to do the perfect thing while they was riding it. Like I said, it will hit 100 FAST, so it runs really good. One more thing I am going to do. I put smaller filters on about a week ago and I am going to change them. Thanks.

[GLoweVA]

Jeff, just one last thought.
It may not be worth a hill of beans, but it may be worth trying.
You say you looped your fuel lines up and around the carb inlets.
So you've got a 'high' spot in the fuel line routing, could there be air trapped in there that's slowing down the fuel flow?
On my SG, I've the fuel lines going down from the petcocks between the 1/2 & 3/4 stacks then the loop around above the breather/transmission area before they come back up to the carb inlets. (crossed over to so the left feeds the right, and vice versa)
So, I've got no high points or vertical loops in my lines, so any air in the lines will either go up to the petcock or the carb.
Maybe the bigger fuel filters might help too.
Sorry I missed your call Thurs. I was out cutting the grass. ( i hate chores)

[jjz28]

Hey George, I think I have mine routed like you do. I lowered my float level a little bit cause I had it maybe 1 mm high so I lowered it to about 25mm even and it pulls much better. It runs really good so I am going to wait until I get it synched and see how it does. Its not fluttering anymore either. Also, I think a pilot jet may have been loose and not seated. I thought the head was stripped and looked down and it was coming out. There was not resistance at all liked most when it first comes loose. Last time I checked before I did anything I was getting 33mpg every tank. Checked 3 times but it was always 33. something so I think it is running good as far as that goes. I ordered a K&N and will put that on but that's all I am going to do until a synch. I can pull the front wheel on a quick 1-2 shift so its got plenty of power and it'll hit 100 really fast and is still going pretty quickly. Thanks everybody. And know problem George, I get up at 3am everyday so I go to bed about 6.

[IanDMacDonald]

Hey Jeff- Yrah, get them synced, you'll notice the difference.

[TopCatGr58]

Hey Jeff,

That 1 vac. slide bothers me! It should drop at the same speed as the others. Is it dropping quickly when you have the arced vent slot blocked?? If so....then you have a leak somewhere. The slide vents thru the small hole in the middle of the slide next to the needle, so it should flow rather slowly. But if there's a hole in the vac. diaphragm, then air is allowed to flow into the upper vac. chamber much faster than it should and the slide will drop. The concern is that that same leak will prevent the slide from rising at the proper rate and position relative to the others. This will also affect the performance even if you are able to get/obtain a vac. synch! That loose pilot jet could also be the culprit of your stutter and low rpm throttle response!

T.C.

[jjz28]

hey TC, when I took the carbs off yesterday, the slides were all pretty close together. I believe its running really good now. either that jet was loose or the lowered float height helped. I wish I had a quieter exhaust. Maybe it was leaning out too much when it ran so awesome those couple of times.