Chitty, Chitty, Bang, Bang!

[CatatonicBug]

After a year in my new location, having changed from my previous 1500 annual miles to 14K annual miles, I am now seeing some strange issues. I don't know that anyone would be able to diagnose this without actually experiencing the issue, but when I figure out what is going on, I'll be sure to post what I find here.

The biggest problem is that the symptoms are rather sporadic. Some days are fine, some days I have a little issue, and other days (like this morning), I think the engine is going to explode beneath me for my entire 30-mile commute. At this point, the bike starts nicely and runs fine for 10 miles or so, then starts to cough a bit, almost as if it's missing on one or two cylinders. The cough will clear for a few seconds, then return. This repeats, and gradually gets worse, adding an occasional mild backfire to the mix. Speed is reduced from 85mph to a top end of 65-70mph. Then, suddenly, everything clears, and I'm cruising again! Then, 30 seconds later, the coughing returns...

I recently did some work on the bike, so I imagine I may have caused the issue myself, but I'm struggling to identify what I did to cause this. Here is what I did, just before the issue started:

• -I replaced the left oil seal behind the timing assembly. I had done this before, but I guess the seal I got failed.
  -I changed out almost all my fuel lines. The Tygon I had in there was hard as a rock, and I can't get it at the local parts store here like I did in Missouri. In this process, I removed the inline fuel filters (one of them broke trying to get the Tygon off of it) but they both looked perfectly clean after 2 years, so I don't suspect that as the cause of this issue.
  -I changed my oil from my summer 20W50 to the winter 15W30
  -I cleaned the carbs and sync'd/colortuned them. The #4 carb didn't seem to respond to the colortuning, so there may be an issue with the fuel/air mixture on that carb.
  -I also adjusted the height of the float on the #4 carb to be more in-line with the others. Visually, it was WAY off. I wonder if this is the primary cause of the problem, and needed to be off to give the proper fuel height.
  -There is also a crack in my left exhaust pipe, just below where my heel hangs on the foot peg. It's not huge, but visible.

Any ideas are appreciated, but I will be working on it over the next week or so, trying to figure it out.

[tcoop]

My first thought would be the vent in the gas cap is getting clogged or a kink in the fuel line.

[CatatonicBug]

My first thought would be the vent in the gas cap is getting clogged or a kink in the fuel line.

I thought about the cap, and even went so far as to open it up as I was going down the freeway. No change in the performance. I don't see any kinks either, but that doesn't mean I didn't miss something. I will be checking that again.

[tcoop]

another idea would be the pickup coil wires

maybe clogged filter or petcock screens... if you have ever filled up at the Willard Flying J (or anywhere for that matter) it could be bad gas. I filled my mustang up there before and I hardly could keep it running, coughing, sputtered and backfired until I filled up again then it ran perfectly.

[CatatonicBug]

Definitely not bad gas, since I go through an entire tank every 1.5 days, and fill up at 2 different brand stations (alternating each time). The problem never changes based on where I filled up. Since I did have the timing unit off with the seal change, I suppose there is a chance I did something to the wires in there. I'll check that too.

[motoman]

Definitely not bad gas, since I go through an entire tank every 1.5 days, and fill up at 2 different brand stations (alternating each time). The problem never changes based on where I filled up. Since I did have the timing unit off with the seal change, I suppose there is a chance I did something to the wires in there. I'll check that too.

Erratic like that C.Bug(comes and goes), have a close look(pull) at specificly the white pick-up coil wire. It failing(breaking) and arcing itself back together had me scratching my head for almost a year with an occassional shot-gun backfire.......JAT.

[Bikes]

Advance plate restricted sometimes??..somehow? Maybe you left your hammer in there.......wire broke? Sounds like it wont advance sometimes and then let go....just thinking....

[CatatonicBug]

I just went out and tried to take the cover off here at the office, but one of the 4 socket head screws has a stripped head. I will try to limp home and use my real tools to get the cover off. Something tells me the problem is in there...

[Schming]

JAT . . . You may want to check #4s plug color and make sure it's not running too lean.

Sounds like PU coil wires, but have you set float levels using the four hose method ?

[donebysunday]

You just need to go back and check all the things you did.
The thing that stands out the most is the setting of number 4 float ? ? ?
Then the timing ?
Sounds like fuel issue but sometimes to much fuel can act like not enough and visa versa, check for kinked fuel lines.
Check plug coloring.
Check plugs for spark.

[CatatonicBug]

Ok, I think I solved the problem. The day of my last post, I ended up stuck on the exit ramp, and it wouldn't go any more... Had to be towed for the first time ever. Thank goodness for Progressive's roadside assistance!

Anyway, after a busy holiday, I finally got to work on it, and discovered that one of the blue wires had been routed incorrectly, so it was being worn through by the timing disk. I also discovered that the PO had been in there at some point and did something with silicone to "waterproof?" the white wire:





I repaired both wires and put heat-shrink on them instead of silicone. Now it runs great again!

Thanks for the input!

[James England]

Erratic like that C.Bug(comes and goes), have a close look(pull) at specificly the white pick-up coil wire. It failing(breaking) and arcing itself back together had me scratching my head for almost a year with an occassional shot-gun backfire.......JAT.

well spotted, that man!

[trbig]

Looks fairly wet with oil in the timing assembly. Crank seal leak?

As a side note, if you are a member of the American Motorcycle Association, for $45 a year, you get the magazine, member benefits and free roadside assistance for you and everyone in your family. I've used it several times with vehicles and even once for Greg's bike on a front blowout. No questions asked, nothing to sign from the towing company, and apparently no limit on the times you can use it. So if your insurance company doesn't offer it, you might give it a look.

[CatatonicBug]

Looks fairly wet with oil in the timing assembly. Crank seal leak?

There was. I had just repaired that when this issue started. Likely it was how I put things back together, routing the wires too close to the timing wheel that lead to the worn wire.

[trbig]

There was. I had just repaired that when this issue started. Likely it was how I put things back together, routing the wires too close to the timing wheel that lead to the worn wire.

No, no no! You just blew your chance to put all the blame on the PO!