Runs Rough Until 3k On Tac

[ultra6xlt]

Hello,

I would like to thank everyone in advance for all the helpful advice posted on this site. You all have made a world of difference when diagnosing problems. I read through the postings regarding the bike running rough, and everyone seems to say it is the pickup coil. Here is what I am experiencing:

I spliced new wire into my pickup coil earlier this year. I had no spark, and found breaks in the wire. Everything was running fine until I washed it last weekend. It seemed to run rough, and bogs down quite a bit when you first get on it. Once it gets past 3k, it takes off fine and runs smooth. Could I have another break in a pickup wire? I thought I might of got water in somewhere, but I rode the bike for a while, and any water should of dried up by now. I am going to test the wires again this weekend, but thought I would see if there might be some other reason for the problem. Thank you for the help! I need to get it back on the road and enjoy the summer weather!

- Matt

[Ken Talbot]

Yes, Matt, multiple breaks are very common. Hope it turns out to be that easy...

[TopCatGr58]

Hey there Matt,

Like Ken said, probably the pickup wire fix, depending on what type of wire you used to fix it, could have been too stiff and constant flexing can cause them to break down again!?

Also, what type of air filter, have you changed/checked it lately? Bogging down in lower rpms could be too rich in the idle circuits? Have you cleaned the carbs thoroughly lately? Tried some SeaFoam in the tank? Just throwing out some other ideas to check!?
T.C.

[ultra6xlt]

Thank you both for your replies. Here is another possibility I discovered. I checked the pickup coil with an Ohm meter, and everything was fine. I then looked at my vacum supply line coming off the diaphragm. It was full of what appeared to be rubber bits. The line was clogged and no air could get through. I cleaned it out and replaced it. The same problem occurs. I also removed it and tried running it. The bike still ran the same. Could it be that my diaphragm is falling apart, and clogging the vacum line? Would a bad diaphragm have similar trouble signs? How do I replace the diaphragm, and is there a kit I need to buy? Thank you all again for the help! Your expertise makes troubleshooting that much easier.

[ratbyk]

Vacuum Advance

I don't think there is anyway to repair the diaphragm in the vacuum advance. You will need a replacement. Someone on this list should step forward and offer you a deal. John in Texas, do you have a spare? Also that truck load of parts in Calif. that Big Pat was interested in. Bet there is an extra vacuum can in there somewhere.
Ken/Sooke

[ratbyk]

Vacuum Diaphragm

Further, after thinking about your deteriorating diaphragm. Make sure that the vacuum line is attached to the nipple on number 2 carburetor, not to the nipple on the intake manifold. The excessive and wild vacuum coming off the nipple on the intake manifold would sure shorten the life of this diaphragm.
Ken/Sooke

[ultra6xlt]

Gentlemen,

Thank you all for the help. I have it running like a champ again. Here is what I fixed:

1. The gas lines have always appeard a little kinked, so I put in new lines with a Y and L connector to keep them flowing.

2. The vacuum line (coming off the diaphragm assembly) that goes into carb #2 did not seem that it was tight enough, so I replaced it.

3. My ignition coil wires always were a little sketchy. They had cracks in the casing, and I cut some off the terminal end due to corrision. I replaced the ignition coils with a set that had better wires.

I started it up, and it is running better than ever. I am not sure what that rubbery deposit was in the vacuum lines, but it appears the diaphragm is working just fine. Thank you all again for the help! You cannot replace experience with a book. It is time to get out there and ride now. Take care!

- Matt