79 XS 1100 SF Vibration

[XS1100Special]

Hi Guys,
I was so amazed to find this forum thru google, a whole new world I never knew existed. I have been the proud owner of a 79 XS1100 Special since it was new.
It just hit 10,000 miles last season and still looks pretty good.
My problem is a vibration right around 5,000 RPMs
Bike is running pretty bad right now but I have fresh fuel, and some fuel system cleaner in it I hope that will resolve but the vibration has been there for the last few years.
Another problem that seems to be getting worse is sometimes while riding it has a sudden loss of power as if the ignition was shut off to 3 cylinders and Im only running on 1 . then it just comes back to normal and power galore. not sure if its in the fuel or ignition.
anyone familiar with any of these problems?

thanks in advance for any help with these issues, and I'm sure glad to have found this place!!! I love my XS1100 Special!!!
I will post a few pics soon.

Be safe and thanks

[Silent]

Sounds electrical to me. I had a similar problem on a Ninja once. Turned out to be a broken coil power wire. It was broken inside the insulation so it would stay connected most of the time. But when it broke connection, I lost the coil until it decided to touch again and bring the coil back on-line. I'd start at the electrical connections. Check for clean and tight connections for the wires off the coils. The XS uses a waste spark, so power to 1 coil actually powers 2 cylenders.

[tarzan]

You may want to search the threads for the pickup fix,actually I think it is in the tech tips.That may be your drodpping a cyllinder problem.
How often do you ride?10,000 miles in 30 years aint much.You may have some gummed up carbs.
I would start at the pickup coil wires first though as they break over time form flexing during operation.The coils them selves usually dont go bad soyou can just solder in new wires.

[dbeardslee]

I'd start by checking wiring with a DMM. Pull the four pin connector at the TCI and holding the connector with the slots horizontal, check the resistance across the top slots and the bottom slots in pairs. You should get a reading of 720k ohms plus or minus 20%. Jiggle the wires around at the pickup coils and see if the readings fluctuate noticeably. If they do you probably need to do the pickup coil wire fix.

You can check your ignition coils for primary and secondary resistance as well. To check the primary resistance pull the big connector at the TCI and jumper the red/wht to the grey, and then to the orange. Readings on each should be about 3 ohms. Pull the plug wires for 1 & 4 and insert the probes from the DMM into each plug cap. You should get a reading of about 25k ohms with the plug caps attached - 15k ohms with them removed. Repeat the procedure for 2 & 3. This is your secondary resistance. If the primary is OK, but the secondary is way off you may need to graft some new plug wires in, or at the very least replace the caps.

The other thing you may want to do is to go through your electrical connectors. They corrode over time and should be cleaned periodically. There are three of them behind the fuse block mounting plate that are often missed. Pay particular attention to any connector that has the red/wht wire going to it, and don't forget the connectors inside the headlight bucket - particluarly the one that runs from the ignition switch. You may also want to clean the connections on the handlebar kill switch. Be careful taking it apart as there are two small springs and a tiny ball bearing inside the switch that can really fly when you take it apart.

Once you have all the ignition components in spec you probably should adjust the carbs and synch. Vibration can cause the screws to move around over time, so it's something that should be checked regularly. My $.02.