XS650 BigFin KIt

[Tomterrific]

You don't need to check the advance under load. Advance is determined by rpm. Kop ment a non advancing engine will rev with small load, like neutral or first but not have the power in the higher gears to achieve higher revs.

When the bike is maxed out WOT, does the engine miss and run rough or does it just run smooth with no power?

It's not running on one cylinder, is it? Not to insult but the number of older bikes I've seen with a dead cylinder is quite amazing to me.

Tom

 

[ihaxs650]

Tom: At WOT, the bike run's smooth with no power and i do not believe it is running on one cylinder.

I have ordered a TCI coil, NGK spark plug ends, spark plugs and new wire from Mike-XS. This will cover all ignition troubleshooting except the pickup coil and TCI unit!

 

[ihaxs650]

An update... Got the new TCI coil, wires, NGK spark plug ends and spark plugs from Mike... Same issue , will not rev above 3k except in first gear. Will measure the resistance of the pickup coil and i have a bad feeling that the bad rectifier/regulator caused the TCI to go bonkers...

 

[ihaxs650]

Got the air box off the 1980 Special. The TCI pickup coil read fine at 752 and 756 ohms. Disconnected the TCI unit from the wiring harness and found a lot of green corrosion in the connector. This connector is located directly underneath the battery vent outlet and the PO "present owner" did not diligently keep the vent tube connected to the battery. LONG LIVE AGM BATTERIES. Cleaned the connector with battery cleaner and electrical contact cleaner. Took the bike out for a test ride and revved to 4k in first and second " a first" then shifted to third and there is a pop sound from the carbs and i find myself limping home in first at 10mph. I believe the TCI is shot!



Gonna ship the unit to Carmo USA in Chico, Ca for diagnostics and repair. Will have another update!

 

[ihaxs650]

Update: Got back the TCI unit from Carmo and it cost me $50 plus shipping to find out that the unit is good! Decided to clean the contacts on the TCI male connector.


The dermal does a good job on the male connectors. Forgot to take an after picture. The female connector's are a lost cause!

Tried to salvage the main harness but I would need my early teenage eyes. Ordered a main harness from Mikes XS.

Here I am finishing the harness install.

To make a long story short. The no revving problem under load was caused by corrosion in the TCI connector to the main harness! The bike runs fine under load! This has been over a year project! I do not know how I could have shortened the trouble shooting process. The last thing I did was disconnect the TCI connector and viola there is mucho corrosion. Thanks everybody for the tips and helpful hints. Thank you!

 

[Bob Kelly III]

well, Now we know that corrosion in the TCI connector can cause that ! I learned something !!!! so thank you !
Bob........

 

[Marlin72xs]

Now there's a little principle that we forget too often, which is that some electrical problems show up only under load.

Grumpy, you are absolutely correct, sir. Not only can we experience electrical problems under load, but with 46 year old wiring and many miles of vibratory vibrations, these old clunkers can and do experience random phantom shorts and high resistance shorts. The 70's plastic wire insulators are cracking and within the bundles, the cracks can't be seen. I've replaced the main fuse holder with a 2-prong car type and carry several extras. I would guess that 99% of us have experienced a total shut down, and with some random tinkering, we find that it starts again. Don't know what I did, Hmmm?

 

[Marlin72xs]

Have you replaced the front brake lines? Now that's an item to REALLY worry about.

Yes, Gary, I have. Much better. I also replaced the jello like substance throughout the entire front brake system.