tci ground question..

on the tci, Do I have to ground the metal frame on the back of it to the ground wire that comes off the engine? its been a while since I tore the bike down and the haynes looks like thats where that extra ground goes. On a test hookup I grounded it and I got a spark, but now im putting it back on proper and curious if this is necessary

 

The TCI has a dedicated ground lead, so it's not necessary for the metal back to be grounded as well. It's more of a heat sink, I believe...

 

^Agreed.

 

^^^ I'll second that.

 

good stuff, then Ill follow it up with another question.. The ground (as shown in the haynes) that attches to the frame right where the holder for the tci and rectifier attach to the frame; it looks like I had it attached to the engine (one bolt next to where the battery ground is attached). What was this for? I dont see why Id be grounding the engine to the frame. Or do I. Ill post some pictures if the discription doesnt do it.

 

pics are always help full

 

heres some pics

 

on both of my bikes, that wire goes from the back of the engine straight to the negative terminal of the battery.

 

there are (should be) two wires attached to the back of your motor. One goes to the negative battery terminal, the other goes to the frame.

 

thanks, glad its figured out. Now my question is why. Is this to add more area to the ground, kind of spread it out?

 

Stereomind & I agree about there being only one thick wire from the engine to the neg terminal of the batterry, it is quite possible that someone has connected the earth from the starter to the engine.

 

While I don't agree that there are two ground cables off the back of the motor, it will not hurt anything to have them there. I wonder what the definitive answer is for the purists crowd? I've never seen two cables on the rear of any of my engines (5 and counting).

 

found this in the haynes in the engine rebuild section (for the purists I guess) "note that bolt 35 retains the engine earth cable (straight terminals) and that bolt 37 retains the battery earth lead (right angled terminal on battery end)." Then in the electrical section shows this engine earth lead attaching to the bottom mounting screw for the tci/rectifier housing. Doesnt seem necessary though. Any thoughts?

 

Just took a look at my 550. It actually has 2 leads attached to the engine. One goes to the negative battery terminal, and the other one (looks to be 10-gauge or so) is attached to the frame under the battery box.

Neither of my bikes have a ground wire attached to the TCI housing, but hey, you can't hurt anything by adding one there.

 

What is the TCI?

I seen you guys say having an extra is a good idea?
Thx
-G

 

Transistor Controlled Ignition. Having a spare is a very good idea, they are no longer available from Yamaha and can be very pricey to buy used. Shop it if you care to get one, it sounds like the advantage of time is on your side right now.

 

Ya, got myself a spare when I was diagnosing an electrical fault. It wasnt the tci and I thought about putting one back on ebay, but probably going to hold on to it. As a backup or a long term investment when I sell it 10 years from now to one of you guys