1981 XJ650 not firing on two cylinders. I know, another one.

Hello all I have a 1981 XJ650.

So here's what I have and have done.

Replaced coils packs (1 was bad due to bad readings). Resistance now good.
No fire on 1&4 but on 2&3 switched input to coils and problem switches. So moved farther back in the system to check the pickup coils. My issue is that I have 4 wires coming from the pickup (picture attached). Mine are not black, orange, and gray. Mine is black, orange, gray and brown. I did measurements across the plug and got 600 ohms across black & orange and 0 ohms across black & gray. However I got 600 ohms across brown & gray. I was looking at the drawings for an 81 XJ650 but I can't find where there is a brown not attached to the black. Any help or ideas would be helpful. Thanks.

 

on some bikes yamaha did not splice the "common leads together

take off the left side crank cover that is where the pickups are located

you will see the pairs

is 600 ohms the spec

do you mean zero ohms or no reading on black and brown?

bronwn and black are the wires that are usaly spliced together and run to tci as a common
black and orange are a pair, gray and brown are a pair

 

The reading is nothing black to gray but 600 ohms brown to gray.

According to this info from xj4ever.com they are supposed to be 700 ohms +/- 20% so it says 560 to 840 so I believe so.

So do I need to make them 1 common or just leave them as they are. It isn't working correctly right now so...

 

The FSM test process is pretty simple. Check coils --> check pickups --> Replace TCI. The coils should be 700 ohms +/- 20%.

The 81 diagram shows four wires, you'll have to pull your cover and see what is going on. Is the harness damaged/pinched where it runs under the motor? There's also a metal cover (on my 82) over that harness just by the pickup cover, that jams the wires into a pretty tight spot.

 

the pick up head on the pick up coil could also be bad.
as it hit with a wrench when doing valve check and out of alinement with rotor

as suggested trace the wires from connector through to the pickups.

ohm them back to pickups

again zero ohms or no ohms ?

 

I just looked at a pickup. 600 across black/orange and 600 across brown/gray should be right. I wonder if you have a wiring issue between TCI and coils?

Ditto. This is important, big difference between them

 

need a little history.
was bike running before or are you a new owner with a non running bike.

do you know anyone who also owns a 650 to do a swap of the tci to test it for you?

 

I'm getting exactly this.

I will check the lines again from the TCI to the coils. I checked them for continuity and had good continuity but didn't check resistance. Will check again when I get home from work today.

I bought the bike from a buddy. Ran years ago but hadn't done anything with it til I bought it.

I don't know anybody else who has one near me or I'd ask to try.

 

That's good then. Still curious about the 0 ohms black & gray. 0 is shorted and not good. No ohms is open and what you want.

I'd be suspect of wiring or the TCI itself.

 

Just noticed your location, our family has a place on Mullet up there. Spent many many summers up there, has changed alot since I was a kid. Neighbors then were post office workers, small engine mechanics etc. Now it's lawyers and doctors.

 

Is there anyway to test a TCI?

I will recheck the black/gray set when I get home and report back.

 

the swap method is one way to test you could mail yours to a member if there is a willing member.
This Yamaha 5V2-82305-10-00 Ignitor Unit Assembly 1 is used in the following models and assemblies:1980 XJ650 (XJ650G) - Electrical 1

• 1981 XJ650LH - Electrical 1

• 1981 XJ650 (XJ650H) - Electrical 1
• 1982 XJ650RJ - Electrical 1

there is another way that shows up from time to time in the forums but is debated as reliable

try checking this
you said when you swaped the coil connectors the problem followed the swap.
unplug your right side connector on the TCI and check your coil primary resistance from the connector.
it should be the same as the test results you got at the coil connectors if it is a big differance it could be the connector, conn pins or wires from tci to coil primaries

jayrodoh is it possible that yamaha did crimp the wires together down near the pick ups and still run both wires up to the tci .
jayrodoh does your left tci connector have 3 wires or a 4 wire config?

you could also have bad spark plugs but where the symptom moved with swap this would be unlikely

 

As far as I know, they both had the 4 wire configuration BUT in 82 one of those was for the ignition cutoff with all the new safety features. I've never looked to see if the modules were different.

The 81 manual shows 4 wires for the pickups. The 82 manual shows the Black and Brown joined. Black and gray showing 0 is what had me concerned.

 

Might need someone who actually has an 80 or 81 to weigh in. There some differences between the colors in the diagrams, your pic, etc. The two black wires shown on the 81 FSM might be common. There's no brown like your pic.

I looked up the modules, the 82/83 is a different part number than 80/81 for the 650 Maxim.

 

part look up
This Yamaha 5V2-82305-10-00 Ignitor Unit Assembly 1 is used in the following models and assemblies
:1980 XJ650 (XJ650G) - Electrical 1

• 1981 XJ650LH - Electrical 1

• 1981 XJ650 (XJ650H) - Electrical 1
• 1982 XJ650RJ - Electrical 1

or an 82 seca 650 to test tci on
he has a few things to check out

 

Yup, I just wanted to give a good answer on the number of wires.

I found an 81H pickup plate and my 82J pickup plate. The H has four wires from the pickups (2 pair Orange/Black and Gray/Brown) and the J plate has three from the pickups (Orange, Gray, and Black common - joined in the harness). So he should have the right one and the measurements are correct on the pairs.

 

My manual shows this for the pick-ups and TCI.

 

So here's what I'm getting. Black to orange

Brown to gray

Black to brown.

 

I also tested the 12V at the primary coil plug(the 2 pin plug) and have 12V there. They drop to right around 10.75 while cranking.

 

I attached some pictures of what I'm getting.

 

O.L on a fluke = Overload or in this case infinity which is good. Your tests look good on the pickup coils.

Test your cabling between TCI and coils. You may have a faulty TCI. No bench test for those, basically find a known good one and swap.

 

what do you get when you ohm test ignition coil primarys from the right side tci connector?


what is the color wires of the ign coil that is not firing?

gray wire or orange wire?

 

From the 2 pin connector?

 

Should be three. Measure Red to Orange and Red to Gray. Make sure primary connections are still hooked up on coils.

 

It's the orange/left side.

 

test the right side connector at the tci those wires feed the ignition coils
redwhite to gray
redwhite to orange
see if you get the same readings as you do at the coil pack connector where the 2 wire connector is

 

Red/orange

Red/gray

 

They are 2.6 red/orange and 2.7 red/gray

 

try cleaning the tabs on the tci they look real dirty for th right side and the connector I use contact cleaner

 

I went from the output of the TCI to ground and got these readings.

Ground to orange 11.88 before crank, 7 during
Ground to gray 11.79 before crank, 9.5 during.

Is there a spec for this or are those acceptable?

 

these are the voltages that go through the primary of coil there is a spec and test for this in the fsm. it is done at the ign coil connector

have you tested the battery
hook meter to battery record voltage then record voltage when you try to start bike you need 10 volts at the battery with starter cranking maybe you just need to charge battery or a new battery

 

The battery is hooked to a tender right now. I'll test the battery while cranking but what would that have to do with one side working and not the other?

 

could be you have low voltage to start with
you could also have dirty connections

your ohm tests have you on the fringes of out of spec at one ign coil
would just like to rule it out

how old is the battery

 

Volts? Ohms? The TCI switches ground to the coils so checking this against ground won't give you anything meaningful. There is no test of the TCI (well technically you can crack it and scope it out etc.) other than switching with a good one.

My vote is TCI. You know your coils are good, they both spark and test out. Pickup coils test out.

 

That's volts. Sorry. Should have put that on there.

 

No worries, just checking. Still won't help anyway.

You did check for 12 volts at both coils right? Check Red/White to ground with meter with ignition on? If so, I def say TCI. I guess you could switch the pins in the pickup coil connector if you really wanted, see if the same side sparks. I wouldn't though, they test fine.

 

after testing your battery open the cover of the tci and check for cracked solder joints.
it is looking like your tci is bad but It would be best to clean connecters check battery volts before spending 100$ or more on a tci

 

Yes I did test the red/white on the in of the primary on the ignition coil.

 

Battery reads 13V key off, 12.6V key on and 11.3V cranking.

Here's what the inside looks like.

 

test all those pick-up wires to ground, they should all be O.L. (open line)

 

They are all open.

 

I was reading through this testing guide for TCI modules and it says that the readings should be 10-11 volts before cranking and should make a large swing while cranking. My module is doing this. Am I reading this wrong or something?

 

I think that test is done with an analog meter and it is looking for needle swing

 

I have an analog meter as well as a fluke and I do get some good meter swing. I don't know. I'm going to take the TCI in to work with me tomorrow and resolder the connections and see if that makes any difference. Thank you for all the help. I'll keep you all updated with how it comes out.

 

link on tci repair and transistor replacment I can not attest to is validity of concept
http://www.xjcd.org/General_Electrical