Seca650 No spark

Hi. I am the proud new owner of a Seca 650 and it's time for the restoration to begin. It's bone stock and It has 22,000 miles on it. It lived in Hawaii for most of it's life and then a second owner had it for about 3 years until I picked it up yesterday. Very excited.
The engine turns over but I'm not getting spark. Ugh! The other two major problems are that the master cylinder needs to be rebuilt and the tank has rust in it.

For now I'm concentrating on the no spark situation. When I bought it the PO believes that the resistance in the plug caps might be the culprit. I checked the primary and secondary side on the ignition coils just in case and it all measures out. I also checked the continuity of the fuse box at the ignition and that's fine (original fusebox). The battery is good, btw. I have to admit I haven't checked the pick-up coils yet. Being a bit new to bikes (one and a half years) I'm not exactly sure what a good cap should measure out to so I checked the resistance on each cap and this is what it came too. 1)5.89ohms, 2)9.45ohms, 3)4.65ohms, 4)9.84ohms. Do I need new caps? What other tests should I do?

Also, if anyone has any good tutorials out there video or otherwise on how to clean and seal a gas tank that would be much appreciated. I guess I should mention that if there's also anything out there on how to rebuild the master cylinder that would also be appreciated.

I'm happy to be part of this group and I look forward to your comments.

Mr. Seca

 

Update: The pick-up coils measure at 629ohms and 646ohms.

 

One more update. I just wanted to compare the results of the ignition coils secondary side with and without the plug caps. Here's what I came up with
#1 & #4 11.36k ohms
/with caps: 30.79k
#2 & #3 11.06k
/with caps: 21.73k

 

Love your handle

 

Welcome to XJbikes, the following link contains answers to many questions and is a must read to get your bike into a safe and reliable state:

https://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

From the above link:

XJ650 models:

Pick-up coils:
1980-81 XJ650 Maxim and Midnight Maxim: 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
1982 XJ650RJ Seca (non-yics engines): 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
1982-84 XJ650 Maxim: 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982 XJ650RJC Seca (yics engine): 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982-83 XJ650 Turbo: 120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug

So based on the reading you provided for the coils with caps it looks like the 1 and 4 caps have an issue - the first post somewhat contradicts that but I suspect a typo there. That said, none of the reading are high enough to prevent a spark so either something else is wrong or the methodology is wrong. One of the most common problems for a weak spark is a marginal battery. The battery should be checked with a load test by measuring the voltage to verify that the battery maintains at least 9.5 volts while the bike is cranking.

 

Thanks Rooster. You're right about the typo. I'll try the load test and go from there.

 

You can also tag a larger 12V battery on for testing or put a 2/3A charger on the battery while it's cranking to rule out a battery issue.

 

Thanks Ryengoth. I was using the battery from my other bike but went ahead and purchased a brand new AGM since I needed a new one anyway.

On further inspection I noticed an odd connection near the starter solenoid (see pic). I'm referring to the blue wire. Does this look right?

 

the connector with the jumper wire is or looks like the solenoid connector from the harness. there should be a mating connector on the solenoid.
what ever it is it shouldn't be


what color are the wires on that connector should be blue/white and red/white

is it black/yellow and blue/yellow?

 

21k ohms with caps is what you should have not 30k. caps should be 5k ohms each

 

It is a plain black wire and a blue wire with a yellow stripe.

 

Here is a better pic.

 

Just did a load test on the battery and it only goes down to 10.63 volts so that seems okay. That odd connection might be the culprit but I can't seem to figure out where it goes.

 

I am guessing a bit but that looks like a L/Y and B wire which would make that the side stand switch connector. The PO likely installed the jumper to bypass a bad or suspected bad side stand safety switch.

The safety system (side stand relay) can disable the TCI assembly so that there is no spark. Since the PO was futzing around with that you could try pulling the side stand relay (blue dot) to troubleshoot the no spark issue. Pulling the relay disables the ignition cutoff feature which is normally activated by engaging the side stand relay to open a set of normally closed contacts. The side stand relay normally can be energized with either the neutral switch or the side stand switch.

Another option to disable the ignition cutoff for troubleshooting is to disconnect the B/W wire at the TCI (Ignition Module) six pin connector. If you locate the B/W wire and follow it there should be a single bullet connector that can be disconnected.

 

Agreed. The sidestand switch has a long lead that connects to the harness near the starter solenoid.
The way it's been bypassed indicates the PO had no idea how to bypass it and have the TCI make sparks.

 

Well, I tried to go to the sidestand and pull the relay switch but I don't see any visible wires coming from there. Is there a pic that I could see to find it's location? I also found the B/W wire at the TCI unit and followed it to the what I think is the bullet connector (see pic) If this is correct is there another way to bypass it. It looks crimped in there and looks like it would be a pain trying to put that back together after I take it apart.

 

you will like this link
The Ultimate Relay, Switch, Sensor, and Diodes Guide

Sidestand (kickstand) relay (blue): behind the flasher relay, under the front of the tank.


Flasher: near the steering headpipe, on right side frame rail, under the right side ignition coil.


the side stand switch does hook to a black wire and a blue/yellow wire .

Rooster53 and K-moe are correct about the jumpered connector being the side stand switch connection.

there should be a black/white wire with a bullet connector coming from tci. if you disconnect that wire it will bypass the sidestand safety switch. try that first before going under tand for the sidestand relay

 

Here is a pic of the side stand. I'm guessing that whatever relay, switch, sensor or whatever it's called has been removed.

 

correct the sidestand switch has been removed.

you should consider replacing it. when circuit functions properly if you deploy the sidestand bike shuts off. if you do not have on the bike you could have a bad left turn incident

sidestand switch

 

Is there a way to hack the bullet connector without taking it apart? I'm just trying to prevent more work in the future trying to crimp that bad boy back together.

 

it is a rubber jacket connector cover a little wd or silicon under end it should pull apart
black/white wire runs from tci connector. bullet con is about 5 inches down the wire

you have to remove tank to find the sidestand relay

 

Ok, I was able to disconnect the b/w wire from the TCI and unfortunately it didn't change the situation. I'm still able to turn the engine over but not getting a spark of any kind. Any other ideas? Everything checks out to spec as far as the coils, ignition and pick up. Fuse box looks good and I cleaned the connections with sand paper to get them bright and shiny. Battery is also good as it's the one that I use for my other bike and it's only 6 months old.

 

Is this the correct side stand switch, btw? Would this be the female connection that would fit directly into male connection that the PO jumped as indicated in the picture I posted earlier?
https://www.ebay.ie/itm/1982-YAMAHA...742749?hash=item4d72dfab1d:g:wV8AAOSwLEtYj2Jo

 

That's the right one.

 

1. Just to be sure you are checking for spark correctly check one cylinder at a time with the other 3 plug wires connected to the spark plugs with the plugs installed. Using a spare new plug for the cylinder under check is advisable but a known good used plug would be OK. It is important that the other plugs are connected with the wasted spark system to have a complete current path to produce a spark. Connect the spark plug to the cylinder under test plug wire and ground the threads to the aluminum head. Crank the motor and look for spark - note XJ bikes produce a weak spark so in the garage or shade is advised.

2. Since there is evidence of the PO being creative check the voltage at the TCI just to be sure 12V is present with the key on and the kill switch set to RUN. On the 4 pin connector at the TCI there should be 12V on the R/W wire in respect to ground. So connect the black lead of the DMM to chassis ground or battery negative and with the red lead back probe the R/W wire at the TCI to verify 12V. Note that the voltage should remain above 9.5 (See edit below) volts during cranking also as the TCI becomes active and draws considerably more current. Next move the red lead to the black wire on the 4 pin connector and verify 0V to verify the TCI is properly grounded.

3. If the voltage checks out OK to the TCI, and since you have verified the external pick-ups and coil resistance, as well as disabling the ignition cutoff by disconnecting the B/W wire, then the TCI could be faulty causing no spark.

4. There are a couple of checks that can be done to check the TCI with just a DMM, but an oscilloscope is really required to test it. Or, the other option is have another member try it on their bike - anyways you can do this also.

a. Place the DMM on the gray wire on the TCI 4 pin connector and the DMM black wire to battery negative. Turn the key switch on and observe the DMM - it should show a low voltage (approx 1.4 VDC) for just a couple of seconds and then change to 12V. If this is occurring, you should also see one spark occur on the 2, 3 plugs as the voltage changes from 1.4VDC to 12VDC. Note this is dependent on the position of the reluctor in relation to the pick-up coils, so if the gray wire does not go low momentarily, try the orange wire.

b. Remove the left side crank cover and turn the crankshaft CCW to center the reluctor between the pick-up coils. Place an external plug in the number one spark plug cap and the number two spark plug cap and ground the threads of the plugs to the aluminum head. Turn the key on and wait a few seconds - one of the two plugs should produce a spark but this can be a bit ambiguous as it does not always occur. After waiting, place a thicker feeler gauge against the number 1,4 pick-up (you should feel the magnet) and then flick the blade sideways. Once again this is a bit ambiguous on which plug will spark because of the internal design of the TCI, but either the 1 or 2 plug should spark after a second or two. Repeat on the 2,3 pick-up (top with gray wire).

Edit: The voltage at the R/W wire during cranking when the TCI becomes active is likely to be in the 8 to 9VDC range. Ideally, it should be higher but losses in the main fuse, ignition fuse, kill switch, and wiring will result in a value lower than the battery load test. Verifying the condition of the fuse box, ignition switch, and kill switch would be advisable for lower voltages.

 

Wow. Quite a list of things to try. I'll get cracking. Thank you.

Btw, for the hell of it I opened the stator cover and measured the copper rings. It came out to 4.1 ohms. Brushes look excellent.

 

In the meantime, are there any Seca or Maxim 650 or 750 owners in LA?

 

Just curious, I have access to a TCI from both an xj550 and an xj750. I know these are not the correct TCI"s but would it at the very least fire the bike up thus showing that my TCI is bad?

 

seca 650 has a non yics motor so that's what you need a tci from,
if the wiring is the same at connectors it will fire the bike but will not run well.

 

Rooster, I have some very telling news. I conducted the test where I attached the red probe to the R/W wire on the 4 pin connector to the TCI and when I turned the switch on I only read 9.98volts (battery measured 12.88 before testing) When I turned the engine over it went all the way down to 8.0volts. However, when I moved the red probe to the black wire it was indeed grounding to zero. What do I do next?

Also, as an experiment I tried my TCI from an xj550 and that didn't change anything.

 

The battery is a goner. Replace with new.

 

Since I've been using the battery from my other bike and I just installed a new one I received in the mail I highly doubt a bad battery is my problem. I also did a load test at the battery terminals and it only goes down to 10.63 volts.

I can't tell but is it worth changing the fuse box? It looks really good and clean but it's the original glass fuse box, however, I measured zero resistance when I checked each fuse terminal.

I also read in another post that a gentleman had a lot of resistance between the R/W and B wire at the TCI unit which disappeared when he replaced it. However, he had 75 ohms and when I checked my resistance it came out to 6.1. It's not as much but I understand it should be zero.

 

have you replaced the out of spec spark plug caps yet?

disconnect the head light or pull the head light fuse to lessen voltage drop

if you wish to stand by the battery you have then it is time to start cleaning connections.
start be cleaning ignition switch.and battery cables. clean the connector that goes from positive battery terminal to main fuse.

a new inline fuse holder for the ignition fuse. clean the run/kill switch and associated connections. tci connections and ignition coil connections.
clean connections on solenoid and at starter.
use electronic spray cleaner and a dab of dielectric grease to prevent future corroision.
Every connector can cause voltage drop do a voltage drop test at tci when cranking after cleaning

if you have 9.98 volts at tci you are at the no start threshold.
if you have access to a car battery that would help with the voltage drop.

your starter could be drawing to much power, causing the voltage drop. it may need to be rebuilt or replaced.

new batteries can be crap from the package. I just got a new battery it was defective . it does happen

I do not want to lead you down the road of parts replacement if they are not needed.

a spare tci is always a good thing but that's money you could have spent on a fuse box or starter rebuild kit.

 

Well, I believe those numbers are OK and your battery is fine. I will edit that number of 9.5VDC at the R/W wire when cranking as that number does not account for the losses that occur in the fuses, ignition switch, kill switch and wiring. For what it's worth, I just checked my 750 Seca which has been sitting a while and the battery is a bit depleted and about 5 years old. Numbers were:

Battery 12.1 volts, cranking dropped to 9.8 volts
R/W wire key on 9.7 volts and then rising to 11.1 volts when the TCI switched to standby mode after approximately 2 seconds - 7.4 volts when cranking.

Note with these voltages it has no problem producing a spark and starts easily.

So, not sure where to say to go next since now you have tried another TCI and verified coil and pickup resistance. Note from the earlier post you do need to replace the 1 and 4 spark plug caps as they are out of spec, but I still believe they are not so far out as to prevent a visible spark. Just to be sure though it would be advisable to check spark on 2, 3 cylinders since those reading are well within spec.

Guess I might ask did you notice a lower static voltage on the TCI R/W wire when the key switch is first turned on and then changes to a slightly higher voltage after about 2 seconds? This is important as it indicates the TCI is going active and one of the output transistors has switched on sinking current through one of the ignition coil primaries. That change in voltage at the R/W wire should also be noted if you do the test with the feeler gauge as it will produce a pules activating the TCI for a couple of seconds much like the power up situation.

That really shouldn't read zero. When you measure between the R/W wire and black wire at the TCI the displayed resistance is the value of the neutral bulb and associated wiring, fuses, and switches. If you switch the bike out of neutral it will go considerably higher. Note also at least on my 750 the neutral switch tends to have a bit of resistance, which makes testing the wires this way a bit ambiguous. A point to point test would be more appropriate - R/W wire to battery positive cable (battery disconnected) with the key and kill switch set to run would show the total resistance of the wire, kill switch, ignition fuse, ignition switch, and main fuse.

.

 

make sure you clean the case and frame ground terminals before going into more voltage drop testing.

 

Rooster, I DID NOT notice a change in voltage at the R/W wire after turning the key on. It stayed at around 9.8 volts the entire time.

Also keep in mind that the TCI unit I used as a substitute was from an xj550 and I noticed the wire arrangement on there is different then the 650. From what I researched the 1982 xj650rj Seca has a TCI unit that's all it's own and cannot be interchanged.

I also checked the voltage at the fuse box when turning the key on. The Main fuse displayed around 12.2volts while the other three would read around 11.23volts. I read that they should all be at least 12 but I'm not sure.

Also remember the side stand switch is completely gone but I think I would not even be able to crank over if that was the issue. Yes?

I'm assuming it would be in my best interest to track down a TCI before completely ruling that out?

 

you will need the correct tci for that motor.


if sidestand were working correctly the motor will not turn over when starter button pushed with the motor in gear and stand down.
your side stand switch bypass does not look as if it a problem.
have you tried swapping the sparkplugs into the other cylinders to see if the problem follows the spark plugs or put in new sparkplugs to eliminate them as the problem?


so if you have your ignition system in spec and are happy with your battery condition then it is time to get another TCI.

 

The spark plugs are brand new. The PO replaced them when he tried to fix the bike. I've tried one at a time looking for spark in all the plugs and was unsuccessful.
The hunt for a TCI is on.

 

With a good battery (which you seem to have) the 9.8 volts is similar to the voltage that is present at power up when the TCI pulls one of the coils low. If it is staying at 9.8 volts that may indicate a constant on condition for one of the TCI channels. You can easily check that by measuring the voltage on the Orange and Gray wires (coil primaries) on the 4 pin connector. With the key on they both should be close to 12 volts after a couple of seconds as the TCI switches to standby mode - normally one or the other will go low for a couple of seconds when the TCI is powered on.

((Edit: This is not true - the pinout is different for the 4 pin connector.))
((Edit the Edit - turns out the below is true, and the Haynes / Yamaha diagrams are incorrect))
From what I can tell from some of the wiring diagrams that I have they should be the same pinout, and the XJ550 TCI should produce a spark. @XJ550H perhaps he could verify as he has both models. We need to be sure the PO did not do something creative here also.

They can be pretty pricey, particularly if you are limited to one model only. It's a bit of a confusing issue as Yamaha manuals are known to contain errors, so choosing based on published timing advance data just doesn't yield a reliable result.

 

The below pic is a XJ550 , does the XJ650 match?

 

My mistake. I forgot about what the expected voltage drop should be where you're measuring.

 

No, the wiring is all different.
I did track down a gentleman who owns a Seca 650 and he was cool with me borrowing his TCI to try on my bike. I also found 4 of them on ebay all within 40-70 dollars. I'm meeting him Monday. We shall see....

 

Hopefully XJ550H will confirm the wiring, but better make sure it is right before trying the gentleman's TCI. Maybe post a pic of your TCI and wiring where we can look at the wiring colors.

 

I will get the pinout for the XJ650RJ

 

Here is a pic of the wiring harness from my TCI unit.

 

I thought I'd conduct a few more tests while I wait for the TCI. I think I did this test right. I measured the voltage at the orange and grey wire. I connected the positive probe to the orange wire at the 4-pin connector side of the TCI and the negative probe to the negative battery terminal, turned the key on, and I measured 1.2volts. Pretty much the same result happened at the grey wire. There was no change of any sort. It stayed at 1.2volts the whole time. Did I do this test right? Should the number be this low?

 

My xj550 Maxim looks the same. What is the TCI type and pn on the sticker?

 

((Edit 4-8-19: Looking like the pinout is the same and the wiring diagrams published in the haynes manual are incorrect so the below statement is incorrect))
Well the pinout for the XJ550 and XJ650 Seca are definitely different for the 4 pin connector, and it looks like what you have is correct for the XJ650 Seca. My apologies for not catching this earlier. Looking at the Haynes manual it looks like the only compatible TCI's with the XJ650 Seca as far as wiring is the XJ650 J and K - none of the 750's are a match.

I would say yes you did the test correctly. I am also assuming that the TCI for this bike has the same built in protection for the coils and that the orange and gray wire should switch to near 12 volts after two seconds or so, otherwise the coils and the TCI would overheat and cause damage if the ignition key was left on without the bike running. So my best guess right now is that TCI is defective.

One other test you could do to look for shorted output transistors is to disconnect the 4 pin connector. Ohm on the TCI from the corresponding orange wire to the corresponding black wire, do the same for the corresponding gray wire and both should be a high resistance.

And, since the XJ650 Seca utilizes the ignition cutoff (B/W) wire normally you could put the bike in gear with the side stand down and both the orange and gray wires would be inhibited internally in the TCI and could not go low. Since you don't have the side stand switch you could just ground the B/W wire to the frame and the orange and black wires should be near 12 volts.

 

the XJ650RJ non yics motor pins out the same as the 550's and 82 XJ650 maxim and 82, 83 XJ750 Maxims

this leaves out compatibility of the 1980 XJ650 midnight (non yics) which is a black label tci.
As well as 80 XJ650 (non yics) and 81 XJ650 which can be yics or Non yics.

 

This is what is on my bike.