I recently, (10-15mins), just posted my first post on the introduction section.
In the post, I stated that my 1990 XJ600 has a particular dislike for rain. In this post I intend to highlight how I have attempted to combat the issue; in an attempt to help any other pre-diversion owners, or indeed anyone who owns a YX600-Radian, FZ600 or FJ600, (they all have the same engine, mostly...).
Firstly, I will say there are some slight differences in the XJ600's made from 1989-91, the only one affecting this post being the fact that those made from 1984-89 have two pickup coils, rather than the one mine has. I think this change occured partway through 1989, so if your bike is 1989 it could be either, sorry :thumbdown: .
Right. The Story:
I went on a trip last weekend from my university city to my home town, (roughly 100miles of sweet riding with my Girlfriend on the back). All was fine, until we stopped for a coffee after around 60miles, I assume the rain on the bike while it was parked got somewhere it shouldn't have done, and the first 10miles after the stop were boggy with jumpy accelaration, which I would assume is due to an intermittent spark in one of the cylinders. Anyway, after 10miles it sorted itself out.
The next issue came about after parking outside of my house, on the centre stand, for roughly 36hours of hard and peristant rain. She wouldn't start, turned over, but wouldn't start. I took her into my garage, (after clearing a bike sized space...), and discovered that there was no spark at any plugs. I left her to dry for around 24hours, and she started on the button with the choke engaged. All seemed fine, so I didn't bat an eyelid at the 100mile trip back to Swansea with my, much heavier than my GF, brother on the back.
We set off fine, and all was smooth until the dreaded half way cup of coffee. Again, it rained on the bike while we stopped; she struggled to start, but she went after a few seconds of cranking, so we got on our way again.
Things were NOT okay this time though, awful accelaration, and cyclinders kept cutting out, the most dodgy bit occuring whilst I was overtaking a lorry in the "fast lane" on the motorway, something bad happened, and she wouldn't break 40mph! I pulled into the furthest lane and she cruised pretty consistantly at 55mph until we reached swansea.
When we stoppped at some lights, she died, completley, no hope. My brother got a lift to my house while I had to push her the remaining 3miles, (very hard walk... did it 30mins none the less, so I was quite happy with that).
I left her for a few days in my hallway to dry out and had a look, no spark!!! I assumed the worst and checked all of the ignition components with a multimeter.
The solution:
I started off checking the primary resistance of the ignition coils, this is done by setting the multimetre to its 2 Ohm setting, and prodding the two contacts in the connector plug for the ignition coil with the multimeter, you should getting a reading of 1.8 - 2.2 Ohms, (I got 2, so all was okay there).
I then checked the secondary resistance of the ignition coils, this is done by prodding one of the contacts in the connector plug, and then prodding the contact area in the spark plug caps, (make sure you are using the correct coil for the plug cap you are prodding), you should get a reading of 9600-14400 Ohms, (I got 11000, all okay here).
You need to remove the tank to do this! There is one tank retaining bolt under the seat, make sure the fuel tap is either in the "on" or "reserve" position, if it is on "prime", you'll get petrol all over the floor
After checking the ignition coils, I checked the Pickup coil, this is where my approach will differ to other pre-diversion owners. I had to locate a connector plug between the pickup coil, (which is located in the alternator cover, behind the alternator stator), and the digital ignition unit, (which is bolted to the side of the battery). This connector happens to be just behind the right hand body panel, at the end closest to the front of the bike... It has a White/Red wire, and a White/Black wire attached to either end of the connector.
Again, you unplug the connection, and prod both contacts with the multimeter, you should get a reading between 81 and 121 Ohms, (I had 100 Ohms, so all okay here). Note: prod the plug at the end of the wire attached to the actual coil, not the end which is attached to the digital ignition unit.
If you own anything other than a 1989-1991 XJ600, you will have two pickup coils, and must do what I just did, but at the connector which is attached to the digital ignition unit. The reading here should be 108-132 Ohms.
As none of these parts seemed to be the issue, I thought the worst: "It must be the Digital Ignition Unit, noooooo!". These are very difficult to repair, (probably beyond my skillset at the moment), and are expensive...
But before buying a new one, I thought I'd check for a spark again... Success! sparks from all cylinders! The spark from cylinder 2 was intermittent and weak; and I noticed the boot between the cap and HT lead was in bad condtion, so I unscrewed the cap and inspected the lead: corroded and in bad condition; I then trimmed the lead until the core was in good condtion: now there is a good spark!
To try and prevent any further water damage, I packed all of the electrical connector plugs with silicone grease to repel the water, and am going to replace them with new, waterproof ones when I get the funds.
I also, bought new plug caps, with good boots at both ends, which I am going to seal with more silicone grease for good measure.
If it starts, I'll let you know! But I wont know if my preventative measures have worked until it is sat in rain... This will be Monday, as I will be in Uni all day, with my baby out in the rain
.I hope this helps a lot of people, and sorry for the length of the post, I wanted to be comprehensive!
Thanks for reading
Charlie.
Note: You can't change the HT leads on this bike without changing the Ignition Coils, they are captive inside the coil. The local bike mechanic said this is the case for ALL Yamahas, but I am unsure if this is the case.