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XT1200Z, not idling properly
Posted: Sat Aug 05, 2017 7:13 pm
by Dark Knight
Was out on the Super ten today and got stuck behind some cars and push bikes for a few miles, afterwords the bike would not idle, sounds like the spark plugs, there is about 10,000 miles on them, pretty unusual?
Re: XT1200Z, not idling properly
Posted: Sat Aug 05, 2017 8:10 pm
by herman
Could be fouled I guess but unusual on a four stroke especially FI. Nail it see what happens

I suspect mine have twice that much mileage on them .
Re: XT1200Z, not idling properly
Posted: Sat Aug 05, 2017 8:16 pm
by Nigel
Service schedule says remove and clean plugs at 6,000 miles and replace at 12,000, all the dealers who have serviced mine said leave alone and replace at 12,000 miles and it runs fine.
Re: XT1200Z, not idling properly
Posted: Tue Aug 08, 2017 7:21 pm
by Dark Knight
Changed the plugs, just look at the state that they are in after about 11,000 miles, service manual says inspect at 6,000 miles and replace at 12,000 miles, who is going to inspect them at 6,000 miles considering the amount of work to get access.
The coil towers were very tight in the cylinder head, had to use a small pry bar to get them out and we all know how dodgy that is.
Some corrosion on the towers, for some reason Yamaha have a steel section in the towers which is corroding.
The spark plug rubber shrouds must be getting hard with age and are not a perfect seal.
Water must be coming through either side of the front engine mounting bracket where there is a gap.
Looks like we need a small shield on this bracket to defect the water, made up a cardboard template.
This must be a common problem.
Re: XT1200Z, not idling properly
Posted: Tue Aug 08, 2017 8:39 pm
by scorparider
I suspect your problems are down to inbalanced throttle bodies. They are not difficult to do if you have some balancing gauges.
Re: XT1200Z, not idling properly
Posted: Tue Aug 08, 2017 10:19 pm
by Nigel
Dark Knight wrote: ↑Tue Aug 08, 2017 7:21 pm
Changed the plugs, just look at the state that they are in after about 11,000 miles, service manual says inspect at 6,000 miles and replace at 12,000 miles, who is going to inspect them at 6,000 miles considering the amount of work to get access.
The coil towers were very tight in the cylinder head, had to use a small pry bar to get them out and we all know how dodgy that is.
Some corrosion on the towers, for some reason Yamaha have a steel section in the towers which is corroding.
The spark plug rubber shrouds must be getting hard with age and are not a perfect seal.
Water must be coming through either side of the front engine mounting bracket where there is a gap.
Looks like we need a small shield on this bracket to defect the water, made up a cardboard template.
This must be a common problem.
Yes it is a problem I have heard of before, my bike would get plugs replaced every year, I would imagine if they are only done every couple of years they could be a real problem to get out

Re: XT1200Z, not idling properly
Posted: Wed Aug 09, 2017 6:13 am
by Ksithumper
Dark Knight wrote: ↑Tue Aug 08, 2017 7:21 pm
Changed the plugs, just look at the state that they are in after about 11,000 miles, service manual says inspect at 6,000 miles and replace at 12,000 miles, who is going to inspect them at 6,000 miles considering the amount of work to get access.
The actual plug tips look fine though? Unbalanced throttle bodies I reckon.
Re: XT1200Z, not idling properly
Posted: Wed Aug 09, 2017 3:44 pm
by scorparider
Dark Knight wrote: ↑Tue Aug 08, 2017 7:21 pm
Water must be coming through either side of the front engine mounting bracket where there is a gap.
Looks like we need a small shield on this bracket to defect the water, made up a cardboard template.
This must be a common problem.
I made a guard, piccies attached

- FB_IMG_1502289485976.jpg (33.62 KiB) Viewed 5747 times

- FB_IMG_1502289499438.jpg (38.93 KiB) Viewed 5747 times
Attached with strong double sided tape
Re: XT1200Z, not idling properly
Posted: Wed Aug 09, 2017 9:41 pm
by Dark Knight
Changed the plugs and the bike is now running fine on a run out today, poor idling may have been caused by the corrosion on the plugs, as I have four bikes which I share the mileage on, the plugs would have been in the bike a few years.
Another point, as there is corrosion on the plugs, probably sensible to blow out the spark plug recesses before changing the plugs with the compressor to stop any bits falling onto the cylinders.
Must see if I can order up some new coil tower rubber shrouds which would be more flexible.
Re: XT1200Z, not idling properly
Posted: Thu Aug 10, 2017 5:50 am
by spasm
the coils on the plugs do give up if not maintained, i kept mine covered in acf50 to prevent the corrosion. it's a known problem on them but not a big problem. i put 57,000 miles on mines and changed the plugs at 43,000 from new, have a good look at the coils because they do crack