[XTZ660 cuts out when warm and won't restart]

Thanks Goff, I had teh valve clearances rechecked and these were OK. Haven't had a chance yet to try a hotter plug but thanks for that advice. Sorry but I'm not a techie guy (I just ride my bikes )) what's a "plug chop"?

A 'plug chop' is when you inspect a spark plug that you have just removed. The purpose is to check that the fuel/air mixture is correct by looking at the colour of the electrodes and the end of the ceramic insulator. In a healthy engine in good tune the colour should be a light tan, brown or grey. Check out the comparison chart here:-

http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm.

You can tell a lot about the set-up/state of tune of an engine by analysing the plugs and the procedure is:-

Gun the motor through the gears on a nice long straight road, preferably one that's inclining so you can labour the motor. When in top and the motor is on-song, whip in the clutch, kill the motor and coast safely to a stop.

Now have a cup of tea/smoke/lie-down for half an hour so the motor can cool, then take out the plug and inspect it's colour and condition. Be careful not to overtighten the plug when putting it back into a warm engine. Also, if you make any adjustments to the ignition and/or carburation, make sure you clean your plug(s) before doing another analysis.

This can be a very awkward job on bikes with loads of fairing panels etc, and the only alternative really is a fuel curve run taken on a dyno which is done by gas analysis - this can be quite pricey though.

[Blue smoke from exhaust...]

Hi,

I have used STP smoke treatment on my bro's old Exup 1000 as that had taken up the smoking habit - It did stop the smoking after it had had a chance to circulate. It's thick gloopy stuff - a bit like treacle, and you add it when you do an oil change. It's worth remembering though that the smoking is indicative of an underlying problem that needs more in depth attention.

http://www.stp.com/oil_smoke.php

P.S. You can pick this up at most motor factors, or Ebay.

[XTZ660 cuts out when warm and won't restart]

My first post - so hello everyone!

I have a 1993 XTZ660 Tenere which is in great condition and has done 25K miles. I have a problem with it when it is warm. After 5 or 6 miles of running when its warmed up, if I stop, the revs and take my hand off the throttle, the revs immediately drop to zero, the bike cuts out and it won't restart until it has cooled down a bit. This happens whenever it is warmed up. Its not running hot. Its had a new battery, spark plug (gap checked), valve clearances checked, mixture and idle checked and its STILL has this problem.

Any ideas? Could it be some kind of electrical issue? I am desperate! This is a lovely bike and great fun to ride but right now anything over 5 miles is impossible.

Cheers.

Hi there,

I had a very similar problem to this on my ZXR750 a couple of years ago - the bugger just would not start or even fire when trying to start from warm. After hours of fault finding I tried changing the ignition coils and it has never played up since. Some electrical components are liable to breaking down under load or high operating temperatures so I can only put it down to this. Oh and at the same time I found that my rad fan wasn't cutting in due to a blown fuse - maybe that's what stuffed the coils as they mount right above the motor.... It might be worth a try!

[1984 Yamaha Dt175mx decals]

Try these:-

they did a set for my '77 250MX and I am very pleased with them.