Dear XT. I'm sorry I did this to you

[stutrump]

Jbrown...thank you...this is all really helpful. This Tenere has not been anywhere near as good as my first Tenere. Yes, it came with a power commander which was rubbish and making it guzzle fuel so i took it off (2 years ago...about 40,000 miles ago).
Since then it was running fine (although never as good as my first S10) ..until now.
No error codes at all. Check engine light came on a couple of times and went off pretty quickly so i just kept riding.
Will try swapping the coils next but it might be a couple of days before i have time so bear with me. Yes..the 02 sensors are still on the bike.
One thing Im wondering is IF it turns out to be the coils, will a knackered catalytic converter (probably is knackered now) make the potential coil problam hard to spot.

 

[blitz11]

I would think that both coils would have to be bad to cause fuel running through the cylinder w/o combusting. Two coils failing at one time (or two coils failing, maybe one after the other might make sense here. it would probably run just fine under most conditions with just one plug firing). Maybe one plug died a while ago, and the second one just let go recently. This seems to be a long shot.

The point of dual coils is to expedite the combustion process to avoid pinging/knocking. My bet is on an injector not fully closing, causing an excessively rich condition so far beyond stochiometric that unburned fuel is making its way into the exhaust. Odds of two coils failing at the same time seems low.

I've been wrong before, however.

 

[stutrump]

Blitz11/everyone.
Thanks for all your help. I swapped all coils last night with another working bike and it made no difference so it might be injectors (thanks for the idea Blitz11). Will check that next.
Whilst working on it last night i noticed that the exhaust had been so hot that it melted the dust cover!! (Only visible on the inside of the swingarm)...and so i was riding for a while with the drive shaft exposed.
Aargghh...this is going to take longer to fix than i have time for.
If i win the lottery I'll get a new S10 for xmas!

 

[ballisticexchris]

Just a stab in the dark but you might want to check your charging system fuel pump pressure as well.

 

[stutrump]

Thanks ballistexchris.
Hopefully get some time at Christmas to get the spanners out again

 

[stutrump]

Hi folks. Just a courtesy update. I'm fortunate enough to still have my previous S10 and so I've put that back into service because I need a bike every day. I wont fix this one for a long time now...probably next summer..but I'll update you when I've sorted it. Thanks for all your help though

 

[Checkswrecks]

Glad you have #1 still and sucks about #2 needing more effort. Thx for the updates.

 

[stutrump]

Thanks checkswrecks. I've got a few things to sort out on No.1 but only swapping things over really (heated grips etc).
In some ways I'm kind of pleased. No.1 was and is a much better bike than No.2.
Strange really...they should be identical but No.2 has never been as good.
Also means I can now try and get my No.1 up to 200,000 miles. It's on 120, 000 at the moment.
I can now try to sort out No.2 at my leisure and may even take the opportunity to do a complete strip down on it.....or worst case scenario if I run out of time just use it/sell it for parts.
Merry Christmas folks

 

[stutrump]

My old Tenere is now back on the road and I'm slowly starting to pull the other one apart (newer one). Just took the drive shaft out and was surprised how rusty it was (see pic)

 

[Nikolajsen]

Åh yes...nasty.
Do you drive all year?

 

[stutrump]

Yes nikolajesen, I do. Pretty wet in uk too so I guess that's it.
The plug in inner swingarm has always been in place so I'm not sure where the wet gets in but it seems that it does!