Does the 1150GS run hotter on the right hand cylinder...or is it just me??

I changed to Iridium plugs recently and noticed that the original plugs were a different shade, left side looked perfect but the right plug was very pale and obviously lean. The original plugs had been changed at approx 1000mls before I bought the bike and the valve clearances checked (no adjustment required according to service notes).

After I'd finished washing the bike the other night (just as it was getting dark) I started her up to help dry out any moisture and let the temperature rise to 2 bars, increased the revs for a few seconds and the right header was bright red whereas the left header was just a dull red I know that this is not the best 'technical' method to determine whether one cylinder is running hotter than the other but it does show that there is a difference!

I've checked the TB balance and they were out at idle but ok at 4k rpm, I've also sprayed around the intake connections with WD40 but there's no change in engine speed whatsoever so can I assume that this may be a fuel issue?
Thought that I'd discovered the problem when I noticed that the rubber nipples that plug the TB balance pipes were perished and cracked (especially on the right side), replaced these and am absolutely convinced that she runs much smoother but it's still showing more heat on the right side.
I was going to do a few hundred miles then pull the plugs again to check the colour. My next option would be to swap the injectors around to see if the 'problem ' shifts to the other side.
Filled the tank today and popped in 100ml of STP injector clean to see if that makes any difference so just need to have a 300+ mile run now (I do love that Kim Kardashian tank ).

The engine's quiet, runs well, starts first press, idles smooth and pulls smoothly right through the range but I'd rather sort out any issues now to hopefully avoid any longer term problems associated with hot running. Does pop and backfire a bit on the overrun though but I have a feeling that they all do this when fitted with a y-piece and can ?

Maybe I'm just a little paranoid

Mike.

Search for a problem and you'll always find one.

Sometimes ignorance is bliss, service and ride and repeat until it no longer starts

...... and dont let the thing run stationary either. That heat goes upwards.

I was expecting replies of either; 'They all do that sir' or 'Just ride the bloody thing' ...and ride I shall.

Still, it's not great to have an engine running weak so I'll be keeping an eye on things!

No clue at all. I just ride it

I'd be dropping off rocker covers and doing a valve clearance check and if nothing out of the ordinary????

I'd do a compression check when cold and one when up to temperature

If she has a tight valve or a cracked valve she will draw air and the fuelling will be wrong and the crack can turn into a burned out valve or the head drop off

Too many folks bury their heads in the sand about this sort of thing, especially when its not their bike!

Get it checked and if its all clear? Sure what did it take you an hour ?? 2 hours???

Better than looking a replacement head or bike off road for a couple of weeks etc etc

DrFarkoff said:

I'd be dropping off rocker covers and doing a valve clearance check and if nothing out of the ordinary????

I'd do a compression check when cold and one when up to temperature

If she has a tight valve or a cracked valve she will draw air and the fuelling will be wrong and the crack can turn into a burned out valve or the head drop off

Too many folks bury their heads in the sand about this sort of thing, especially when its not their bike!

Get it checked and if its all clear? Sure what did it take you an hour ?? 2 hours???

Better than looking a replacement head or bike off road for a couple of weeks etc etc

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Sound advice, I ran a garage for 30 years and a high pre portion of customers facing big repair bills said something like " I have been meaning to get you to check it for the last month or so" Often a minor defect ignored leads to an avoidable major failure.

John

DrFarkoff said:

I'd be dropping off rocker covers and doing a valve clearance check and if nothing out of the ordinary????

I'd do a compression check when cold and one when up to temperature

If she has a tight valve or a cracked valve she will draw air and the fuelling will be wrong and the crack can turn into a burned out valve or the head drop off

Too many folks bury their heads in the sand about this sort of thing, especially when its not their bike!

Get it checked and if its all clear? Sure what did it take you an hour ?? 2 hours???

Better than looking a replacement head or bike off road for a couple of weeks etc etc

Click to expand...

I'll be doing this in the next few days when I get some time, had a 100 mile run tonight so that should be enough to read the plug state after putting the new rubber caps on the balance pipes.
I can't imagine that there is much wrong as the bike is running really well and pulling stronger than ever!

Thanks for all the advice and suggestions.

IME the plugs on an 1150 always look like they are running weak. It's the richer one I might be worried about.

cookie said:

IME the plugs on an 1150 always look like they are running weak. It's the richer one I might be worried about.

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Bloody hell, something else to think about!

I'll pull the plugs again tomorrow before I do anything else but now I am totally confuddled (normal state of mind for me).

cookie said:

IME the plugs on an 1150 always look like they are running weak. It's the richer one I might be worried about.

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The leaner one is the biggest concern and will be running hotter. That's why the exhaust is getting red on that side.

alfazer said:

The leaner one is the biggest concern and will be running hotter. That's why the exhaust is getting red on that side.

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the headers always glow red if you run the bike with no cooling airflow. it's not a good thing to do.

the fact is, the normal colour for 1150 plugs IME is white with maybe a bit of very light grey, so they do look like the motor is running lean, but that's just the way they are.

what i am suggesting as a possible diagnosis, without seeing anything, is not so much that one side is running lean, but one side might be running a bit richer.

It gets more confusing!

Pulled the plugs tonight and they are both looking pretty damn good now after replacing those caps although one is still 'slightly' weaker looking than the other, the ever so slightly richer plug is on the side that shows the hotter header pipe??

I've checked the valve clearances as well and they are bang on what they should be so I'm not going to bother with a compression check as there's nothing untoward looking now, it's maybe just an anomaly in the manufacturing of the header pipe and it could be made of a slightly thinner skin than the other

I'm careful not to let it heat up too much by letting it idle but there are some maintenance procedures (TB balancing) that requires the engine to be at operating temperature so I assume that short term idling for these purposes won't cause any long term problems?

I'd say that she's running pretty well now and could only be improved on with more technical knowledge and specialist tuning equipment (Dyno, MoDiTeC unit).

Still, that exhaust is definitely hotter on the side with the 'less weak' plug! They do run lean though, don't they

I am also running an accellerator module but I doubt if that is responsible although, I'm sure that there are some people who would blame it anyway...

Thanks for the replies.

Mike.

Swap the coils left right. If hot pipe swaps you have a weak coil


Sent from a widget that can't spell.

Bendy toy said:

Swap the coils left right. If hot pipe swaps you have a weak coil


Sent from a widget that can't spell.

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Good shout, I'll try that, thanks!