Excess heat under seat?

[mikef]

Riding home tonight on my GSA, I noticed my backside getting very hot, so much so that I had to stop the bike at the side of the road and get off! I took the seat off and found that the Bosch Motronic unit underneath was very hot, in fact almost too hot to touch. I managed to get the bike home by standing on the pegs most of the way. I've never noticed anything like this before with my bike and I've ridden it in significantly hotter temps recently than it was today

Bike is a 2016 GSA LC with about 6000miles and it has a Sargent seat fitted (no seat heating!)

Any ideas?

 

[fred_jb]

Could be a failing rectifier if is packaged into the same unit, but I've no idea if that might be the case. Another possibility is that something has blocked the normal air flow to the unit.

 

[dave hendy]

Could be a failing rectifier if is packaged into the same unit, but I've no idea if that might be the case. Another possibility is that something has blocked the normal air flow to the unit.

Aren't they separate units?


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[Sea Dog]

Could be a failing rectifier if is packaged into the same unit, but I've no idea if that might be the case. Another possibility is that something has blocked the normal air flow to the unit.

Ah, the old favourite - the "Rectum-Fryer"! The symptoms certainly fit!

 

[fred_jb]

Aren't they separate units?


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I would have thought so, but they may be close together. According to the following forum post about diagnosing such problems, the regulator/rectifier lives under the plastic tray holding the engine ECU, so if it is overheating it may well be making that whole area hot. If it is this, then it needs fixing quickly before it damages the alternator as I believe it is an expensive engine out job to replace the alternator.

http://advrider.com/index.php?threa...ator-and-vintage-regulator-rectifier.1119480/

 

[dave hendy]

You don't want an alternator going out of warranty! Did you look at your charge rate while you were riding?


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[mikef]

You don't want an alternator going out of warranty! Did you look at your charge rate while you were riding?

Sorry no I didnt but I will take it out for a short run and check it

 

[dave hendy]

Just as well you are still under warranty, if charge rate is too high call BMW assist


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[Iverbiggin]

This is my second wc, and I have noticed the same thing, mines 2months old and a 17 plate, I didn't have this problem on my 15 plate in the time I had it! Would like to know, what your dealer says about it....
I have noticed the the number plate on mine is fcuked with the heat of the exhaust again.... not sure if the two are linked?

 

[Fullchat]

Strangely enough I also am experiencing exactly the same. 15 GSA no issues. 2 month old 17 plate and noticing heat coming up from the cylinders onto my thighs. Could this be the cause of the sudden increased discomfort in the seat department as mentioned in the seat thread???

 

[Boshman]

This is my second wc, and I have noticed the same thing, mines 2months old and a 17 plate, I didn't have this problem on my 15 plate in the time I had it! Would like to know, what your dealer says about it....
I have noticed the the number plate on mine is fcuked with the heat of the exhaust again.... not sure if the two are linked?

No issue with underseat heat but I've also got a fooked number plate from the exhaust heat. I'm on my second plate now, Initially thought the first one had not been made well but the second one has gone the same way. Is this a common phenomenon? Mines a 66 plate EU4 GSA.

 

[ReGenesis]

BMW have just replaced my pannier and indicator under warranty after they melted from exhaust heat last month!
Number plate is fine though....

 

[fred_jb]

BMW have just replaced my pannier and indicator under warranty after they melted from exhaust heat last month!
Number plate is fine though....

The current fashion for high level exhausts has a lot to answer for. They compromise luggage carrying ability, and unless you are expecting to be fording rivers do they have any real purpose?

Not going to be a problem with my GS though! I did about 1200 miles on a trip during the mini heatwave last month with no issues:

 

[Clifton]

The current fashion for high level exhausts has a lot to answer for. They compromise luggage carrying ability, and unless you are expecting to be fording rivers do they have any real purpose?

Not going to be a problem with my GS though! I did about 1200 miles on a trip during the mini heatwave last month with no issues:

I also dislike the trendy upangle exhaust, especially on a bike supposedly made for function over style like a GS.

I like it. How did you accomplish getting the silencer mounted low?

 

[fred_jb]

I also dislike the trendy upangle exhaust, especially on a bike supposedly made for function over style like a GS.

I like it. How did you accomplish getting the silencer mounted low?

Thanks. I bought an RT exhaust from a breaker on eBay, only cost £57 plus another £30 for an RT heatshield section. Both parts fit perfectly on the GS, just needed to make up an extended hanger strap to the frame exhaust mounting point. An aftermarket RT exhaust would also work.

More info here: http://www.ukgser.com/forums/showthread.php/453817-GS-Tourer-Mods

 

[Clifton]

Thanks for the links.

Since I already have factory panniers on my GSA I'll leave it as it is but when/ if I buy a new GS I might do what you've done. Maybe stock RT panniers could be made to work? I think they'd look great but oh my the cost.

 

[Hairyweasel]

Mikef did you get an answer from the dealers?
I just finished a 2 hour motorway trip on mine and the seat was that warm you would think it was heated.
The Bosch unit under the seat was very warm to the touch.

 

[Majesty]

I don't know if it's connected but I was recently horrified after washing my 2014 GS LC and lifting the seat to find that the drain holes in the bottom of the ECU retaining tray were blocked (presumably by the ingress of road spray from the rear wheel) which meant that water was retained in the tray
It's worth checking out after you've washed the bike

 

[JerseyNeil]

I don't know if it's connected but I was recently horrified after washing my 2014 GS LC and lifting the seat to find that the drain holes in the bottom of the ECU retaining tray were blocked (presumably by the ingress of road spray from the rear wheel) which meant that water was retained in the tray
It's worth checking out after you've washed the bike

A water cooled ECU. Might even catch on

 

[marchie]

Not just me!

Thank you all for the previous posts

Just wanted to say that I experienced the same hot seat 3 weeks ago on my 2017 Euro 4 GSA TB to the extent I also pulled over and checked things out. Been riding it for about 80 mins at the time.

It was then seen by my dealer who reported back (not unsurprisingly) that all was well with the ECU no error codes etc - mm!!

I also have melting number plates!!

My previous 2016 GSA did not have either of these issues.

Perhaps a techie amongst us could confirm if the euro 4 exhaust gasses are at a higher exit temp?