Burnt Legs

[DaveR]

Whilst out & about enjoying the good weather, i have noticed that my S4R is running so hot that the heat from the engine is making my legs uncomfortably hot. As a long time owner of a '94 900ss I don't recall ever experiencing this before, even when riding through Italian traffic jams in 40 deg heat.
Is this a particular issue with the 'water cooled' Monsters? Under normal circumstances my bike runs at around 78-80 degs, but any hold up will cause this to quickly rise, with the fans cutting in at 104 degs. Once on the move again the temperature quickly falls again, does this point to a problem with the cooling system?
On a recent ride which was blighted by a number of slow moving tractors & other factors, I had to resort to a dual carriageway blast to bring the temperature down.
I have also noticed a hot bum, caused no doubt by the positioning of the rectifier under the seat, where it gets no cooling!
One further question, why does all this warming have no affect in the winter ?
All help gratefully received

Dave

[Jez900ie]

Originally Posted by DaveR

Whilst out & about enjoying the good weather, i have noticed that my S4R is running so hot that the heat from the engine is making my legs uncomfortably hot. As a long time owner of a '94 900ss I don't recall ever experiencing this before, even when riding through Italian traffic jams in 40 deg heat.
Is this a particular issue with the 'water cooled' Monsters? Under normal circumstances my bike runs at around 78-80 degs, but any hold up will cause this to quickly rise, with the fans cutting in at 104 degs. Once on the move again the temperature quickly falls again, does this point to a problem with the cooling system?
On a recent ride which was blighted by a number of slow moving tractors & other factors, I had to resort to a dual carriageway blast to bring the temperature down.
I have also noticed a hot bum, caused no doubt by the positioning of the rectifier under the seat, where it gets no cooling!
One further question, why does all this warming have no affect in the winter ?
All help gratefully received

Dave

It might be age related? How old are you?

[damien666]

I think personally i’d be going down the shindengen, Mosfet, rectifier/regulator route sharpish!

[mickj]

I don't know anything about the older bikes but my 1200 runs quite cool (low 70's) and I have not noticed any real heat even in slow moving traffic with the fan coming on. I tried a KTM once that got very hot in a similar situation, now they do run hot.

[Dukedesmo]

Air cooled Monsters run quite cool, at least mine does (same engine for SS models).

I have a 916 (similar engine to the S4R) and it runs considerably hotter than my Monster despite it being water cooled, it also warms up quicker. In all I think the water cooled bikes run hotter because it's they way it's designed to work - by having better temperature control it can run at a higher, more optimum temperature which is ultimately better for performance/economy/longevity/emissions etc.

Air cooled models generally over cool because they have to be able to cope with very high ambient temperatures in different climates etc. without having the benefit of better temperature regulation/control.

Ultimately, like it or not water cooling is a technically better setup, able to better maintain ideal conditions more easily and why most bikes are going that way.

916 can get quite uncomfortable in traffic - hot legs, thighs and arse and then when the fan cuts in you get a nice extra blast of hot air to your left leg...

[Uncle Bob]

Originally Posted by Dukedesmo

Air cooled Monsters run quite cool, at least mine does (same engine for SS models).

I thought the same, but last Wednesday (a scorcher) I went up to the Earls Barton meet and had to filter past a couple of miles of traffic that was ultimately queueing to cross a motorway junction. By the time I got to the junction my bike was running quite hot, and I could feel it on my legs. The other side of the junction was clear dually for five or six miles and the temp came down again.

When we arrived at Earls Barton I could feel heat all through the frame and the rear subframe too. This wasn't just engine heat of course, but in that slow moving traffic \ filtering I had seen four bars on the gauge for the first time since I've owned it.

It's definitely better whilst moving, obviously, but on a warm day with very slow moving traffic etc. it didn't really like it (and neither did I to be honest).

[Nickj]

My S2R has been up around 80-100 on the recent days I've been out.
My 748R has been up to the same and more just heats up more quickly, I expect without the fairing that it would give me warm legs. I regularly see well over 120 with no issues .. That's degrees C not MPH Honest!!

[Darren69]

My S4 runs the same and gets hot, it was even worse before I fitted an oil cooler (which it didn't have as standard like the S4R). I also find the side air scoops help when on the move, they force cool air onto the rear cylinder.

The rectifier will get hot under the seat and will probably burn out before too long. Its a stupid place to have it really. I moved mine so it gets cooling air and fitted a big metal heat sink, its been fine since.

Originally Posted by Darren69

My S4 runs the same and gets hot, it was even worse before I fitted an oil cooler (which it didn't have as standard like the S4R). I also find the side air scoops help when on the move, they force cool air onto the rear cylinder.

The rectifier will get hot under the seat and will probably burn out before too long. Its a stupid place to have it really. I moved mine so it gets cooling air and fitted a big metal heat sink, its been fine since.

This is interesting - do you have photo's of where you moved it to? It's quite a sizable beast - (the rectifier I mean)

[Darren69]

Originally Posted by Dilkris

This is interesting - do you have photo's of where you moved it to? It's quite a sizable beast - (the rectifier I mean)

Badically flipped it over so its on the underside. You used to be able to get kits for this mod. t dont know if you still can. Do a google search but if you cant find one i can post pics.

[Darren69]

Originally Posted by Darren69

Badically flipped it over so its on the underside. You used to be able to get kits for this mod. t dont know if you still can. Do a google search but if you cant find one i can post pics.

Something like this

https://motowheels.com/i-7774617-cor...ter-00-08.html

[jerry]

In thailand my S4 gets very hot in traffic the fans come on a lot,,, out on open road its better but its never cool there is always a lot of heat around thighs and bits ,,I have re-located my regulator to left side of bike next to front cylinder in front of water pump its a mosfet and there it gets a lot of air flow unlike under the seat ...

Try a 1299 Panigale if you want a hot leg, ridiculous, had to get off the seat in traffic, obviously they are not designed for queues in the first place, but blimey!

[Flip]

See now I have always thought my 900 runs quite hot and obviously as the ambient temperature goes up then cooling air is not so erm, cooling. It certainly runs a little crisper when the air cools during Summer evenings.

It's never caused a massive problem other than the dreaded vapour lock that can sometimes affect the carb'd engine- I have had this happen twice both on extremely hot days and when stuck/filtering in traffic but happy to say (touch wood) it has been fine since I replaced all the fuel lines and overhauled the vacuum tap and pump,

Conversely my Yamaha Thundercat runs pretty cool all the time, on my trip to France two weekends ago a couple of thermometers outside the Pharmacies (funny how all Pharmacies seem to have those over there) in the towns were reading 35 degrees and the bikes gauge only rose from 60 to 75 when slow moving in traffic the whole time I was there.

It might be worth noting for those of you with plumbing that I had recently flushed and changed the coolant to Silkolene Pro-Cool which may have helped.

As hot as it got:

[Goofle]

Originally Posted by Mark9

Try a 1299 Panigale if you want a hot leg, ridiculous, had to get off the seat in traffic, obviously they are not designed for queues in the first place, but blimey!

Mine hits 105 then the fan kicks in. It's never showed any signs of overheating however, unlike me! It does get very uncomfortable in slow / town traffic though especially as the exhausts run up and down just under the seat!