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How hot is your Swing-arm/Final Drive?


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How hot does your final drive housing and swing arm get?

I know it's 35-ish degrees in the UK at the moment, but mine is getting to the point of being too hot to touch with a bare hand for more than a second or two.

Although I've posted elsewhere about my issues with clearances on my final drive, there's no drag from the pads and no rubbing or fouling of the disc on the caliper mount. There's the correct amount of oil in the final drive housing too and no signs of a leak.

The bike was a 2 years newer when I had the recall work done, but it's never been the same since going into the workshop and I'm wondering if something is amiss - there's no noticeable slop in the drive or odd noises (other than the hunting when in Drive mode at low speeds - yes it's a DCT).

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My instant  read point and shoot thermometer read 85 degrees F (29C) before a 20 mile ride of mixed street/highway and now reads 108 F (42C).  Warm to the touch.  

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Thanks for your measurements Andy - interesting that there's been only a 13ºC rise.  I'd estimate that mine was up to around 65-70ºC after a 15 mile fast motorway trip (3 figure speeds).

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You're putting a lot of power (heat) through the bevel drive and the oil will be trying to cool it as well as lubricate

 

I'd drain the oil and put some fresh in, you may be getting condensation in the hub

 

My Le Mans used do this when thrashed in very hot weather 

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Thanks Thumbs.  I tend to change the final drive oil every time i do the engine oil, s0 around every 8k miles.  I found it pretty alarming that such heat could build up in a relatively short journey, no more than 20 mins - and cause so much weight of metal to heat up - the entire swingarm housing, the final drive, the caliper and wheel rim were all very hot.

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After a 40min ride, most on the highway  with some slower riding at  the end, my swingarm and FD were almost too hot to touch.  Guessing 85C maybe.  Ambient temperature was 108F/42C.

 

Normal.  Running synthetic gear oil that gets changed approximately every 6-7k miles.

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Hi checked mine after 100ks, and yes could hold my hand on it for a long while...

 

How ever at risk of starting an oil argument I do use a special gear oil that I used in heavy equipment in a previous life.

 

My choice is based on 12 plus years of oil analysis so I come from a different direction to most.

 

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10 hours ago, weven said:

Hi checked mine after 100ks, and yes could hold my hand on it for a long while...

 

How ever at risk of starting an oil argument I do use a special gear oil that I used in heavy equipment in a previous life.

 

My choice is based on 12 plus years of oil analysis so I come from a different direction to most.

 

Ambient temp?

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It's been consistently in the mid-high 30's (C) or mid 90's to 100F range where I live, and my ride to work is roughly about the same duration, 90% highway at 70mph/112kph.  My swing arm and final drive are usually hot enough that you can touch it for a few seconds and it would be uncomfortable, but nowhere near hot enough to burn me.  Final drive has Redline Synthetic "light shockproof" 80w90 gear oil with maybe 2k miles on it.

Now, if I ride to work with my hair on fire (lots of hard acceleration and braking) then it can get pretty darn hot, but that is to be expected.

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Sounds like ambient temperature is a significant factor in the swingarm and FD temperature.  When it's really hot outside the swingarm gets hot, when it's cool outside the swingarm gets just warm.  Bizarre.

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Well if you consider the load going through these components & the fact that ambient surface cooling is the only heat exchange pathway, plus no direct airflow, as it’s running in the hot air washed off the engine & rads, then it’s expected to get hot when ambient temps are hot. 

 

Heat exchange works best with the highest temperature differential, so hot part cold day = good cooling. Hot part hot day = poor cooling.

sou DSTL like you want to rig up a transmission oil cooler !  But bear in mind, that your engine oil runs at 80c nominally & transmissions often run hotter, which is one of the reasons they run thick shear resistant hypoid oils. So you would not be able to hold your hand on your engine at working temperature, why would the rear drive be any different. Shaft drives are very inefficient & that inefficiency generates heat as waste energy. 

 

Have you noticed how quickly your engine gets up to working temp now the ambients are above 30C ? when on a normal UK summer mornings you are lucky to get 15C !

 

Sounds like normal to me. Ride, enjoy, don’t worry.

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