Bitubo Rear Shock is an Engine Heat Sink

[sweetscience]

Since any metal part bolted to the engine case will essentially be a heatsink, that is a design flaw for an aftermarket shock.

The stock shock seems to use a rubber bushing for the top eyelet.  The rubber also acts as an insulation, thereby negating heat transfer to it.

In my case, the Bitubo shock uses bearings in the top eyelet.  So we have full metal contact with the engine.  I know suspension oil will heat up when in motion, but I find the shock body gets excessively warm, as far as to the ends of the rezzy. It gets as warm as the other parts bolted directly to the engine.  Kinda like holding a very warm potato, lol.

This seems abnormal to me.  Engine heat plus suspension oil heat combining is probably bad for longevity.  Will this cause premature damage or frequent servicing.  What are your thoughts?

[M. Hausknecht]

How hot do you imagine the shock is getting? All decent shocks avoid rubber mounts, but I suspect the temp doesn't get much over 120-130f (like hot water, out of your tap) which shouldn't matter much. if at all. But I'll confess I'm just guessing based on decent synthetic motor oil not being harmed below 230f.

 

[shinyribs]

If it helps you feel better, motocross shocks are regularly tucked tight against exhaust systems that run much hotter than engine cases, and those shocks get worked pretty hard. 

Servicing dirt bike shocks that have 40-50 hrs on them, I always see dark, dirty fluid. 

Servicing the (custom)  shock on my FZ07 at 8,000 miles showed the fluid still looked fresh. 

Good eye, but I don't believe we have any temperature concerns to worry about with these shocks. 

[sweetscience]

Well, glad to know it is nothing to worry about.  Yeah, it gets hotter the longer the ride is.  But not hot enough to burn skin.  Wish I have a temperature reader device to get values.  For shits and giggles, one could route some type of air duct to blow cooler air there.  Or add heat sinks to the shock itself.  Not really bothered at this point.  

Folk's running aftermarket shocks should observe this as well.

[Pursuvant]

Just now, sweetscience said:

For shits and giggles, one could route some type of air duct...

If you're creative brain needs ideas, how about a simple "ram air duct" that picks up clean cool air and dumps it above airbox (with the snorkel removed) to replace that hot air envelope around rear engine head (and feeding the airbox) at slow/moderate speeds?

 

[sweetscience]

On 10/10/2022 at 3:37 AM, Pursuvant said:

If you're creative brain needs ideas, how about a simple "ram air duct" that picks up clean cool air and dumps it above airbox (with the snorkel removed) to replace that hot air envelope around rear engine head (and feeding the airbox) at slow/moderate speeds?

 

Only if I had the time and resources, eh!  Technically speaking, the cutouts are already there in the side panels.  One side can be used for the intake, the other to cool the shock.  Fiberglass, 3D printing...  Could be a fun project.  Probably already done by some, and kept secret.