So how are they making engines out of aluminum?

Instead of cast iron sleeves bored to fit the aluminum cylinders, they now spray a silicone base to the cylinders and hone to fit the pistons. Notice no size over pistons for reboring like the old days. Sure you can have the cylinder resprayed and fit for oversized pistons, but you'd have minimum wall clearance boring thru the water jackets. The rings would eat the aluminum being so hard and minimum oiling. Where a set of cams mounted within the aluminum half caps are bored for clearance and the oil pressure surrounds the cam to float in the bore holes.

Aluminum is not malleable to shape a curve like the header needing to turn down from the head. The aluminum would crack when it would curve. An enclosed muffler, sure, its straight when made.

---

You can pick up the five ball miniature turkey baster thing at any auto parts store. That's what I use. It's nice to the bike to change the coolant every couple years. I've heard of people never changing coolant and the bike runs fine. Same with brake fluid. Some people never change it and it still works.

That mini baster is what I figure on using, and good
to know that some riders seem to get along without even
changing the fluids, I wonder if what Hub said about the coatings
comes to play there, I guess maybe the water pump and
thermostat housing might be the
first things to fail, due to having old coolant, before areas in the block,
protected by the 'coating' he mentioned.

Interesting off topic topic: motorcycle engines are aluminum? Why don't they make exhausts out of aluminum? I always thought the answer to that question was that aluminum gets soft at high temperature. So how are they making engines out of aluminum?

I see that Hub has answered this question, with a lot of points
I wasn't aware of.

* Last updated by: Stratovarious on 1/27/2026 @ 3:40 AM *

Thanks again,Hub.

I wonder if what Hub said about the coatings
comes to play there, I guess maybe the water pump and
thermostat housing might be the
first things to fail, due to having old coolant, before areas in the block,
protected by the 'coating' he mentioned.

If I may step in for the Hubster and explain, he's talking about the cylinders. The cylinders are where the heat generates in the engine. The aluminum cylinders used to have steel inserts that the the pistons pumped in. The block was aluminum, the insert (sleeve) was steel. Apparently, the steel took the brunt of the heat. No idea if the Gen2 has sleeves or the silicone coating. The block is aluminum though.

I guess maybe the water pump and
thermostat housing might be the
first things to fail, due to having old coolant, before areas in the block,
protected by the 'coating' he mentioned

Probably, you are correct but I believe the silicone Hub referred to would only be in the cylinder where the greatest heat is. You need water pump and thermostat for the bike to run at all but there are coolant galleys that can be obstructed and still function subpar. I don't think these have any heat resistant coating and if they do, you're not fighting heat with ol coolant, you're fighting the crud that builds up and clogs these passages. It can only help to change coolant regularly and flush any crap that collects in there before it becomes a problem.

---