can these pushrod engines spin up that high?
-internally what needs to be done?
serious replies only please.
10k rpms, not really, especially not with hydraulic lifters.
I recently heard harley is coming out with water cooled heads. I'm not sure what engine they are for, I was hopefully they'd be for the sportser and could be bolted onto an xb engine. I really don't know much about this though or if it's even true.
I seriously dont have a clue:D
if you have enough money anything is possible.
Youd have to start all the way at the crank......i dont think so unless you built a crank with some smaller balances.
You looking for more top end??
Hey mosh,
It is pretty unlikely you would get an XB engine spinning that fast without some very major and expensive work.
The XB motor is inherently poorly balanced and requires a (proportionately) huge counterweight on the crank. Buell's racing bikes had different engines than the XB's with much smaller and lighter counterweights.
So apart from the heavy masses whirling around at 10,000 RPM you also have the breathing problem.
It is very difficult to get intake and exhaust valves to open and close that fast, especially if the valves are big - which is why high performance engines have as many small pistons as possible and the heads on them have multiple valves per cylinder which are driven by overhead camshafts in an attempt to control or eliminate valve float as well as inertia and play in the system.
IMO you couldn't get it spinning that high with pushrods, definitely not with hydraulic lifters, not with any type of hot cam in it anyway and have any reliability. You'd be putting valves through your pistons on a regular basis.
I would be tempted to try using rotary valves on the heads if I was going to build a 10K + RPM engine, but then you are talking head re-design and I doubt it would fit into the existing XB frames.
The basic problem is that the engine is fundamentally a low-RPM-high-torque design and while it is always possible to make a decent purse from a sow's ear, it is often easier and more satisfactory to start with more suitable materials.
Now, before I get flamed, let me state that "…from a sow's ear" is an expression denoting unsuitability for a purpose, not a reflection on the HD engine. I like the HD engine, it is a great design for what it was intended for, but it was not intended as a high-revving race engine.
I like the HD engine, it is a great design for what it was intended for, but it was not intended as a high-revving race engine.
call s&s they would be happy to spend your money.
If so I give it a lifespan of maybe 2 minutes :D10,000 RPM aircooled XB12... can it be done?
I fixed it for you.:pIf so I give it a lifespan of maybe 2 seconds
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