Random Thoughts - Part Deux [NO POLITICS]

[NoHaveMSG]

Originally Posted by ichitaka05

Yeah, just finish watching Engineering Explained (also your vid)... just don't get how compression changes. Well more like don't get how stroke changes. I get that distance changes when it's at the piston is at the top... but how would piston distance change when it's at the bottom... or they don't? IDk

From what I understand, and I am not the brightest , is that they are changing the size of the rotation path of the big end of the rod.

[Lantanafrs2]

Imagine a dealer mechanic opening one of these up on flat rate

[Clutch Dog]

Quickie question

is there an official form, or do i make one. Allowing a coworker/friend at work to borrow my vehicle for an extended amount of time? up in washington state, you literally just needed a piece of paper that said something to the effect of "Im the owner of this car and know that person A is borrowing the car." And then you assume them on the cars insurance.


I didnt know if it was different for california

[NoHaveMSG]

Originally Posted by Lantanafrs2

2020 bmw s1000r sportbike has a torque dip. Pretty drastic one too lol. Only American models. Meeting epa standards. I thought the euro standards were worse?

My KTM 690 is terrible out of the box. It runs in closed loop below 4k RPM and is super lean. Back fires on decel loud enough to make the pops and bangs crowd happy even with stock muffler and cat. I bought a jumper for it that tricks it into running richer at lower rpms and it runs way better. You would think for a big single it would have some torque but it has nothing until you wring it out.

[Lantanafrs2]

Originally Posted by NoHaveMSG

My KTM 690 is terrible out of the box. It runs in closed loop below 4k RPM and is super lean. Back fires on decel loud enough to make the pops and bangs crowd happy even with stock muffler and cat. I bought a jumper for it that tricks it into running richer at lower rpms and it runs way better. You would think for a big single it would have some torque but it has nothing until you wring it out.

Power commander?

[NoHaveMSG]

Originally Posted by Lantanafrs2

Power commander?

No not yet. I might do a cat delete but keep the stock muffler. I would do a PC then.

There are a couple companies that sell this plug that has resisters wired into it for 30 bucks. It deletes the O2 sensor to fix the issue. So that is what I am running in the mean time. Bike is fast enough for the roads I take it on anyway.

[Ultramaroon]

Originally Posted by NoHaveMSG

It's pretty cool. Lots of monkey motion going on though.

Not any worse than vtec.

[Spuds]

Originally Posted by NoHaveMSG

It's pretty cool. Lots of monkey motion going on though.

Originally Posted by ichitaka05

Yeah, just finish watching Engineering Explained (also your vid)... just don't get how compression changes. Well more like don't get how stroke changes. I get that distance changes when it's at the piston is at the top... but how would piston distance change when it's at the bottom... or they don't? IDk

A. That's really F'in cool! Added mass though...

B. I haven't given much thought to it yet, but even if both the top and bottom of the stroke change by the same amount, the ratio of volumes should change. There's less max volume in the high compression mode, so the same reduction in volume is a greater percentage. Thus, higher compression.

[ichitaka05]

Originally Posted by Spuds

A. That's really F'in cool! Added mass though...

B. I haven't given much thought to it yet, but even if both the top and bottom of the stroke change by the same amount, the ratio of volumes should change. There's less max volume in the high compression mode, so the same reduction in volume is a greater percentage. Thus, higher compression.

Also to add... stroke changes, so not only compression ratio change, but displacement changes (bore x stroke)? So is it more (or less) than 2 liter?

[p1l0t]

Sent from my SM-G975U using Tapatalk

[NoHaveMSG]

Originally Posted by ichitaka05

Also to add... stroke changes, so not only compression ratio change, but displacement changes (bore x stroke)? So is it more (or less) than 2 liter?

From the looks of the animation, yes. I never really noticed that, but if BDC is changing then displacement is variable as well.

[ichitaka05]

Originally Posted by NoHaveMSG

From the looks of the animation, yes. I never really noticed that, but if BDC is changing then displacement is variable as well.

Yeah... I really don't know. This KR20DDET is unique engine and interested to see if they do in endurance and mods.

[Spuds]

Originally Posted by ichitaka05

Also to add... stroke changes, so not only compression ratio change, but displacement changes (bore x stroke)? So is it more (or less) than 2 liter?

I don't think the stroke changes, but I'd have to actually do real analysis and math to determine that. Anyway, I'm saying that stroke doesn't need to change for the compression ratio to change. I don't think the stroke includes the height of the combustion chamber.

[ichitaka05]

Originally Posted by Spuds

I don't think the stroke changes, but I'd have to actually do real analysis and math to determine that. Anyway, I'm saying that stroke doesn't need to change for the compression ratio to change. I don't think the stroke includes the height of the combustion chamber.

Don't think it would... but idk. Just there are too many unknown stuff in that engine