Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: paulx66 on October 10, 2010, 09:37:53 PM
-
hope the link works
http://www.off-road.com/dirtbike/tech/extreme-restoration-on-a-1991-honda-cr-500-52819.html (http://www.off-road.com/dirtbike/tech/extreme-restoration-on-a-1991-honda-cr-500-52819.html)
Enjoy
Paul
-
Man that thing is clean.
-
that's sick :O
-
The chain looks too tight... :D :D
Seriously, that's a good looking bike except for the KTM style front fender.
-
Port 'work' is a laugh....................... ::)
-
I would love to pull the trigger on this thing, all that hot shit and a Cheng Shin on the rear???
-
Well, I was gonna say it was built somewhat weird, using so many different things including ninja stuff. But I'll just say. "It's alive!" (Frankinstein) :-) But it's cool, don't get me wrong.
-
Crazy!! Bike looks very nice with the attention to detail but over 70 ponies!!!! That thing would hurt, throttle control is a must especially on a moto x track....................wonder how the Cheng Shin tyre would hold up ::)
-
Nice ;D
He has put alot of effort into it.
-
I'm curious as to what 2T Institute meant by saying that the port work was a laugh. Does it mean it wasn't good, overkill, or what?
-
I'm curious as to what 2T Institute meant by saying that the port work was a laugh. Does it mean it wasn't good, overkill, or what?
I was wondering the same thing. My guess, is that you probably wouldn't need it. I have a CR500 that I ported big time, and probably didn't need it either. But, talk about big power. None of us need CR500 power, but dang it is badazz. 8)
-
I've read before that polishing the ports is actually counter productive and that rough edges on the ports is actually perferred. Something about an air boundary layer which can cause worse flow instead of better flow. Sizing of the ports also has some limitations and moves the power in the revs, from what I have heard.
Of course, I don't really know :)
-
I've read before that polishing the ports is actually counter productive and that rough edges on the ports is actually perferred. Something about an air boundary layer which can cause worse flow instead of better flow. Sizing of the ports also has some limitations and moves the power in the revs, from what I have heard.
Of course, I don't really know :)
The simple version: Make more fuel/air flow and it needs to be mixed. Smoothing the actual path of the fuel/air is bad because the air and fuel if seperated will not burn as clean, thus less power. But lot's more involved.
-
I've read before that polishing the ports is actually counter productive and that rough edges on the ports is actually perferred. Something about an air boundary layer which can cause worse flow instead of better flow. Sizing of the ports also has some limitations and moves the power in the revs, from what I have heard.
Of course, I don't really know :)
The simple version: Make more fuel/air flow and it needs to be mixed. Smoothing the actual path of the fuel/air is bad because the air and fuel if seperated will not burn as clean, thus less power. But lot's more involved.
I guess it's the same reason that they have dimples on golf balls vs smooth balls?? or not lol
-
The ports has all the hallmarks of the many US based Banshee(and big bore/stroker variants) sand drag tuners. Namely the 2 extra ports below the transfers and above the inlet. If you ever ask for an explaination on what they do goes like this "the air goes in there, up there, around there, through there back through there an then out there".As when the the transfers are open thse ports are closed.Next is the knife edge on the transfer divider, don't start me on those.
I would regard it as 'show' porting, not hard to port the shit out of a 500 cylinder and see some big dyno numbers..........................
The factory finish is usualy good enough, and yes boundry layers and dimples are the reasons. As I said with the Aprilia GP 125/250 cylinders a lot of those look like they 'don't work' but they do
-
When I took my 83 Maico 490 apart, someone had polished the connecting rod smooth, it was all shiney. They also coated the crank with some black stuff. They even had carbon fiber reeds in the bike. Someone went through a lot of trouble.
-
I'm sure this baby could spray some mean roost. It would look cool with a 2010 CRF front fender on it. This would take some customization, but would look pretty tough.