KDXRIDER.NET

Nothing to polish on the exhaust side. 2 strokes do a back and forth motion with the exhaust note.... really super fast though.

Google it...

How a 2 stroke works

Polishing to get rid of the casting marks is a good idea.But you should also use some dimpling in areas to create attached flow, and cause turbulence Secretes of the trade ,don't tell.

I looked a bit for that CD (KDX dyno info) this morning. Didn't find it.

I KNOW I've seen it recently........

Lookin' forward to seeing the KDX with rev pipe vs KDX with torque pipe comparison.

Rick

Dyno charts are cool to look at, but I think they can be deceptive. in some cases an improvement on the dyno looks small, but yields a very noticable gain on the trail if it works well with how the transmission ratios are laid out. You can also see at times a small drop in low rpm hp, but a big gain over 10K. On a trail bike, this can be catastrophic in technical terrain.

They why do guys port and polish the hell outta 2 stroke snowmobiles? those things habe 600 cc twin motors that are ported and polished like mad to crank out more poines...whats the mechanical difference?

Don't own a snowmobile...

motorhed220 wrote:They why do guys port and polish the hell outta 2 stroke snowmobiles? those things habe 600 cc twin motors that are ported and polished like mad to crank out more poines...whats the mechanical difference?

Twins benefit greatly from matching each cyl. intakes and exhaust to each other. Removing casting differences between the two cylinders.

Still haven't found the CD that has the charts I'm looking for.

But, I'd forgotten about these:






Rev first, torque second. Engine FRP ported for 'scoot' as I recall. DO note the scale of the two is NOT the same!


Pics are in the gallery. You can download and make'm bigger if you wish.

These pics from CDave's site: Here

Click TechTips then DynoTesting.

There are also dyno charts comparing punkin and Kaw, too.

FINE smarty pants!

Maybe I wanted 'them' to have to GET there..see some other stuff on the way!!!


And YOU ruint it!!


Or...I didn't open it in a separate window, so didn't get the correct URL link.

Obviously, you spotted the wrinkles in my duct tape!

They why do guys port and polish the hell outta 2 stroke snowmobiles? those things habe 600 cc twin motors that are ported and polished like mad to crank out more poines...whats the mechanical difference?

As mentioned for matching the cyl's, but this would be sled racers or wide open trail riders. No tight mountain sled rider would want a radical port job, just like a KDX'er wouldn't. It also doesn't affect the sled as much because sleds use a variable drivetrain, and the clutch engagement can be set quite high helping keep the drivetrain in sync with the power output of the engine(and it's port design). Take a radically ported sled, and set the clutch for 2k engagement, and it will never run....It will be a total dog until it gets to the point where the ports have been set for power delivery, and then will take off like a rocket....Just like a radically ported bike. Hey, MX guys, especially pro's will ask for the highest revving/hardest hitting port/head setup possible. This is fine for a pro mxer, but even the pro wouldn't want that engine on a woods bike.

These are great graphs . . . for the 200.

'Know of any for the 220?

The 220 graphs look about the same....just subtract a couple of divisions off of each axis.

canyncarvr wrote:The 220 graphs look about the same....just subtract a couple of divisions off of each axis.

You mean, the x-axis . . .

Well, no. I was TRYING to be snotty about the BOTH of them..rpm AND power.

I have failed yet agin!!