Cool old school ported cylinders

[bkm]

I recently did some horse trading and ended up with a ported Chuck E Racing 86 cylinder and a B&B ported 88 cylinder.

Several guys have said the Chuck Edwards engines were very strong back in the day. I haven't found much info on the b&b cylinder.



I'm going to run the Chuck Edwards cylinder on my ATC racer.

[Hawaiiysr]

Knife edge vs smooth. I wonder which one flows better? I would say the smooth but some builders swear by the knife edges.

[Flyin_250r]

I had a Chuck E engine and man it ripped!  Always regret selling it. Message C.Leigh. He knows a bit of history on him.

[trx250scar]

I sold a chuck e national cylinder to someone on here. Wonder if they ever ran it. I never had.

[C-Leigh Racing]

Ol Chuck Edwards, he was doing ok until he moved out to Cali, got crazy after that. B&B I think is Batista work. A rider ran with us from Cali, Franky Batista, his dad did port work & that is probably one he did.

When you knife blade something, that is to direct the flow, but a rounded edge is like an air plane wing & will not cause a drag. A smooth surface will cause a drag as well, where a texture will speed the flow up.
Neil

[Higgy87trx425]

Isn't that why people port the intake and polish the exhaust! Just sayin!
 Thanks Higgy

[Higgy87trx425]

I kinda came off as a smart ass in that last comment and it wasn't inteneded to be that way. Sorry Higgy.
 Thanks Higgy

[udontknowme]

wish i knew more about leading edges of dividers. i always thought a rounded shape worked best in subsonic airspeeds like those found at the inlet tract of a engine. my personal rule of thumb is simple: never knife edge any inlet divider

[MANIAK]

OK, dump question or statement or thought to ponder here.....

Most engine guys seem to think the same way for the most part. Open up the intake and smooth out the exhaust. Which is correct on a 4 stroke where your only using 1 side of the piston.

On a two stroke where the bottom side of the piston both draws the mixture in and then compresses it to push it into the cylinder. Wouldn't removing more metal from the bottom of the cylinder effectively increase the total volume inside the crankcase and thus lower the pressure created by down stroke of the piston. The lower the crankcase pressure, the less total volume of mixture that will get into the cylinder and thus less efficiency.

I can see increasing port opening in the sleeve and runners but your not getting linear flow over the port dividers so turbulence shouldn't be an issue.

FYI.... I don't do my own porting, I have just wondered for years...

4 strokes can be related to DC voltage, linear air/fuel flow much like liner voltage power to ground
2 strokes are like AC voltage where the fuel mixture goes back and forth much the same way that current reverses.

Just my stupid ramblings.....

[C-Leigh Racing]

OK, dump question or statement or thought to ponder here.....

Most engine guys seem to think the same way for the most part. Open up the intake and smooth out the exhaust. Which is correct on a 4 stroke where your only using 1 side of the piston.

On a two stroke where the bottom side of the piston both draws the mixture in and then compresses it to push it into the cylinder. Wouldn't removing more metal from the bottom of the cylinder effectively increase the total volume inside the crankcase and thus lower the pressure created by down stroke of the piston. The lower the crankcase pressure, the less total volume of mixture that will get into the cylinder and thus less efficiency.

I can see increasing port opening in the sleeve and runners but your not getting linear flow over the port dividers so turbulence shouldn't be an issue.

FYI.... I don't do my own porting, I have just wondered for years...

4 strokes can be related to DC voltage, linear air/fuel flow much like liner voltage power to ground
2 strokes are like AC voltage where the fuel mixture goes back and forth much the same way that current reverses.

Just my stupid ramblings.....

You got a whole lot of that right, but the things you mentioned, that is just a small part of the whole engine build.
An engine build, one that will match what the owner/riders wanting to use it for, thought has to start from the inside of the air filter element, through the carb & engine clean out to the tip of the silencer outlet. Every thought you put in to the air/fuel mix flow through that engine has to be addressed & matched up to each other.

The last part, 4 stroke 2 stroke, yes, but in reality its 4 stroke street fighting, 2 stroke is Kung Fu :chuncky: when your behind those handle bars. This is why you see so many jumping 2 stroke camp & climbing on 4 pokers, cause they are easier to handle & win with, but it will have a price.

The cycle of a 4 stroke takes so long, the exhaust has to be smooth so it will be fast getting out. More you can compact in a 4 poker, more it will produce.
A 2 stroke, smooth exhaust in an attempt to stop anything from sticking to it that would disrupt that pipe wave travel.
Neil

[MANIAK]

I just realized I misspelled "dumb".... oops.

I grew up in an auto racing family so I learned Cam Timing, valve lash, piston clearance, etc. When I was 8 was when I first started rebuilding my dirt bike motors (with help from my dad).

I understand all of the mechanical aspects of 2 strokes but not the intricacies of finite tuning. I have made lots of set up mistakes along the way, mostly due to comparing power gains in relation to 4 stroke engines.

"More is better!!!"........... well I learned not always.

It is so easy to have a bada$$ 250r with every possible thing added to it and then it run like crap.

I bet there are lot's of people on this site that thought they would gain tons of power just by adding a stroker crank to their R...... two words = port timing

I know that when you take a long rod 265 with an ATAC cylinder, add a 41mm carb, and a CT whale pipe..... Not so bueno.

Now, take the same engine and throw on a 36mm carb, and a Paul Turner mid-range pipe and...... Holy Sheep $H17 BATMAN !!!!!!

I don't understand exactly how each thing is effected but I do know the benefits of have matched set ups vs throwing on everything you can find cheap on ebay.

Sorry for diving off topic..... here is a redirect....

Has anyone ever ran any CR cylinders or a Hiperdyne?  Better yet, anyone ever heard of a Hiperdyne?

My favorite cylinder of all time was my ATAC CR250 cylinder. I believe it came from like an 84 or 85 CR250, it was a non powervalve cyl. much like a modern pro-x or ESR

I also use 88-90 CR HPP cylinders with power valve block offs set to wide open....... no bottom end but man they screamed.

The Hiperdyne was I believe an early version of what became the pro-x. It was an awesome cylinder but I never could get my set up correct with it.

[C-Leigh Racing]

Another one is, take a fresh stock 249cc ATC/TRX engine, do the CR ignition change over & be like, wow who ported this engine.

That little small flywheel will pump it up.
Thats what the deal is with these new 4 pokers, same engine function for years, just a little flywheel & thin skirt piston & charge 4 times what a 250R build will cost.

I dont remember the Hiperdynes your refering to like a Pro-x, but you should have seen some of the way early Duncan cylinder projects, weardest welded up stuff ever, but they got it right.
Neil

[MANIAK]

I bought my hyperdyne from Duncan a really long time ago along with a Paul Turner pipe and silencer.

Duncan used it on a baja 500 project bike that was in Dirt Wheels. The cylinder that I purchased was used and I was told it came from their baja project. I'm not sure if it was the same cylinder from the magazine article or not but either way it ripped but I didn't like the powerband. It more closely resembled a 300 shot of nitrous.

[C-Leigh Racing]

I bought my hyperdyne from Duncan a really long time ago along with a Paul Turner pipe and silencer.

Duncan used it on a baja 500 project bike that was in Dirt Wheels. The cylinder that I purchased was used and I was told it came from their baja project. I'm not sure if it was the same cylinder from the magazine article or not but either way it ripped but I didn't like the powerband. It more closely resembled a 300 shot of nitrous.

You got any pics of it ?. Had to be some of those early Duncans.
Neil

[MANIAK]

I will have to find the photo album. Back then digital hadn't been invented yet. Lol ........... Good Ol' 35mm.

If I can't find a pic, I might have the dirt wheels article somewhere. I'll see if I can dig it up.