i didnt know

[udontknowme]

i dont keep up on the older stuff and usually learn something new everyday but im browsing through ebay and i see a old cr250 jug. appears to have a floor port and judging from the cases its a factory thing atleast for a year or two around '88. seems like it would be rather easy to put one of these ports in most any engine that didnt have one. obviously the reeds would have to be back far enough so it wasnt blocked but anybody tried it ?

[rsss396]

If you look at JasonB ATC build you will see Adam Millar does this on some of his cr500's

You can see the tunnel in the cases that feed the hole








this picture is upside down

[udontknowme]

thats cool. im half tempted to give it a try and see if its does any good or not. i wonder why honda gave it a shot for only a brief time then abandoned it ?

[C-Leigh Racing]

Remember these two words, "brief time".

Sometimes builders, do things to engines to make them into a type that they only do. Sometimes, the things being done to them, when it is fresh up time, you can only get some of the parts for that engine from the one who built it to begin with.

Just because you see something done to one type of engine, dont mean its good for all types of engines, because no two engine will perform the same.

Just like, you may be the biggest & baddest engine builder around the world, have riders racing for you, build your engine & put everything you know into each  engine build, no dollar spared to make them fast & then at a race, this kid comes up, does his on work to his engine on a 55 gallon barrel in his back yard & ported his cylinder with a drill & grinding stone & then when the gate drops, he just leaves your riders in his dust, after all you put into & spent on the engine to beat everything out on the track.
Neil

[udontknowme]

i hear ya neil but i was just wondering if anybody had tried it on a engine that didnt originally have a floor port. nothing ventured nothing gained is what i say. if i had 24hrs a day to work on engines there would be no stone left unturned  :congratulatory:

[FerrinMotorsports]

Remember these two words, "brief time".

Sometimes builders, do things to engines to make them into a type that they only do. Sometimes, the things being done to them, when it is fresh up time, you can only get some of the parts for that engine from the one who built it to begin with.

Just because you see something done to one type of engine, dont mean its good for all types of engines, because no two engine will perform the same.




Just like, you may be the biggest & baddest engine builder around the world, have riders racing for you, build your engine & put everything you know into each  engine build, no dollar spared to make them fast & then at a race, this kid comes up, does his on work to his engine on a 55 gallon barrel in his back yard & ported his cylinder with a drill & grinding stone & then when the gate drops, he just leaves your riders in his dust, after all you put into & spent on the engine to beat everything out on the track.
Neil

Reminds me of a kid who really wanted to race quads....picked up a basket case 250r that was in pieces,  This kid didn't have much money so he put all of his money into the motor..Set up his stock suspension..And re-grooved  worn out tires that his buddies had given him , again because of no money to buy new ones....Then went out and raced against everyone's high dollar tricked out machine.....And won!..

[udontknowme]

i guess jason is the only one to try it. maybe he can report back

[trx88]

ask millar racing he will fill you in on what and why and when

[Jerry Hall]

i dont keep up on the older stuff and usually learn something new everyday but im browsing through ebay and i see a old cr250 jug. appears to have a floor port and judging from the cases its a factory thing atleast for a year or two around '88. seems like it would be rather easy to put one of these ports in most any engine that didnt have one. obviously the reeds would have to be back far enough so it wasnt blocked but anybody tried it ?

This floor port will sometimes help an engine that is deficient on intake area at low RPM.  The floor ports are not usually beneficial on intakes that have the Boysen ports and or the piston skirts cut away like the stock CR 250s and CR500s.  High velocity air does not like to turn sharp corners.  Creating an intake port with the most direct path to the void being created by the rising piston is usually the best intake.  

I tried the floor ports for the first time on the factory Kawasaki "Works" KX 250s engines in 1978.  It helped a little in the 5000 to 6000 RPM range where we did not need it except when one of the riders screwed up in one of the corners on a stadium race. Riders at this level do not screw up very often or they will be looking for a new job.   When we cut the intake side of the piston skirt we had the same power in the 5000 to 6000 RPM range as the floor port and gained power in the 6000 to 8000 RPM range.

[trx88]

yep