Air Cooler R Port Job Pics

**toocheaptosmoke** · 03-06-2009, 12:05 PM

Here's how I make my maps, put the paper in the cylinder so the top edge is flush with the top of the cylinder.* Tape it in place. use a pencil or a grimy finger to feel along the port edges and imprint them to the paper. Then after you remove the paper record some measurements. The vertical measurements show the port timing, and the horizontal measurements show the arc lengths of the port widths.

*If the crown of the piston does not sit exactly flush with the top of the cylinder this must be taken into account for port timing.

**1upfront** · 03-06-2009, 01:22 PM

Yeah Denny at Flotek did the port job on the 300r cylinder.

**freaksfix** · 03-07-2009, 05:56 AM

Here is some good info on the RPM port work.. It talks about the "coating" this jug has too... There is alot of simularitys between DW's motor and this one im going threw,, maybe we've got DW project 250R??

http://www.

s.com/magazine/r...icalracer.html

Ive been reading how to do the port maps little by little, i'll try to do one this week... If i can sucessfuly make one Id be more than willing to mail them out to you guys..

**firefirefire90** · 03-07-2009, 06:56 AM

Originally Posted by freaksfix

Here is some good info on the RPM port work.. It talks about the "coating" this jug has alittle too... There is alot of simularitys between DW's motor and this one im going threw,, maybe we've got DW project 250R??

http://www.

s.com/magazine/r...icalracer.html

Ive been reading how to do the port maps little by little, i'll try to do one this week... If i can sucessfuly make one Id be more than willing to mail them out to you guys..

Should have never given you that link!

**Saul** · 03-07-2009, 09:13 AM

working link to DW Project 250R article

**88 Turbo Coupe** · 03-07-2009, 02:19 PM

Who's got the talent to full circle a crank?

**freaksfix** · 03-07-2009, 07:57 PM

Originally Posted by firefirefire90

Should have never given you that link!

na,, ive been snoopen around over there little by little, I would of found it... We've got every part the motor, carb, intake, and exhaust in that build, but only have 2 gen chassis..

**Daddio** · 03-07-2009, 08:09 PM

Originally Posted by freaksfix

na,, ive been snoopen around over there little by little, I would of found it... We've got every part the motor, carb, intake, and exhaust in that build, but only have 2 gen chassis..

What color is that engine. If it was part of that build it would be nuts. Maybe someone read that article and and duplicated it, and that would be equally nuts.

**freaksfix** · 03-07-2009, 08:27 PM

Originally Posted by Daddio

What color is that engine. If it was part of that build it would be nuts. Maybe someone read that article and and duplicated it, and that would be equally nuts.

It is red but this motor came on one bike and the carb and intake came on another along with the pipe.. But it does seem to be the stage 5 motor having the full circle tubro crank and the coating..

**firefirefire90** · 03-08-2009, 07:15 AM

It shall be mine someday!

**freaksfix** · 03-10-2009, 11:26 AM

Kinda have a problem with the port map.. It says to start with a mark where the top of the cylinder starts.. We'll the cylinder is decked alot, and chances are your guyes cylinders are not.. So I need to come up with an accurate measurment of how much the cylinder was shaved first...

**toocheaptosmoke** · 03-10-2009, 11:34 AM

Do you still have the bottom end of the engine together? If so, put the cylinder back on and check to see where the piston sits when at TDC. A lot of times the edge of the piston comes right to the edge of the cylinder, but, if an extra or thicker base gasket was used to raise all the ports, the top of the cylinder could have been machined to get it back even with the piston. Thanks for trying to get this port map.

**freaksfix** · 03-11-2009, 09:00 AM

I'll se what I can come up with tonite.. However it did have a stock base gasket.. Im going to try and measure how much it was decked too.. The head is also shaved, so someone was looking for some serious compression.. I wish I checked the compression on this befor I tore it down..

Why would "you" wanna change the height of the ports, what is the gain from this? Is it just changing the port timing right, so its a quicker transfer of the exhaust and fuel? So the fuel comes in quicker or I should say sooner? Am I on the right path of thinking here?

The cylinder is at 70.85 on the top, havent checked it all the way down yet to see if its outta round..

**freaksfix** · 03-11-2009, 09:12 AM

The reason for tearing down the motor was because it was folding over spark plugs.. All the bearings are good and tight and there is no signs of interferance on the piston or plugs.. I realy dont see compression folding plugs over, do you?

It had ran fine with a b8cv or something like that. I changed it to the right plug br8es and it started folding plugs.. The b8cv is alittle shorter with different style electrode, but the same heat.. I was worried it was a hotter plug so i changed it out, then ran into the problems, and assumed crank bearings so I tore it down.. Should have researched the plug first, it would still be in the bike and running.. But then I wouldnt have found all the motor work...

**toocheaptosmoke** · 03-11-2009, 08:55 PM

You're on the right track, if you wanted to increase the duration of your transfer ports a few degrees it is a lot easier to raise the whole cylinder that amount, instead of having to actually remove material from each transfer port. Raising the whole cylinder will also increase the exhaust port's duration, but generally that's a good thing because more exhaust duration generally means more peak power, but narrows the power band. And it's a lot easier to modify the exhaust to where you want it anyways.

There could be a couple possibilities for the head. One major mistake a lot of people do when modding their engine is to simply "mill the head." This alone is not the way to go about things. (On some engines though, they are so "loose" taking a bit off the head can help, but it's not set in stone) First off, you need to figure out the squish, which is the distance between the edge of the piston and the head, at TDC. That distance can be determined through some number crunching, but say around .050" or so. You can find the squish by smashing a piece of clay or solder between the piston and head. Too mush squish and things are not as efficient, and detonation can happen easier. Too little and metal can start making intimate contact. Just the right amount and you get better heat transfer out of the a/f mix to the head, and you "squish" as much of the mix into the center to ignite.

So anyways, most engines have way too wide of a squish band stock, to make up for production tolerances. If you simply milled enough off the head to set the squish, the compression would be through the roof. So, most of the time unless you're running some crazy race fuel, you have to re-dome the head to get the compression ratio back down. In this engine, when it came from RPM it was probably set up correctly, and it is possible you need a certain plug. When you put the br8 into the head, are there many threads showing below the dome of the head? Or, some later owner could have just took the head in to the local machine shop and had .020" taken off. If that's the case, engine probably wouldn't have ran for long like that. But it's hard to really say sitting here in front of the keyboard.

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