Boost Port - porting guide - HELP :)

[axo]

Ok.. Coming from this thread: http://www.hondaspree.net/phpBB3/viewto ... =4&t=15362

First off... thank you Trafficjamz for the help.
Today i worked on the engine, with the intention of putting it together and checked the boost port on the new cylinder against the passage on the engine block and it is effectively being almost completely blocked. Took a few pictures and measurements so i can show you what i got and get as much help from the pros here so i cut the blockage in the case.

I spoke with Steve at VTCycles. He told me it is better to do the porting job so the engine runs more efficiently, gets the fuel better so the cooling should improve.
Besides that, do you think there is also any performance improvement? I really care about the cooling more than anything else because that is why i screwed up my first attempt with a cylinder like this before. Too much heat.

Ok so what i am asking here is for some help to cut the case.
I will do this with the help of a mechanic friend of mine, who works on cars so i do not screw things up because i do have a clue about technical stuff and setting up things on the scooter, but i am also a newbie at doing it

Here are the pictures:



and



So......

Picture N1 shows my case. what i need advice for here is if i should mark and follow the gasket like on the picture Trafficjamz showed to me on the other post.

Picture N2 ... im just pointing that my cylinder is different as the one you showed to me on this pic:
Your cylinder has that opening that i guess it would help a lot the flow. Mine came like that, without the opening so my question is if you did it yourself, and whether i should do it or not?

Picture N3 shows how much material i have to play with on the inside. The "wall", at the thinnest point is just 5.5 millimeters.
To measure this, i lay the caliper flat on the inside, and for the other leg, i used a piece of screw which i subtracted its length to the caliper, so the reading you see is the actual thickness of the wall at its thinnest point.

Picture N4 shows the front of the case, the picture does not show this but the idea was to point that it is not a flat surface. So i marked the deepest spot with the dotted line, and that is the area where i took the reading with the caliper and the screw.

So all this means that if i were to cut the case straight down, i would end up with a hole in the front so i understand the cut should be at an angle right?
So the question is... do you have a picture of the open case, seen from the side, so i can see the angle you cut it?
And what is the limit in thickness of the wall that i should not go beyond, when i shave the metal at that point where it is only 5.5mm now? 1, 2, 3 mm?

I will split open the case, and use probably a grinder machine, dremel and my friends help to not screw up the block.
Do not worry, i will take care of not letting the pieces of aluminum getting stuck inside the bearings or the cylinder.

Here is a good video showing the problem i have for those reading that are in ":*: is this guy talking about" mode: http://www.youtube.com/watch?v=QX3x18waJMQ

Thank you for your input.

[Trafficjamz]

I did not cut the window in my bore. It came that way.

Here are a couple pics that shows the taper from to to bottom.
Be careful The case does get pretty thin( about 2mm) in spots.




When your case is apart you should smooth out the area under the reed cage as well.
before

after

[axo]

Ok.. that picture from the side helps a lot. Thank you very much

Now im going to find out about the opening at the end of the cylinder... may be i can cut it myself or get an exchange from VT

Thanks again

[axo]

Did you just smooth a bit the area there in the reed valve ports or you also made the holes larger?
What is the idea with this if the area is still kind of rough ?

[Trafficjamz]

Did you just smooth a bit the area there in the reed valve ports or you also made the holes larger?
What is the idea with this if the area is still kind of rough ?

The holes are not actually larger, but the ends are tapered.
Better flow. No hard edges for turbulence to take place.

[Clivester]

Its generally thought that keeping the fuel intake smooth with no rough edges or sudden turns that may create turbulence is best, but that the surface should be slightly rough and not mirror polished. Supposedly this aids in fuel vaporization i.e. reduces the time for fuel deposited on the surface to evaporate and perhaps increases air velocity by effecting the boundary layer between the air flow and intake wall. Exhaust ports on the other can be polished.

[axo]

Thank you for the info..
I will also polish the exhaust port on the cylinder as the one i got looks very rough ...
I will also cut the opening on the cylinder to help with the boost port flow. Any advise or measurements on this? (see picture 2 and the first post to see what im talking about)

[evilone]

I will also cut the opening on the cylinder to help with the boost port flow. Any advise or measurements on this? (see picture 2 and the first post to see what im talking about)

I wouldn't cut a hole in the cylinder, the mixture will go up boost port behind the cylinders skirt.

[axo]

Ok.. I finally did it.. here is what i got:



A bit awkward because the Dremel is thick so the cuts were not perfect.. but made it nicer with a file in hand.

Now... another question before i put it together... Would polishing the walls inside the case make any difference or improvement?
I am not talking about the ramp where the red valves are.. i understand it must be rough so the fuel will atomize and all that.. im asking about the other walls inside..
Any suggestions by looking at the pictures?

Thank you guys.

[Trafficjamz]

Now... another question before i put it together... Would polishing the walls inside the case make any difference or improvement?
I am not talking about the ramp where the red valves are.. i understand it must be rough so the fuel will atomize and all that.. im asking about the other walls inside..
Any suggestions by looking at the pictures?

Thank you guys.

Looks good. I don't know if you will see any difference in performance by polishing the in side of the case halves.

Make sure you get all of the shavings out before you put it together.

[evilone]

Would polishing the walls inside the case make any difference or improvement?

Leave the walls alone! The fuel needs to stay atomized in the case too. Boost port looks nice.