Ok, so a better description of what the series of pictures was all about. I had a birthday dinner to attend so I just kinda threw them up there....
Remember every bit of this work is done with basic hands tools.... no milling machines or lathes, the most whizzbang tool I have in my shop the Tig welder...
The first picture is the "access" to the rear mounting holes. It will work kind of like a LA sleeve cylinder, you won't be able to get the back cylinder nuts out with the head on.
That second picture is looking straight down at where the intake side mounting nuts will be sitting. They'll actually be bolting down on top of the bottom most "large" cooling fin.
The third pic is showing what the back of the cylinder looks like from the intake window end. I have drilled large "upper" ports directly into the rear transfers. Instead of a little "kicker" wall, it will use the incoming charge to redirect the transfer flow out into the center of the combustion chamber. Should also be a nice boost in flow too as the intake windows are closed by the piston sliding by.
The fourth picture is of the right side of the cylinder. What I used was 1" round aluminum rod stock cut to length to fit between the mounting ear and the bottom most "large" cooling fin. I also removed the transfer cooling fins to gain access to the forward most side of the rid to weld it. The fuel I'm running should MORE than adequately cool that area.
The fifth picture shows the other side rod and the clutch apparatus. I was initially worried about the clutch cable perch but figured some 1/2" round aluminum rod stock drilled through 9mm and slotted would hold the clutch cable adequately. Positioning it was the hardest part. I measured my yellow blaster to make sure I had the position close. I also took the transfer cooling fins off that side to allow access to weld the rod in.
The sixth picture is showing my trash can...... and there's a blaster motor somewhere in there. Yes, I know those mounting bolts are too long. They're actually the two bolts for the carrier but they *happen* to be M10 X 1.25 and long enough to allow me to test the fit. I plan on getting some threaded rod and cutting it to length and running flange nuts down inside the access holes.
The 7th picture is a closer shot of the left side with the cylinder sitting on the bottom end. This is the actual bottom end I'm using and this shot was really to show how the clutch perch aimed at the actuator arm...
The last pic is just a shot from the top to show how the studs will stick out into the middle of the large holes in there.
Now for the "how-to". Just a warning.... this is NOT for the weak of heart. It requires PERMANENTLY altering your cylinder but I believe this can be a HUGE boost in top end power.
The first steps are as such.... you need to take the transfer cooling fins off somehow. I took a 5/16" drill bit and drilled holes right along the transfers until I had removed enough aluminum to grab the fin with a pair of pliers and snap it off. Then I used a carbide cutter to smooth the outside of the transfers so they weren't all ragged and jagged.
The next step is to take a piece of 1" aluminum round stock and drill a hole STRAIGHT down the middle. It took me three pieces of aluminum before I got two good ones... remember, I did this with a hand drill so patience is KEY. You'd drill yours 8.1mm I did mine 10.1mm.
Take a piece of 1/2" round stock and drill the middle of it out while you're in the drilling mood.... I think the end of the clutch cable is 8mm so I drilled my hole 9mm and go ahead, cut a slot in it with whatever cutting tool you have handy, and cut the last 1/2" off that round stock.
The two 1" long pieces have to have the "inside" edges sanded down to get them to fit properly but I started out with them about 1.5" long and sanded until they fit (which is a LOT of sanding BTW).
Next, flip your cylinder over and clamp the head studs in a vise. Find a drill bit which just barely fits down through each of the current cylinder mounting tabs and hit the bottom most "large" cooling fin to make a mark so you can drill straight up through the cooling in line with the mounting hole. Visually confirm you are lined up with that hole, a misalignment here will spell disaster towards the end. Using a smaller drill bit (to keep from elongating the current mounting holes) drill "up" through each large cooling fin. The smaller drill bit I used was just a bit too short to punch through the top fin but it nearly made it all the way through. Now trade up to the 8.1mm drill bit (or the next size available over that) and finish off all the way through the top fin making sure to stay centered and straight all the way.
Now comes the tricky part.... I happened to have a large diameter drill bit with a 1/2" shank lying around. Most won't have that luxury but you need a large drill bit to drill out the top three cooling fins to allow a nut to slide down through them. I drilled mine by hand using my 10.1mm hole as a guide all the way through.... it was tough and I went a little too far on the right side but not too far as to hurt anything. As with any large diameter drilling, patience is the key here. Large drill bits into soft metal can HURT you if you're not super careful.
I them slid my round rod pieces into place and slid the super long bolts down through the mounting tabs from the top to keep the holes aligned. I welded the round rod to the cylinder making extra sure I penetrated for strength. I allowed the cylinder to air cool so I didn't stress the new welds and then I coated the inside of the sleeve with oil again.
I then ran the clearance drill back through the whole assembly in case the round rod shifted during welding (which it did just a TINY bit)
The trickiest part of all is drilling the boyesen's.... because the drill bit wants to "walk" on an angleI used a 1/4" drill bit and drilled 3 holes on each side. I then "twisted" the drill to wallow the holes out until they connected. Then I took a 7/16" drill bit and drilled each of the holes out CAREFULLY (warning, that bit wants to catch sideways and twist the drill out of your hand!) to connect them all. Once the hole was connected I used the pencil grinder and alumihog burr to clean up the drill marks some.
I still have a LOT of cleanup to do inside the intake window plus a bunch more work to do to the porting in general but I will take VERY clear pictures of the portwork when I'm done with it!
