What to remove while porting??

[FurryOnTheInside]

so you would cut the piston not only on the intake but also the exhaust side?

What? No! I would lower the intake a tiny bit at a time, while I was there widening it into the conventional rounded trapezoid. It could be a good idea to notch the skirt (only on the intake side!) by a millimetre or half so that when I find the point of "oops I lowered the intake port too much" I could swap back to the stock unmodified piston and that would bring back the intake duration to the previous and hopefully the optimal duration.
But the notch should be the same width as the widest point on the intake port, not the shape of the top of the intake port because that's irrelevant.

Also you quoted me but that post didn't mention the piston or the intake at all.

 

[Carl Walichnowski]

Yeah. I had one without a flex shaft and I did manage to get it done, but I used it a lot on the build and wore out the motor so I have got myself a new one and it has the flex shaft whatsit. I am using the very cheap tungsten carbide burrs sets from ebay/ China that are frustratingly just a little bit shorter than would be ideal. That's why I came up with the plan to scallop the bottom of the transfers to get a bit more reach.

I know Dremel makes a long Tungsten Carbide burr that may reach, I believe its about 3/4" longer then your typical burr.

 

[FurryOnTheInside]

I know Dremel makes a long Tungsten Carbide burr that may reach, I believe its about 3/4" longer then your typical burr.

Sounds good Where can you find it and how much is it? Not for me of course as I'm not in North America (and I'm quite looking forward to seeing how my plans work out) but for those who are.

 

[Carl Walichnowski]

Sounds good Where can you find it and how much is it? Not for me of course as I'm not in North America (and I'm quite looking forward to seeing how my plans work out) but for those who are.

I have purchased from eBay for almost $5 less but recently I purchased one from Lowe's for about $13.00. If I remember I'll take a picture of it or get the item #.

 

[Cole Emslie]

Also, delay your timing by grinding the wood-ruff key. Slightly better top end. I have 2 bikes. I removed part of the cylinder skirt on the intake side, and ground down the piston on the exhaust and intake side and polished it. Removed the head gasket as well(engine was almost new so it sealed), delayed the timing, fully gutted the exhaust and BAM. Sounds amazing and is more responsive through out the power curve and better top end by about 4-5 mph. Was it worth all the trouble...I mean I guess