DP50 Cylinder Porting

Im porting this Daliem 50 cylinder and Im wondering which directions you guys think I should take? I have an extra cylinder to decided to try and port 1 and get my Gfs bike over 35.

This is cast Iron

That exhaust port looks ridiculously small

D exhaust.jpg
D cylinder.jpg
D C Exhaust.jpg

Re: DP50 Cylinder Porting

Don’t just go in there with a dremel if you have to ask what to do. First do a port map, then take measurements, then put it on and check the durations with a degree wheel. After you have done that you can see what can be improved upon without going too far and having a boat anchor. It is easy to go from perfect, to a little over, to unusable.

Re: DP50 Cylinder Porting

just follow that burnt carbon line to match the exhaust . pretty safe to go wider by a few mm and up a couple. fun time.

Re: DP50 Cylinder Porting

. Chudas. /

Ended up raising the exhaust about 1.5 mm and opening up the exhaust a bit, glass sanded the head removed the head gasket and replaced it with some copper spray, seemed like it revving a few hundred RPMs higher.

Also I just realized this is in the wrong section, sorry.

Re: DP50 Cylinder Porting

Looks like the only mods you could fit in there would be to open up the exhaust port , channel and port match it with you're header , maybe room to get a auxiliary exhaust ports , transfers i would not touch besides mild reshaping with a file for symmetry , but if you were able to dig a couple pockets into the bore between the transfers without breaching into cylinder studs , and add precisely timed charging holes into the piston , youd have some boost ports . Modifying the combustion zone and getting more compression and a squish would help too. I still dont know why people think spray on copper is a suitable head gasket , the reason you have a seal is because youre head is aluminum and the cylinder is iron .

fWFFF (fuckjbg rong forum fuck face)


Re: DP50 Cylinder Porting

Have never found the source or patient 0 for spreading the copper spray gasket virus

Not sure where the idea came from, maybe a guy under torqued a cylinder and had to use spray in a pinch, then his buddy saw him do it, and it spread like wildfire

At any rate, where in the service manual does it say ‘Use pt no xxx-xxxx spray gasket’ ?

How in the fart are you able to tell it raised rpm by a couple hundred by feel?

You’ve got lots of splainin’ to do!

Re: DP50 Cylinder Porting

EH 📣FCC of the QCB /

> SABAT! andDestroy Wrote:

> -------------------------------------------------------

> I still dont know

> why people think spray on copper is a suitable head gasket , the reason

> you have a seal is because youre head is aluminum and the cylinder is

> iron .

Glad someone else said it. I was once sick too. I was always developing leaks. Turns out gas breaks that spray down easily. Lots of people still use it and say how good it is.....Head gaskets all day everyday.

Re: DP50 Cylinder Porting

Does that mean copper blinker fluid is worthless also?

Re: DP50 Cylinder Porting

. Chudas. /

Lol I guess next time Ill just spray the copper spray in a brown bag and wear it like a mask.

I did a pre and post port map and only raised the Exhaust 1.5mm and widened and matched to the pipe.

I could tell it was revving a little higher cause I ride it every day and I know the wall it hits, this time it went past a little but nothing high strung.

Re: DP50 Cylinder Porting

your required to a post a post port picture.

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