cylinder head porting

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showoff588 · #1 Post by **showoff588** » Sat Jan 07, 2017 6:03 am

Ok so iust about have all the parts i need to build a new engine. It is a stock stroke updated crank with 450 piston. I was hoping to get some of the cannondale geniuses to chime in on this and maybe give me some experienced advise on head porting. I have some experience in porting mainly cars and some clean up jobs on other motorcycles. i already know about doing the combustion chamber area. What i really want to know is if it should be really hogged out or is it better to do just a really nice clean up, smoothing and polishing. I know its important to keap the intake velocity correct but i hve also heard that even a stock 432 cannondale responds well to really big ports. What areas to stay away from. Also what cam settings will be good for my new found combination. I do some motocross for fun but mostly just freeriding. id really apreciate any info or tricks you guys have picked up over the years.

showoff588 · #2 Post by **showoff588** » Sat Jan 07, 2017 6:08 am

QUOTE (showoff588 @ Jan 7 2017, 06:03 AM) <{POST_SNAPBACK}>

Ok so iust about have all the parts i need to build a new engine. It is a stock stroke updated crank with 450 piston. I was hoping to get some of the cannondale geniuses to chime in on this and maybe give me some experienced advise on head porting. I have some experience in porting mainly cars and some clean up jobs on other motorcycles. i already know about doing the combustion chamber area. What i really want to know is if it should be really hogged out or is it better to do just a really nice clean up, smoothing and polishing. I know its important to keap the intake velocity correct but i hve also heard that even a stock 432 cannondale responds well to really big ports. What areas to stay away from. Also what cam settings will be good for my new found combination. I do some motocross for fun but mostly just freeriding. id really apreciate any info or tricks you guys have picked up over the years.

Im sure many others have already built this combo, so please post your results and what you think about it.

SlOoT · #3 Post by **SlOoT** » Sat Jan 07, 2017 8:29 am

I did my own head porting on a 432cc engine and it made a HUGE difference.

In the link is a topic of mine were I posted some pics and there is also some good info in there. Also added some pictures.
Throttle body is easily bored to 45-46mm.

When porting be careful around the "edge" at the intake ports near the valve seat, if you take away to much material you will end up in a water pocket.

I timed my camshafts at:
Intake: 109
Exhaust: 107

Timing the cams higher like this will make the engine much smoother in the low range and hit harder from mid range.

Later I changed timing to i110/e108 but that was a bit to high, the engine lost some power in the low range and didn't gain anything in the high range
making it feel a bit like a 2-stroke.

http://www.cannondaleriders.com/forums/ind...=22465&st=0

showoff588 · #4 Post by **showoff588** » Sat Jan 07, 2017 7:36 pm

Wow, some good information there. looks good. The edge your referring to, is that the step shape corner that sticks up in an untouched head? Is there enough material there to knock it down, like gently flow it in?

showoff588 · #5 Post by **showoff588** » Sat Jan 07, 2017 7:56 pm

I know that larger ports are for higher displacement or higher rpms. id really like to get verification as if opening up the ports on 450 is going to be affective throughout the power band or is it just going to move it higher in rpm. In short, YES hogg that baby out? Would I be correct to raise the roof and walls but just clean up the floor, open up the exhaust port leaving it in a D shape? I do like high rpm but of course dnt want to lose any low end, i dnt really care if it doesnt gain any low end as long as it doesnt lose low end. Also that being said, you think these would be good cam timing for mid to high rpm band?

SlOoT · #6 Post by **SlOoT** » Tue Jan 10, 2017 4:54 pm

The edge is indeed that step shape corner. I used to have some pictures of a head cut in half and in those pictures you could see how much material there was to take away.
There is enough material to make a nice smooth corner.

Making the ports to large would be bad on a carb engine but on EFI engines it seems "bigger is better".

Timing the cams at intake 109 and exhaust 107 didn't realy take away much low end power but it did get rid of that "snappy" feel the engine had in low rpm's.
Making it feel smoother in the low rpm's.

showoff588 · #7 Post by **showoff588** » Thu Jan 12, 2017 1:44 am

awesome, thanks a lot for the info. I think i now have a plan of attack. Ill try to get up some pics of my progress as i go.

POWER MAD MAN · #8 Post by **POWER MAD MAN** » Fri Jan 13, 2017 2:26 am

[attachment=13859:IMG_2017...2_205739.jpg]
[attachment=13860:IMG_2017...2_205754.jpg]
I'm not sure how much it matters on EFI but I always do a rough sand blast or grain finish on the intake ports so the gas will atomize better. Also make sure you don't do any under cuts around the intake valves. It doesn't do much but doing D ports around the short turn of the ports will help with flow on both intake and exhaust. D ports on the exhaust ports will help less carbon build up over time and more power. Watch out cutting to wide or deep on the exhaust ports because you can break into water. Like sioot said boring the throttle body will help a little bit on peak and over rev.

POWER MAD MAN · #9 Post by **POWER MAD MAN** » Fri Jan 13, 2017 2:29 am

[attachment=13861:IMG_2017...2_205733.jpg][attachment=13862:IMG_2017...2_205638.
jpg] This throttle body isn't CNC bored yet

POWER MAD MAN · #10 Post by **POWER MAD MAN** » Fri Jan 13, 2017 2:38 am

[attachment=13866:IMG_2017...2_213943.jpg]