DDIY!- Cylinder Porting
- Thread starter yfz450bence
- Start date
just got the cylinder decked 1mm locally for $20, cheap! Now for the head mod, im taking it to a shop here in or that specializes in atvs machining porting etc. ill measure the spuish and he should be able to mod the head for my needs.
the pics of the porting look pretty much the same except widened trasfer windows, i do plan to get the head done, but might not this week, im going to the dunes saturday and want to take the blaster, so i might just put the head on the way it is, and check compression after break in, should run just fine, hope to get some vids if all works out, piston should be here today some time.
compression is at 140, before even starting it, now just for some gas and break in, compression should rise to about 150-155 im thinking which is perfect.
damm i would like to try this on a old beat up cylider to get my own port shop going with my pop
after some run time compression is at 150, which is fine. did some jetting today, needle ended up at 3rd clip from top, and pilot is 40, 1.75 turns out.
i started with the richest setting on the needle (5th clip), it wasnt even funny how bad this thing was smoking and sputtering, amazing what 2 clip changes can do. still need to do main jet, starting at 160. the cpi pipe is a mid to top pipe, it has a noticable kick to it, soft on the low end, hope to race a vitos 240 blaster at the dunes, also the stock 660 raptor.
some pics, rear plastics are off
i started with the richest setting on the needle (5th clip), it wasnt even funny how bad this thing was smoking and sputtering, amazing what 2 clip changes can do. still need to do main jet, starting at 160. the cpi pipe is a mid to top pipe, it has a noticable kick to it, soft on the low end, hope to race a vitos 240 blaster at the dunes, also the stock 660 raptor.
some pics, rear plastics are off
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i forgot exactly what the specs were for the poting on this, this will be a ruff but close of what i did, raised the intake 4mm, widened the exhaust 4mm totall, widened the main transfers 1.5mm, widened the rear transfers 3-3.5mm, smoothed out tunnels, added boost ports in intake, raised cylinder 1.1mm over stock. left the roof of the ports alone, raised the exhaust .5mm if that, chamfered ports butter smooth.
and from the butt dyno, it feels good, its hard coming off a yfz450, but it feels good for a blaster.
and from the butt dyno, it feels good, its hard coming off a yfz450, but it feels good for a blaster.
will eventually, on the way there, trailer tire blew up, lost 2 hours had to get tire service from les slow schwab, just wanted to ride, didnt even get videos, on the drive back, my buddies truck tranny went out, started slipping to the point it wouldnt move, got home 2 in the moring. worst trip ever.
next trip will hope to get some vids
next trip will hope to get some vids
keep in mind that when you raise the cylinder, it'll affect your transfer timing.
also, if you're running a mid/top end pipe, why not port the cylinder to match the pipe? mismatching porting w/ the pipe is a debilitating error.
but great thread man. and def looking forward to the vids!
also, if you're running a mid/top end pipe, why not port the cylinder to match the pipe? mismatching porting w/ the pipe is a debilitating error.
but great thread man. and def looking forward to the vids!
thanks your right on what you said, yes i did have that in mind, thats why i didnt raise the transfers any, the pipe is a mid to top pipe, and since the whole jug was raised 1.1mm over stock, that increased the timing quite enough, exhaust was raised .5mm max, and i feel it has enough mid to top, i think the porting is matching pretty good, infact it needs a tad more low end, and im hoping to get that when the head is reshaped eventually and cut for a squish of 1mm or so. right now the squish is close to what a stock blaster has, so there is more room to gain a bit of power still. it does wheely easily in 4th gear without tugging on the handle bars with a +2 in swing arm once in the powerband, and a very noticable power band lol, it hits hard, there is no inbetween its either on or off, and im 100% positive thats how this pipe works, i guarentee if i put on a stock pipe, it would have mostly low end and no top, the pipe is number 1 in determing where you power comes in, the porting i did benefits the mid to top mostly but if user wants more low end, its as simple as switching the pipe.
now there is a point in where the porting can have a bigger effect then the pipe i think, and taht would be a drag port, and i mean 100% drag with no low end and mild mid, and all top end, then switching to a low end pipe wont benefit. when i had the shearer pipe it was a low end monster, power started right off of idle, and fell quite short up top. overall a decent pipe, not so with this pipe, its got a soft low end that builds into the midrange, im tempted to see what a right bend pipe would do like a power pro, or dyno port, but i dont got that money to blow for a new pipe.
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Nice dyi. Didn't see pic of right angle for Dremal. Posted in thread on Banshee HQ wondering how many cyls the "Experts" F-up before they got it right (or numbers didn't work) and I didn't get any answers. I pose same ? here. Any "Expert" man enough to admit failure? I've done a few and haven't f-up, YET.
you might seriously want to reconsider that, i suggest doing it on a spare oem jug you have lying around unless you want to f*ck up your jug.
^^ Ya not to be a dick but its more than likely you will mess up your first time. I went way overboard with my spare jug but i have another so its ok
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