port timming

[Surfrjag]

Hello, i have put my vitos 240 kit together Had some fun cleaning the casting marks and doing my own little bit of porting and been on it for the past 6 months running great. as i always feel the need for more speed... now comes the stroker crank. what i am wondering is what i can do to maximise the port timming with the stroker. i plan on getting the hotrods crank +4. just guessing but raising the exhaust port 2cm would help? maybe lowering the intake port a bit too? any help would be appriciated. thanks!

 

[brandoz28]

there's some software for a reasonable amount of money that you can get that will help you out with this, i just asked this not too long ago and there wasn't much input on the subject.

 

[02yamaturd]

pm ken oconnor...he'll be able to help you out probly....

 

[super noober]

i dunno dude i would leave that to the pros unless you can find some very reliable instructions, seems you could really mess the cylinder if you take too much off.. you looking for a rematch at busco next year lol?

 

[Awk08]

you do also know that the +4 crank is gonna require the cases trenched ????

 

[hotrodaj_2]

I would not touch anything unless a pro has told you to do so. If you go a hair ( really, a hair) to far you can cause the engine to run worse than stock. 2 strokes are much much more touchy than a 4 stroke. If you want it to run worth a damn then you need to talk to a pro or just have them do it for you, dont guess and just start removing material. You will junk it. I think it's great that you are not afraid to take the porting job on. If you get some numbers then "do it to it" dude.

 

[Surfrjag]

how safe is it to take material off the piston itself on the intake side divider specifically? It seems that its a bit bigger than the divider on the intake port on the cylinder.
noob I did beat my bike to death at busco, got a bunch of bushings and bearings seals to replace but im def. down for a rematch!! place was so fun. i try telling ppl about it and they just dont understand....

awk08 i do know it requires trenching, i think i can manage that.

i dunno if i want to bug mr oconnor to help me not give him money to work on my bike...

guess port timming is one of those trade secrets that are learned and not talked about too much and probobly depends alot on what im doing with the bike anyway. i would like to say i built the bike myself to make it fast but i guess i will have to experiement myself or pay someone thanks for the replys

 

[brandoz28]

here are some things i've been looking over, i'm going to do some porting on my stock jug this winter since i got a 240 jug to build another motor with...
MacDizzy's Two Stroke Technology Exchange - TRX - YFS - YFZ - Glamis Sand Dunes

http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf

this is for a stock jug, so it doesn't really apply to the vito's
http://www.racelogic.com/whatissportport/

and the aforementioned software

porting-programs.com

and a link to my thread about this as well

http://www.blasterforum.com/engine-mods-swaps-129/anybody-wanna-talk-about-port-timing-29871/

 

[FLOTEK]

just as a caution for the do it yourselfers on here : stroker porting is nothing like the standard stroke porting ,you can really screw things up by going in with a dremel and not understanding what needs done and why ..especially when you add the complication of a stroker crank .porting a single cylinder isnt really all that expensive at most shops and it will be money well spent knowing its done correctly,its not so much a secret as it is a complicated process and words only can explain so much .most dont have the right tools ( a dremel is not one of them lol) or get inot the areas that make the bulk of the power and giving specs is just a number ,really thats just a fraction of what needs done even if that was dead on ..what about the shape size area radii angles and so fourth theres way more to a port than some random numbers to grind to and making it look shiney in the exhaust port (which does nothing by the way ) software is handy ( i often use one ) but basically should only confirm what you should already know and alot of it is way outdated like those based on graham bells book .and cutting your piston (there is a right way to do it however) can drastically reduce its service life ,i would not touch the divider.~ my 2 pennies

 

[brandoz28]

thanks for the input again flotek.


i'm probably going to do my OEM cylinder but this vito's jug is going to get done by a pro...

 

[Surfrjag]

thank you flotech and brandon for the input. as much as i want to take on this project i guess it would be better to take my 240 stroker to a pro... you have an email flotech

 

[OConnor Racing]

I don’t believe “a polished export does nothing” is an accurate statement. A polished exhaust port does almost nothing would get my vote. The biggest reason I do it is to deter the port from building up any carbon deposits. Carbon deposits in the exhaust port will hinder performance. My personal engines (the ones I run) are never together long enough to develop carbon on the head or in the ports. I tear my stuff down a couple of times a year just to see what’s going on. Not going to be the case with 75% of the cylinders and heads I ship out. Customers are going to use crap oil, over jet and try to run the same set of rings for 4 years no matter what I tell them. A polished exhaust is just an additional precaution I take to offer customers the best possible job I can give them. The other reason I do it is purely for the bling. Men like shiny ports and chicks dig shiny rings. The polished port doesn’t hurt anything so from a marketing standpoint, I’m just giving the customer what they want. I will say it is a bit time consuming but what the hell if it makes them smile.

 

[scotj77]

I:Ihey ken I take offence to that! there is no way I would ruin all your hard work by not maintaining and checking on my topend on a regular basis. lol. right on with the smiles. guys dig shinny sh#t too. why do you think we put crome and plished alluminum all over everything.

 

[OConnor Racing]

I said 75%. You're in the other 25%.

 

[scotj77]

oh ok I missed that part. i was just jokin around any way

 

[Surfrjag]

also a good read...
2 Stroke Tuners Handbook by Gordon Jennings

these helped a little but not much on changing the timing for a stroked motor.