Porting!

[tubes380]

DONT polish it will allow the fuel to come out of the fuel and not be a homogenous mix, therefore not burning properly and power loss, the intake is only needed to be smoothed out, ie the big burrs and changes in diameter between joins smoothed. leave a rough finish so the fuel can mix properly

 

[bigd]

sorry wrong choice of words tubes, what i meant was i smoothed it out, but is there any point at all if im not doing the same to the head ?

 

[tubes380]

there will be a minimal change but nothing serious, the only reason you smooth it out is to get better airflow and it really helps when you add a hc piston or cam or something like that to the engine as it combines for add. power

 

[bigd]

i also noticed my intake measured 22mm and my carby is 25mm,
should i get a noticable gain by matching them ?

 

[tubes380]

is your carby really 25mm??? most china carbys are smaller than advertised

 

[bigd]

yep sure is, 25mm

 

[C50DRAG]

hi guys!my name is Gregory and i am from Greece.this is my first post.
i have an engine from a honda bike that is called honda supra.
is like your mini's motor.i have tune it many times with different set ups.from a 72cc and even 150+cc with 60mm piston and 54mm crank.all of these 2 years ago.
now i have a street set up at 128 with 55mm piston and 54mm crank that is very good[for me].i use a hand[machine]made camshaft with 318 durationin/out and 7.2 liftin a lifan head.
and now my question-how can i prevent the jb weld from fall in the compastion champer?i know that i most make some grooves in the port to catch from there but..i most do something else?

 

[Mack]

hey there greg, if the port is clean and you make good size grooves in two directions you will not have a problem with the weld moving. If you are still nervous then drill shallow holes in two directions as well. Make sure to do this only where you have available material.

 

[C50DRAG]

hey there greg, if the port is clean and you make good size grooves in two directions you will not have a problem with the weld moving. If you are still nervous then drill shallow holes in two directions as well. Make sure to do this only where you have available material.

thank you Mark!i will do that!i will keep you informed for the progress!

 

[sean01]

ok, i just read all this post from start to finish just now(last couple hours)
i must say there is an awesome amount of info here and its good to see that ppl are starting to share there hp secretes.
1 question tho, since a couple of you have benchflowed your heads what are the standard flow figures?
and have you flowed them with the larger valves, cut at different heights in the camber. i would imagine this would have some sort of impact.
as in the past i have built different breeds of heads and have had to cut them differently to achive better flow. ie.. some heads require sinking the valves alot and some require them raised.
also have you tried 2 angle valve facing as i know this helps alot?
and also i have found flowtesting heads as the same as dyno's are only usefull if you are using the same flowbench/dyno all the time as all benchs and dynos are calibrated differently as well as the software gives different results but if using the same equipment it will show you improvements and losses.
and this is coming from experience from sending heads to different guys for flowing.
hey has any1 just tried using an oversized exhaust valve opposed to oversized inlet and exhaust as i would image the exhaust would be most of the restriction ,the 27mm inlet should be plenty for promoting good low end torque altho these engines dont mind to rev its just not good.

anyways guys iv said enough. and if my thought are true or false well i guess you's will let me know..

cheers ppl..

 

[C50DRAG]

ok, i just read all this post from start to finish just now(last couple hours)
i must say there is an awesome amount of info here and its good to see that ppl are starting to share there hp secretes.
1 question tho, since a couple of you have benchflowed your heads what are the standard flow figures?
and have you flowed them with the larger valves, cut at different heights in the camber. i would imagine this would have some sort of impact.
as in the past i have built different breeds of heads and have had to cut them differently to achive better flow. ie.. some heads require sinking the valves alot and some require them raised.
also have you tried 2 angle valve facing as i know this helps alot?
and also i have found flowtesting heads as the same as dyno's are only usefull if you are using the same flowbench/dyno all the time as all benchs and dynos are calibrated differently as well as the software gives different results but if using the same equipment it will show you improvements and losses.
and this is coming from experience from sending heads to different guys for flowing.
hey has any1 just tried using an oversized exhaust valve opposed to oversized inlet and exhaust as i would image the exhaust would be most of the restriction ,the 27mm inlet should be plenty for promoting good low end torque altho these engines dont mind to rev its just not good.

anyways guys iv said enough. and if my thought are true or false well i guess you's will let me know..

cheers ppl..

i would like to know too!
can someone tell us if all this porting can make a different flowtesting results?and something else,can a chines head lifan or jialing make the same or better flow with the take plus r head in the same lifts?
[someone here is saying that use the rollers and the s35 cam from takegawa in a lifan head.with modifications of course1]if a take fhotos i will post them!]

 

[CYCO-VS]

hay guys yesterday i cleaned up the intake on my 140 looks alright also did a little bit on the head then i put it all back together started up re tuned the carbie and i noticed its a lot more responsive when you crack open the throttle haven't ridden it yet so don't know what its like to ride

 

[kesman20]

hello i am matias from argentina photo how porting head cylinder dedidas?

 

[kesman20]

please medidas intake port

 

[Chooky44]

Lol

u funny bugger. I read those exact words in a street machine magazine a while back. what you said is true to an extent but next time do your homework at TAFE or something instead of copying words out of a magazine

 

[swifty_ano]

Hey guys...looking at getting my cams ground...how much do i tell them I need taken off? pm me if you can. or post up here others might want to know aswell.

 

[fusedminis]

we have A2 cams that should be cheaper than regrinding your cam, and youll have a spare.

 

[Mack]

Hey guys...looking at getting my cams ground...how much do i tell them I need taken off? pm me if you can. or post up here others might want to know aswell.

Your cams generally need to be made bigger so they build your stock cam up by hardwelding, then regrind to the profile of a master they have.

Cam grinding outfits are mostly just copiers. They get a cam they want to copy and put in their grinder. The machine follows the profile very slowly and grinds the shape onto a large iron disk. This is then stamped and becomes for eg profile no. 10245 and info about the profile is entered into the database along with what is good for ect. and the ground master (which is just a big cast disk) goes on the rack. When you want that cam they hardweld your stocker, put the mastercam (iron disk) into the grinder on one side and your cam on the other and copy the profile across. Thats it. To develope different cam profiles is a totally different kettle of fish and needs very expensive and complicated machines and testing. Mostly only big engine manufacturers have this capacity.
Having said that though, what you can do with a grinding outfit who understand cam theory well is alter your cams by using differnt profiles from their stock of masters onto the intake and exhaust fror eg. a takagawa z40 intake profile and a r20 exhaust etc. also the lobe centres can be placed where you want and the timing of the cam altered by moving the lobes compared to TDC. This can also easily be done at the sprocket though.
You will find all the aftermarket cams and their various names will be copies of some previously well known cam usually for honda applications that have been around for years. Find out what cam they are based on and design around what others have successfully done before with that cam. If you want to go grinding outfit you need to know exactly what you want or know they can do a cam that someone else has figured out using their mastercams.

 

[born2slide1980]

I am an idiot

EDIT: I now realise how stupid it was puttting up these porting posts and pics... I did not try to stuff anyone around or anything like that, or know how much trouble it would cause... I am so very sorry for my actions ( I spent frigging ages trying to get the ports etc. right and did not think it through properly, or realise how secrectative it all is) and have now removed them...

 

[daimojay]

not going to go in depth pics of mine, but just showing the size differance of my yx150 stock port. and my TBv2 port job for the 187cc.