Spectroplasm's Port diagrams section (aka portmaps)

hey again mates, i would like to contribute to our fine forums and post up some collections i made of port maps and custom dremmeled ones too

these are all measured by me and then redrawn in photoshop to clean the picture up. since i live in a far away country i don't have the money or the means to get me top end parts for my scooter, and i always live by the motto "it's better to achieve it through knowledge than do ride it with confusion". Since most of us here (if not all) are die hard scooter lovers i thought it would help us all to have the needed examples of the real racing barrels and some homemade ones too. so here is the first port diagram i ever made on my pgo it's patterned after a friends real bidalot kit. enjoy lots and lots more to come. and if anyone else has some of their homemade ones or real make ones please by all means post them here

 

so what is this port map for? a minarelli or piaggio barrel?

essentially to port an engine you need a dremel, vernier (digital caliper?), some w+d and a fine file.

color in around the ports with a black marker, use the vernier to mark where the ports need to be reshaped, dremel away til your around .20 mm off the maximum tolerance, then file any rough edges and sand away with w+d, then give the port a polish up.

also you can use liquid metal to beef up the engine casings in places, then dremel them to match the ports and flow them, or smooth them out with w+d and some metal polish.

something along these lines?

i really wanna have a go with my stock 50cc lc barrel at some point, see what i can make of it

before anyone says it, yes i know anything i do is at my own risk and i will not hold someone responsible for providing me with information which may cause me to damage my spare engine :nerd:

 

i only work with mina engines m8 i don't have any piaggo scoots around but i can ask my shop dealer if you want portmaps for piaggo types too .

 

theres plenty of port maps around, you just gotta look. Port maps are useless to 99% of people because they cant even name the ports, let alone change them.

sam you have the right idea, i never use a file or wet and dry, dremel attachments do the lot as its more uniform then using manual tools. Polishing the ports really isnt necesary, in some cases it can cause problems because the atomised mixture sticks to the shiny surface, like water on a windscreen. most people use weld to "beef up" the barrel, thats for using huge transfer feeds really. Dont start off by following a map, because the grinding will be sloppy first time and you will get annoyed. all you should start by doing is opening up the feeds, its simple grind work but there are big gains to be made. Then work on the boost feed, widen it about 1.5mm either side and remove the lip on the outer edge of the barrel. dont grind away too much on the inside as the walls need to be parralel for the feed to perform properly. Once you've widened everything, wash the barrel out with petrol and refit/test the barrel, you WILL notice a difference through the power range, but once you've tested it and you know it works, you can start raising the ports, 0.5mm each time, then grind the top edges of the ports out slightly to keep a scale verison of the curve that was originally there. each raise of the ports, wash, refit, and test, marking done your results, for example:

0.5mm raise all round - good power, lots of bottom end power, feels loser top end

1mm raise all round - better power, loads of bottom end power, feels much stronger top end

etc etc, if you dont care about the barrel you can keep going till either the performance drops, or the barrel blows, that way you will know the limit

this is just a small idea into the world of 2stroke tuning, its not a difinitive guide and im not telling you to all grab your barrels and start grinding.

 

thanks swift, i apprechiate it this info is just what i presumed went on, i have done a basic engineering course which involved working within .100mm, most of it was making tools with a lathe

when i get my dremel im gonna play with a malossi 70 kit off me old piaggio 70 engine (has a 2mm deep score down the barrel so its fucked basically) will post it in another thread and see what everyone thinks


sam

 

i like this guy already.


might put the stock evo rubbing up later, if i can find it.

 

indeed, minarelli ftw imp: can you post up some more port maps and pics of your own work

 

ok mates will post up some more as i clean the pencil etches in photoshop i love collecting these stuff since i usually get shot stock 50 barrels every now and then aint no way i paying for a real kit unless i have a real use for it

oh and to sw1ft you're right about the useless to 99% of most people but you can't leave out the 1% die hard scoot lovers out there who love to get down and dirty with their scoots. my scoot is off road atm due to a piston ring snap. but i got a new set today and will fix her up again tonight .

and also i'll post up the Pipe belly measures as i get time to make them too you just have got to love homemade pipes m8 nothing better than having one especially when its honed for your scoots specs

 

spectroplasm do you have a recomended porting map for a malossi mhr replica barrel please (minarelli of course ) ? thanks

 

yep lemme dig it up and i'll post it for ya.

 

thanks m8

 

as promised m8 here is your tuned mhr replica barrel , it's as aggressive as i could make it, just adjust squish clearance but i usually operate without. think i'm gonna right up a long detailed post on Engine porting here so everyone can get the basics and advanced basics .

 

You havent put how far apart those ports are on that last one

 

yeah i did that intentionaly since if i still put the gap measures i'd end up with a complete mess of a diagram XD, you can still get the spacing throught he port width measures tho

 

thanks again spec m8 the barrel would be ok to ride on a daily basis yeh for say 8 - 10k miles? also instead of cutting the port right down to the lines could I chamfer the to the marks or cut and leave say 1 mil of a chamfer angle?

thanks again

also do you recommend specific veneer calipers, brands etc specific types ?

 

no problems J-Nitro , yeah the barrel is ok for everyday use (also if you have octane booster it would be wise to dab a few drops in your gas as 98 gas isn't really nice on your barrel , always ride with 100 or 105 octane, if you are doing a race and have a race kit run with no less than 108 octane, most people ride with stock gas and that is why their barrels self destruct or detonate on them.)

you should always leave a chamfer on the cuts as this will be very helpfull for the ports, open the ports till you're 2mm away from the final cut line then do a 1.5mm bevel till you reach the out limits of the diagram, bevels prevent your rings from catching the port hole and reduce your chances of barrel squeeze damage.

for the veneer calipers any will do there is no recommended specs.

 

Anyone got a stock mhr rep minarelli port map?

 

i got one but i'll need time to dig it up mate will post it up when have it

 

spectroplasm, is there any chance when you get time to maybee post a guide on porting barrels and work out timmings etc , would be well appreciated. cheers