porting for dummies

[GreenLightening]

Allright its already too late to tell me not to start on it. Heres my situation. Ive got an old 88 blaster that I bought cheap. fixed it up for the old lady to ride on. I put on a fmf sst pipe and v-force reeds. the motor blew up after about 30 minutes of riding a couple of weeks ago. they told me at the shop that they thought it burned the piston because I had the wrong jet for the pipe. does that sound right? so anyway they bored it out and got me the parts. I will put it back together. So I thought since I had the top end off I would just clean up the casting practice porting it . I figured I couldnt really hurt it that much. I cleaned up the ports and smoothed them out.

I was just wondering if someone could tell me a little about it before I go too far with it and mess something up. seeems simple enough to me. make port smooth= air and fuel flows nice=more power. Dont get the wrong idea here. I didnt hog it all out , all I did was save myself about a hundred bucks by smoothing it myself.

Thanks for the info. and I think I will probably pay somebody to port the tecate, But I wasnt too worried about an old blaster.

[TimSr]

There are differing opinions on whether smoothing intake ports is beneficial, with smoother giving better flow, but rougher enhancing air/fuel mixing. Probably more would be inclined to accept the benfits of a smooth intake. Most believe smoothing the exhaust port is benefical. What you are referring to here, though, is "polishing" and is not "porting". Porting involves altering cuts, widening ports, and changing angles, as well as "raising" or "lowering" ports to help achieve the type of powerband and engine response desired. Porting should definately be left to those who know what they are doing, and not be attempted by somebody with a fresh 12 pack, aching to try out his new Dremel Tool!

[Wickedfinger]

... to ad to Tims point, I and alot of the people I deal with at the machine shop believe in a roughed up intake and port for the same mixture reasons. It creates "turbulence" in the charge helping to mix it. As far as altering the port timing goes on your wifes bike, I wouldnt go anymore aggressive than a "match" port, which is just matching the I and E ports up with the new piston (im assuming a Wiesco?). When you bore away the liner in a jug to the next size, you need to cut back the ports (either the top or bottom depending on the manufacturer and angle of the intake and exhaust manifolds) to the new bore-out to gain any power advantage. If you dont, you will actually lose horsepower. This is a problem in that many people are under the mistaken assumption that by boring out a 2 stroke, you will gain the same effects as if you increased the displacement of a 4 stroke which is simply not the case and why you need to re time the jugs ports. Also, most of your Aftermarket pistons have "altered" piston ports to help either "increase" horsepower or shift it around the powerband. Matching up the jugs ports to meet up perfectly with these altered piston ports is the only real way to take advantage of the "better" pistons porting. Oh, and definately up that main jet by at least 2 sizes - if you didnt and ran that new pipe - oh boy - BLOWTORCH!!!. Also, by boring out the jug you did actually increase volume and if you are still running the same stock sized main jet, you are going to lean out the mixture even more (more air will take up the volume difference, not fuel) so, maybe try 3 sizes up and work backwards - you dont need to blow it up again.

[deathman53]

one dumb question? did you check if the oil injection was working? alot of times they fail on blaster and cause the motor to blow very fast. or run very lean on oil. Everybody I know that has/gets blaster, immediatly gets the block off kit. there must be a reason, why.

[GreenLightening]

thanks for the info guys. Ill let ya know I just smoothed the ports out. nothing drastic. Hearing from you guys helped me so I wassnt tempted
do anything crazy. The thing would be put back together already If it wassnt so hot with so many mosquitoes outside tonite.

I rejetted the carb. the stock carb is a 220 I replaced it with a 250. does that sound about right for a starting point? the last thing I want to do is burn this sucker up again.

One of the first thing I did was block off the oil injector and remove the oil tank. I would rather mix fuel any day of the week then deal with a oil tank and injector. more reliable, less weight and mess since the second thing I did to it was repaint all the plastic..

thanks again for the info. Il try to keep ya up on how it works out for me.

[GreenLightening]

sucker. sucker suck3r. why does it post lolly pop?

[Jeb]

the last thing I want to do is burn this Lolliepop up again.



LMFAO!! I just thought you were being clever in your choice of words when I read that! So it replaced S_U_C_K_E_R with the word lollie pop!


That's too funny!

How's that awesome Tecate doing? I wish I still had my swingarm & axle!! :(

[GreenLightening]

LOL Jeb. I thought it was kinda clever too when I first read it. until I reminded myself that It was my post and I sure didnt remember typing that.

still mighty funny though.

The tecate is doin great. Im happy that you dont have that swingarm and axel anymore. :) they are right at home on my machine. I wouldnt know how to ride it without them anymore.

Ill have to get some more pics of it up on here sometime. Ive been wasting all my time and money on my new toy the blaster here lately.