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Discussion Starter #1
hey guys, rebuilding my 02 MXZ 800 and i have two cylinders and one has some trail porting on the intake and the other is completely stock.
my question is, would it be alright to use them together, or do i NEED to match them???
thanks
 

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Basically you have two engines in one if you install the stock and trail ported cylinders together. The power delivery would not be balanced and output would be less than that of a stock motor. I would establish whether the trail ported cylinder was done correctly then match the stock cylinder to it. Otherwise find another stock cylinder. Post some detailed photos of the reworked cylinder, I'm sure you will receive plenty of opinions.
 

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Looks like a Race Logic "Sport Port" job,

Measure how far down that centre port has been dropped and do the same to the stock cylinder. The rest of the intake has only been deburred. Also check the height and width of the exhaust port. Try using "Macro" on your camera for close up shots.
 

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thank you for all of your help! im going to be working on them over thanksgiving break, as im off at school and no where near the sled or motor right now.

anyways i have a few more questions, is this porting legit...will the motor actually be putting out more hp(or be more efficient)? if so whould i need to adjust the jetting and clutches?

also what is the best way to make sure the ports are the same shape and all...i mean i can get the proper dimensions but how do i make sure that the curves on the lower parts of the ports match? eyeball it?

PS sorry about the blurry pics...that was either my father or younger brother taking the pics :D ...i havent been home in a while.
 

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thank you for all of your help! I'm going to be working on them over thanksgiving break, as I'm off at school and no where near the sled or motor right now.

anyways i have a few more questions, is this porting legit...will the motor actually be putting out more hp(or be more efficient)? if so would i need to adjust the jetting and clutches?

also what is the best way to make sure the ports are the same shape and all...i mean i can get the proper dimensions but how do i make sure that the curves on the lower parts of the ports match? eyeball it?

PS sorry about the blurry pics...that was either my father or younger brother taking the pics :D ...i haven't been home in a while.[/b]
Grab the ported cylinder and line it with a piece of paper cut flush to the top and bottom. Get a soft pencil or charcoal rubbing stick and make a rubbing outline of your porting layout (Port Map). Remove the paper and cut out all the port window tracings then install it in the UN ported cylinder aligning the side and exhaust ports being sure that the top & bottom are flush to the cylinder. Now you can transfer the differences using a sharpie or machinist's blue dye. Just like stencilling. Now the image of the ported cylinder is transferred to the stock one. Use aluminium oxide 120 grit sanding drums to slowly remove material. Be aware of rotational creep of the drums opposite the direction of the drum rotation as this tends to make the straight lines bend. Keep the sander moving along the material to be removed. When the port windows are done. Cut some 600 grit emery cloth into strips and drag them through the North and South edges of the ports where the piston rings travel to prevent ring hang up once the motor is assembled.

BTW. the porting job looks OK but try not to raise the height of the exhaust port or change the side transfer ports, just concentrate on matching the rear boost port and removing lumps 'n bumps beyond the reed cage of the inlet tract.

[attachment=40278:port_Map.jpg]
 

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