reults from porting?

[rideracelivemx7]

thoughs of you who have a 440 and similar build and had the head ported, say a 500$ job or less, what are your results? what are possible hp gains? very curioius, and if my bike quad dont sell this summer, im probly going to cave in and do a stroker and ported head

[Duke Nukem]

If you spent $500 bucks on a port job, you should anyway have a beast. I spent $230 I think for my port work and it gained me about 6 hp, no dyno charts though.

how do you figure 6hp with just porting if you dont have dyno charts?

[Duke Nukem]

Well I did have it dyno'd before the port work, and was 35hp. The performance guru at the shop said it would add 8-9 hp. But I said on an old school motor like this no way. I'm thinking 6 hp gain because I've seen other port work done, and the work he did on my EX head was excellent.

[rideracelivemx7]

35? what do you have done to it. just a 440?

[Duke Nukem]

At the time, 440 kit (really a 450cc) 11:1 true compression, Hot Cam stage 2, a custom exhaust and intake. Now it makes around 41 hp with the porting.

it surprises me the HP on 440's. Stock is 27 and change, I know for a fact just and HMF slip on and jetting makes it just over 1HP so thats 28.. then removing the airboxlid and jetting adds about 1HP as well and when you add the HMF and remove the airbox lid and jet its not a 2HP gain its a little bit more because it works in junction so thats lets call it 30HP. Idk with my mods I figured I might be at 31HP adding the numbers and looking at the different dyno charts for the mods I have. i really want to dyno my quad to know what its at now like i said I figure 31HP, then I want to dyno my quad when I rebuild my motor to a 406cc, 9.8:1 compression, and a stage 1 hotcam and see what those gave me and looking at dyno graphs for torque i'm thinking i will be near 27ft. lbs but like I said its impossible to know for sure unless i get my quad dynoed.