well i have a 00' trailblazer...hd it ported, polished, head milled, new weisco piston, have a "DG" pipe (anybody switched from a dg to another brand before?) HPD clutch kit, and it just doesnt hve the power. took it to a guy and he came up with the compression is at 155, no air leaks and the shop who performed the mods said it should be 175-190 compression. no i have to get the head milled down some more....anything ele should do or check?

 

I don't think 155 pounds of compression is the problem .

 

well, i understand that there are hundreds of variables, at 3/4 throttle to full, it just seems to bogh down.....jetting is ok, clutch is ok....you really dont think thats it????? what else should a desperate guy to check...thanks for your time...what i really want to do is ship the whole bike to ritter cycle, but with three kids my budget is very limited...have to think of the first you know

 

You are being freakin ripped off. Plain and simple. If he did a compression test, and said it's a 155 psi, what the heck is he milling the head for? If 155 is not enough, which it DEFINATELY should be, WHY are they not replacing the COMPRESSION ring on the piston, rather than milling the head for static points of compression?
They are 2 different things. Each affects the other, and you will get more power from milling the head, but the test he performed was on the rings. And BTW, that's a good number. What elevation are you at?
Ask him what he thinks the compression ratio is at. 10:1, 11.5:1 or whatever, based on his lil test. Tell him there has been head work done, and you don't even know if it can be milled anymore. Ask him how he'll then determine compression ratio, and go about the work to change it.
Hope I helped. Let me know if you get anymore bozo things happening on this.

 

155 lbs cylinder pressure is right on the borderline for running premium gas where I come from. 175lbs is race gas only....gets pricey! If it boggs at 3/4 to full throttle something is not right. You say the clutching and jetting is right on.....how can you tell? If it was ported for a race-only set up, then maybe, just maybe, getting the compression higher and running straight C-16 fuel might bring it around....but its going to be a peaky runner!