JUST GOT A CLEAN 97 MACH Z ALL STOCK OTHER THAN A HI-PERFORMANCE CAN , WITH 2080 ORIGINAL MILES, RUNS GREAT & FAST AND ALL BUT BOG'S
REALLY BAD WHEN YOU NAIL THE throtle FOR A SECOND OR SO THEN COMES ON HARD AND RPM'S RIGHT UP TO SPEED. IV'E HAD THE CARBS CLEANED,
EVERY THING OTHER THAN THAT IS PERFECT . IS THIS NORMAL FOR A STOCK MACH Z ?
IV'E GOT A 94 MACH 1 670, A 95 MACH 1, 670 & A 97 MXZ 670, AND THE OUT OF THE HOLE RESPONSE IS MUCH BETTER! I'M A KINDA DISAPPOINTED IN THE MACH Z'S HOLE SHOT PERFORMANCE.
I KNOW THESE SLEDS SHOULD KICK ###, ANY thoght's OR IDEA'S ON WHAT'S WRONG? :slick:

Have you tried turning the air mixture screws in a little at a time until it goes away?. I have a 93 Mach 1 670 and thats what I had to do. The manual spec said 2 to 2.5 turns out, but it runs way better at 1.5 turns out(with 280/300 jets). It's a little rich at idle, but no bog and pulls strong all through the rpm range.

I'LL TRY THAT TODAY , HOPE THAT CURE'S THE BOG! THANK'S

Check your RAVE valves and make sure they are clean, also make sure that your oil injection pump is set properly. 97 Mach Z's came out from the factory plenty rich and if I remember right I came down to 350's on my main jets and I ran K&N air filters. Also like sagebrush said, play with the air screws, first determine if it is a lean or rich bog. Going in with the screws richens the mixture, taking them out leans the mixture on the bottom end. If this fails raise your engagement RPM, I think stock they engaged at about 3800 which is too low, bring it out at about 4500 by either grinding a notch in your ramps or by getting a different clutch spring. (200/350)

A few other things you can check are: the belt- is it the proper belt and length and is it in good shape (if it's worn down too skinny, that could cause a bog), motor alignment- is motor in good alignment and center to center good, along with motor mounts (a broken mtr mount will cause a bog from engine twisting), as c to c of clutches that are too close, causes a bog from belt deflection too loose, reeds- are reeds in good shape (broken or worn reeds cause a bog as intake air/fuel charge not staying in engine which leans out), rubber intake boots- are boots between engine and carbs in good shape (my '97 Mach 1 is on it's third set, as these are known to crack/split underneath, causing a lean bog), and also that "performance" can- this could also cause a lean or rich bog as this can's backpressure could be different than stock, requiring a fuel screw adjustment (mentioned by others). To adjust fuel screw (Mach Z's have flat slides which have a fuel screw between slide and engine of carb (turning in leans mixture, turning out richens mixture), remove airbox, warm engine up outside in cold, bring idle speed up to about 2200-2300rpm, then adjust fuel screws a quarter turn at a time in or out until highest idle speed is achieved, and finally bring idle speed back down, re-install airbox and try it out. It should have quick response without bogging, otherwise check all other possible problems above.
Hope this helps !

Mach Z's have an air screw so taking them out leans the mixture, taking them in richens the mixture!!!

Sorry ! for above post, I made a mistake when describing Mach Z carbs. I checked my manual and the Mach Z, although having the flat slide carbs, it also has an airscrew on the carbs like my Mach 1's roundslides and not a fuel screw that I thought it had. An air screw is located on the right side of carb between airbox and slide of carb. Turning air screws in, richens mixture, while turning air screws out leans mixture. The rest of adjustment is done the same.
Hope this Helps ! :p

You might want to check the primary clutch spring, make sure it's in spec. & that the sec. clutch is in good shape ex. buttons, and the spring pre tension is set.