Can you port and polish a motorcycle?

Question

I have a 1980 Kawasaki KZ440 w/ dual carbs. and was wondering if there is any cheap tricks to get more power?

Answer 1

Yes, you can "port and polish" the heads which will give you an increase in power and throttle response but, not to the extent that you are looking for and, more power is not cheap. Actually, the more power you look to gain, the more expensive it is.

Porting and polishing, for example, will cost you a few hundred dollars at a machine shop. Are you planning to remove the heads yourself ? If not, count on at least another few hundred dollars for labor to remove and replace the heads plus gaskets and hardware for your rocker boxes and heads.

Boring and honing the cylinders and installing larger and higher compression pistons ( and maybe a higher lift cam ) will be a much more noticeable increase in power and torque but ( as I mentioned before ) is also much more expensive. First the labor to remove the cylinder heads and cylinders, are you doing it yourself ? If not, figure on about $1000 or so just for labor. Parts ( machining of cylinders, matching pistons, gasket sets, camshafts, camshaft bearings and rejetting your carbs after the work is done ) will run you around $1200 - $1800 depending on the parts that you choose.

NOS, I really can't speak on because I have no experience with it. I do know however that it's expensive and, of course, is exhaustible ( you have to refill your bottle eventually ). Also, in my opinion, NOS is not "mechanical horsepower", its a performance enhancer that puts undue strain on all engine components that, unless modified to tolerate the additional stress, will wear or fail. Another point to consider with NOS is ( for those who can correct me on this point, please do cause I really am only assuming this ) youre going down the highway and want to hit the "gas", once you press the button, you are committed to that ride, regardless if a car pulls out in front of you or not. I prefer the "mechanical horsepower" mods ( pistons, cams, head-work, etc. ) where, you "twist the wrist" to accelerate and, in the event that something happens, you "untwist" it to slow down.

Answer 2

First of all, the following is crazy talk

Bore out the top header, by a machine shop and order your pistons to align, the more compression the more horsepower. Then mix a richer flow of gas per oil with the carb.

I have never in all my life heard of boring out the top header?? Possibly what he meant was having the cylinder align bored and installing a larger diameter piston. Higher compression will give you more power as long as it's done properly. As for mixing the oil and gas?? I think he is living in 2-stoke land. He gets an A for effort though. You only mix the gas on 2-strokes and most of the old street bikes that were 2-stokes like the H-1's for example had automatic oil injection but I believe they could be calibrated for richer or leaner conditions. Your 440 is a four stroke, pump the gas and go. You can have it ported and polished by someone who knows very well what they are doing. If you have it ported and raise the compression and change the air filters you will need to either install performance carbs or re-jet the existing. Hope it was helpful. No slam intended on Patrick C, I am sure he is well intentioned

Answer 3

Yes you can port and polish. I would start be rejetting the carbs or by drilling out the existing jets-if you feel comfortable doing that. You could also change the carbs to a newer version. Get a high flow air filter such as K&N if available. The next step would be to get into the engine, check with a reputable machine shop and ask if they do any performance mods on motorcycles. The other option would be a larger engine from another KZ like the KZ1000.

Answer 4

Port And Polish Kit

Answer 5

Bore out the top header, by a machine shop and order your pistons to align, the more compression the more horsepower. Then mix a richer flow of gas per oil with the carb.

Answer 6

Better breathing can help a little. A freer flowing intake and exhaust, and remapping to take advantage of it. There is very little you'll be able to do to add more than a few horsepower to such a small engine.

Answer 7

All the tricks to horse power cost money and time.

Yes, you can polish & port the motor.

You can put a NOS system on it.

Answer 8

yes but if u had to ask it would be way beyond your skill level don't try it !

Answer 9

not sure but i hope you wear a helmet

Answer 10

you get what you pay for; that simple