Head porting or not - ***updated with dyno graph***

[mppzx12]

Hi Im new here. And I have been working in my garage with the porting hi vel for some time for some proyects.

I realy like your gains. Since I saw some other post I whant to make some aclarations.

1- the new heads of gixxers CANNOT be done like the old school, you need another numbers and another way of reducing ports.

A friend of mine that works on race engines gets +8 midrange and +5 on a NEW K5-6 engine. with smaller ports.

2- smaller ports sometimes fooll you thinking you have less topend. the thing is now you have so much mid that you dont feell the top coming.

I recived as a gift a XX, with the front end crashed. If I see that the engine is nice I will do the porting and biuld a naked bike.

I have ported zx12r. K2, zx9. F2-3.

bye

[R1000]

Hi Im new here. And I have been working in my garage with the porting hi vel for some time for some proyects.

I realy like your gains. Since I saw some other post I whant to make some aclarations.

1- the new heads of gixxers CANNOT be done like the old school, you need another numbers and another way of reducing ports.

A friend of mine that works on race engines gets +8 midrange and +5 on a NEW K5-6 engine. with smaller ports.

2- smaller ports sometimes fooll you thinking you have less topend. the thing is now you have so much mid that you dont feell the top coming.

I recived as a gift a XX, with the front end crashed. If I see that the engine is nice I will do the porting and biuld a naked bike.

I have ported zx12r. K2, zx9. F2-3.

bye

Looking forward to see your result after porting :-) The dyno read 155 rwhp on my bike this Monday, but after correction to STD conditions the figure was 152 rwhp. I was surprised that the bike delivered that power at such a high temperature, +28.5 deg C, but he air pressure was above STD and the humidity below STD, both resulting in more power vs. STD condition. The higher air density made the A/F ration to now read 13.4, in the previous benching the power figure was about the same (uncorrected) and the A/F ratio was then 12.8 to 1 at about zero deg C. It was snowing that day I rode to the shop

[pug]

R1000, what tire (type & condition) was on the Bird during the dyno tests? :icon_think:

[R1000]

R1000, what tire (type & condition) was on the Bird during the dyno tests? :icon_think:

It was a light Michelin Pilot Power 2CT with about 4000 km's, not bald but very soon to be replaced. I did that a few days later. The tyre had done two track days on my GSX R1000, so it was more than 50 % worn out to the edges. The chain and sprockets are in good condition. I figure the power on the Dynojet bench figures would have been slightly less with a heavy tyre or if the chain had been bad. The bike actually did a few more ponnies due to low humidity and high air pressure but was corrected to 152 hp at STD condition. The correction factor was 0.97 so the measured power was 156 to 157 rwhp. It may not sound a lot but I'm happy since it is far more than the modern 1000 RR bikes did a few years ago and I dont think all of them are on that level even this year. There was a GSX R1000 -07 that had been dynoed on the same dyno and the same operator the day befor, it produced 153 rwhp with slip-ons and a PC III. That sound a little low to me since they are claimed 180 hp on the crank stock.

Blackbirds are about 152 hp on the crank stock, so the about 175 that it has now on the crank is not bad.

[pug]

R1000, what tire (type & condition) was on the Bird during the dyno tests? :icon_think:

It was a light Michelin Pilot Power 2CT with about 4000 km's, not bald but very soon to be replaced. I did that a few days later. The tyre had done two track days on my GSX R1000, so it was more than 50 % worn out to the edges. The chain and sprockets are in good condition. I figure the power on the Dynojet bench figures would have been slightly less with a heavy tyre or if the chain had been bad. The bike actually did a few more ponnies due to low humidity and high air pressure but was corrected to 152 hp at STD condition. The correction factor was 0.97 so the measured power was 156 to 157 rwhp. It may not sound a lot but I'm happy since it is far more than the modern 1000 RR bikes did a few years ago and I dont think all of them are on that level even this year. There was a GSX R1000 -07 that had been dynoed on the same dyno and the same operator the day befor, it produced 153 rwhp with slip-ons and a PC III. That sound a little low to me since they are claimed 180 hp on the crank stock.

Blackbirds are about 152 hp on the crank stock, so the about 175 that it has now on the crank is not bad.

With a sport tire, you get less hp because it is possible to overheat and start sticking (ok, a bit) to the rotating drum.

With the OEM Dunlops , mine was about 147 RWHP, next year on Michelins Pilot power was 140.5. Some loss goes to the 1 year older chain, but I think that most of it ('bout 5 hp) was due to the tires.

[mppzx12]

The midrange of that bike must be fenomenal, and rool ons with your bike, if geared to redline to 180 mph, must be interesting.

[R1000]

I believed that the Dynojet benches give higher readings with a light tyre since the bench measures how fast the rpm increases and a light tyre is easier to accelerate. I've also heard that true track tyres gives low values on Dynojet benches since there is a lot of rubber on such tyres. Well, I can’t say that I am an expert on the subject, I’m more or less guessing.

The bike is geared for about 180 mph with 16F/44R and it pulls nicely at all rpm's and quite hard above 5.5 grand. It is by far stronger than it was stock and the driveability is a lot better. The bike is a heavy beast though, so it really needs all the power and torque it can get to perform even with newer sport bikes.

[mppzx12]

to accelerate like the new liter bikes especialy K6-7 suk, you need like almost 180.

My zx12r is a beast and accelerates even with a K6 with -1 on the front.

[R1000]

to accelerate like the new liter bikes especialy K6-7 suk, you need like almost 180.

My zx12r is a beast and accelerates even with a K6 with -1 on the front.

Yes, to stay even up to top speed about 180 is required. The Bird is however very quick even stock up to some respectable speed due to low first gears and its weight.

The XZ12R is a strong performer.