What have my mods done?

So, y'all can see the mods I've done in my sig line. I'm going to go up to a 120 main jet. Now, to my understanding by putting pods on I've increased the air flow and have compensated by increasing the gas flow w/bigger jets. According to the kawasaki.com parts site, and my FSM, anything over a 115 main is considered "for racing only". I also understand that by going to a 2 to 1 exhaust system I've improved performance. Presumably "for racing only" would indicate that my performance has been enhanced. So I've "increased performance" because I'm now burning more gas which is being supported by more air. I'll also be adjusting the airfuel mixture screw to something other than the, inefficient, EPA mandated stock adjustment and have a "more efficient" exhaust system. Now my question is what have these mods actually done?:huh::blush:
I also guess I've done something to improve the performance by adjusting my valves? Manuel says stock puts out 55hp@7K rpm.

Post edited by: ronjones, at: 2007/04/13 00:56

I'm certainly not an authority on the subject, but the BS34's may be a bit much for a 750 . What does everyone else think?

austin3119 wrote:

I'm certainly not an authority on the subject, but the BS34's may be a bit much for a 750 . What does everyone else think?

The 34's are stock, Austin.

Now don't I feel like a moron. Haa. :blush:

austin3119 wrote:

Now don't I feel like a moron. Haa. :blush:

He!!, I'm the one that doesn't know what he's done to his own bike:laugh:

ronjones wrote:

austin3119 wrote:

Now don't I feel like a moron. Haa. :blush:

He!!, I'm the one that doesn't know what he's done to his own bike:laugh:

I understand you have done some performance mods, but you don't list the REAL performance mods? How much shiny stuff have you added? Have you painted anything? Did you put in any neon lights colored turn signals or blue tinted head lights?

Seriously though, I have no idea in terms of real HP what you gain but if you can feel a difference than it's significant. My personal theory is that you can't "feel" less than about a 10 HP difference

austin3119 wrote:

Now don't I feel like a moron. Haa. :blush:

Then you "really" don't want to hear that the 76-80 750 twins had BS38's stock


As far as a performance gain goes, maybe 2-3 hp, but you need to keep a couple of things in mind.

55 hp was the factory rating, in other words a brand new motor in perfect tune under ideal conditions. A long time ago someone posted that they had put their 750 twin on a Dyno and it made 44-45 hp at the rear wheel.

Regarding not being able to detect anything less than a 10 hp increase, I think it is more a percentage increase than a fixed number. You would probably not notice a 10 hp increase on a 400 hp motor, but I'm sure you would notice a 10 hp increase on a 10 hp motor

steell wrote:

austin3119 wrote:

Now don't I feel like a moron. Haa. :blush:

Regarding not being able to detect anything less than a 10 hp increase, I think it is more a percentage increase than a fixed number. You would probably not notice a 10 hp increase on a 400 hp motor, but I'm sure you would notice a 10 hp increase on a 10 hp motor

You know you make a good point, I'm still thinking in terms of cars where your starting out with HP measured in hundreds I'm not great at math but I think 3 HP would be like 18% which would be pretty significant.

before you start changing jest and such, have you read your plugs?

AR15Ron wrote:

I'm not great at math but I think 3 HP would be like 18% which would be pretty significant.

OK, I am good at math, and 3 horses are 5.45% of 55 horses, and are 6.6% of 45 horses. To get an 18% increase on a 750 twin you would need about 8 more rear wheel horses, which would take, what, at least three more squirrels?:silly:

The only way to have known for sure was a before and after dyno test. Otherwise you're just comparing the present performance to your memory. And since you're spending time and money, you'll subconsciously judge the present performance as improved even if it actually the same or a bit worse.

Mr. Ronjones,
I did comparable mods to my bike about a year ago. I have a 750-4cyl., but for the sake of discussion let's just say the mods are similar. Steell is probably pretty close to the mark on this. I had mine dyno'd after I'd fiddled with it and I think the results showed about 62HP. I remember being a little disappointed at the time, but after keeping an eye on other people's posts I've come to the conclusion that that's pretty respectable without any major engine work. As Steell said, we're dealing with 30 year old bikes here, and the factory manuals would have been optimistic anyway. Bottom line, if you can feel a difference after all your work, then you should be proud of yourself.
So to answer the question posited in the title of the post...spent some time, money, bloody knuckles, and energy making you feel good about doing something you enjoy!

Post edited by: Wirewulf, at: 2007/04/13 09:41