kz700 modifications

Well I start working full time on June 1st. So I am going to put some money into the kz. I was thinking about a smaller front sprocket. But my question to you is, how much smaller? Also I am thinking of the Vance and Hines 4-1 exhaust. My question is about it, what all will I have to do to get it to fit and work properly. Also what are the expected horsepower gains with this exhaust? Also, I want to get the K&N pod air filters. With these mods, do you think I will need to rejet? I am asking all of these questions because I am hoping to do it all in one shot with very few problems and would like to know what to expect..



THX IN ADVANCE
BLAIR

I recently put new sprockets and an chain on my KZ700.
I already had a nearly new 525 chain from my old (crashed) bike, so I searched for some fitting 525 sprockets on www.jtsprockets.com .
I ended up with a 16 tooth front and a 43 tooth rearsprocket, which makes the ratio 2,69 as opposed to the standard 2,54.
The bike pulls much faster now, without revving too much on the highways.
It used to do something like 5000 rpm at 120 kph, now its near 5500.

If you use the podfilters you have to rejet, there is a specific KZ700 kit from Dynojet, so maybe you can buy that one.

I also put a 4 into 1 exhaust on my bike and I did not rejet it. But it took me several hours to get the old exhaust off. I had to buy new studs and nuts, because the old ones where not really good anymore, and I didn't want to risk damaging the threads in the head...
Recently I put a 2001 Kawa ZR-7 exhaust on my KZ700, and that was a bit more complicated:
click

If you combine the exhaust with podfilters and a jetkit I think you will gain about 8 to 10 hp.

Another mod you can think of is putting in the cams from a GPZ750A. They have a different shape from the normal 700/750's cams, and will give you a bit more topend without loosing lowend power. I'm not exactly sure what to believe, but I've read that this may gain 4 to 10 hp.
The standard GPZ750A was rated at 88 hp, while most other Z750's were rated at 78 to 80 hp.

Post edited by: Paling1, at: 2007/05/18 09:45

the 84 700 had a 630 chain when i put the engine on a 78 650 frame I used the 650 sprocket and a 530 chain, the engine has GPZ cams installed and I am rejetting the carbs, you can still get mikuni jets from some dealers for it I am going to use 152.5s these are the same as 165 dynojet items, if you go to the dynojet site they offer instructions for jetting process

Included in the jetkit are also the needles, which have a different shape from the standard ones. This helps getting the mixture right in certain rpm areas.

I think that after 23 years the original needles won't be in perfect shape, so you might improve on your milage too.

My KZ700 does about 16 km's per liter of fuel ( thats about 40 mpg I guess) at best.
As far as I know that should be around 1:19.

I have been thinking about buying the jetkit, but I'm also thinking of other possibilities.
I think it's quite expensive. Over here the jetkit costs a little over 100 euro's (135 dollars)
Original K&N's are about 150 euro's (200 dollars) So we're talking big money here...

You will find the "one size fits all" jet needles which are definitely not the same length or taper as the originals will prove a challenge to tune. If your stock jet needles are worn, buy a rebuild kit where new jet needles are included but stay with the stock jet needle taper/length. The Dynajet jet needles are the same for almost all BS series carbs; 650-1100cc so I suspect they won't work well in every application. I generally remove them and replace them with stock jet needles when rejetting a customer's carbs due to tuning issues. I have never seen fuel mileage improve either since the jet needles are far skinnier and have less taper (far richer than stock).

If you use pod filters, the carbs need to be rejetted. Let me know what jet needle badge number you have and I will tell you what jetting you need when you get to that point. The BS series jet needles seldeom show wear over the years... the needle jets are what wear (the tubes that hold the main jets).

So you are saying that instead of buying the Dynojetkit, just buying new jets would give the same (maybe even better) results?

BTW the specs of the KZ700 carbs:
Mainjet: #105
Needle jet: Y-9
Jet needle: 4BE04
Jet needle clip position: fixed
Pilot jet: 37.5


The needle has a fixed clip position. I think the Dynojet needle has more clip positions. Does that have a big advantage over the stock needles?

wiredgeorge wrote:

[...]
Let me know what jet needle badge number you have and I will tell you what jetting you need when you get to that point. [...]

wiredgeorge can you give me some advice on what jets I need when I install podfilters?