stealth exhuast question

how much power is a stock z1/kz exhuast giving away over 4n1?was just eyeballing an extra fairly complete 77-78 1000 sitting in corner while looking for something else.anyway i had one of my sick sleeper streetbike ideas and was just wondering if anybody had any ideas :evil: :woohoo:

ok let me rephrase my question.is there a stock exhuast thats any less restrictive than the rest of them 900-1000?:blink:

I think a really good aftermarket header/canister might give a +10% increase over stock if you rejet to optimize. Stock exhaust systems are not that bad usually. On mine, when I added a Kerker clone there was a definite power surge in the "user band" between about 3k and 6k RPM, maybe lost a bit at low RPM. But, it was a lot louder than stock. The MAC header I have now has has less power, probably about the same as stock.

i was thinking about one of my 1197s with a set of 29s and a little head work in a really stock looking bike to go fishing at stoplights with,ive got about 20 other things i need to accomplish it was just one of those ideas i get when im wandering around aimlessly!:laugh:

One gain you will have is reduced weight. I pulled the stock exhaust off my 1100 and installed a MAC, to do a bit of testing, and I bet I saved 50 pounds of weight...chris3

im thinking stealth,ill overcome weight with a bit of traction and some power:laugh:

77-78 1000 would be an OEM 4 into 2 system, right?
You might be able to get away with replacing the OEM mufflers with Dunstall Megaphones which allow you to run as much or as little packing as you want. Or straight pipes, even, if you just take out the baffles entirely.

www.jcwhitney.com/autoparts/Product/Pr-p...hGroup?Ntt=megaphone

Ok guys, here is what I have found! Any kz900 with a stock exhaust and STOCK motor with STOCK 29 carbs will run on my dyno around 87 horse (yes! I know it sounds weak but very true). If you increase the size of the engine in cc the exhaust will become extremly restrictive due to the cross over that is used - you may recognize this part of the exaust because it is always looks to have been super hot(it is where the 4 primary tubes come together). The MAC system may look bad but does offer about a 7 horse gain in the low end and mid range, with about 3 horse on top. I have tried cutting up the stock exhausts and putting them together with different configuration that were tried on my flow bench and no dice. The collector is somthing that was made for a dozer or something and just will not flow correct. IF you can find an old YOSHIMURA exhaust with the race baffle (YES, They are UNGODLY loud!) you will have the best system I have ever tested. These were from back in the days when POPS YOSH was still alive and are still the best I have found! I have had all kinds of problems trying to tune any bike for power with a stock system as you WILL hit a wall that you cannot go past when tuning with a stock system. If anyone is interested in some modern problem cures for our bikes this is what I have found; Carbs- Get rid of the stock carbs and get a set of the large manifolds and go straight to ebay and buy a set of carbs from a 600 suzuki Katana(non TPS sensor). You can bolt them on and with very little tuning gain around 13 horsepower and NEVER have to worry about the finicky crap we deal with. A set of the 31mm carbs from a 86-87 GSXR1100 work excellent as well-same deal (I have had people tell me that they have used these with the stock manifolds - But, I doubt it). Oh, by the way if you combine a set of these carbs with a good exhaust you will Pick up around 20 Horse on the top end and have a very smooth power delivery. Try the 31mm carbs with the stock exhaust with the baffles removed and I garauntee you will like (I have probably done this to 70 or so bikes in the last 20 years). You will need a daul outlet petcock from pingel though(you need it anyway as the stock unit starves the bike of fuel on the top end anyway. Oh well, that's all for now talk later!
Ride fast and brake shit, theeen make it FASTER!

Mcspeed.1 wrote:

Ok guys, here is what I have found! Any kz900 with a stock exhaust and STOCK motor with STOCK 29 carbs will run on my dyno around 87 horse (yes! I know it sounds weak but very true).

No such thing as stock 29mm carbs for the Z. Stock 28mm carbs measure almost 29mm but they are for sure not equal to 29mm smoothies.

The original Yoshimura cyclone exhuast is still available. Its about $1200 but available.

When you say "Large Manifolds" what do you mean? Specifics please. And what year Kats have the no TPS carbs?

Yes! you are rite they are 28's I have always called them 29's though as you stated you measure the ID on the cylinder side and it is closest to 29. The manifolds are from the late kz 1000 -1100. ape sells them and so does schnitz and paul Gast,Etc. I want to say that the Katana carbs you will be looking for are from 88-1998. The very latest 600 Katana had the TPS sensor. You can use any of the GSXR carbs from 86-1992 as long as they are off of an oil cooled model(no liquid cooled as the carbs were tilted). That will give you a range from 31mm, 34mm, 36mm,38mm, and 40mm (from Canadian GSXR1100s). If you pay more than $100.00 for any of them you are getting it in the hinny:S . The Yosh exhaust I am talking about is from the mid 70s and has the pipes coming into the collector that only reduces about an inch and maintains that same OD all the way back(with a tiny baffle inside of it). I have not ever tested a zyclone on a KZ! However, I can tell you this(and I am sure anyone who has been around for a while can vouch for) I have never tested ANY Zyclone system that made more than just a gain in noise.

Mcspeed teh Yosh pipe they make in Japan
is a replica of the original pipe that was made for the KZ in 73 and on by Yoshimura. I have seen it with my own eyes while in Japan on several trips. Again about $1200 and it can be had. I will try to scan the Japanese Magazines that i have to show it to you.

i just found it on the Yoshimura Japan site.

yoshimura-shop.netmove.co.jp/ap/dtcat?p=...2_e/c_cycl3_e&d=1607