How much can our frames take?!

Assuming gusseting is done, how much power can our old frames take before they start to flex and pop?!

I'm looking for responses from people where who have hands on experience with high powered modifications in our frames, so please, if you haven't personally had your time in on one of these machines, don't toss in your 2 cents.

I'm not trying to offend, but it seems that the internet is a great place where you hear a lot of "Well, I read on a forum somewhere that this one guys little brothers next door neighbor has a KZ with a million HP, and blah blah blah...".

I'd like this to be a 100% first hand basis responses only thread.

I'm sure everyone can understand the good part of that!

Thanks!

I have built two racers from ground up, stripped everything off frames and started with the gussets. I had a cheater of an engineer help me. He was the head of Honda ATV frame design in Marysville and had a soft spot for KZ's and Ducati's. My KZ650 is a sweet ride. I need to post pictures and will when I get back home. I felt the biggest problem wasn't the 80 hp at the ground. The problem with road racing is with the rubber and wheels. I've got 17 with the best Michelins available every year. The stress is on the frame with the sticky tires. We cut every tab off the bike and spared no weight to gusset. With all of that I wish I had weighed the bare frame before and after. I am itching to redo my little girl and get a little more hp and upgrade front end. My 74 Z-1 was a lot more work, because everyone scared me about the flexi flyer frame. She is 920cc and 100hp at rear wheel. We gusseted down the frame tubes by the header. We replaced the spine tube with a heavier guage steel tube. Tied them together with plates at the rear and up at the front by the steering neck. We also welded a tube across the front down tubes below the steering neck and took it up to the main spar under the tank. Another spar was added across the frame rails in front of the battery box and it was tied up to the main spine just above the carbs. All corner of the rear sub frame under side covers were webbed. We then had a tube bent by tubular technique and added a lower tube to the swingarm with a boxed section added. I ended up a bit off on the Z1. The rake is 22.5 with a 57 inch wheel base. She wants to tuck the front at full lean and I have to fight her. My wrists get sore, but she has never shown any frame flex. It is steady as a rail in a high speed run and turn in. Seriously, no frame flex. Going down off the banking at Daytona in to turn one with that rubber on the road should produce moments. But it does not. I think another 30 or 40 horsepower would be Ok. I am going to find out because she is due for an upgrade to 33 or 35 smoothbores. Oh, the race weight for her is 440 with stator and starter which is now gone. I don't know about dragracing. They seem to get away with a lot lighter frame.

So it's feasable to think that our frames with proper gusseting could withstand 125rwhp then?

caffcruiser wrote:

So it's feasable to think that our frames with proper gusseting could withstand 125rwhp then?

my 1327 had a stock 80 ltd frame without gusseting and had no problems i could really notice and it was pushing 130 plus at rear wheel but while its apart im going to gusset it anyway just because.my z1 on the other hand is getting a serious brace job ,but im planning on 200 plus horse at back wheel with the semi mild tune!:evil:

wireman wrote:

caffcruiser wrote:

So it's feasable to think that our frames with proper gusseting could withstand 125rwhp then?

my 1327 had a stock 80 ltd frame without gusseting and had no problems i could really notice and it was pushing 130 plus at rear wheel but while its apart im going to gusset it anyway just because.my z1 on the other hand is getting a serious brace job ,but im planning on 200 plus horse at back wheel with the semi mild tune!:evil:

I was hoping you would post up man. That was kinda what I was thinking too..

Thanks for the info!

My 750 turbo frame is totally stock. Junking the stock suspension, wheels and tyres for later stuff took care of the weaves and wobbles. On the bends it will go right to the edge of the 180 tyre and scrape the pegs (even with ZX9R rearsets), exhaust and bellypan. 130mph bends are not a problem. Over 200mph on the straights is a little "floaty" due to the aerodynamics but not unmanageable, and no hint of a weave. The turbo frame is made from larger diameter, thinner-walled tubing than the stock GPz750 though, itself an improvement on the 650 frame.

lol how much will they take lol well i do build race bikes out of the kz 900 and 1000 i myself have gone 9.00 at 155 mph in the 1/4 on a stock cradle with just carbs lol then i sold it to my buddy and we put his turbo motor in it he went 8.13 in the 1/4 at 176mph lol so if you think you wana do this pm me ill help you in any way i can ok my profile has my web site in it ok all my contact info is there ok if i could figer out how to post pics here i would there are some pics in the web sit ok
OH if any one needs little things from the kz famaily i may have some lol