New KZ750B Rider

Good evening all,

Names Leigh, I'm a new KZ rider from NJ. Shes a '79 KZ750 with around 10k on the Odometer. I got her for a great price and couldn't be happier with it being my first bike ever. I rode it for a few months last summer before putting it away with power and starting issues. Over the last few weeks I have rebuilt the starter clutch myself as well as the carb rebuild/cleaning. I am happy to say she is up and running with a perfect idle now (was idling at 2k when i got it). For jollies, we threw it on my buddies dyno to see how the 40 year old bike held up and was pleasantly surprised. Best run being 39.04HP at 39.21ftlb it felt amazing getting it running again and seeing it able to push to just over 8500rpm. I think thats enough of an introduction I guess. Looking forward to meeting you guys. Have a great night.

Here's a picture of the dyno numbers if anyone's interested. Not as much a "look at all the power" type of achievement, more a cool look into how an old bikes survived.

Congrats on the new wheels and for bringing it back to life. I thought they were rated closer to 55hp but, I wouldn't be concerned about that frankly. Running right and reliably is more important.

My assumption is that over the years it's lost.some of its oomph. She rides well and that's all I care about. Thanks for the encouragement and I'll see ya around.

I would expect 45-50 at the rear wheel, but what I am more curious about is the air-fuel ratio. I don't understand the data, and I can only see a bit of the graph. However, what I see of the graph looks like reason to be concerned. The ratio should, ideally, stay below 14:1. What little of the graph is visible seems to indicat a dangerously lean condition at lower rpm, then heading toward too rich as the lines go out of sight. If that is the case, I'd bet that the pilot circuits are still clogged and that the carb holders are leaking badly. Is the factory air box and filter in place? Stock exhaust? Removing them is all too common, and always leads amature mechanics into a pit of misery and frustration as they try to get the engine to run well without them.

Good on you for getting the old bike running and on the road. With a bit more effort, you might be surprised at how quick an old 750 twin can be.

Stock Airbox, but aftermarket crap exhaust. 2-1 with no brand name on it. My buddy running the dyno said the air to fuel reading was going to be off because of the baffle inside the exhaust getting in the way of a real reading. Said it looked lean at low, but lev eled out up top.

Good deal. That should be easy enough to correct.

To be honest, I'd love to find a stock exhaust to put back on it. The only things I'm planning on not being stock on the bike are lights and that's only for easy of maintenance and draw on the battery.

Good plan. You might want to post in the Wanted section of this site, and keep an eye on eBay and such. Good stock systems are getting harder and harder to find. You may even stumble across a decent aftermarket system, but they are few and far between as well.
Since you want to stay stock, I probably shouldn't mention this, but there are a couple of really impressive 750 twin build threads on this site. :whistle: :evil:

Welcome Lkean2135.