Z1 frame is cracked
Shit… My kawasaki z1 frame is cracked. Anyone know anything about fixing frames?
That’s the z1…
The frame is cracked to the point where it’s sort of scary. Both my main downtubes are cracked. The left one is cracked all the way through. All the way around. Can’t believe I never noticed it. Adam randomly saw it!
This winter I’ve been doing some little engine stuff to the z1 making it faster and fixing a few things. While tinkering with it, that’s when the frame was noticed.
So I’m taking the entire thing apart down to the frame and Adam is going to help me repair the frame. Not only are we going to repair it, we’re going to strengthen it by doing some of the old school race frame mods in below pic.
Below pic shows the left downtube cracked through the gusset and completely cracked through the round tube.
Below pic shows the right down tube cracked completely through the gusset and about to start cracking the round tube. Hard to tell but it’s cracked.
Ok, enough about the frame for now.
Below pic shows a pair of vintage Kenny Harmon L1 cams I picked up. The Webcam 110 are the new version of these. Same specs. I’ve been told for a fast “streetable” bike you want cams around .400″ because above .410″ you have to go to shim-under bucket. And more duration = high rpm power, but the head / carbs have to be able to flow the power up top. So everything has to match.
- oem cams – .325″ lift intake – .300″ lift exhaust – 235˚ duration at .50″
- webcam 118 – .365″ lift both – 246˚ duration at .50″.
- KH L1 / webcam 110 – .400″ lift both – 256˚ duration at .50″
I had the cylinder head ported by the well known KZ engine guy – Larry Cavanaugh. He ported it to match my set up. Head should be able to take better advantage of the wiseco 1015 / L1 cams / CR29 smoothbore carbs.
Below pics show the porting Larry did.
Not only did Larry port the head but he also fixed my broken cooling fin, and fixed a broken bolt stuck in one of the cam cap holes. He also clearanced the tapped bores so the high lift cams fit. All seen in below pic.
Below pic shows some more goodies like ape clutch kit, ape cam gears, better master cylinder. Lots of little stuff.
Also lacing up 2 new rims.
So, if anyone knows anything about fixing frames, or if you’ve had experience with anything similar, feel free to chime in… thnx.
14 responses to “Z1 frame is cracked”
Published - Jan 4, 2016
First step in modifying… Take a good part and render it useless. I’ve also found that one of my favorite bikes is based off a 77 or 78 CB750F that has a wheelbase of 58.9″. My modifications should give it a comparable look with the rear wheel placement. ****EDIT the wrenchmonkee bike description says it […]