82 750 Monoshock Cafe Build

New member here, been reading a ton over the last couple of days. This is my first cafe build and also first time venturing out of the supermoto world. I snagged an 82 kz750 off of a professional builder. He had many beautiful bikes and projects going and then was forced to move so I swooped in on a good project for a good deal. I did not do any of this to the bike thus far.

The frame has been cut/narrowed and measured using a jig. Rear was converted to a zx-1000 OEM shock. Tank inside has been cleaned and lined. Dyna Electronic ignition. Full 4-1 Kerker header/exhaust cut to fit the angles and split back to 2 upon exit. All welds looks great. Powdercoated ink black swingarm/ valve cover and on other parts. Wheels too. Pro motorcycle painter did the tank and rear cowl OEM kawi colors. It could use a good polish and buff. Maybe a refresher wet sand as well. Por-15 on the engine and cases/covers. Which could be redone, in some spots its super rough texture.

Fork seals need replacing, also repainting fork tubes, PO said brake fluid leaked out the front master and created a mess on the right side. The front and rear master also need full rebuilds. It could use some wheel bearings.

So as it sits now, I want to have the cams checked for specs, also the cam chain needs replacing bc its pretty stiff. Ive read that the bottom end doesn't have to be split to do this. The top end was refreshed before paint minus a valve job. I will go thru and inspect the head. I remember reading somewhere saying the `82 750 could use a cam upgrade? am i correct in saying the 84 gpz 750 cams? or someone have a link to reliable aftermarket cams. I am getting my links down and saved but haven't found those yet. The whole bike needs wiring including getting a taillight/taglight. I was told the carbs were cleaned before shelving... 4 years ago, so those will get refreshed too. Theres a ton of rubber on this bike that needs to be replaced including seals, master cylinders, brake calipers. Clutch grommets.

Hate me or love me but I think I want to convert the front end over to a sport bike front end. I found cognito moto does a front end conversion for gsxr forks, and yamaha r6/r1 forks. I also think the larger front wheel thats stock looks off and would better match the 16'' rear with a 17'' front.

I know I'm forgetting many things. It needs all the loose ends tied up.

All in all it just seems like a lot of labor, busted knuckles and many trips to the beer fridge.

Welcome Mr. Bean.

I had thought it was not a good idea to have a radial tire on one end, and a bias ply tire on the other.
Although I have seen a number of bikes set up that way.
Have you considered putting an 18" KZ rear wheel on the back?
Would have the same spoke pattern, and should be an easy swap.
I agree that the wheels don't look right as is.
It's the rear though, it's too small in my opinion.

Not a bad thought, although might run into tire fitting issues with the swingarm being narrowed and also clearing the rear brake bracket . I was actually gong to put a sportier tire on the rear and front when its all said and done. I figured the rear is updated suspension it could do well with front updated as well. Its a dual purpose move with that front setup

MrBean23 wrote: New member here, been reading a ton over the last couple of days. This is my first cafe build and also first time venturing out of the supermoto world. I snagged an 82 kz750 off of a professional builder. He had many beautiful bikes and projects going and then was forced to move so I swooped in on a good project for a good deal. I did not do any of this to the bike thus far.

The frame has been cut/narrowed and measured using a jig. Rear was converted to a zx-1000 OEM shock. Tank inside has been cleaned and lined. Dyna Electronic ignition. Full 4-1 Kerker header/exhaust cut to fit the angles and split back to 2 upon exit. All welds looks great. Powdercoated ink black swingarm/ valve cover and on other parts. Wheels too. Pro motorcycle painter did the tank and rear cowl OEM kawi colors. It could use a good polish and buff. Maybe a refresher wet sand as well. Por-15 on the engine and cases/covers. Which could be redone, in some spots its super rough texture.

Fork seals need replacing, also repainting fork tubes, PO said brake fluid leaked out the front master and created a mess on the right side. The front and rear master also need full rebuilds. It could use some wheel bearings.

So as it sits now, I want to have the cams checked for specs, also the cam chain needs replacing bc its pretty stiff. Ive read that the bottom end doesn't have to be split to do this. The top end was refreshed before paint minus a valve job. I will go thru and inspect the head. I remember reading somewhere saying the `82 750 could use a cam upgrade? am i correct in saying the 84 gpz 750 cams? or someone have a link to reliable aftermarket cams. I am getting my links down and saved but haven't found those yet. The whole bike needs wiring including getting a taillight/taglight. I was told the carbs were cleaned before shelving... 4 years ago, so those will get refreshed too. Theres a ton of rubber on this bike that needs to be replaced including seals, master cylinders, brake calipers. Clutch grommets.

Hate me or love me but I think I want to convert the front end over to a sport bike front end. I found cognito moto does a front end conversion for gsxr forks, and yamaha r6/r1 forks. I also think the larger front wheel thats stock looks off and would better match the 16'' rear with a 17'' front.

I know I'm forgetting many things. It needs all the loose ends tied up.

All in all it just seems like a lot of labor, busted knuckles and many trips to the beer fridge.

I clicked on this post thinking "another monoshock meathead." Im happy to say I am pleasantly surprised. Your bike looks amazing and very tasteful. Well done!!!

Damn I had no idea monoshock related to meathead around here. Interesting

Thanks tho.

If you click "insert" when adding photos they will show up in high resolution without having to click a thumbnail.

Regarding the build, do the photos properly represent the seat height and angle of the swingarm relative to the ground? It seems the swingarm is at an extreme angle and the seat sky high. Don't mean to sound negative but if something needs correcting now is the time.

Welcome to the forum.
Nessism is right that rear end looks like a death trap. Not only is the swing-arm angle WAY too steep, the stock dual shock swing arm is not capable of handling the torsional forces that a mono-shock will place on it. Also its hard to tell in the photos but it looks like that shock is setup so that its falling rate, meaning as it compresses it becomes softer... not good. Not trying to shit in your cereal, but since you just got this project and aren't in super deep, now is the time to make these big changes.

MrBean23, here you will find a real good made mono shock conversion for your KZ750

www.swervecustoms.com/the-shop/80-kz750-mono-shock-conversion/

The seat rides high (I'm 6'1'') and the sportier line Im ok with, going for more of a sportbike cafe modern look than the brat cafe. The swingarm is at an extreme angle, I would agree it needs some adjusting. Underneath the swingarm there is a black bushing that has room to add or remove washers on top of it. I take it he was still figuring out the ride height as well. And the rear shock will have to be re configured for my weight 175lbs. It does currently sit at the fully out adjusted spot so Im sure with proper dampening it could be shortened and moving the swingarm up with proper bushings/spacers would bring it in too. Also I can agree with the fact the the rear swingarm wasn't built for a mono shock, but Im not at the cut and weld disposal as the previous owner. It won't be a daily. If I did do this conversion I would have added the extra rear supports just my 2 cents. Thanks for all the good replies guys!

Putting in a shorter shock won’t change the geometry. You really need a rising rate here. The only way to achieve that is to move one of the shock mounting points. If you were to draw a line through the upper shock mount through the bottom shock mount then to the swingarm the angle between those two line should be 90 degrees at full compression. Anymore than that and the shock will get softer as it compresses. I understand that you don’t have the personal means to fix it and even if it won’t be a daily rider you still are taking a big risk by riding that rear end. I have seen someone break a shock in half with incorrectly setup mono