78 Kz650D

So I bought this for a good deal, alot of new parts and was running good. It turned into a project less than 24 hours after owning it. Blew a piston, so I began the journey of rebuilding the engine and doing some other stuff while i'm at it. Keep in mind this is my first time getting this involved with a motorcycle.

Here she is how I got her.


The old bars have to go.


New bars, lowered headlight, and new turn signals


There is the crap piston


Another look


This is through out the engine

Got it tore down some more


Slug and metal in the oil pan, not looking good.


Engine out and metal everywhere.


New garage, how she sits.

Piston


and more piston


Figured I work on the seat while I have the jug and head at the machine shop.
Rusted seat pan needs some grinding and painting.


Got it ground up and painted.


Shaved down the old goofy seat, trying to get a 2 up cafe seat.




Going to have my mother do the upholstery. Waiting around to get the parts back.

You have your work cut out

I would suggest finding a second-hand engine instead of repairing the damaged one, as debris so easily can have clogged a small oil orifice. Also, complete engines likely cost less than new parts needed to repair what you have.

yeah I looked around for another engine but couldnt find one, there was a parts bike but the guy wanted $600 for it. Right now with the cylinders honed and cleaned and new pistons im in about $85 bucks, plus whatever the head will cost. I am going to flush out the bottom end as much as I can.

Hope it turns out all right for you!

Thanks! im sure ill have plenty of more questions to come.

Be on the look out for the Cause of the damage. Wrong heat range plug (HOT), or to lean on jetting, possible vacuum leak/ lean, Stuck ignition advancer (not returning), or plugged fuel screen above float valve, plugged jets, etc.

I think its down to three possibilities: 1. The petcock was leaky and when I drained the oil there was alot of gas in it, so I was thinking the gas diluted the oil and made the engine overheat. 2. The number 4 carb could be running lean. 3. the timing was possibly off but I didnt look to see when I was dismantling the engine. Ill have to check the plugs and I will have to just take the carbs apart and clean them and check them. Whats the best way to clean them without taking them all the way apart and taking all the gaskets and stuff out?

Still waiting on head to be looked at. In the mean time started working on getting the crankcase cleaned for paint.



Anyone know a good way to get into these fins to clean




I also got a new set of pistons in, only $30
Let them soak in kerosene and then polished the tops

Also anyone know what brand exhaust this is, part of a 4-1 system. Previous owner said that he got it online and had it painted.

I wouldn't recommend painting the engine as it will look sad when stones thrown up by the front wheel starts chipping away at the very paint you put on to make it look nice. But it's up to you, of course.

You probably need a blaster to clean those ribs, either soda blaster or nutshell blaster. Sand will of course work fine, but will change the surface structure, something you won't do unless you are going to paint it.

Cannot help with the pipe, unfortunately.