75 KZ400 Break it Loose!

knitt31

New Member
Hello! First post here, and I'm hitting the ground running with a build thread!
Daily rider is an 81 GS550T that I've had a few years, so I'm familiar enough with what it takes to get these old ladies up and running. However, I had been looking for a project that I could really sink my teeth into, and learn the ins and outs of these old bikes.
I picked up this bike in the condition shown in the photos for $200, with boxes of the original parts.
My plan is to do a slow-burn winter project to keep me busy through the cold winter here in Milwaukee.
I'm an architect/designer by day and a custom airbrush artist by night, with really no metal fabrication skills, so we'll see where that lands me with this bike!
I'm posting in the Specials forum because I really don't have a genre pinned down. My goals for myself are to gain a deeper understanding of the bike, and to gain simple metal fabrication skills.
For the bike, I'm putting an emphasis on minimal controls,design based on reliability, and something that I can jam through logging roads on the weekends. Mostly Desert Sled, a little tracker, a little scrambler, and a little resto.
80% commuter, 20% scrambler, but I want to bring that "backwoods" attitude to the city.
Photos as I bought her:



Table built, bike carried into basement (that was a treat).



And here we go! The bike came with all new gaskets, and mentioned that the bike leaked, so without knowing where exactly, I'm replacing them all. I'm not planning on splitting the cases, though I probably should, and I have the gasket sitting on my bench (advice?).

Engine is out of the bike. Cleaning up with simple green and a wire brush. Debating on whether to paint the engine or leave it lie. It's in such nice shape that I'd almost hate to take away from that.


And that's where we sit! I've got an airbrush project I'm finishing up the next couple of nights, then I'll be back at the bike!
 
Hey man welcome!
Nice work so far.i brushed my KZ400 motor with a brass wire brush and it came out nicely.heres some for you.
 

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Cool project bike there fella. I really like your idea of where you're heading with it. Just watch the tail to make sure you don't limit the rear travel. The front forks aren't very beefy for of roading but some heavier oil will give you better damping, maybe 15w. And better possibly long rear shocks might help, careful not to jack her up too much though and change your head angle.
I love my KZ's. I caféd a 305 last year and just resto'd a Z750E. You probably don't wanna hear this but tuning for pods takes a lot of time and effort. If you can put the stock air box back on it your carbs will love you for it. Then you can fab up some fancy custom side covers for it which will probably go well with the style you're looking for.
Tons of info available on Kzrider.com they'll all tell you to get a manual and keep the stock air box straight off the bat.
Good luck with it!
Hama

Sent from my HTC_0P6B using Tapatalk
 
Ryan Stecken said:
Hey man welcome!
Nice work so far.i brushed my KZ400 motor with a brass wire brush and it came out nicely.heres some for you.

That's a beautiful bike! I like the knee scallops. They add a nice crisp line to the top of the tank. Do you have a build thread for this? I'd love to read up on it.
 
Rustyhama said:
Cool project bike there fella. I really like your idea of where you're heading with it. Just watch the tail to make sure you don't limit the rear travel. The front forks aren't very beefy for of roading but some heavier oil will give you better damping, maybe 15w. And better possibly long rear shocks might help, careful not to jack her up too much though and change your head angle.
I love my KZ's. I caféd a 305 last year and just resto'd a Z750E. You probably don't wanna hear this but tuning for pods takes a lot of time and effort. If you can put the stock air box back on it your carbs will love you for it. Then you can fab up some fancy custom side covers for it which will probably go well with the style you're looking for.
Tons of info available on Kzrider.com they'll all tell you to get a manual and keep the stock air box straight off the bat.
Good luck with it!
Hama

Sent from my HTC_0P6B using Tapatalk

Hama,
Thanks for the thoughts!
In regards to rear travel/clearances, I'm considering swapping the front fork tubes with those form a KZ440 (2" longer), and getting taller shocks in the back. I'm hoping to simply swap the tubes and keep my lowers, but we'll see how that goes. I don't plan on taking this thing off any jumps (not big ones, anyways :p) but the extra clearance will be nice for ruts/rocks etc.

In regards to jetting with the pods, I was going to go one of two routes: Either keep the stock carbs and get a nice set of K&N filters, or ditch the stock and get mechanical carbs. Seems that they respond better the to variable pressure due to pods.
 
knitt31 said:
That's a beautiful bike! I like the knee scallops. They add a nice crisp line to the top of the tank. Do you have a build thread for this? I'd love to read up on it.

thanks man!all hand made and puttied up .-) man that was hell of work....no sorry no build thread if you need any advice let me know!
 
Broke a case stud off in the case.
Finally got it drilled, tapped, and coiled. I need to shave down the coil a bit, as it's protruding above the mating surface. Will continue to clean and make progress! Ordering new seals for the lower end, then starting a clean/fresh rebuild.

Quick question:
When tapping the new hole for the helicoil, a few shavings found their way into an oil passage. Before reassembly, how do I endure that all passages are clear of debris? A good shot with the air compressor?

 
I would take a shop vac and neck the hose down to a piece of fuel line and suck it out.

I've done this before, it doesn't have to be pretty, just stick the fuel line into the hose and wrap some duct tape around it. Probably not the best thing for the shop vac so don't run it longer than you have to but it works.
 
I'm at the point where I can't decide whether I want to leave the engine bare, clear coat, or paint.

After all this hard work getting the engine clean (scrubbing by hand, blasting is out of budget ((baby on the way)), I'd hate to have the engine just get dirty again once it's up and running.
Would painted cases be easier to clean?
Or, is the majority of the grime on the cases simply due to leaks, and if sealed correctly, the engine will ultimately stay a lot cleaner?

Having the engine completely torn down, I'd hate to do anything less than a proper job here.
 
knitt31 said:
I'm at the point where I can't decide whether I want to leave the engine bare, clear coat, or paint.

After all this hard work getting the engine clean (scrubbing by hand, blasting is out of budget ((baby on the way)), I'd hate to have the engine just get dirty again once it's up and running.
Would painted cases be easier to clean?
Or, is the majority of the grime on the cases simply due to leaks, and if sealed correctly, the engine will ultimately stay a lot cleaner?

Having the engine completely torn down, I'd hate to do anything less than a proper job here.

i left my KZ 400 project engine bare.
my RD motor got painted satin black with polished fins.
imo it is a PIA to always look out for gas not spilling over your engine.it comes down to gas durability.
i used Dupli Color and it holds up fine so far,i see sometimes slight blurrishing when gas touches the satin black.
your decision!
 
knitt31 said:
I'm at the point where I can't decide whether I want to leave the engine bare, clear coat, or paint.

After all this hard work getting the engine clean (scrubbing by hand, blasting is out of budget ((baby on the way)), I'd hate to have the engine just get dirty again once it's up and running.
Would painted cases be easier to clean?
Or, is the majority of the grime on the cases simply due to leaks, and if sealed correctly, the engine will ultimately stay a lot cleaner?

Having the engine completely torn down, I'd hate to do anything less than a proper job here.

You can do great things with a little elbow grease. I hand scrubbed and polished an entire KZ650 engine, and it turned out nice. Aside from the tubes of metal cleaner and wire bushes, it was free. I would avoid paint unless you do it professionally, or you're able to cure the paint properly in an oven. If done incorrectly, it will chip off, and it'll look worse than a dirty engine.

My HANDywork ;)

bikepics-531979-full.jpg
 
Thanks for the advice everyone.
While leaving the engine bare was clearly the most durable way to go, I got to looking at the "show of your engines" thread, and the coordination between painted/polished/bare parts was just magic to me. So considering that, I'll be painting the lower end, and leaving/polishing parts of the upper.

I needed to build a spray booth for my airbrushing/clearcoating endeavors, so I set that as a priority before I started painting the cases. Now that it's done, I can spray fume-free through the winter. (A necessity with baby #1 one the way!). Here are a couple photos of the booth/primer, and black paint. Will give it a good cure in the oven this evening before my wife gets home..



 
You don't want to put that in your oven in your house that you use to prepare food. In my opinion its going to make your house smell like paint and your food will taste like paint for awhile.
 
The impression I had gotten (after reading various other threads) is that if you let the paint cure for a full day before baking, the vast majority of off-gassing has already happened, so the fumes are quite minimal. I'll probably test it out for a minute or two and keep a close eye on it.

If it's too smelly, it'll get the heat-gun treatment.
 
I've put stuff with spray engine paint in my powder coating oven after it cured and it smells a lot more than powder coat does. Then the next few times I use the oven I can smell it a little less each time. I would use the heat gun.
 
Great job, it's soooo time consuming but I am hoping for a lot more satisfaction then my last build of a 2007, this is more a real make over, just keep chipping away at the project, looks like you have a great base to build from.
 
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