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Author Topic: 78 KZ400B1 Scrambler To Be  (Read 719 times)

Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #10 on: Jul 06, 2017, 11:44:42 »
After a trip to Walmart for a foam camping mat and some upholstery foam and a trip to Goodwill for a donor leather coat it is time to make a mess:



And it did make a mess. After cutting and sanding this stuff I had pieces of foam everywhere. And the spray adhesive was everywhere too. I am still cleaning it off parts of the bike. I don't think I'll ever do this again.

Loosely fit to see how it will look. Ugly, looks like a big black brick.



Maybe it will look better after it is tightened down... a little better.



Now that it is warmer outside the leather has stretched out a little and I need to remove the cover and re-stretch it over the pan. It may look better yet. We'll see, at this point I'm still thinking that it will need to go to a professional.

Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #11 on: Jul 06, 2017, 11:51:42 »
At this point I realized that I didn't like the superbike bars that I had chosen for this bike originally. They were a little too low and just did not have an enduro/scrambler look. Still under budget crunch and with lots of stuff left to buy I did not want to spring for expensive bars so I did a lot of looking and found some Emgo MX bars. They were chrome instead of black but this bike has a lot of black so a little chrome will be okay.







Better. Now I just need a cool vintage Kawasaki crossbar pad that is not neon green. Then I found one on Ebay, NOS still in the packaging.





This thing is starting to look pretty good. It is now the end of March, 2017. I got quite a bit of work done over the winter for the first time and I am pretty proud of myself. Time to get it running and that means either using the stock carbs and creating some kind of airbox, since the original was shredded, or switching to Mikuni VMs.




Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #12 on: Jul 06, 2017, 12:14:08 »
I inspected the stock carbs, the PO said they were in good shape and the diaphragms were good, but both diaphragms had several small tears. The intake boots were in good shape though. The stock carbs on my 76 kZ400 worked pretty well and I had them sitting in a box so I pulled them out but they will not fit the 78 - the spacing is different. I would have to separate the carbs and build custom linkages. Not an attractive option.

So I could either order some new diaphragms and spend money fabricating an airbox and hope the carbs were in good shape and worked well otherwise. Or I could go with Mikuni VM carbs and K&N or Uni filters. I would need a new throttle cable either way and the difference in price between the two options was not that much. I swapped on VM30s on my 76 KZ400 and it took a while to get them dialed in but I am more than happy with them over the stock carbs. Pretty easy to tune, easy to get parts, etc. There is a guy active on the KZ400 FB group that runs Keihin PE 26s (IIRC, may be 28s) on his KZ400 race bike. That thing rips and is no way starved for fuel. I had read before that VM28s are probably the ideal size for a KZ400 but I had used VM30s before because they were a lot easier to find and others had blazed a trail before me. I decided that since this bike was a dual sport and I would probably need the bottom end grunt more then I would go for VM28s. I looked around for use PE carbs first but they are not super easy to find (especially not in a pair) and I would probably spend nearly the same amount of money for a used pair of those over a new pair of VM28s.

There is a guy that sells VM28s on Ebay for $75-80 ea. and I had them on my watch list for a long time and finally pulled the trigger. I also ordered a 2-1 throttle cable for VMs and Uni filters to fit. I did a lot of measuring for the filters and read the sizes many times and mocked up some cardboard prototypes before ordering to make sure I got something that would fit.

End result, everything fit well and looks pretty good.









And it started. Took quite a bit of starting fluid but it started and idled for a bit. Oil light went out. This project may actually end one day. Time to order some main and pilot jets and get this thing dialed in. ... Wait, there are some drops of oil on the floor. Several drops at the front forks and a few drops on the right side of the engine. Uh-oh.



Offline canyoncarver

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Re: 78 KZ400B1 Scrambler To Be
« Reply #13 on: Jul 06, 2017, 12:20:36 »
Nice work so far, now it's time to chase those gremlins.
--
YZF750/1000R The Fly
KZ 750 Twin
ZRX 1100
The Shovelhead springer chopper
A bunch of KZ's...some Suzukis', and a disassembled CB550
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Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #14 on: Jul 06, 2017, 12:28:35 »
The VM28s came with 35 or 40 pilots and 190 mains. I thought the pilots might be a little too big, I run 30s in my VM30s on my 76 KZ400. My Dad runs 30s in his VM30s on his 72 Triumph Bonneville. So I ordered some new pilot and main jets from Niche Cycle. They were 2-day priority mail. Two weeks came and went and still nothing. Checked tracking and they appeared to be stuck in Tampa, FL. I emailed Niche Cycle and they sent another package immediately and 2 days later I had some jets to start playing with. It is now around the first of June.

In the meantime I set about checking all the fasteners and making sure that everything was tight and I'm glad I did, I had missed a few things here and there the first time through.

I also pulled the front forks off and found that they were leaking from the allen bolts in the bottom of the forks on both sides. One side looked to be okay, had a copper washer under it but still leaking. I happened to have some rubber o-rings sitting on my work bench. I replaced the copper washer with an o-ring and it sealed up well. The other side it seems I had forgotten the copper washer altogether. I put an o-ring in there and everything was good there too. I reassembled the forks and all appears fine now.

The leak at the right side of the engine was coming from behind the points cover. It appears that the RH crankshaft seal was leaking. Not a lot but enough to cause a drip. People want way too much for Kawasaki parts, I'm not paying $20 for a simple oil seal, so I found the dimensions and one of the auto parts stores sells a National seal of those dimensions for $5 shipped. A couple of days later it arrived in the mail. I drained the oil, changed the filter (I had run the bike a few times around the yard while trying to get the carbs dialed in), pulled off the right side cover and replaced the seal. No leaks since then. This engine now appears to be leak free and running pretty well.
 

Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #15 on: Jul 06, 2017, 12:53:20 »
Carb tuning started out a little rough. It was a bitch to get the thing started. I know from experience these things are cold-blooded. But once warmed up it ran well and it would start up fine afterward. I changed to 30 pilots and started with the air mixture 1.5 turns out. It ran pretty lean. At one turn out it was better. At 1/2 turn out it was even better and plugs look pretty good. Actually one looks pretty good, the other still looks a little lean but that could be for a couple of reasons. I've had to mess with the idle screws on both carbs because it wanted to surge, idle high and not return to idle when it was lean. I checked for air leaks and tightened up all the connections. I synced the carbs again and at only 1/2 turn out I need to go up a size on the pilots. Last weekend I pulled the carbs and changed to 32.5 pilots and got ready to begin chasing it again.

At this point my Dad reminded me that I'm going to have to do this all over again, maybe starting from scratch, once I get the exhaust in place and am not running open headers. So I stopped and this is how it sits now.

But man it was so much fun to ride around the yard with those 50/50 tires. I've ridden around the yard with my 76 with street tires and I'm always pretty careful. But this thing had some grip and I was really able to get on it, lean it over a bit and have some fun. I'm looking forward to getting this thing done and on the road.

So my next question is do I take it to someone, I know a guy who does custom exhausts for a living, and pay to have my high pipes done. Or do I buy the pieces (I think I can get what I need, minus muffler(s), for $100), but a cheap welder to tack it together and then take it somewhere to have it welded up. I've read of several guys doing it themselves and have encouraged me to do the same and I obviously am a DIY kind of dude. I'm leaning toward doing it myself but I will ponder it for a bit and save up some money.

I'm thinking something like the attached pic but on the left side of the bike. Not sure if I'll wrap it though. Might have it coated. Might just spray it with ceramic paint myself. And I'll probably use a heat guard or two as well.

In the meantime I had to tear down the top end of the 76 KZ400 to fix some oil leaks that have gotten worse over the last couple of years. That's in the process of going back together. I'd like to ride at least a little bit this year. I had hoped to have both bikes ready for the Cincy Cafe Racers / Garage Brewed tent for Vintage Motorcycle Days at Mid-Ohio, but neither will be.
 

Offline doc_rot

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Re: 78 KZ400B1 Scrambler To Be
« Reply #16 on: Jul 06, 2017, 13:03:12 »
Having a custom exhaust made will probably cost almost as much as a cheap TIG welder. Plus once you have a welder you can make all types of cool shit. There will be a learning curve and it will take some fucking up before you're able to make some good welds but you can always blend them out of they are not satisfactory.
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'78 KZ1000  Project

'80 KZ750 Twin Project

Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #17 on: Jul 06, 2017, 14:12:05 »
Thanks Doc. That is what I am thinking as well. Thanks for helping to push me over the edge :)

Offline diggerdanh

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Re: 78 KZ400B1 Scrambler To Be
« Reply #18 on: Jul 06, 2017, 14:37:41 »
Couple of other things I forgot: new brake shoes in back, new brake pads in front. New tapered bearings All Balls bearings in the neck. Both wheels got new bearings. I believe that all bearings, seals and gaskets have been replaced (other than in the bottom end, I did not split the crankcase).

I also swapped over the the electronic ignition from the later KZ440s. I'm pleasantly surprised that with all the electrical system changes I made with this thing all at once that it started right up and everything seems to work properly. (Knock on wood).

If I think of anything else I will update as I go along.

Oh yes, one thing I did forget. The first time I started putting the engine back together I broke an oil ring on one of the pistons. I had to pull the barrels back off and luckily I had a spare set of rings. I used the oil rings from the new set and everything went back together fine.

The bores measured a little on the large side but still within spec so I just honed them a bit with a nice crosshatch pattern and put the original pistons and rings back in (other than the oil rings that is). Pistons and rings all measured fine.
« Last Edit: Jul 06, 2017, 14:41:04 by diggerdanh »