KZ650 Semi Street Fighter Build

Been lurking for quite a while, absorbing as much as I can from the site. I've finally made enough progress on my bike to warrant a project thread of my own, so here we go...

To get a decent idea of what my end goal is, we have to look back to my previous bike - a free 1979 GS750. It was a basketcase, mostly just parts in boxes with a frame that had been bobbed, then welded back together with a back end from a different bike. My plans were pretty lofty considering this was to be my first ever bike build. I accumulated lots of GSXR bits, a fork, a couple swing arms, etc. I was moving my car parts to the attic to make room for bike parts on a daily basis it seemed. I tweaked a photoshop of my "vision" until I had what was to me a pretty cool bike:



About then a deal fell into my lap I couldn't refuse - a true "barnfind" KZ650. I actually found the bike for a friend and he snatched it up. After letting the bike sit for 6 months he decided he didn't want another project and handed the bike over to me. To please the wife, I gave the GS (in many boxes) to a buddy and proceeded on now with the KZ project.

A little back history on the bike - it was originally purchased in 1980, ridden for a year, and then the owner passed away. It only had 4500 miles on it! The bike sat since 1981 parked until March of this year, when it was resurrected, advertised on Craigslist, and eventually sold to me. Overall it was in pretty good shape, but most importantly it was a complete and running bike.

Unfortunately between 30+ years of aging and the "work done" in the 6 months before it got to me, it is going to need a lot of cosmetic work. The chrome was ruined in many areas with what I assume was the use of sandpaper to remove rust. The wiring harness was cut to remove indicators. All the aluminum is badly corroded. Leaks are starting to appear from degraded seals and gaskets.

Anyway, I'm not shy when it comes to modifying things as evident by my LS1 powered BMW, so I'm not keeping this one as an original restoration. My original thoughts for the GS are pretty much getting carried over to this build, but I'm going to make this more of a rolling project so I can enjoy the changes each step of the way.

So onto some pictures. Preparing for the first ride, I had already swapped out the bars:

Made it to our destination! Did I mention that was the first ever ride on anything larger than 50cc?

Now some changes are starting to happen. Got the 2007 GSXR fork fitted up, mostly with a bearing swap. Had to turn down one of the races and make a couple other things skinny, but it ended up fitting nicely. Went with a top yoke from Coolncomfy, kind of expensive but it made things easy. Made some quick brackets for the headlight and started powder coating black...




I found a nice Corbin seat but it was intended for the bigger KZs, the 900-1000 I think. With a little massaging, mostly just moving the hinge points, it fits pretty well. Certainly looks better than that tribute to the 70's seat that came on the bike


Next up is a functioning instrument cluster (a koso rx-2gp), the exhaust, and then over the winter I'll be tackling the rear mono shock conversion.

great work looks awesome! I'm not a purist by any means but as they say it takes a real man to cut one up LOL! she was so pretty before you started

Im in no position to give advice but if there is any way get with les and have him bui;d you a bolt in for the mono That bike is was too nice to cut up

keep the pics coming

Ramtough, I'm not totally opposed to doing some sort of swingarm swap that would allow the traditional shock location and thus no cutting on the frame. Who knows, if I find a good deal on a pair of shocks I might go that direction. For now all the stock parts are getting stored in the attic, and pretty much everything could be returned to stock if needed...

As for progress, the brown trucks were good to me today! My gauge cluster arrived, and I couldn't wait to go test fit it.





Using the included bracket the gauge cluster fits pretty well. I need to space it down a little closer to the headlight but I'm thinking I also need to bring it 1/2" or so back towards the top yoke. My biggest concern is it being off-centered. The CNC top yoke was intended for a 2007 GSXR, so it has provisions for the ignition, which are preventing me from centering the cluster unless I mount further away than I would like. With the asymmetrical nature of the cluster, I kind of think it balances pretty well being off center to the right. At least that's what I am going with for now if anyone asks why it wasn't centered .

Made a little time to work on the bike over the past week. Mainly little detail stuff that was perfect to continue to learn with my new (to me) emco compact 8 lathe.

Finished up the front indicator/headlight mount with some delrin "spacers". I used the OEM indicator stalk to mount the new lights so I could preserve part of the OEM headlight mounting hardware/rubber isolators. Well that and the new indicators had a smaller and shorter thread - they were sloppy and not long enough. Using the OEM stalk, I cut it down, and tapped it for the new indicator thread - effectively making a bushing/spacer out of it. I left the splines and drilled the delrin trim pieces to be a press fit. Anyway, here are the results:



While I was at it, I made a little adapter for the ignition to fit the new top yoke. I still need to finish the bottom half but this at least holds the ignition switch so I can get some riding in before winter. The picture isn't the greatest but you can kind of get the idea.




Last update is really nothing major, just maintenance. My petcock wouldn't shut off so I ordered a rebuild kit from Z1. Upon disassembly it became obvious where the failure was!

What gauge cluster are you running?

650mod wrote: What gauge cluster are you running?

It's a KOSO RX-2 GP Style cluster, part number BA010001

www.kosonorthamerica.com/new/shop/motorc...edometer-gp-style-4/

You can get it for about $100 less than their suggested retail from Amazon.

Nice man, cant wait to see where you go with it. My 650 is a bit more of a purist machine with stock suspension, but the next one is going the ridiculous route.

That's a really clean cluster. Is it easy to set up with everything, including mounting?

650mod wrote: That's a really clean cluster. Is it easy to set up with everything, including mounting?

It comes with everything needed to get it setup, including the mounting bracket. The only issue I'm having with it is the tach signal. I've moved mine around a couple places, currently pulling a signal from the - side of the coils. It seems to like that. Everything else was super easy to setup.

Not a lot of progress, just plugging away at little projects.

After rebuilding the petcock I slowed the leaking, but it was still a problem so I ended up buying a new replacement (44mm Suzuki from Z1). Takes a little reworking of the vacuum and fuel lines but works great now!

While I was on their site I went ahead and picked up a V&H exhaust. I had been holding out on a Kerker but decided to save a little $ and get this one instead. I'm pretty happy with it as it sounds good and arrived in good condition. The rear mounting tab isn't at the correct angle for the frame but that's not going to be an issue much longer if I proceed with the mono-shock/swinger modification.


(and yes, my front tire is on backwards :whistle: )

Pulled the carbs off to inspect. They were advertised as being rebuilt and re-jetted but the dirt-dobber nests still hanging on the bowls made me question if they really were or not. As it turns out, they had been taken apart and cleaned. I couldn't really tell if the jets were replaced or not, the patina of the brass was the same and they were buggered up with tool marks. The retaining clip for the accelerator pump weight was missing on a couple bowls and the gaskets/diaphragms appear to all be original. Since the "rebuild" more debris had accumulated in the bowls, and I assume everywhere else so they got a good cleaning and I built a parts list for my next ordering spree. With a fuel filter installed, and clean carbs it's running pretty good again. When the bike goes down for winter, I'll rebuild them properly.

Also got revision 2.0 of my tail light/license plate holder done using a simple bracket and a Ducati tail light I had purchased for another project. I think there might be a version 3.0 in the near future, where the light a little further out on the tail but for now this will work.




Now I just need to get the bathroom remodel done so I can get cranking on the swingarm swap!

Nice! You mentioned not cutting on the frame to do a single shock conversion. That's what I shoot for in my designs. I've got a 650 coming in this winter to use to design a bolt in single shock conversion. I also have an H2 and a GS1100 coming. Buzz me if your interested.

Les

Finally getting some other projects out of the way to get back started on the KZ again.

First thing before getting into anything major was to finish up the smaller "ride-ability" issues. You know, pesky little things like fuel and spark... The bike has always been hard to start cold, in fact it would take an excessive amount of cranking to get it to start. The headers showed varying discoloration from cylinder to cylinder and it felt often the bike just didn't feel like it was firing on 4 cylinders.

The carbs were advertized as being rebuilt and jetted up for an exhaust and pod filters when I got the bike. That wasn't the case, they were cleaned and reassembled, using the existing gaskets and o-rings, stock jets, and almost all the parts that came off them. They leaked horribly and of course after installing an exhaust and pod filters were not correctly jetted any longer. A couple boxes from Z1 and 12 people at the office letting me know I smell like gas later, we are leak free and correctly jetted this morning. I still need to fine tune a little but I got lucky with the initial setup as prescribed in the dyna-jet directions.

Next on the agenda was the ignition. With less than 5k original miles the points actually looked really good, as one would expect. They were correctly set but I still had weak spark on 2 cylinders, indicative of a coil failure. So instead of simply replacing the coils and wires I opted for an electronic ignition with the dyna 2000 setup. Installation was straight forward and a couple hours later I have spark.

The bike now starts immediately, idles great and has excellent throttle response. I've only had it around the block a few times but man what an improvement!

So now that all the running issues are sorted, I'm ready to move on to the next phase - the rear mono-shock conversion. I have most of my parts gathered and am ready to get rolling. The one thing I am lacking is a solution for the rear sets. I know Les had a really great solution for bolt on rear sets, but I don't see on his FB page, or in limited searching here that those actually made it into production. I'm shooting him a PM to see what he has available but I'm also looking at Tarrozi rear sets. They don't list one that directly fits my 650 but the ones they show for the kz750 sure look like they will bolt right up.

Pictures to follow...