KZ650 - 810cc

It was recommended to me by Jay at APE to take my cases to an Automatic Transmission shop that rebuilds trannies in-house. They have washing machines designed for cleaning aluminum casings. Since I had my cases blasted with who knows what, I'm gonna have mine cleaned to clear out and residual crap.

Hmmm, I'll see if theres anything like that around here.

T_Dub wrote:

Mark, I don't think I need to brace the frame. Look at all the neck bracing that came stock on these. And the down tubes also have a plate welded on them, as well as a crossbar. I'd say it should be fine.

porchev914 wrote:

It was recommended to me by Jay at APE to take my cases to an Automatic Transmission shop that rebuilds trannies in-house. They have washing machines designed for cleaning aluminum casings. Since I had my cases blasted with who knows what, I'm gonna have mine cleaned to clear out and residual crap.

Take the main oil galley plugs out of the cases. Get yourself a couplf of cans of brake clean. Spray out every oil passage using the straw on the can. Flush them with a garden hose.

When you spray them out with the hose, plug one end of the main oil galley and watch all the main bearing passages flow water. Then do it from the opposite side.

Do this EVEN AFTER YOU GET THEM CLEANED ELSEWHERE. You should see with your own eyes that the passages flow properly.

CHECK ALL YOUR ROD AND MAIN BEARING clearances with plastiguage. Do them again with the new bearings if you're replacing any.

The brake clean thing was exactly what I was thinking about doing!! I'm gonna do that. As long as the main gallery plugs are open, you can already see inside all the other passages in the engine.

I'll be sure to check my clearances, and I already polished my cam lobes and buckets like you said! Just ordered some plastigauges on ebay.

T_Dub wrote:

T_Dub wrote:

Mark, I don't think I need to brace the frame. Look at all the neck bracing that came stock on these. And the down tubes also have a plate welded on them, as well as a crossbar. I'd say it should be fine.

Kawi gusseted that frame for a 650cc, and what are u doing to that motor????:woohoo:
i would put in a few more . a couple to tie together the backbone, and a few at the back end, above the swingarm.
u are firming up the arm, so what part is going to flex now? dont wait untill its all painted.

Additional sage advice, thank you Larry

T_Dub, look at it like this: your bike was barely braced well enought to handle the stock power, and you are adding what, 20% more? You're smart enough to brace your swingarm, which is a known weak point. Why not brace a few of the other known weak points? Now's the time to do it while its apart, and it won't cost but $10 in materials, some time and a guy with a welder. Just some food for thought bud

I don't not want to do it, I just figured she was fine. I see you guys bracing up the Kz1000 frames, which makes sense because they look especially weak at the neck. I don't see why I would have to tie my backbone together, unless you mean shell it out, some tubular members there wont have much effect against torsion. And the swingarm area is held together by the engine quite nicely.

I just don't see where the forces are coming from to necessitate extra bracing. I'll have a look at the bare frame when I get home, but she looks fine to me as is, from a bracing perspecive.

Has anyone passed you the articles on Tony Foals work? I would feel the same way as you if I thought my frame was fine stock. Here is a picture of a stock ZRX frame

Note the bracing between not only the perimeter top tubes but the triangulation bracing around the neck. There is no bracing in front of the cradle because the engine is much more of a stressed member in this frame. It has to be to allow for the removable down tube and not compromise the structure. The KZ engines are not utilized as structural members. The engine being bolted in does help, but there is too much slop in the mounting points, which allow movement of the frame around the engine. One way to help combat this is to ream/drill the mounting points to employ tighter fitting hardware. The stresses on the frame are not in straight line performance, but in mid corner where the force of a bump or dip puts a torsional stress on the frame.

Even if you don't brace your frame anymore than stock, I do recommend reading Tonys work I can send it to you, or you can get it from Mark, or Josh, or probably many of the members here.

Oh I know a lot about frame design, I do it all the time, and do FEA on them to make sure they're strong. I know just from looking at it that the ZRX frame is better in torsion than mine, but then again mine also has triangulation at the neck, hence all the plate welded on. The backbone isn't as good but aside from boxing it in there's not much you can do there. What you're doing with your front down tubes would be the only thing I would think would be worth doing in a KZ frame that already has a triangulated neck.

Here's an example of a frame I designed for a CBR600. It's crazy strong in torsion.

Ahh, sexy...visions of a Duc....

I'll leave you be. I'm sure you know know more about frame design than I do

Tony Foal claims doubling the torsion strength of frames by adding the front cradle X brace. We'll see! :ohmy:

The Duc's were my inspiration for that one, and it should even be stronger than a duc frame, since its wider. I really would like to make the bike I designed around that frame, I have a CBR engine handy, just need some cash. I could have done it instead of the KZ, but I wanted to do the KZ first instead of leaving her sitting. BTW, the thing under the seat in that render is the fuel tank. All you see in front of you when sitting on that bike is a gaping hole with some velocity stacks staring up at you. :woohoo:

I might have a bit more theoretical knowledge, but theres never a substitute for seeing things from a different perspective. Me and Josh had a similar discussion a while back. Just because I'm an engineer doesn't mean I know everything. The only reason I argue is that I don't see where the forces are coming from to make those braces necessary. The one thing I do have a lot of experience with is calculating loading on various bodies.