FZR/XR650R Build Thread....... It's Alive!

[tgold]

So I got back my parts from the welder and the welds were very nice. However, the swingarm pivots were very distorted. Without some complicated setup and machining I would not be able to use the swingarm. My next thought was that maybe I could just move the engine forward about 30mm so that the rear mount would clear an unmodified swingarm. Two reasons that I didn't like that option: One, I wanted the countershaft as close to the swingarm pivot as possible, and two, it would mean that all of my other brackets and mounting points would change(basically it would be back to square one).

What to do? And then it hit me: Why not just remove the rear mounting point from the engine and add a mounting point elsewhere? So I went online and searched for some pictures of XR650R cases and I found that the rear mount area is isolated from the part of the transmission that contains oil. Plus there is a small area that I could use for new mount holes after removing the rear mount. So I did what any sane person would do and I removed the rear mounting point off of a perfectly good engine using a hole saw.


Pictures will be posted tonight.

[tgold]

BTW, Now I am looking for another swingarm to replace the glorified doorstop that I now have. I'd prefer the deltabox style aluminum one but I'll settle for a 1st generation one.

Also, if anyone can measure and tell me the height of the swingarm pivot (While the bike is vertical) it would be very helpful as a starting point for my adjustable ride height.

Thanks!

[kirbster]

Sounds to me like a good candidate for the yzf600 swing arm and wheel.

[reelrazor]

What distorted from the swingarm welds?

Did the pivot tube get ovaled, or bent?

[tgold]

What distorted from the swingarm welds?

Did the pivot tube get ovaled, or bent?

c
No, I cut a section out of the middle of the pivot tube so that the rear engine mount could fit. Welding in the reinforcement plates was what caused the distortion.

[tgold]

As I mentioned yesterday, I had a problem with the modified swingarm that made it pretty much unusable. I could have done a lot of work to realign the swingarm pivots that are now misaligned due to the distortion caused by welding in the reinforcement plates. It would have taken a LOT of effort and the results would have little chance of being good. This is because I have no easy way of insuring the straightness of the swingarm as a whole. It's probably better that I found the swingarm pivots were misaligned because that tells me the other end of the swingarm is misaligned as well. And that could cause handling problems that would be hard to diagnose. Those thoughts and the rapidly approaching track season made me want to move on with the show, so here's what I did:

I still needed to position the engine so that the rear mount would be aligned with the axis of the swingarm pivot. I thought about moving the engine forward 30mm and just living with the extra chain length and its effect on the swingarm. But if I did that I would have had to make pretty much all new engine mounts.

What about just removing the rear mount?
I found that (on the XR650R) the rear mount area is separate from the parts of the engine that are lubricated by oil by looking at pictures of case halves online. My next thought was to take the entire engine to work and machining off the rear mount on the mill. Because I wanted to leave as much material as possible, I wanted to make a cut concentric with the rear mount hole. I realized that a hole saw with a bore guide would do the trick. I went to Home Depot and bought a 1.5" hole saw and a 5 inch long bolt. Back at home I drilled a 1/4" hole through a 3" long piece of 1" diameter dowel. The dowel was just slightly larger the the rear mount hole, so I chucked it up in the drill press and sanded a bit off the diameter. This would serve as the bore guide for the hole saw:



Cutting through the rear mount:





Done:


Cleaned up and motor installed for a test fit with nice clearance for an unmodified swingarm:






The welder did a very nice job on the upper shock mount:





Starting to look like we're getting somewhere:

[gre3nskeeper]

[tgold]

I've been making some progress... Put on a Deltabox swingarm I and fitted an SV650 rear wheel on. Centering the rear wheel was quite a project.

I just bought a TIG welder so I can fabricate the exhaust myself. Definitely looking forward to that!

[pefrey]

Looking good. Valentino and Casey approve.

[Fizzinatorr]

Still lurking on this one

can't wait to see what's next

[tgold]

Well, Lots of time has gone by since the last update. Not much progress was made over the summer, but in the last month I've made some headway:



Fairing doesn't fit so great yet. I still have some decisions to make on how I'll fix that:

[dash]

You have constructed and designed a very nice build. I hope that others will read up on your design. I'm looking forward to future updates. I'm also interested in your fairing mods/construction details. Keep up the good work!

[tgold]

TZ250 bodywork will need some mods to fit properly:





View of LH headpipe, temporary hi-tech reservoir mount, and shift linkage support bracket:



Oil tank... If it looks suspiciously like a fire extinguisher bottle, that's because it is




ZX6R radiator. There shouldn't be any overheating problems here!




Shift linkage support:










45mm flat slide carb. I'm not really liking how the filter sits in there, so I'm going to build an airbox with the goal of eventually incorporating a ram-air setup.

[dash]

Fairings look great.

What is the flowrate on the oil pump? I'm just thinking about the laminar flow and cavitation inside the tank.

[tgold]

Fairings look great.

What is the flowrate on the oil pump? I'm just thinking about the laminar flow and cavitation inside the tank.

There are two oil pumps because this is a dry sump motor, I'm not sure what the flow rates are. Basically one pump supplies the oil pressure and the other clears the oil from the bottom of the crankcase. The oil tank is truly is a reservoir, so the flow rate through it is not high enough to worry about cavitation. The main thing to avoid is overfilling the tank because that can cause the system to over-pressurize and blow out the weakest seal (which happens to be the countershaft seal).