Riven Motors cafe build

motoTrooper

motoTrooper

XS400 Addict
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Hey everyone, been lurking a bit. Really enjoy this forum and the creations that spring forth. So I chose to finally start a build thread. I've built some other cycles but this one has a bit of significance. This was the first motorcycle I ever wanted in my life. Back in 1978 my brother and I dragged our father to the local Yamaha shop and out on display were these gleaming XS400s and 360s. We begged and pleaded with Dad and even though he had a Triumph 650 in our garage he said no to us… well we were 8 and 9 years old at the time so probably a good call.:D

As some will observe this is not a restoration to days remembered but the pursuit of a riding experience according to who I am now. I am also creating my own branding, Riven Motors, for the builds I make as I build too many damn vehicles and people should know who to blame when their car or bike explodes.:shrug:

So with that, here was the initial mock up midway into the build from a pile of parts.

 
The donor parts come from other (mostly) Yamahas:
front end -SR500 -bigger 35mm forks and beefier triple clamps, bosses for dual calipers (one xs400 one sr500), 19" front wheel, and fender. With FZR600 brake rotors.



headlight - xs400 shell with FZR400 lens and led turn signals ringing it, fork mounts xs400 with ends expanded to fit larger 35mm forks.



XS500 tank (had to relocate the front frame receivers higher and add threaded frame bosses for twin rear tank mounts, relocated coil mounts as tank ate all the room around frame backbone)

FZR600 rearsets, mounts, levers, linkages, rear master cylinder and mount, heel plates, and kickstand (longer).

FZR400 seat unit mounted to xs400 seatpan cut and shut and functions like standard xs400 seat with lock and hinge up. Had to make my own key and rekey ignition, tank, and seat release myself.

Honda(!) CB/CBX FVQ shocks with compression/rebound/preload adjustments custom mounted to the modified swingarm. Honda shocks have clevis bottoms, so I cut off the rings from the old standard shocks and mounted them to the swingarm via pieces from another (bent) XS400 swingarm.

Had two sets of xs400 headers and (rotted) pipes and wanted to mount the emgo reverse cone megaphones. So I cut the receivers off the pipes, double butted them, and then cut the second set of headers short so they begin to kick up at the end where I mount them to the emgos.



and of course drilled the rear rotor

 
Okay so let's start of with creating some controversy -namely performance and appearance over possible safety concerns. Those of us who have the cast wheels know they are referred to as 'boat anchors'. Made in the early days of 'mag' wheel construction which was a catch all description in those days for any wheel that wasn't spoked or pressed steel. Yamaha covered their corporate asses by casting them heavy. I love the look of them but since I was adding further unsprung weight in the form of dual brakes I decided to get creative. More than speed holes were required.



*disclaimer* I neither condone or encourage what I'm doing. Not from a safety point of view, but this was a shitload of work that I never will do again…unless I have a CNC mill doing all the work. Sorry for the shit pics…



I have removed over a pound of aluminum from each wheel. The thickness of the centers is over a quarter inch! Also I was careful to have curved radii at the corners of each cutout to minimize stress points.

Also without controversy, I built my own electrolysis rust removal setup because I wanted to keep the battery box in my build. It was rusty on the bottom and difficult to reach the rust. An overnight immersion also resulted in the paint being removed like sunburned skin off your back!





And lastly here are the seat pan mods in all its prepaint glory.



 
:cheers:Nope, while I liked the shape of the stockers, I did want to encourage a bit more air and rakishness to the build. So I shaved the lips on the battery box down to a hint of what they were. Thanks for the kind comment.
 
They do look beautiful though. Any chance you've got an engineer friend who could run the cut out versions through some sort of stress-testing software?
 
Ahh no, I don't have any of those associations yet. However, my experience and gut tells me they should be okay. For what that's worth. I've left a bit of a ridge along the transverse 'spokes' in all the holes and the connecting pieces seem large enough to keep everything behaving. As long as the bike isn't jumped or otherwise abused (I don't think there will be any way it could be wheelied at its power level).

Also I did a fair amount of research looking at wheel construction, particularly Moto Guzzis. They had cast wheels back then in ten and twelve 'paired spoke' versions with the spokes unconnected and not nearly as wide as these Yamaha's were cast. So with that and that we have essentially fourteen paired spokes and connected seems safe. And while I was machining all this I never encountered any occlusions or voids in the metal. Yamaha did a thorough job in their casting process apparently. Guzzis are also a fair bit heavier and torquier than our xs400s. So I'm standing by what I've done unless someone can show me the error of my ways...:devil:
 
I know a few guys over on the xs650 forum have done some wheel mods like this. You may want to do some reading over there on that. I know your rear brake rotor is a no no because of the holes at the edge can chips and cause brake issues. The holes has to be closed on them. The xs400 rotor is already slim (5mm) so it is not very strong.
 
Hey xschris can you give me the names of the guys who've done those wheel mods? I went over and couldn't make any headway with the site search. Also, not quite done with the rear rotor but with all the new 'wave' rotors that are far thinner than this I don't think I'm crossing any line. And with the cafe setup probably seventy-five percent of braking will be done by the front brakes. I have been riding since '88 so I'm not new to the dynamics. Give me till I've finished for concluding thoughts though.

Yeah jthiessen, the headlight was a bit of work, I removed the old lens, cut out the back of the reflector making space for circumferential tabs, bent the tabs, centered the FZR light in place, spot welded the tabs, epoxied it front and back, ground 48 evenly spaced cutouts for the leds in the stock trim ring, and recast a missing chunk from the shell. Then I read about how you can buy one made like it!! It is an H4 now and am looking at an led bulb to reduce power draw overall. I'll pop out tomorrow and take a couple pics of its construction.
 
LED bulbs in H4 headlights are crap. The light pattern is very bad. A 35W HID will be brighter and have a better pattern, if you get a decent kit. Some of the cheap HID kits are also have very bad light patterns. I'd strongly recommend a 4300K bulb as they are the brightest and nicest light. 6000K and above are very white and cause a lot of glare.
 
It has been a few years since I have seen the xs650 wheel thread. Maybe pose this question to that forum as I know a few have done mag mods. As for the rotor you have said it yourself. The "NEW" wave rotors are far thinner than these. Yes they are, I think most are 4mm but they are also new and made of better metal designed for this app. Been riding since the mid 80's also:)
 
motoTrooper, Welcome. What a nice write-up and excellent pictures...I have an exhaust question...Just below the left side shifter, where you have the pipes connected, what kind of fitting is that...Could you elaborate...I have a 79 XS400 that I am making into a café racer. Nice to see someone doing a café XS with Emgo pipes, which I have. Going to mount them pretty soon...Again "Welcome":bike:...Spad
 
Hey Spad, thanks for the comments. So that fitting. If you have the original exhaust pipes -the ones that look like baseball bats- they have this coupler fitting right? When I was buying my stuff, I acquired a totally disassembled basket case and then purchased another with an assembled running engine. I had four exhaust pipes but they were all rotten at their exits. All four headers were good and I wanted to utilize the emgo reverse cone megaphones. So I chopped the fittings off the bad pipes and double butt welded them so I could have the headers come from the engine to the fittings going into the second set of abbreviated headers cut where they begin to 'kick up' where they then attach to the emgos. All the header exhaust ring gaskets slip into the coupler fittings perfectly and I had adjustability to rotate the header pipes independently for the desired angle of the emgos.

Hope that helps.:bike:
 

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