XV920 EFI Turbo.... Done (mostly)

Re: XV920 New suspension

The only caveat regarding the CBR setup is that the lower linkage anchor point will need to be pretty beefy since it;s taking all the force of the suspension. I will be fabricating my rear pivot section, likely welded from machined 7075 sections if I can manage the material costs this winter otherwise I'll use steel but will account for the additional strength required at that point.

I will be running 2-2 pipes, the rear will have to make a pretty decent turn right off the port probably to the right side where I'll run a short loop along the side and back under the carb and exiting with the muffler along side of the seat cowl or possibly routed under. I have a seat assembly and cowl from a Ducati 749 that I have been considering but I'm not totally sold. I like the idea of tucking either a pair of cans or one unitized "box" under the seat and I think if I make it myself I can keep the weight from being an issue up there. No room for anything under the sump unfortunately.
Re: XV920 New suspension

I may have to steal, er, I mean, take inspiration from your solution. I made my aluminum undertail muffler for the turbo bike. It's probably overkill, but, yeah, lighter than any factory piece, at least any within my budget.
Re: XV920 New suspension

Minor update. All the hardware is mounted, wiring up the Megasquirt now.

Long time since last report. Had the turbo bike on the road for a very short time a few years ago. First trip was to get it inspected. Stranded me on the way home.

Next trip was to the auto parts store. Stranded me on the way home. Both times it ran great to the destination, sat for 10 - 20 minutes, started right up, then a few minutes into the ride home, it quit running just like if I flipped the kill switch. Not a hint of fire when trying to restart. After a while, it would start running again. My theory was (is) that the cam position sensor IC was getting too hot when heat-soaked.

Also in that short time, I determined:
- the seat was too high. I'm inseam-challenged. If I'm building a bike for me, I want to be able to flatfoot it.

- The sheet metal plenum built into the frame was a bad idea. Between heat cycles, boost/vacuum cycles, and my poor skills at thin-metal welding with a wire-feed welder, it was constantly developing leaks.

- I had mis-judged the rear suspension. The swingarm was extended down too far even with me aboard (adding to the seat height, but causing other bad behaviors as well)

So, I took it completely apart. Re-imagineered the frame and intake:

I lowered the frame under the seat, then raised the rear end of the rear subframe to allow the swingarm to have the correct range of motion without the rear tire hitting the mufflers, and substituted some Two Brothers Racing cans for the old Seca Turbo mufflers:

In the background is one reason for the slow movement on this project. I built a sidecar rig for my dog, wife, and myself (in priority order!).

I got sick of the Yamaha wiring rat's nest, and designed a circuit board assembly to condense all the headlight bucket AND underseat wiring/relays into a small package that will nestle between the fork legs in a small NEMA enclosure:

I have a few more intake items to fab (air cleaner-to-turbo, intercooler-to-throttle body).
I am working on my plan for insulation the cam sensor from cylinder head heat.
I am still struggling with what to do for bodywork. I really want the turbo to be out of sight. I also am counting on side scoops (not unlike the factory XV920R) to route cool air into the intercooler. So, sidecovers TBD, but the rest will look similar to this (parts from old projects, not exactly what I have planned):


Then paint and final assembly.
Well, I've seen a few threads revived from the dead lately... so I guess I'll join the crowd. I finally got my turbo EFI XV920 to a rideable state. EFI tuning and the seat cover are still in progress:
Left Side New Version.jpg

right front new.jpg

Right Side new version.jpg
Last edited:
Well, following a life-long philosophy of "anything worth doing, is worth doint to excess", I built another motor for the turbo bike:
XV1100 L.jpg
XV1100 R.jpg
Top Bottom