,
If the shaft is one piece, the flywheel end has to be the right size for the pilot diameter of the flywheel and for the rear main seal to ride on. And if the bearing is going to live in the wedge plate (it has no choice, really) that means it has to slide past the big end of the shaft as the wedge plate goes on.
That led us to this monstrosity. To allow the shaft to grow, the factory double-row ball bearing next to the gear is pinned in place, while this gear and the needle bearing on the small end are both free to slide axially along the shaft as it grows.
It really is a comically huge bearing… Here it is held into the wedge plate with a comically huge snap ring. The inner bearing race is press fit onto the shaft.
As complex as the shaft is already, it's even more complex than you think. On the small end, the shaft is rifle drilled.This rifle drilling is done not only because we're weight weenies, but also because the factory Hayabusa oiling system feeds oil into the needle bearing at the small end of a hollow input shaft to lubricate all the gears.
This little hole on the needle bearing race picks up oil from a passage in the lower crankcase.Oil flows in through the bearing, around to the front of the shaft and into the center of the shaft. On the other end of the shaft are two diagonal holes that lead out to two of these tiny little jets that will spray a little bit of oil on our comically huge bearing.
Finally, after all the fancy machine work and case hardening, the bearing-related surfaces are all precision ground to ridiculous tolerances.
In another bit of weight weeniedom, over a pound of steel is hogged out of the big flywheel end of the shaft.
Fancy.
Pants.
11 comments
Finally an update!!
Happy to see that the project is still alive!!
I have no idea when this was posted, since I did not recieve an update.
I also cannot see any comments, also not on older posts…
The redesign of the website looks great.
Hopefully ticking the notify boxes again enables me to see the comments again…
The comments unfortunately were part of the information we weren’t able to transfer over from the “old” MotoIQ 🙁
“The engine is going back in the car now. ” What’s the date on this article? I don’t know if this ‘update’ is from 2014 or….?
Good to see an update after 2 years. Hopefully it wont take that long for the next one….
What happened to the Part 18 content (with the clutch exploded clutch basket) ? Was the information lost somehow, or has it been omitted from the new MotoIQ site for… reasons? Those failures contain good, hard-won information. It would be a shame to not post them!
Stumbled onto this build the other day and I think it is the most relevant piece of kit I have seen in a very long time. Have looked at a Busa swap from many different angles and there always seem to be more cons than it is worth. Grafting the Miata trans to the Busa engine in this way is a game changer. eagerly waiting for another build installment and I hope you guys can produce a kit that is affordable to the shade tree swapper.
Cheers
Larry
And here we are over two years later. I really would like to see this finished….
Update please!
Is there a website where you guys sell this kit and what are we talking about price wise .
And any update on the car ?
So? Did this just get scrapped or something? Nothing in almost 4 years….
there is a miatabusa website which doesn’t have much info, but if you look up miatabusa on instagram looks like it is alive and well.