Quantcast

Gen 1 diff on a Gen 2 swingarm

Yamaha Star V-Max VMAX Motorcycle Discussion Forum

Help Support VMAX Forum:

jedi-

Well-Known Member
Joined
Apr 17, 2008
Messages
1,248
Reaction score
17
Location
Auckland NZ
A project that is almost complete. A bit off messing around but it's sorted out now and really not that difficult having sorted out all the measurements now.Need to just screwcut the thread on the high tensile axle.
The diff shown is only an old unit and won't be the diff used .
We just need to finish up the drive splines which I will update shortly as I machine it.
 

Attachments

Fire-medic

Well-Known Member
Joined
Mar 25, 2011
Messages
10,046
Reaction score
543
Location
Miami Florida
I assume the install is for a Gen 1? How much difference is there in swingarm pivot width, and pivot pin diameter?
 

Fire-medic

Well-Known Member
Joined
Mar 25, 2011
Messages
10,046
Reaction score
543
Location
Miami Florida
I can see it being fitted to a Gen. 1 but why would you want that on a Gen. 2? Sounds like putting a 7.9" rear end and a cast-iron Mexican 4 speed behind a hot Fox-body 302 Mustang GT like Ford did, before wising-up, and going to a Borg Warner T 10 5 speed, and an 8.8" posi rear end.
 

adambweird

Well-Known Member
Joined
Sep 2, 2013
Messages
925
Reaction score
1
Location
Oak Harbor
Only thing i can think of is, it might have a numerically higher final drive than the gen2 does... if so, this would be the easiest way to help a heavier bike hustle down the track faster. Like switching to 3.73 gearing from 2.41.
 

jedi-

Well-Known Member
Joined
Apr 17, 2008
Messages
1,248
Reaction score
17
Location
Auckland NZ
Why? I can't really go into much detail as it's not mine to discuss but other than to say it changes the ratio obviously
It may blow itself to bits? But on the other hand it might be a solution...

I'm sure we will know for sure in due course :moped:
 

adambweird

Well-Known Member
Joined
Sep 2, 2013
Messages
925
Reaction score
1
Location
Oak Harbor
Very true, wasnt thinking of that. I think though the gen
1 is higher than the gen2. Gen1 is 3.66 or 3.67 if i remember correctly and i think the gen2 is a little bit over 3.
 

Traumahawk

Well-Known Member
Supporting Member
Joined
Dec 12, 2011
Messages
7,921
Reaction score
168
Location
Lawton, OK
Very true, wasnt thinking of that. I think though the gen
1 is higher than the gen2. Gen1 is 3.66 or 3.67 if i remember correctly and i think the gen2 is a little bit over 3.
If thats correct, it will allow the gen 2 to get out of the hole quicker.....if it will stick.

Thats like going from 3.23's to almost 4.11's.
 

Fire-medic

Well-Known Member
Joined
Mar 25, 2011
Messages
10,046
Reaction score
543
Location
Miami Florida
Better buy the Gen 1 pumpkins by the 6-pack. They aren't designed for 200 RWHP a modded Gen 2 can provide.
 

1FK00

Well-Known Member
Joined
Apr 24, 2006
Messages
258
Reaction score
3
Location
Wsconsin
I wouldn't want to be on a bike at any speed with a disintegrating ring and pinion.
 

adambweird

Well-Known Member
Joined
Sep 2, 2013
Messages
925
Reaction score
1
Location
Oak Harbor
Cryogenically harden the gears to help em out like they do with the driveshafts, put the widest slick possible on, add some wheelie bars and let the carnage begin! If it holds together and has grip, should FLY outta the hole!
 

one2dmax

Well-Known Member
Joined
Apr 6, 2006
Messages
15,445
Reaction score
260
Location
Derby Kansas
We asked Steve to take on this project and sent him all the parts. The goal was to have another gearing option for the gen 2 Battlestar bike and of course anyone else with a gen 2 that wants an option.

The stock Gen 2 rear diff is a 3.22 Ratio rear end.
With this conversion we can run either a Venture/Royal Star diff which has a 3.33 ratio OR
A Vmax rear diff which has a 3.66 ratio.

We're going to give up top speed for acceleration.

I did make two conversion kits to install a gen 2 rear swingarm to the gen 1 vmax (and have enough parts to make one more but it's not a cheap kit). This setup would also be able to be used if so desired. I didn't ask Steve to make it possible to fit a gen 1 wheel but I imagine that could be done (though not sure why you'd bother).

As far as durability. They hold up to 170/180 rwhp bikes and gen 1 rear diff failures are pretty rare to have complete failure anyway. I don't think i'll be launching it off the two step but rather launching it with the normal hand slide release. On the street in short runs the 3.66 gear will be awesome for acceleration! And it's a LOT lighter rear diff so more HP makes it to the ground and less mass to move along.
 

Fire-medic

Well-Known Member
Joined
Mar 25, 2011
Messages
10,046
Reaction score
543
Location
Miami Florida
Well Sean is the authority on the Gen 1 mods, so if he says it's good-enough for a stock bike Gen 2, there it is.
 

rebeltaz83

Well-Known Member
Joined
May 8, 2013
Messages
754
Reaction score
211
Location
Anderson, SC
As far as durability. They hold up to 170/180 rwhp bikes and gen 1 rear diff failures are pretty rare to have complete failure anyway. I don't think i'll be launching it off the two step but rather launching it with the normal hand slide release. On the street in short runs the 3.66 gear will be awesome for acceleration! And it's a LOT lighter rear diff so more HP makes it to the ground and less mass to move along.[/QUOTE]

The hp numbers are close, but I'm more leaning towards the torque output, that will do the diff. In. And the added weight of the gen 2 compared to a gen 1?? I snapped a shaft on a stock gen 1, so would the shaft be the weak point, not the diff??
 

Fire-medic

Well-Known Member
Joined
Mar 25, 2011
Messages
10,046
Reaction score
543
Location
Miami Florida
That's correct from my mechanic friend who's built power adder VMaxes.

As far as durability. They hold up to 170/180 rwhp bikes and gen 1 rear diff failures are pretty rare to have complete failure anyway. I don't think i'll be launching it off the two step but rather launching it with the normal hand slide release. On the street in short runs the 3.66 gear will be awesome for acceleration! And it's a LOT lighter rear diff so more HP makes it to the ground and less mass to move along.
The hp numbers are close, but I'm more leaning towards the torque output, that will do the diff. In. And the added weight of the gen 2 compared to a gen 1?? I snapped a shaft on a stock gen 1, so would the shaft be the weak point, not the diff??[/QUOTE]
 

Itgoes

Well-Known Member
Supporting Member
Joined
Sep 16, 2008
Messages
2,152
Reaction score
398
Location
NY
That's correct from my mechanic friend who's built power adder VMaxes.



The hp numbers are close, but I'm more leaning towards the torque output, that will do the diff. In. And the added weight of the gen 2 compared to a gen 1?? I snapped a shaft on a stock gen 1, so would the shaft be the weak point, not the diff??
Piped and tuned Gen 2's are 190 - 210 HP and 135 lbs + TQ.

I appreciate the effort going into this but I don't think the Gen 1 rear stands a chance on a built Gen 2......especially at the track where it will hook.

Might get away with it on the street if not abusing it.
 

Latest posts

Top