Final drive change?

[Brstar]

I have a 2016 V9 Bobber fitted with a Watsonian sidecar.
Two main issues are trail reduction to make the steering easier.
I have a plan in place for that.
The other is  a change in final drive ratio.
A big ask in a Guzzi.
Earlier Tonti framed bikes could be had with a 33/7 ratio  instead of the current 33/8.
I feel a bit Don Quixote here with this but does anyone know how the actual innards compare over the years?
I'm guessing splines and dimensions vary a lot.
But if I can lay my hands on a 33/7 and make it fit...
Current solution is a 165/45/16 car tire but less than elegant and cost a bit in ground clearance.
I have a lathe and access to a milling machine etc.
And not afraid to try it out.
I mean how hard is it to tilt at windmills?

[bigbikerrick]

I dont have any useful information on the gearing, since its a "smallblock", I have used the 7:33 gearing in a "tonti" based tug, instead of the 8:33, with excellent results. what are your plans for trail reduction?
Beautiful looking rig, by the way!
Rick D.

[Frenchfrog]

The earlier small blocs certainly varied the drive ratio's by changing the primary drive ratio's in the gearbox and there are plenty of variations there.With the newer box's there are likely to be fewer options .
As far as I've seen all the rear drive ratio's are the same ,certainly until the newer V 7 series anyway.Not even sure whether an older drive box or gearbox would swap over but probably needs a lot of modifications.
The only way to check the ratio's is to do some research and you would most likely find that info here with a bit of digging https://www.guzzitek.org/f/parts_list_f.htm

[guzzisteve]

Looks like rear wheel change is best bet. Rear drive is different from earlier small block as there are 2 ujoints on driveshaft not the sleeve & ball type shaft. There are no primary changes I know of for the 6 speed gear box.
Front forks are easier to get a Earles fork for sidecar use. You could also make your own triple trees for forks to change trail.
A member here Dirk has a sidecar on smallblock but not a V9.
Good Luck with your project.

[Dirk_S]

Brstar, I’m sure you know (and maybe we talked before about it, and you’re influenced by it)— the rare NTX Baja incorporated a big block final drive and swingarm. I haven’t found info on what all they had to do with the installation, but it’s certainly something that would be on my radar as well for my rig.

That said, I hopped over to the awesome Guzzitek.org and took screenshots of the transmission ratios from many of the small blocks over the years. Including them here if any of it might help (I know you specifically asked about big block ratios, but maybe…).

Gear ratios are still a little Greek to me as I’ve yet to get a full understanding of gear ratios (like electronic circuitry, it makes sense when explained, but then I almost immediately forget).


V85TT:


V9:


V7 850 E5:


V7 Classic:


Breva 750:


V35III / V75:


V35 / V50:


NEVADA 350 & 750 / 750 SP / Targa 750 / NTX 750:


V35 / V50 III:


V35 Imola / V50 Monza:


V35C / V50C:


V65 / V65 SP:


V35TT / V65TT:

[Brstar]

I dont have any useful information on the gearing, since its a "smallblock", I have used the 7:33 gearing in a "tonti" based tug, instead of the 8:33, with excellent results. what are your plans for trail reduction?
Beautiful looking rig, by the way!
Rick D.

Thanks for that.
I got an email saying two chunks of 7000 series Ali landed at my gate today.
I have a friend with a milling machine and we plan to make lots of shiny scarf.
Hopefully resulting in usable raked triple trees.
Also have an eye on an USD front end ex Ducat monster.
Yes I love Watsonian look.
Would be a lot stiffer than the 40mm Guzzi ones.

[Frenchfrog]

Brstar, I’m sure you know (and maybe we talked before about it, and you’re influenced by it)— the rare NTX Baja incorporated a big block final drive and swingarm. I haven’t found info on what all they had to do with the installation, but it’s certainly something that would be on my radar as well for my rig.

The conversion on the 650 TT Baja's is basically a modification to  the swinging arm and diff off a big bloc .The UJ spline on the sb gearbox(from the Monza onwards) and that on the bb uj is the same so no issues there. Info and pictures here https://www.desertpistons.com/guzzi-v65-ttr-tutto-terreno-racing/

[Brstar]

The earlier small blocs certainly varied the drive ratio's by changing the primary drive ratio's in the gearbox and there are plenty of variations there.With the newer box's there are likely to be fewer options .
As far as I've seen all the rear drive ratio's are the same ,certainly until the newer V 7 series anyway.Not even sure whether an older drive box or gearbox would swap over but probably needs a lot of modifications.
The only way to check the ratio's is to do some research and you would most likely find that info here with a bit of digging https://www.guzzitek.org/f/parts_list_f.htm

Yes it seems they have been the same 4.125 to 1 for a long time.
The primary drive from the V7111 is a tiny bit different and would most likely fit.
But worth the cost/effort??
Early small blocks???
If they fitted?
Could take the load?
Were available?
Be nice to have some on hand to experiment.

[Brstar]

Looks like rear wheel change is best bet. Rear drive is different from earlier small block as there are 2 ujoints on driveshaft not the sleeve & ball type shaft. There are no primary changes I know of for the 6 speed gear box.
Front forks are easier to get a Earles fork for sidecar use. You could also make your own triple trees for forks to change trail.
A member here Dirk has a sidecar on smallblock but not a V9.
Good Luck with your project.

Currently running a 165/45/16 car tire on the rear.
Reducing the ratio by about 14 percent which makes it much more drivable especially taking of.
Loss of ground cearance and looks I find annoying
Committed now to fabricating triple trees.

[Brstar]

Brstar, I’m sure you know (and maybe we talked before about it, and you’re influenced by it)— the rare NTX Baja incorporated a big block final drive and swingarm. I haven’t found info on what all they had to do with the installation, but it’s certainly something that would be on my radar as well for my rig.

That said, I hopped over to the awesome Guzzitek.org and took screenshots of the transmission ratios from many of the small blocks over the years. Including them here if any of it might help (I know you specifically asked about big block ratios, but maybe…).

Gear ratios are still a little Greek to me as I’ve yet to get a full understanding of gear ratios (like electronic circuitry, it makes sense when explained, but then I almost immediately forget).


V85TT:


V9:


V7 850 E5:


V7 Classic:


Breva 750:


V35III / V75:


V35 / V50:


NEVADA 350 & 750 / 750 SP / Targa 750 / NTX 750:


V35 / V50 III:


V35 Imola / V50 Monza:


V35C / V50C:


V65 / V65 SP:


V35TT / V65TT:

A lot of information there Kirk.
Thanks for that.
Only minor differences with the six speed models.
V7 (850), V85 and V9.
I think the same with the V7111.
About .2to 1
A couple of the 5 speed V7's said they had a 4.8 to 1 final drive but had the same actual gear ratios at 8/33 or 4.125 to 1???
The V35 had a 2 to 1 primary with the following larger engine running progressively higher ratio's.
Working my way through responses..
At this point it might be a physical swap with a 33/7 big block final drive.
Measurements permitting.s
Still feeling Don Quixote.

[Brstar]

The conversion on the 650 TT Baja's is basically a modification to  the swinging arm and diff off a big bloc .The UJ spline on the sb gearbox(from the Monza onwards) and that on the bb uj is the same so no issues there. Info and pictures here https://www.desertpistons.com/guzzi-v65-ttr-tutto-terreno-racing/

That would be an ambitious fab job for me. Good info on the splines though.
Mine has a 2 uni drive shaft for the offset to the wider wheel.
Still the spline to the cardan shift and the spline to the wheel plus the bolt pattern to the swing arm all need to line up along with the opposite side of the swingarm.
What  could go wrong???

[Frenchfrog]

Oh yeah....something like that needs to be done by a very competent person !
Frankly , staying with smaller wheels is the easiest way to go for doing gearing changes on a shaft driven bike for sidecar use.

[Brstar]

Oh yeah....something like that needs to be done by a very competent person !
Frankly , staying with smaller wheels is the easiest way to go for doing gearing changes on a shaft driven bike for sidecar use.
[/quote.

Can't say you are wrong about smaller wheels and it being something for a competent person.
But I'm aiming for something better.
Or at least I have picture in my head that I will do my best to achieve.
If I ran rear V9 rims all around they are wide enough to take a 165/45/16 car tire.
A bit of work and money to mount a rear to the front.
The down side is ride quality and not the look I want.
Like I said it's a bit of a Don Quixote challenge.
But recently I put a 1903 Minerva Romania motorcycle back with a friend.
This should be easy in comparison.
Appreciate the comments though.