V-Star 1100 Classic Trike project questions

Greetings All

I have a V-Star 1100 Classic that I want to convert to a Trike.

I'm looking for info on which rear axle and diff ratio would be best to make this happen.

This is a winter project for my sons and myself.

Aurbo, Welcome to Trike talk from West Virginia, USA.:wave4::wave4:

The ratio should be close to 3:1 on most shaft driven bikes.

You will need to do some research since your drive is on the left side and rotates opposite of most conventional rear axles.

Trike manufacturers sometimes flip the rear upside down to accommodate.

There are some smaller 4X4 vehicles that use a reverse rotating differential that can fix this.

Time for some homework.....(Headbang)
 
Aurbo, Welcome to Trike talk from West Virginia, USA.:wave4::wave4:

The ratio should be close to 3:1 on most shaft driven bikes.

You will need to do some research since your drive is on the left side and rotates opposite of most conventional rear axles.

Trike manufacturers sometimes flip the rear upside down to accommodate.

There are some smaller 4X4 vehicles that use a reverse rotating differential that can fix this.

Time for some homework.....(Headbang)

Thanks for the info.

The shop manual for the VStar indicates a 2.875/1 ratio.

I think I got lucky acquiring a mid '60 Ford 7.25" 3.08/1 for under a hundred bucks so, for now, This project is in the garage beginning this weekend.

Shortening the axle carrier to around 42" then send the axles for a re-spline after trimming. I will have to flip the axle which may result in an even narrower axle base to keep the diff close to the output shaft.

Re-use the rear pivot/wheel frame assembly as a base for the new axle yolk, replace the original mono shock for a dual mount.

mini Truck box fabrication from sheet metal

I'll try pressing my luck with a rerouted rear cylinder exhaust out the left side to even the exhaust appearance.

This will either become a fun project or a slow way to create scrap metal!
 
I can tell you from experience the rear cylinder out the left is tricky and very tight due to the extreme bend.I had duals on mine years ago.Its been done better than I did by those with really great fab skills though.The side cover may or may not need to have mods for exhaust clearance.There is a section on a few different ways here https://sites.google.com/site/vstar1100kb/home/5-modifications/exhaust Post pics we love pics here.I may still have some of mine left.I made some changes that didn't work out and life happened and I sold everything off.I couldn't make myself really like it but its almost easier to bring the front out the left.0612101032.jpg0825001919.jpgdownsized_0408111920.jpgth_downsized_0407011926.jpg
 
Thanks for the info.

The shop manual for the VStar indicates a 2.875/1 ratio.

I think I got lucky acquiring a mid '60 Ford 7.25" 3.08/1 for under a hundred bucks so, for now, This project is in the garage beginning this weekend.

Shortening the axle carrier to around 42" then send the axles for a re-spline after trimming. I will have to flip the axle which may result in an even narrower axle base to keep the diff close to the output shaft.

Re-use the rear pivot/wheel frame assembly as a base for the new axle yolk, replace the original mono shock for a dual mount.

mini Truck box fabrication from sheet metal

I'll try pressing my luck with a rerouted rear cylinder exhaust out the left side to even the exhaust appearance.

This will either become a fun project or a slow way to create scrap metal!

SWINGARM

The integrity of your build utilizing a straight axle is the swingarm. It needs to be rigid (stiff) enough that the weight of the motorcycle in turns will not be allowed to let the motorcycle frame to lean. If it leans, it is flexing and prone to immediate failure. You also need to make sure where the swingarm attaches to the motorcycle frame will not become a point of failure. Some trike manufacturers increase the pivot pin size to overcome the possibility of snapping where the pivot bearings are. The trick is making it strong enough and light enough with the limited room you have to work with.
 
Hi from the UK.

Hi, i've got a vstar 1100 here in the UK that i built 8 years ago. We have a strange little 3 wheeled car over here called a Reliant Robin. Many trikers use the rear axle & driveshafts from these as the ratios are about right. They have to be turned upside down for the correct rotation but work really well.

I'm now building a vstar 650 classic for my wife Tina. As it has mostly similar parts to the 1100 i thought i'd show you how i converted both swingarms. The 1100 has had no problems with handling or stress to the frame or swingarm & i don't see that the 650 will be any different. I did all the fabrication myself including making the axle brackets & being a coded welder, was quite a straightforward job.SS850001.jpgSS850002.jpgSS850007.jpgHope these are of interest. Bob.
 
back at it

Greetings All

It's been a few years but I am knee deep into this conversion now.

1100 Classic, rescued from parked under a tree for 12 years! stripped down, rebuilt and ready for it's new life.

propshaft/driveshaft question- the final drive wheel will be replaced with an Audi or BMW final drive unit so I need to sort this out. Any recommendations on how to convert the shaft to mate with an input flange?

I know the u-joint requires a yoke flange, but I am unsure of the shaft side of things.. get the shaft shortened and re-splined, slip yoke with lock screws, weld the slip yoke?

firebob22 - did you reuse the stock rear shock with the modified swingarm or did you weld it onto the frame?
 
Flange yoke search

My intended differential input flange has the following dimensions;

flange diameter = 114mm (4.48")

6 bolt circle diameter = 94mm (3.7")

pilot hole diameter = 72mm ( 2.83")bolts areM10 (.40")

Any recommendations for a compatible flange yoke would be greatly appreciated.
 
Greetings All

It's been a few years but I am knee deep into this conversion now.

1100 Classic, rescued from parked under a tree for 12 years! stripped down, rebuilt and ready for it's new life.

propshaft/driveshaft question- the final drive wheel will be replaced with an Audi or BMW final drive unit so I need to sort this out. Any recommendations on how to convert the shaft to mate with an input flange?

I know the u-joint requires a yoke flange, but I am unsure of the shaft side of things.. get the shaft shortened and re-splined, slip yoke with lock screws, weld the slip yoke?

firebob22 - did you reuse the stock rear shock with the modified swingarm or did you weld it onto the frame?

There was a fellow that used the driveshaft out of a f150.If I remember right it was a late 90s but not sure.The ID of the f150 shaft was close to OD of the Yammy shaft.He was doing a XS1100.It gave him a workable flange style mounting. Went by DC Cryder I think. I have pics of the in several places.
 
XVS1100 suspension.

Hi Aurbo, sorry for the very late reply to your question. I had a custom suspension unit made that is the same dimensions as the original unit but has uprated spring & internals to handle the extra weight of an axle & wheels. It also has a remote preload adjuster as trying to adjust the original unit through the very small gap underneath the back of the seat was virtually impossible.

The new unit works extremely well but was eye wateringly expensive! Worth it overall though. Good luck, Bob.:D
 
Hi again

Slow progress but progress non the less.

Bit of an odd question regarding the use of a BMW e39 rear differential.

The e39 input has a flat flange that connects to the drive shaft using a CV joint instead of a Universal joint.Cv1.jpg

The e39 output is a typical CV axle configuration.

tearing down the drive shaft CV joint and the CV axle joint, I cannot see a difference between them, in fact when you remove the grease/retainer end cap then the remaining CV axle shaft mates up to the driveshaft input flange, bolt holes included.halftshaft1.jpg. The half shaft with the end cap removed looks exactly like the drive shaft cv end.

Now this results in a freakish contraption where you have 1 cv axle shaft on the input flange and 2 cv axle shafts on the output flanges.

The cv axles are hollow and my prop shaft from the bike is solid375591363_970345724295102_7290119097613669834_n.jpg

My question is what prevents me from using the axle CV end welded to the bikes output prop shaft to drive the Diff?

Is there something on the safety, engineering, or anything else that makes this not worth trying?
 

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