Setting up Differential

[pofarm]

Does anyone have, or know of a how-to on setting up our Royal Star differential gears?

[dingy]

Does anyone have, or know of a how-to on setting up our Royal Star differential gears?

 

Service manual details it if you are refering to setting backlash between ring gear and pinion gear.

Gary

[djh3]

I have not peroused that part of the service manual. But its a ring and pinion set up very simular to a car type rear end.I dont think I would be hesatant to do one.

[pofarm]

I'm considering picking up a Vmax differential and transferring the gears over to my Royal Star differential. Thoughts?

Edited January 25, 2013 by pofarm

[MiCarl]

You will need to get to get an assortment of shims and set the gear lash properly.

 

The speedometer will be off because of the different ratio.

[MikeWa]

I'm considering picking up a Vmax differential and transferring the gears over to my Royal Star differential. Thoughts?

 

Yes. Pick up the whole assembly ready to install.

 

http://www.rmsportmax.com/rsrearendex.html

 

Then review Freebird's article in the tech section.

Makes this job very easy.

 

Mike

[MiCarl]

Yes. Pick up the whole assembly ready to install.

 

http://www.rmsportmax.com/rsrearendex.html

 

Then review Freebird's article in the tech section.

Makes this job very easy.

 

Mike

 

I agree. Just replace the whole thing.

[pofarm]

You will need to get to get an assortment of shims and set the gear lash properly.

 

The speedometer will be off because of the different ratio.

 

I was told that the speedometer won't be effected because the ring gear is the same tooth count?

[MikeWa]

I was told that the speedometer won't be effected because the ring gear is the same tooth count?

 

That is correct. The speedo is unaffected. But you will notice the increase in performance.

Mike

[Yamamike]

"That is correct. The speedo is unaffected. But you will notice the increase in performance."

 

I don't see how that is possible if the V-Max has a different gear ratio???

[pofarm]

"That is correct. The speedo is unaffected. But you will notice the increase in performance."

 

I don't see how that is possible if the V-Max has a different gear ratio???

 

This is what I've been trying to find out for sure. Some say it will effect the speedo, some say it won't. It all depends on whether the sensor picks up on the ring gear or the pinion gear.

[dingy]

This is what I've been trying to find out for sure. Some say it will effect the speedo, some say it won't. It all depends on whether the sensor picks up on the ring gear or the pinion gear.

 

Sensor absolutely picks up on pinion gear teeth. Pinion is what changes in VMax gearing. It goes from a 10 tooth (Venture) to a 9 tooth (VMax).

I have One of these apart right now in garage. I am putting gears from a VMax into a Royal Star drive. I needed the hall effect sensor to run the didital dash I am using on Hybrid RSV that came off a 97 Royal Star.

Gary

[Freebird]

I can tell you without a doubt that it did NOT affect the speedometer when I changed mine out. If it did, I would just recalibrate the speedohealer that I already had installed anyway to correct the factory settings.

[MiCarl]

If the ring gear tooth count is the same then the speedometer won't change.

 

I hadn't thought it through.

[pofarm]

Thanks, guys. That's what I was looking for. A DEFINITIVE answer to my question. It's great to have access to people who know.

[dingy]

Looking at pictures below, it can be seen that the sensor reads the revolutions of the pinion gear.

 

The VMax/FJR gearing swap puts a 9 tooth pinion gear in the final drive in place of the stock 10 tooth pinion. Both gear sets have the same ring gear tooth count (33). Both gears should be changed though due to wear patterns on matching gears.

 

When a VMax/FJR gear set is put in a stock Venture, the result is the RPM's increase when the bike is traveling at the same speed as prior to swap. This is about a 9% increase in motor RPM's at same ground speed.

 

The result of this increase in RPM's is that the teeth on the pinion gear now pass the sensor 9% faster, given the same ground speed.

 

What I don't understand is how this can not change the speedometer reading. If the input to the speedometer is 9% faster given the same ground speed, there has to be something I am missing. It's been a long week with doctors & hospital, so what is it??

 

Attached are some pictures of a couple of components of a Royal Star final drive case and a pinion gear. Ring gear is not shown in any pictures, but its teeth are on opposite side of the sensor/pinion interface point.

 

 

1st picture shows pinion gear laying beside case.

 

[ATTACH]73680[/ATTACH]

 

 

2nd picture is case almost fully disassembled looking from what would be the inner (wheel side towards the pinion pocket (front of housing)

 

[ATTACH]73675[/ATTACH]

 

 

3rd picture is same side of housing, but viewed down, now seeing the sensor pocket.

 

[ATTACH]73676[/ATTACH]

 

 

4th picture isl looking from outside of housing with front on left. I have a yellow marker in through hole that pinion gear is in.

 

[ATTACH]73677[/ATTACH]

 

 

5th picture shows pinion gear in housing, but not fully seated ( I don't want seat it at this time).

 

[ATTACH]73678[/ATTACH]

 

 

Last picture shows opposite side of housing with pinion in its pocket.

 

 

[ATTACH]73679[/ATTACH]

 

Gary

[Venturous Randy]

 

When a VMax/FJR gear set is put in a stock Venture, the result is the RPM's increase when the bike is traveling at the same speed as prior to swap. This is about a 9% increase in motor RPM's at same ground speed.

 

The result of this increase in RPM's is that the teeth on the pinion gear now pass the sensor 9% faster, given the same ground speed.

 

What I don't understand is how this can not change the speedometer reading. If the input to the speedometer is 9% faster given the same ground speed, there has to be something I am missing. It's been a long week with doctors & hospital, so what is it??

Gary

 

Gary, what you are saying would be true if the reading was taken off the ring gear, but what you are not taking into consideration is even though there is a 9% difference in speed versus RPM's, with the reading taken off the pinion with nine teeth instead instead of ten, you actually have 9% drop in impuses per revolution, therefore it offsets the change.

RandyA

[MiCarl]

Gary, you need to count teeth, not rpm.

 

In one revolution of the rear wheel 33 pinion teeth go past the pick up. Since there are fewer teeth on the V-Max pinion the shaft must revolve faster for 33 teeth to go by.

[MikeWa]

Why the speedo is un affected.

 

The speedo reads off of (counts) the ring gear teeth. The v-max rear end has the same number of teeth on the ring gear. Only the pinion is different. Since it is the ring gear that connects to the wheels the speedo reading will not be changed.

 

Mike

[Venturous Randy]

Why the speedo is un affected.

 

The speedo reads off of (counts) the ring gear teeth. The v-max rear end has the same number of teeth on the ring gear. Only the pinion is different. Since it is the ring gear that connects to the wheels the speedo reading will not be changed.

 

Mike

 

 

The speedo sensor reads off the pinion gear, not the ring gear.

RandyA

[MikeWa]

The speedo sensor reads off the pinion gear, not the ring gear.

RandyA

 

It still takes thirty three teeth of the ring/pinion gear mesh for the ring gear to go around one time. In other words it takes thirty three pinion gear teeth to turn the ring gear one revolution. It doesn't matter if it is the V-max pinion (9) or the Venture pinion (10) it's 33 teeth (meshes) for one ring gear revolution. So the speedo counts ring gear teeth off of the pinion.

 

Mike

[Flyinfool]

To say the same thing another way.

Since the ring gear is connected directly to the rear wheel it will turn at the same rpm regardless of gear ratio.

since the pinion is meshed directly with the ring gear its speed will be directly proportional to the wheel speed.

So the speedometer sensor needs to see 33 teeth go by to know that the rear wheel has made one complete revolution.

 

If you have the stock gears with the 10 tooth pinion, the pinion will make 3.33 revolutions for every complete revolution of the rear wheel. in this same time and distance there are 33 gear teeth that went past the sensor.

 

If you change to the vmax gears with a 9 tooth pinion then the pinion will make 3.66 revolutions in the same time and distance and there will still have been 33 teeth go past the sensor.

 

If the sensor was reading drive shaft rpm then there would be a calibration issue, but it is not reading rpm, it is reading teeth, so there is no issue.

 

I know that gear ratios are hard to wrap your head around sometimes.

I hope this helps.

[M61A1MECH]

Jeff

Very well stated, had my head wrapped around it, just could not get my fingers to say it as well as you did.

[dingy]

To say the same thing another way.

Since the ring gear is connected directly to the rear wheel it will turn at the same rpm regardless of gear ratio.

since the pinion is meshed directly with the ring gear its speed will be directly proportional to the wheel speed.

So the speedometer sensor needs to see 33 teeth go by to know that the rear wheel has made one complete revolution.

 

If you have the stock gears with the 10 tooth pinion, the pinion will make 3.33 revolutions for every complete revolution of the rear wheel. in this same time and distance there are 33 gear teeth that went past the sensor.

 

If you change to the vmax gears with a 9 tooth pinion then the pinion will make 3.66 revolutions in the same time and distance and there will still have been 33 teeth go past the sensor.

 

If the sensor was reading drive shaft rpm then there would be a calibration issue, but it is not reading rpm, it is reading teeth, so there is no issue.

 

I know that gear ratios are hard to wrap your head around sometimes.

I hope this helps.

 

That now makes sense !!

Thanks Jeff.

Gary

[pofarm]

I do love a good debate...