Scootworks pulley for Vulcan 900 - too heavy?

[RichLockyer]

If the pulley is properly balanced, the added weight is not a problem.
Wider truck rims and tires chew up wheel bearings not because of weight, but because of the additional side loads caused by the change in offset. You can't take off a stock 6" rim with a 0 offset and pop on a 10" rim with a 0 offset and expect the tire to clear the frame... so you hold the same backspacing, which would make the 10" rim a 7" offset. 70% of your tire/wheel mass is now "outside" of the bearing's designed loading point.
Hold a pencil in the center and have a friend push on both ends. It stays straight. Now hold it 1/4 of the way along it's length and have a friend push on it... the long end will move.

If the pulley is NOT balanced, then yes, it will destroy the output bearing, but that would be the case with the stocker as well.

[fljohnboy]

Originally Posted by Bender

what the @#! ?? people here say the P.O. scale says 3.7 lbs for the scoot pulley, and other people say the P.O. scale says 8.7 lbs...

I don't see how people can get such a huge difference

I'm not seeing this either. I made a special trip to the post office to weigh the scootworks and it was 3.7 lbs. I weighed my self on the house scale too then held the pulley and I weighed about 4 lbs more. When I take the stocker off I will weigh both again.

[Somerset]

Originally Posted by fljohnboy

I'm not seeing this either. I made a special trip to the post office to weigh the scootworks and it was 3.7 lbs. I weighed my self on the house scale too then held the pulley and I weighed about 4 lbs more. When I take the stocker off I will weigh both again.

Really strange. Can you post a picture of it? Is it solid, made of two parts, one seems like steel, the other solid aluminum, bolted together with 6 bolts?
When did you get it from SW? I got mine last week.

S.

[mavulcan900]

I just installed the scootworks front pulley this morning, and while I didn't weigh it, it's definitely heavier than the stock one. I just weighed the stock one on the (imprecise) bathroom scale, and it's around 4 lbs. I'd guess the scootworks is probably around 8 or so.

That said, the weight won't have any negative affects on the bearings. The extra couple of lbs of sideways force from gravity is way less than the sideways force generated by the belt. Especially when the belt is under load (accelerating and decelerating). Try this experiment: Loosen the nuts on the back wheel of your bicycle, and try to hold the hub in place while someone pushes down on the crank pedal. The sideways force from the chain tightening under load will rip the hub right out of your hands.

The only possible (negligible) effect of the weight increase is that you've increased the mass of the drivetrain's rotating assembly, so it will be a little harder to accelerate it. Will you be able to notice it? I'd bet that the change in drive ratio (from the larger pulley) decreases the acceleration more than the change in mass.

[Bender]

would there be any benefit from slight vibration smoothing?

[Somerset]

Originally Posted by mavulcan900

I just installed the scootworks front pulley this morning, and while I didn't weigh it, it's definitely heavier than the stock one. I just weighed the stock one on the (imprecise) bathroom scale, and it's around 4 lbs. I'd guess the scootworks is probably around 8 or so.

That said, the weight won't have any negative affects on the bearings. The extra couple of lbs of sideways force from gravity is way less than the sideways force generated by the belt. Especially when the belt is under load (accelerating and decelerating). Try this experiment: Loosen the nuts on the back wheel of your bicycle, and try to hold the hub in place while someone pushes down on the crank pedal. The sideways force from the chain tightening under load will rip the hub right out of your hands.

The only possible (negligible) effect of the weight increase is that you've increased the mass of the drivetrain's rotating assembly, so it will be a little harder to accelerate it. Will you be able to notice it? I'd bet that the change in drive ratio (from the larger pulley) decreases the acceleration more than the change in mass.

Thanks, I was hoping someone will say something like this.
So, how is the ride now? My bike is really irritating me with vibrations when going faster than 65 mph indicated. Even when I am going through the local park I need to be in 3rd gear, 2nd sounds too busy. I am hoping to this with the new pulley.

S.

[RichLockyer]

Originally Posted by Bender

would there be any benefit from slight vibration smoothing?

Perhaps, but nothing major. The pulley is really spinning too slowly and too far down the gear line to have much of a flywheel effect.

[joesk]

What it will change as far as the vibes is that you will go faster with lower rpm's so the vibes will come at higher speeds. I still get the high vibes I had before the pulley but now I am going faster before they kick in. A guy was explaining that the vibes are caused by the counter balancer. It is designed to counter vibrations to a certain degree, but as you get further from its balance RPM the vibes kick in.

As for the heavier weight. I remember in our old school backyard mechanics days. A lighter flywheel meant faster acceleration We would drill holes in the flywheels then balance them by spot wielding them. But the radius of a cars flywheel is like 5 or 6 times the pulley so I think the weight is going to be negligible. Its that old equation of mass*speed equals inertia thing.

[Bender]

well, I've got a scootworks front pulley on order now. As long as I can cruise at a "true" 72/73 I'll be happy. With the pulley on, the speedo error should be way closer than 9 or 10%, so when I'm going a true 73, speedo may show 76 or so. As long as the seat and floorboards aren't buzzing yet, I'll be happy.

[Gnash]

Well I installed my Scoot Works rear pulley about 3 weeks ago. And yes, the weight difference was almost double...but I tell you, the torque loss is minimal...I only barely noticed it when it was first installed.....however....I noticed that accelerations times actually stayed (crude test method) but because I was able to pull longer in each gear....maybe this even things out. My favorite part is definitely the fact that I can cruise at 120KPH and feel nothing thru my grips or pegs. Yes, I do realize that this is a 900 and not a 1300 cc machine....but darn it, if you can do something to improve your ride, who cares...as long as I am happy hammering down the highway or cruising the boulevards....I love this bike....and the Scoot Works pulley is the cat's meow!

D

[Somerset]

Hi all,

I've installed the pulley few weeks ago, but didn't have much opportunity to ride during this period. I did however one longer ride and few shorter trips and wanted to share the experience.
Overall I have rather mixed feelings. I am very surprised how "only" two teeth difference affects the bike behavior.
I've bought it mainly to address the highway vibrations issue. What have I found:
1. The bad - the vibrations at higher speed are still there. I get then at almost the same speed (may be few mph higher), they feel a bit "milder". Of course I have to account for the fact that my speedo is now probably closer to reality, so I probably moved my "vibration zone" realistically by about 5-6 mph. I expected bigger change.
Question: could there be something in the road surface that causes the vibrarions??? I know there were some experiments done in some countires related to this.
2. In town the lower gears are a lot more usable. The feeling of huge torque at low RPM however is gone, now I need to rev the engine a bit more in order to get the bike moving. Overall the bike kind of feels "happier", with one person on board it seems that now the demand is better meeting the engine output - before it was like that engine is either has too much torque or gets into the vibration zone. I am not sure how it will be with two people though.
The fourth gear is now much more usable.
Surprisingly, I can still ride the bike comfortably at 60 km/h in 5th gear (around 40 mph).
3. (This is personal specualation) The engine now sounds a bit more like "parallel twin" than V-twin, nicer in my opinion.

So, to sum it up, I guess the results depend on what you are looking for. If you are not interested in much highway riding, probably installing the pulley doesn't make much sence. If you are looking for most "torque" don't do it.
Installing a new 2-into-1 pipe along with the pulley probably is a good idea - it should bring back some of the "lost" torque, while still getting lower RPM on the highway.

I guess the "ideal" formula would be one tooth less front pulley. May be Kawasaki will make this change in the future.

Just my 2 cents woth of opinion and experience. Your mileage may vary.

Cheers,
S

[RichLockyer]

Originally Posted by Somerset

Overall I have rather mixed feelings. I am very surprised how "only" two teeth difference affects the bike behavior.

Typically, one tooth on the front sprocket = 3 teeth on the rear sprocket.
6 teeth on the rear is pretty significant. On a dirtbike, going between 12 and 13 teeth on the front is significant.

1. The bad - the vibrations at higher speed are still there. I get then at almost the same speed (may be few mph higher), they feel a bit "milder". Of course I have to account for the fact that my speedo is now probably closer to reality, so I probably moved my "vibration zone" realistically by about 5-6 mph. I expected bigger change.

Without correcting your speedo with a device like a Speedo Healer, your speedometer will ALWAYS read the same at a given engine RPM, because the speed sensor is on the transmission output.
IE: Before 3,000rpm was indicating 75mph but you were really doing 68.
With the pulley, 3,000rpm still indicates 75mph, but now you're doing closer to 73.

So the vibrations and "sounds" associated with 75mph before will remain unchanged with the new pulley.... some vibration from the road surface might actually increase since you'll be going faster.

[vmuth]

Just got back from another ride.

I will say it again.

Best mod on my 900 was to put back on the stock pulley.

Let it run!!

[MrClean]

Try adding some Dynabeeds to your front and rear tire. It'll be a pain in the rear tire but the front is easy enough. Perhaps you have a slight imbalance that is giving you these vibrations. Or, you could add Ride On tire treatment to the bike, it's supposed to help with balance too while protecting you from punctures. Don't do both.

[Somerset]

Originally Posted by vmuth

Just got back from another ride.

I will say it again.

Best mod on my 900 was to put back on the stock pulley.

Let it run!!

What was the part that you didn't like? Loss of power/torque? I would really like to get your input as well.

S.

[vmuth]

I was skeptical from the begining when i bought the pulley because it is just a compromise to a situation some of us do not like. Percieved high RPM at highway speed. When i had the pulley on it definetly made interstate riding more tolerable. I also noticed loss of spunk throughout the whole RPM range that i expected before i put the thing on. Also roll on idle speed through say a parking was a lot faster than i liked.

But even with that i would have left the pulley on except that belt noise (chirping and squelling) began after a couple hundred miles. It got worse and worse. So i took it off right before a long trip i made.

When i had both pulleys in hand the quality between the orignal and scootworks was like night and day. The coating had worn down and the teeth on the scootworks pulley were not as smooth to the touch as the original. That had to be causing the noise. Maybe some folks pulley are better made than the one i got.

As a bonus the original makes the bike feel quicker and more fun to ride in my opinion. With that as fact to me i can put up with sightly higher RPM. I am now riding and holding forth gear up to 60 indicated MPH and it does not bother me.

[RichLockyer]

Just a thought on belt squeal.

If anyone has been around funnycars or street rods with a blower, you'll notice a whine coming from the belt drive.

The whine is from air being compressed out from the ends of the teeth.
A trick to eliminate that is to drill a small hole in the center of each "valley" on the pulleys. This provides an extra place to relieve air pressure and the whine is either eliminated or significantly reduced.

Don't know if this would help on a bike, as the belt is pretty narrow compared to a blower belt.

[Amy71076]

I ordered the pulley, but it isn't here yet. I received an email from scootworks with tracking info. It states that the weight is 9 pounds for this package. The pulley will be the only item in package.

Amy

[vmuth]

I am not talking about the normal whine that you may get at certain RPM ranges and loads.

I am talking about chirping caused by the air being pushed out from multiple imperfections in the machined surface of the pulley.

But that is ok, since most of my riding is 0 to 65 two up the stock pulley serves me better.

[Bender]

the majority opinion seems to be that it's "the greatest thing ever"...
but I'm still waiting on mine so I don't know.
I'm having second thoughts now that I'm reading some negative opinions on it though...