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Discussion Starter #1 (Edited)
changing gear ratio, (engine sprocket) VID attached

I am strongly contemplating changing gear ratios, I want to lose a tooth on the sprocket on wheel.

I race shifter karts, gear ratios are my specialty. I taylor different ratios to different race tracks, even have had custom gears made.

With my weight 135 lbs on the bike, i feel i need to loose a tooth on the sprocket. This would mean less rpm specially on the freeway. The bike picks up too fast and hardly feels my weight.

If i lose a tooth, the wheel would go farther back beyond what it can do, i may have to lose a chain link. With chains, you can only lose 2 links at a time.

This might be complicated to some...
What pitch is this chain again 512? karts use 428.



parts fiche for vulcan s http://www.alaskafuncenter.com/page...AFT(S)//TENSIONER/EN650BFF-2015/I19I1950E1230
 

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Discussion Starter #2 (Edited)
since theres no parts fich yet, i googled the versys, and that comes with a 46t sprocket. Online they have different sprockets for the versys. i think the Vulcan is on a 46t also.


OK so Stock 2015 Vulcan s comes with 15/46 gear ratio 42041-0087 same part numbers as 2015 versys

2015 Versys 650 comes in 15/46 ratio. the sprockets are same on either bike!
Going thru versys forums, alot of them change gearing,
 

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Discussion Starter #5
i decided to change the engine sprocket instead, gona do 16 tooth, this will do a more significant change



13144-0038 oem Kawasaki part number for a 16 t
 

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What is the goal for a 16 tooth front sprocket? Lower RPMs at freeway speeds? Any special considerations to this project? I wouldn't mind my freeway RPMs to be lower myself.
 

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Discussion Starter #7
What is the goal for a 16 tooth front sprocket? Lower RPMs at freeway speeds? Any special considerations to this project? I wouldn't mind my freeway RPMs to be lower myself.

IMO, these bikes are made for light weight to heavy riders as well as 2 passengers. so its understandable for them to be designed to be able to carry 2. Im 135 lbs and the bike takes off easily, i can benefit from lil less torque and more speed with a bigger engine sprocket. i find myself at 6th gear all the time and i havent ridden on the freeway.

the part number is actual kawasaki, itl bolt right up, the stretching of the chain after break in will take most of the slack, the rear wheel will probably move forward only minimal
 

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Good find with the 16t sprocket.
I thought about changing a while ago as I do a fair bit of high speed riding.
The bike does rev high to maintain high speed but with increased servicing the bike will be fine.
I'll get one for when I do a long distance cruise to save fuel.
Theres no way Im giving up that punchy take off power for now.
If Kawa released this bike with 16t everyone would be changing to 15t just because.
 

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You will probably like the one you just bought....If not enough, you could also go down one tooth on the rear sprocket.

my two cents.
 

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Discussion Starter #10 (Edited)
Gear Swap results!

I might be the first to do this swap, it is totally worth it. The pic below is the 16t installed. the pic above is the 15tooth.
16 is the biggest that will fit as you can tell. You lose -HARDLY notieceable take off from first, but every other gear is fine. Freeway speeds, the motor isnt screeming as much compared. I would recommend this if you are 150 lbs or less. 150lbs or more, doable if you have a tuned exhaust and like powercommander.
the gearing does really feel better suited 16-46. I did it by myself, tho two people would be safer.

Kawasaki oem gear part number 13144-0038
need a 27mm socket for rear axle and engine sprocket nut
12mm for adjuster chain tension
10 & 8mm sockets to get housings out.


 

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Hi JR.
Were you able to find torque settings for the front sprocket nut?
You could possibly reverse eng. by taking it off with torque wrench and creep up on settings until it cracks although it usually gives a higher reading.
Better to have the right numbers.
 

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Hi JR.
Were you able to find torque settings for the front sprocket nut?
You could possibly reverse eng. by taking it off with torque wrench and creep up on settings until it cracks although it usually gives a higher reading.
Better to have the right numbers.
The correct torque is important but that nut has a locking washer on it so it doesn't rely on the correct torque to keep it from coming loose. Really tight and then the locking washer should suffice. I doubt you could strip that thread or nut.
 

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J, what kind of difference have you noticed? Did you take any before/after samples (say @ 70mph cruise @ OEM gearing you're @ 5500 RPM, and with a gear change you're @ 5000 RPM resulting in a 10% change)? It would be much more difficult to quantify low level torque loss, unless I imagine you timed a 0-60 run in OEM config and retimed in gear change.

What I'm curious about is attempting to get the best of both worlds. I installed the TBR exhaust which claims about an 8% increase in power & 12 lbs weight savings. It certainly feels a bit faster to me. I'm going to research the air intake and try to figure out if a filter change or plenum increase or ram air will be benificial. Couple that with the freer flowing exhaust & a power commander w/ good tune & I think maybe there's a potential of up to 20% increase in power (10 - 15hp).

If I did this, and changed up the gearing to stretch out my RPM range, then I could essentially keep my low end takeoff the same (or maybe even slightly bump it up) and run at a higher (highway) speed at a lower RPM resulting in less work for the motor.

I've only looked into the Power Commander tuning capabilities a little. I plan to delve deeper. But it may offer a way to run more than one map. And switch them on the fly. If so I could tune a power map, then swap to a gas saver map for highway cruising. It would all depend on the quality of tunes & the module capability.

I'm like you in the aspect of having experience in an offshoot area but understanding gearing. I have raced high end RC cars for a couple years now. And gearing is important & complex in the sport. As well I work in a specialized area of HVAC so I understand fan principles (pulleys or "sheaves" and relationship to volume increase based on size) as well as the properties of air, which is good for intake increase. I also have done some major car modifying. What do you think?
 

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Discussion Starter #15 (Edited)
Brandon, sorry, i got lost when you got technical with powercurves and etc. I strongly feel the benefits outweigh the veryminimal slight loss in torque.

The loss in torque is only from take off from dead stop. VERY minute, Easily overcome with the rpm. i still take off fast, as i am 135lbs but i feel the bike can do it with a heavier rider, tuned exhaust. im on stock exhaust too.

at 65mph im at 4800 rpm now. i might be wrong as i have alot in my head right now, i will confirm when i get home.

Also, the speed will be wrong since the pickup is at the engine pinion gear sensor. im obviously faster than 65 if reading is at 65.

with a tuned exhaust like yours, you probably will even out. the motor just screams less with a 16 tooth.


Disclaimer:
when you swap to a 16t, at first few miles of downshifting, you will hear slight chatter or rubbing, it is the chains outer side rubbing on the plastic shroud u see in the picture. It is very minute and after a few downshifts, it goes away, it is material in the plastic that slowly gets rubbed out, IMO very minute. i look at my chain and i doesnt even look like it rubbed.

Basically, when u downshift, the motor doesnt want to be forced to turn, the gear. so the chain sort of goes outside thus pushing the outer shroud n rubbing.

I dont get the rubbing anymore and gearing is perfect for me now.
 

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DNA are the only ones making cotton filter to my knowledge. I ordered mine from italy last week.
PCV have twin tune capacity with an optional switch.
Our ozzy version ecu might have 2 inbuilt tunes. one to comply with learner legal requirements. on previous 650 kwakas usually its a jumper which means a switch can be wired in. the learner tune is ideal for wet weather.
 

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Evil, do you know if the Power Commander is considered open source? Meaning is it point customizable through software? I haven't looked at filters yet. I know there are some drop in oil filters for the ninja & Versys. I'm not sure if our intakes differ. But for the reuseability of oil types, there is plenty of debate on wether they actually flow more air or not. Does anyone know if our bikes uses a Thermoanemometer (Hotwire) type Mass Air Flow sensor? I'm very unfamiliar with bikes and I'm coming from an automotive base. I'd really like to come up with a ram air that captures cool air and aesthetically works with the design of the bike.

J, I don't imagine it throws off the speedo a terrible amount right? It should be an electric signal so potentially there's a fix that can be applied? Regardless it wouldn't be a big deal to just visually calculate as you go along.
 

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Discussion Starter #18
Evil, do you know if the Power Commander is considered open source? Meaning is it point customizable through software? I haven't looked at filters yet. I know there are some drop in oil filters for the ninja & Versys. I'm not sure if our intakes differ. But for the reuseability of oil types, there is plenty of debate on wether they actually flow more air or not. Does anyone know if our bikes uses a Thermoanemometer (Hotwire) type Mass Air Flow sensor? I'm very unfamiliar with bikes and I'm coming from an automotive base. I'd really like to come up with a ram air that captures cool air and aesthetically works with the design of the bike.

J, I don't imagine it throws off the speedo a terrible amount right? It should be an electric signal so potentially there's a fix that can be applied? Regardless it wouldn't be a big deal to just visually calculate as you go along.
Ya, i dont know how it can be recalibrated. but yes, its sensor on the gear side. you can see it in the first picture of my post.
when i ride on 65mph or 5o etc, i will make a note and tell you the rpm. compare with yours. i should have compared before.
 

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Ya, i dont know how it can be recalibrated. but yes, its sensor on the gear side. you can see it in the first picture of my post.
when i ride on 65mph or 5o etc, i will make a note and tell you the rpm. compare with yours. i should have compared before.
I'll take a wild guess and say 6.66% increase. 16/15
 

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Discussion Starter #20 (Edited)
I already forgot what speed is at 4k rpm, but my 65mph is 4800 rpm.

that's 65 on the speedo, but actual speed is probably more, its stock un calibrated.

google the part number, 13144-0038 that's Kawasaki part number, oem Kawasaki gear

got mine new from ebay was partzilla I think.
 
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