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Author Topic: 10T / 65T sprockets & chain protection  (Read 2633 times)

rayivers

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10T / 65T sprockets & chain protection
« on: April 09, 2017, 11:39:25 PM »

My 12T front sprocket was absolute toast and the 71T rear sprocket a mistake, so I tried something different this time.  I was looking for max torque using the Zero rear sprocket, which is ultra-light and readily available.  As others here have noted, 10% more torque is a very significant increase, even on my 2.8 (a 5.7 / 6.5 FX would've been much more impressive, especially on the street).   The brief initial road test was a bit disappointing, but recent dirt rides were another story.  Above 90% SOC most of the gain was lost in wheelspin in the dirt, but definitely good for a near loop-out in my driveway. :)  It was great having the added 'pop' and drive out of corners, but even better was maintaining a decent power level down to lower SOC's which made the last lap nearly as fun as the first.

Here's the complete installation - the entire lower chain guide was replaced as the old chain had cut it in half (!), and the new mini chain guide and motor-mount protector are visible in the upper left, ahead of the shock:



Removing the old front sprocket wasn't too bad, but had its moments.  I held the sprocket with a Motion Pro 08-0008 clutch-holding tool & heated the M10 shaft screw for 60 sec. with a propane torch (no effect), then another 80 sec. after a 1 min. cool-down (screw came right out, using an M6 key socket & impact gun). The hollow motor shaft was half full of PB Blaster or similar anti-rust fluid.  The setscrews came right out with an M3 key socket / impact gun.  A gear puller was then used to pull the sprocket off the shaft; it was on there pretty tight.  I ran the center bolt of the puller thru the bearing hole, with the clamps either side of it to the sprocket O.D.  I wouldn't recommend using a pry bar against the motor casing, even briefly.

Here's the new 10T front sprocket, retaining dome washer, and M10 shaft screw:




The front sprocket machining requirements are also mentioned in this thread (10T & 11T are the same).  The end of my ΒΌ " motor-shaft key end had been peened over the shaft end, so I smoothed it down with the Dremel so the new sprocket could slide on easily.  I tapped the new sprocket on using a 30mm socket thru the frame bearing hole (my bearings were out for replacement at the time; if they're in, an M20 bolt thru the bearing center with a flat plate over the sprocket end should work).

The OEM sprocket retaining washer is too large to use with a 10T sprocket (it might be OK with an 11T, I don't know).  It can be turned down on a lathe, or these washers can be used (the M8 hole & countersink will have to be enlarged for the M10 shaft screw head, but the O.D. and strength are fine).  I used a thin steel washer under the aluminum one to give a hard stop for the washer & bolt against the motor shaft, rather than just letting the aluminum bow inwards into the air gap (torqued to 35 ft/lb). Clearance from the motor shaft screw head to the 'stub axle' swingarm pivot was @ 1mm /  .040".  Rear sprocket screws (M8x25 black-stainless flatheads) were installed w/Belleville-type lockwashers, flange nuts, & blue Loc-Tite, then torqued to 20 ft/lbs; if these loosen up, they can oval the hub holes & gouge the hell out of the swingarm.

The chain was replaced with the same excellent D.I.D. 520NZ non O-ring racing chain as before.  The new chain/sprocket setup sounds completely different, though.  Before it was a cyclic zipper-type noise, but now it's a strange chordal drone; it reminds me of the intro to the 'Ancient Aliens' TV show, during the episode-title screen.  I think most of it may be chain/knobby-tire noise interaction.  It isn't super loud, just weird.

Current Zero motorcycles are clearly designed mainly for belt drive, which has little in common with a chainsaw.  :D  In addition to wasting the Zero guide, the chain began taking bites out of the LH rear motor mount and chipping powder coat off the swingarm after it got worn a bit.  I made up a steel motor-mount protector (seen in the next pic, covered w/JB Weld) which halted the damage and worked OK, but then I decided it would be better to keep the chain away from that area altogether rather than let the chain and protector duel to the death. 

Here's what I call the 'mini chain guide', which mounts atop the LH swingarm using another M5 Riv-Nut type threaded insert (the notch cut in the top edge is only needed if the swingarm is lowered as in this thread):



Here's the diagram:



This does an excellent job keeping the top chain run on the straight & narrow, and is very easy on the chain.  If the end 'rub' is removed, this guide can also be used to hold the front / top end of a belt guard plate between the tire and belt run (the bottom of the plate could be bolted to the chain-guide mount, and channels could be mounted top & bottom to partially shield the belt runs).

It's also very important to use the swingarm crosstube protector sleeve included in the chain kit, but unfortunately this did not fit well or clamp tightly.  I had to cut off the screw flanges & secure it to the crosstube using double-stick tape and two giant tie-wraps, which works great and hasn't budged at all.

Ray
« Last Edit: July 30, 2017, 08:37:52 AM by rayivers »
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StraydogEOMFD

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Re: 10T / 65T sprockets & chain protection
« Reply #1 on: April 10, 2017, 02:09:39 AM »

Thanks for the informative post, I'm halfway through the chain conversion on my '16 FXS (going to hit a true supermoto track with dirt) and you've got some great tips here plus it's nice to have a chain guide plan posted.   Sub'd for future use :)
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #2 on: April 10, 2017, 03:33:58 AM »

Cool!  Supermoto tracks can also create big WOT tension spikes at dirt/pavement transitions, which you won't even think about when using a chain.

Once the motor shaft is bare & ready for the new sprocket, it should be pretty much all downhill from there.

Ray
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #3 on: April 13, 2017, 06:53:39 AM »

Tried the sprockets out again this week - twice on power-line trails (15-50+ mph), and again this morning on a medium-speed track (10-40 mph).  Today was the first time it felt exactly like I expected it to, given the calculated rear-sprocket torque numbers below:

My bike455 ft/lbs
'16 SR:   460
'16 FX:    370

The track ride was amazing.  The last time I rode there (mentioned in my initial post), the bike was in Eco mode the whole time by mistake.  In Sport mode this time, and given sufficient traction - I'm still playing with tire pressure - the front end was popping up 1-2' on every throttle twist below 30 mph & above 75% SOC. I thought earlier that the bike basically runs similar to before but at lower SOC levels, but today I noticed the bike has an additional peak spurt of acceleration immediately following each throttle twist which it didn't have before, making it feel 'snappier' as well as faster.  Not surprisingly, wheelspin's a bigger issue now.

The power-line trail rides were basically faster and longer-lasting than before, with the acceleration spurts felt less often at the higher speeds & motor rpm's.  This is a 2.8-battery thing; between the safety-first! Zero throttle curves, current limiting, and field weakening, the 2.8 only makes full torque from maybe 500 to 2K rpm.  I'm working up simplified torque/hp curves for 1- and 2-brick FX's that combine Zero & Motenergy specs with what I feel when riding the bike, hopefully they'll give at least some idea what it's like.

IMO those hoping for an 'FXR' at some point and serious about acceleration should at least consider this setup.  Sure, there'll be chain noise/maintenance and top speed & range will be lower, but so will the weight - and price. :)

Ray
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Keith

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Re: 10T / 65T sprockets & chain protection
« Reply #4 on: May 01, 2017, 05:53:48 PM »

My front sprocket is toast after 2000 off road miles on my '16 FX, no surprise. I'm thinking about going to the Martin 11T for more torque, and I like the idea of a 530 chain, it should last longer with the wider teeth, right? Anyway I wonder if anyone is running a 530 and whether the chain guide can be modified to handle the width?
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #5 on: May 01, 2017, 10:00:39 PM »

I briefly considered running a 530 chain for the same reason as you, but decided against it.  The 530 is heavier & has more drag, needs a custom rear sprocket, and will most likely require the OEM chain guide liner to be widened a bit as you mentioned (my mini guide will be fine).  Also, in any 10/11/12T setup the front sprocket's going to wear out much faster than the rear, so IMO you're better off just replacing the front sprocket after 750 miles or so.

Ray
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acacia1731

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Re: 10T / 65T sprockets & chain protection
« Reply #6 on: May 01, 2017, 10:07:02 PM »

My front sprocket is toast after 2000 off road miles on my '16 FX

Would you mind posting a pic when you take it off?  I am curious about the wear pattern, especially if you use much regen?  Does it show the classic dirt bike pattern of thinned teeth all tilting in the same direction, or something unique due to being loaded in both directions?

On a related note - Zero made it tough to monitor sprocket wear, since the swingarm blocks your view!
« Last Edit: May 01, 2017, 10:09:45 PM by acacia1731 »
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #7 on: May 02, 2017, 02:21:32 AM »

30% regen, 30% brake regen:



The 10T is almost impossible to see clearly from the side even with a bright light & small mirror, so nowadays I mainly inspect the teeth through the chain links.

Ray
« Last Edit: July 15, 2017, 08:21:25 AM by rayivers »
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Keith

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Re: 10T / 65T sprockets & chain protection
« Reply #8 on: May 05, 2017, 07:34:09 PM »

What is the overall width (bore length) on the stock Zero front sprocket? Is it 0.875", equal to the difference between 1.0" #50 standard sprocket and 530-520 chain width (0.375-0.25)?
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #9 on: May 05, 2017, 07:59:28 PM »

The OEM Zero 12T front sprocket is .840" wide.  The Martin bores are a bit longer than they absolutely need to be which wouldn't be an issue in most applications, but on my bike the new sprocket clears the swingarm by .040" / 1mm, which seems real tight to me.

Ray
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #10 on: May 05, 2017, 09:26:17 PM »

Now that the new chain/sprockets are broken in, I realize this setup is much quieter than the 12T/65T chain-kit setup.  From the new tonal characteristics of the overall noise level in motion, I think it may be due to three main factors:

1) Less front sprocket teeth engaging the chain links (the bulk of the chain noise comes from the front-sprocket area)

2) Higher frequency of front-tooth 'engagement events', turning what used to be a loud ZZZZZZZZZ sound into a quieter higher-pitched whine

3) Increased motor rpm, allowing the PWM drive-waveform sound to compete with chain noise

Now I can hear the motor all the time, like my belt bike (which is still quieter but not by nearly as much anymore, with a lot of it being reduced tire noise).

Ray
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Keith

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Re: 10T / 65T sprockets & chain protection
« Reply #11 on: May 05, 2017, 10:56:41 PM »

Just how crazy/stupid would it be to run a 530 chain with a 530 front and a 520 rear? Sure the chain would wander side to side on the rear some, possibly letting the rollers go to a very slight angle, but probably it would settle on one side and mostly stay there. Probably a really bad idea but I'm kicking around all of the possibilities...
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rayivers

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Re: 10T / 65T sprockets & chain protection
« Reply #12 on: May 05, 2017, 11:06:41 PM »

Machining the sprocket teeth to .227" takes 15 minutes, tops.  My guy charges me for everything, but he threw in doing two of them for free.

Ray
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Keith

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Re: 10T / 65T sprockets & chain protection
« Reply #13 on: May 05, 2017, 11:21:27 PM »

Not many machine shops where I live. Would Sprocket Specialists do the width reduction on a Martin? I guess I'll ask them. I got a custom rear from them recently. The stock rear is light but that means it bends when you drop it on the rocks. Voice of experience.
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Keith

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Re: 10T / 65T sprockets & chain protection
« Reply #14 on: May 06, 2017, 06:38:01 PM »

Sprocket Specialists could do it, but they suggest using a local shop, so that's the plan for now. That sprocket is available hardened or not, I bought hardened, hope that isn't too difficult to machine. I'm going with 11 teeth, might try 10 someday.
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