23 Tooth Transmission Sprocket

[Ohio HD]

2008 Touring bike, six speed transmission, will be changing the rear belt to a chain drive. What I would like to know, who has used a 23 tooth PBI sprocket on one. Also was there aby clearance issues>

[kd]

I believe I'm using a 24 x 3/4" offset PBI with the same swingarm I think you are going to be using. No problems here.  RB racing offers a combination using a 26 tooth sprocket so I expect you should be golden for clearance.

[Ohio HD]

I would think it would clear, just being one tooth less. I guess I'll be able to see once back in there.

I decided to make the gearing changes that I want to do outside of the primary case. I'm running into what I assume you ran into, pre-2014 MT9 TTS maps have no user adjustment for primary ratio.

[kd]

I didn't bother trying to change the ratios because I was trying to get it to the tuner to dial in an exhaust mod.  My TTS tuner however is the post 2014 blue dongle so I believe it can be done.  He's about 9 hrs. away and the border has been locked up for two years.  The closest in Canada I would trust is days away. I've been just using my GPS. 

I also discovered a homegrown fix for the Cruise not working.  The 6th gear light comes on in 5th so cruise isn't available in 6th gear. While was practicing my clutchless quick shift    and noticed I could trick the ECM into leaving the cruise control on. This has made it easy for me to live with it all.   

[Ohio HD]

I think all that you have to do is change the primary ratio in your map to 1.440, that takes care of the 49 tooth sprocket. Then the gear ratio changes I think these below would work, these are from Joe Lyons calculations.

The problem I have is in the MT9 maps below 2014 model year, you no longer can change the primary ratio, and there is not a gearing table. So I may switch this upcoming tuning plan for the new 124" to Power Vision. All of the adjustment tables are there for my year ECM.


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[kd]

Thanks for the info (again  ).  I copied it for my bench and a reminder to try when I get the opportunity.  I believe I did save Joe's contribution But didn't file it where I would remember it is.    I'll admit that I have a fear of losing something in my tune while I am in there and not having the skill to fix it by myself.  Once I figured out the hillbilly workaround I stuck my head back in the sand and continued to ride.

[Ohio HD]

Just make sure to keep an unmolested copy of the tune on your laptop. That way if anything does go south, you can always load what was tuned.

TTS can make changes on my map, but I have to send it in, and maybe some back and forth. But I also have the new Dakota speedometer to deal with. So I'm thinking I want to be able to make changes when I want to myself. SO I may be going to PV on this one.

What frustrates me is the MT8 maps have the ability to adjust the primary values. The MT9 map for the same bike it's greyed out and won't let you change anything.

I updated my PV firmware, and software, tried the latest maps for my year of bike and all of the values I need to change are there.

[kd]

It sounds like you have already discussed things with Steve Cole but I will ask anyway. Have you been keeping up the TTS updates? It may be the MT8 file problem you are having has been addressed.

[Ohio HD]

I have the updated software. And emailed Steve a few days ago. He said I have to send it in for him to change. So the functionality is there in the MT9 file, just that for some reason the end users can't change it anymore. But, when going to 2015 and up touring bikes, the functionality for the end user is back. 

 

[kd]

Is there any differences in the ECM that would not allow you to just call it a 2015?  Does the VIN you have presently entered cripple you?

[Ohio HD]

Yeah, I verified I can't use a newer calibration. My ECM is based on AFR values and the 2012 and up are Lambda values. So they can't interchange.

Like I said it makes no sense to me that the feature is locked now from the tuner / user.

[kd]

I see.  Well, if Steve will update it at no fee, I would consider getting it done now and if / when you go with a PV you'll at least have an up to date tuner no cost spare.  That's just me though.  I hate to pitch something into the bin that has service life in it.

[Ohio HD]

My main concern is if one day they won't adjust it, and I want to play around with gearing, then I have to pay for another tune to change tuner brands. Better to start with something that fits all of my needs.

[kd]

That's kinda where I'm at.  Bob gave me the production line machining blueprint pattern for the rear sprockets and Sprocket Specialists made them for me.  Easy peezy. I wanted steel because the one aluminum PBI one I was using was showing wear already. (I couldn't get that in steel before either)  Chris Products (PBI) didn't have the material when I wanted to order them last spring. Sprocket specialist didn't either but offered me a case hardened aluminum.  I bought a couple and I can say I am pleased with them.  No wear showing up after a few thousand miles of hard use.  Bob gets his personal race hardened aluminum sprockets done there also and he tipped me off to them.  Their sprockets or at least the ones they made for me are relief drilled around the circumference and look real sharp.

When I set up my RB swingarm chain I used the tallest (lowest ratio) sprocket and set the chain up as short as I could in the slot.  Bob said I could lower the rear tooth count a few stages on the same chain because the slot length allows 2" travel. A sprocket change gets real quick and easy. The speedo change is only over one sprocket in the drive. 

I chose to stay with 24 X 53 / 55 / 57 combinations.  I like to keep an prime odd / even tooth count on my sprockets to stop them from repeating. I run the 57 (3.15 with the 49 tooth basket) around here where my highway trips are within a couple of hundred mile or so each way. It is perfect for me as a daily driver.   

[Ohio HD]

I still want to try and poke that 32 tooth motor sprocket in the primary with the 49 tooth clutch basket. I think I can, if they ever come off backorder. Not that I'm in a huge hurry. I can wait.

That gives me (49÷32)x(55÷24)=3.509

I'm more interested in pulling power with this bike. I'll have several guys around here to dust off. 

If I can't mix up the primary, and can get my hands on a larger rear wheel sprocket I'll go this route.
(46÷34)x(61÷24)=3.439
or
(46÷34)x(63÷24)=3.551

[kd]

Is your rear wheel OEM pattern?  I think John Morton is running a 58 on an 07 (?) but I don't know if he's still stock pattern. Either way, they can be made. IIRC John had is made somewhere.  That'd likely get you close and it should fit.  My concern would be the angle of the upper drive chain causing clearance issues above the transmission sprocket.  John may be able to confirm the clearance he has. If he has lowered it that makes it even closer but good for you if you don't.  I have run into it on a shovel primary where on decel the top of the chain arcs up enough to  rub the inner primary under the starter shaft housing.  The TC housing may be more open on height though.

[Ohio HD]

My wheels will accept a direct bolt on sprocket. You see the rotor side here, but the other side is the same, the sprocket bolts on solid to the wheel.

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[kd]

I sent a PM to John.  He may have some info on the top chain run clearance and sprocket sourcing he used.

[Ohio HD]

Flat steel sprockets are easily found. I need a dished sprocket, which is much harder to find in tooth count over 55. PBI shows them, but then they also state only up tp 55 tooth when trying to order them. I guess a call is in order.

A lot of stunt riders get there rear sprockets here (see below). They laser cut them. I have access up to 4KW fiber optic lasers. But I need the sprocket stamped with a 0.240" dish. Not so easy to do without properly made custom tooling and a hydraulic press.


https://www.bungking.com/front-sprocket-for-chain-conversion/

[kd]

Unless John chimes in with some info, give Sprocket Specialist a call.  I was suitably impressed with the conversation I had with them.  I hadn't hear of them before but they claim to be  able to make any custom sprocket you want.  I suppose that's within reason, but dished sprockets are not that rare. They also do chain conversions so probably dabble in dished rear units.

https://sprocketspecialists.com/

[jmorton10]

My wheel is also a direct bolt on sprocket (2007 RK). My ratio right now is 30T engine/37T clutch/24T tranny/58T rear.  The rear is a dished steel sprocket that IIRC came from Vulcan.  I run 21" front/18" rear with 124" motor & that gearing gives me great hole shot gearing & my Baker Grudgebox with its mild OD 6th gear goes nice with it.

Running a Pingel air shifter, the Grudgebox is the first setup I have had the lasted a whole Summer without tearing teeth off the 3rd gear cluster (I'm sure I could R&R this tranny blindfolded at this point lol).

My bike is lowered, 12" OHLINS rear shocks & 2" lower Progressive monotubes. That was not for looks, my legs are so short (plus I am 70 years old) that even lowered I try to park where I never have to back it up lol.

~John

[kd]

John. with the 24 on the front and that larger 58 on the rear plus being lowered 1", how much room do you have between the top of the chain and underside of the inner primary starter housing casting extension?  Has it touched on decel with a loose chain or not ever?

[jmorton10]

It is pretty close Kirk, but at least last time I checked it hasn't actually touched.

~John