What's the fascination with a 114 link chain? if there's an advantage i'm curious?

 

Wouldn't call it fascination, but with 17/40 @ 114 you pick up ~7mm additional swingarm length and ~2mm additional ride height over stock gearing/chain length. And obviously a little additional squirt out of corners.

Gen3 SDR Eccentric / Ride Height Charts

All Sprockets, All Chains: Clock Grid Front Sprocket 16, Chain 112: Clock GridFront Sprocket 16, Chain 114: Clock GridFront Sprocket 16, Chain 116: Clock GridFront Sprocket 17, Chain 112: Clock GridFront Sprocket 17, Chain 114: Clock GridFront Sprocket 17, Chain 116: Clock Grid All sprockets...

superduked.com

 

Just popped the 16t front on the bike. Bit of a PITA if I'm honest.

You have to remove the slave cylinder (which has a few mystery components behind it and requires careful realignment during reassembly!) and loosen the chain slack all of the way to allow chain removal from rear sprocket which provides just enough slack to get it off the front sprocket! Damn!

Turned what should have been a 10 minute job into an hour. Anyway, all back together.

Hopefully get a putt in this weekend to evaluate the change. Hopefully it's a home run as I'm not keen on undoing it any time soon!

Cheers

-John

 

Okay, first ride with the 16t front sprocket (16/38 @ 112 links). Damn! Bike was quick out of corners on tight & twisty backroads before but it's on a completely different level now. It's silly fast....and I like it!! I knew the wings KTM added to the 1390 were pretty much for show (keeping up with the Joneses) and didn't really do much but with this gearing they are just flat out broken in the first 4 gears! 🙂

Sadly, not all of my riding is on tight & twisty backroads. We have to endure a bit of freeway to get to them and with this gearing, the RPMs at 85mph jumped from 4k to 5k. While not terrible, vibrations did increase a bit in the pegs and bars, something that's not noticeable when you're rowing thru the box and RPMs but when droning along at 85, gets a little annoying. I'm sure fuel mileage suffers a bit as well but didn't do a comparison....sorry.

So, what gearing to chose? Definitely will not be going with 17/41 @ 114 (it's the same final drive ratio as 16/38). I still think 17/40 @ 114 is worth trying. Should bring RPM down to 4.6k/4.7k at 85mph and retain most of that ferocious acceleration out of tight corners. 17/39 might be the best compromise and worth a try as well.

One word of caution. I would not recommend this gearing with the stock chassis geometry. The stock bike already has an issue with excessive squat under hard acceleration causing frustrating understeer and instability. This much additional acceleration would just exacerbate the issue.

Cheers

-John

 

Thanks for the info. I´m also thinking on changing the rear sprocket to 40 teeth and keeping the 17 tooth front socket on my SDR1390. I was hoping on keeping the 112 link OEM chain if possible since I want a shorter wheelbase for easier wheelies out of corners. I´m not doing trackdays anyhow and kind of miss the wheelieness of the gGen1 and Gen2 chassies. I asked a question on the FB Superduke 1290 group if anyone had done this gearing (17/40)with the OEM 112 link chain on their 1390 and one said yes it is possible and another said no its not possible, haha so pretty confusing answers.. Anyhow hoping on it beeing a good mod for my needs of easier wheelies on the 1390. And with easier I mean at lower speeds..

 

If that is what you're after, the 16/38 gearing with 112 links will definitely give you what you want!!

According to GoGos data, a 17/40 combo with 112 link chain is possible. I would trust his data rather than some random person....especially on Facebook. He has installed and measured every sprocket combination in the attached charts (link provided below) and provided documented changes to chassis geometry.

Gen3 SDR Eccentric / Ride Height Charts

All Sprockets, All Chains: Clock Grid Front Sprocket 16, Chain 112: Clock GridFront Sprocket 16, Chain 114: Clock GridFront Sprocket 16, Chain 116: Clock GridFront Sprocket 17, Chain 112: Clock GridFront Sprocket 17, Chain 114: Clock GridFront Sprocket 17, Chain 116: Clock Grid All sprockets...

superduked.com

Good luck on your quest!

Cheers

-John

 

I ran 17/40 sprockets on my 1290GT for 42,000kms on stock chain. On my 2020 1290 after 2000kms (time for the chain to stretch) i fitted a 40 tooth, 28'000 kms and one stuffed chain, so new DID and a new 16 tooth front sprocket and Go Go 20mm plates. (planned to go 16/38) I thought id measured the same as stock length for the chain, but after fitting i realised it was 2 links longer and couldn't tighten to the right slack, so refitted the 40 tooth sprocket. So now have 16/40 set up. It goes like fuk, but i may get a new 17 tooth for an up coming trip.

 

16/40 would be insane on the 1390 and I would assume the 1290 as well. I bought the 16t for my 21 1290 but never got around to mounting it. 16/38 probably would have been really good on the 1290 with the taller 5th and 6th but I find it's just a bit too short on the 1390 (at least for the combined riding I'm currently doing).

Cheers

 

^^^ Ordered a 17 tooth today (Plus some hand guards, saw some on a new GT shop had foresale, they come stock on the 23 GT, and look really good) I noticed some wear on the chain links, must be rubbing in the swing arm guide, so back to a 17, and my chain is more than long enough (114 i think now) PS my 1290 would still pull 250 kph with the 16/40 gearing, just got there a bit quicker.

 

I just ordered the 39 and 40 rears as I want to go back to the 17t front for that very reason.

Cheers

 

From memory when i fitted the 40 tooth paired with the 17 tooth the revs went up by about 300 doing the same speed in 5th.

 

I just read something very interesting in the service manual. Don't know what the malfunctions could possibly be other than TC/Slip Control related. I didn't experience any issues @ 16/38 but will keep my eyes open. Think I'm going to check my old 1290 service manual and see if it says the same.

1/2 way down on page 417:

Secondary Drive Ratio
17:38
• Info
I Modifications to the transmission ratio are not
permitted and can lead to malfunctions.

 

Apparently something new for the 1390, the 1290 service manual does not have the same statement.

Interesting.

 

KTM blamed the 16x40 gearing for the Cruise Control issues that I have been having on my Gen 3 SDR. No details have been provided, though. While this has not been stated in the service manual, it seems to have been KTM's concern.

 

I was using cruise control while running 16/38 last weekend without issue. Think your dealer is grasping so as not to have to trouble-shoot and get to real cause of your issue. Shame really.

 

That was BS, indeed. My CC issue emerged long after I tweaked the gearing.

 

Interesting I thought ktm lowered the gearing on the 1390. I know on my 1290 I experimented with gearing. 17/38 being stock. I first went 16/42 114 chain. It was quick out of corners but the gas mileage suffered quite a bit. Had the low fuel warning coming on at 80 miles if I road it hard. I wanted a little bit better mileage so I put the 17 tooth sprocket back on keeping the rear sprocket at 42 and the chain at 114. I also should say I have GoGo rear linkage arm on the bike as well. This setup has proven to be the sweet spot for my bike. I now get about 120 miles before the low fuel like warning comes on. The bike suspension balance seems better than ever. Bike still effortlessly does clutch up wheelies at 90 miles an hour in 4th gear😆 One more unintended bonus The auto shifter got smoother with this gearing. Not trying to hijack your thread. Just wanted to tell you and others that OEM gearing and chain length is not always best to leave stock if you want a better balance between performance and fuel economy. Disclaimer: I have no experience with the 1390 so the gearing I have chosen will not work the same for the 1390.

 

Interesting I thought ktm lowered the gearing on the 1390. I know on my 1290 I experimented with gearing. 17/38 being stock. I first went 16/42 114 chain. It was quick out of corners but the gas mileage suffered quite a bit. Had the low fuel warning coming on at 80 miles if I road it hard. I wanted a little bit better mileage so I put the 17 tooth sprocket back on keeping the rear sprocket at 42 and the chain at 114. I also should say I have GoGo rear linkage arm on the bike as well. This setup has proven to be the sweet spot for my bike. I now get about 120 miles before the low fuel like warning comes on. The bike suspension balance seems better than ever. Bike still effortlessly does clutch up wheelies at 90 miles an hour in 4th gear😆 One more unintended bonus The auto shifter got smoother with this gearing.

Not trying to hijack your thread. Just wanted to tell you and others that OEM gearing and chain length is not always best to leave stock if you want a better balance between performance and fuel economy.

Disclaimer: I have no experience with the 1390 so the gearing I have chosen will not work the same for the 1390.

 

KTM lowered 5th and 6th gears on the 1390. They still use 17/38 as the final drive ratio....and apparently forbid you from changing it!! I plan on installing 17/40 later today (currently running 16/38).

Cheers

-John

 

Installed the 17/40 combo with a new DID ZVM-X chain at 114 links. Unfortunately I hamfisted (over torqued) the rivet tool on the masterlink which split the end of one of the roller pins....doh! Probably would've worked fine but I'm not taking a chance and have the chain come apart and destroy the engine case and/or clutch slave cylinder.

Sadly I only had a 520 spare and a search of all local shops came up empty so had to order new masterlink (bought two!) online. Didn't get to ride this weekend...bummer! Hopefully they arrive before the weekend.

Insert face-palm here.

Jeers

 

Installed the 17/40 combo with a new DID ZVM-X chain at 114 links. Unfortunately I hamfisted (over torqued) the rivet tool on the masterlink which split the end of one of the roller pins....doh! Probably would've worked fine but I'm not taking a chance and have the chain come apart and destroy the engine case and/or clutch slave cylinder.

Sadly I only had a 520 spare and a search of all local shops came up empty so had to order new masterlink (bought two!) online. Didn't get to ride this weekend...bummer! Hopefully they arrive before the weekend.

Insert face-palm here.

Jeers

I see Acosta broke his chain while racing Moto GP, and Binder broke one in practice. Best not take a chance.

 

I saw that as well!! And, he flipped off the bike like it was KTM's fault....and not DID, Regina or?? Apparently they lost 3 over the weekend! Must've gotten a bad batch from which ever chain supplier they use....or they have an incompetent chain riveter.....doh!

I still can't get my head wrapped around a 520 holding up to the torture those bikes put out!

 

I kinda screwed up. I modified too many things at once and lost my way a bit.

I installed 17/40/114 gearing. Due to my hamfisted torquing effort I didn't get to ride the bike with just the gearing change. I also installed the OFT Stage 1 map as the tuner came in last weekend. First ride with both mods was today. I have to say, if you like ferocious acceleration (I mean really FEROCIOUS), this is the setup for you. Substantially more violent than the 16/38/112 gearing (with stock ECU mapping) I had installed on my last ride...which if you read the post, you'll recall I stated was a huge gain in acceleration over stock gearing (with some fairly minor short comings). With effectively a one tooth step taller final drive ratio and OFT S1 map, the bike has gained a massive step in acceleration which points to the OFT S1 tune being something really special.

Another thing I noticed is that for the tight twisty bumpy roads I'm riding, the extra length in the swing (due to the 114 link chain) may not be the best chassis geo change. Bike didn't do anything evil but I got a sense of slightly less feedback for traction under hard acceleration. This probably wouldn't be an issue on smooth roads or a track but I noticed it nonetheless. May have been the extra leverage ratio on the spring making it slightly softer in rate creating some vagueness at the tire, don't know but (at least where I ride) I think I prefer the 112 link chain. A one step stiffer spring might sort the issue but not prepared to go down that path....just yet anyway. It didn't really slow me down at all but more feedback is always welcome! Another possibility is a slightly more forward weight bias (shifting more of the bike/rider weight from the rear to the front).

So next logical step is to revert back to stock gearing (17/38/112). If nothing else, it'll allow me to test the OFT S1 tune on it's own which I'm sure Stic is waiting for (teaser, pretty sure it's going to be really good).

Cheers

-John

 

^^^ I would presume 17/40/114 would give a similar wheelbase as 17/38/112. With the 112 link chain and 17/40 the concentric adjuster is right forward, a 114 chain puts it somewhere in the middle with those sprockets. But a 114 with 17/38 might put the concentric adjuster at its furtherest out position.

 

Yep, 17/40/114 is just under 8mm longer than a 17/38/112 combination. That is a pretty sizeable change. I base these #s of Eric's eccentric ride height charts on his website. Very useful tool!

 

So, plan was to go back to stock gearing (17/38/112) to evaluate the OFT Stage 1 tune on it's own merits. However, I really wanted to try the 39t rear sprocket before removing the 114 link chain. The 17/39 combo is good, really good from a balancing acceleration/RPM compromise. Problem is it makes the swing arm even longer reducing effective spring rate even more. Heavier spring rate would definitely be required if one were to stick with this combination.

So what has all of this experimentation taught me? KTM's choice of 17/38/112 is probably the best combination for the riding I do. If you're on track, the longer swingarm from a 114 link chain will offer slightly more stability but the ability to accelerate harder with shorter gearing is the real bennifit. If your looking to get every ounce of performance out of the bike on track this would be the path I'd choose.

With the OFT S1 tune, the 1390 accelerates so much better that a shorter gearing choice has proven to be unnecessary, at least for me on road (a dedicated track bike would be a different story). The Spark Ti pipe has arrived so another step in performance with the OFT S2 is expected which would make a shorter gearing combination needed even less.

Don't know if this excersise was helpful to anyone other than me and my curiosity but there it is. Obviously if you own a 1290, it's a different story. The bike with its taller 5th and 6th gears definitely bennifits from shorter gearing but the 1390, not so much.....IMHO of course.

Cheers

-John