Sprocket change to shorten gearing - who has done it?

[Captainbeaky]

Thanks for that.
How many "teeth" of adjustment has the chain adjuster got?
If I drop a tooth off the front, will the adjuster cope?

 

[ld_rider]

But I ideally want 6th to drop down to the same ultimate ratio that 5th currently is

Try this and see if your plan has merit: Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator

Understand that these New Concept engines are more like a diesel in their character than most modern motorcycle engines so don't be fooled by their tractor like response and the resultant auditory feedback ;-)

 

[Grrant1058]

Hello Captainbeaky,

I have a 2016 NC750X which came standard with 17:43 gearing. As the speed limit in Australia is 100kmh (60mph) 6th gear was just too high so switched to a 16t front. Bike is definitely more user friendly now and no problem to use the original chain. Even had the benefit of a slight improvement in fuel consumption. Fitted a Healtec "speedo healer" to get the speedo reading correctly again. That was a very easy fit and fix. Highly recommended modification.

Cheers - Ron

 

[Nofear2trek]

If I drop a tooth off the front, will the adjuster cope?

Dropping teeth means less chain length, so if the chain is too long for the adjusters, just cut a link off. Easy peasy.

I always buy my chains with extra length, I find the cheapest length (number of links) that exceeds what I need and cut it to length. Chain prices vary drastically by length, most of the time longer chains are cheaper than shorter lengths (same brand and model chain).

Ray

 

[rpvanoyen]

I wouldn't be worried too much. If the chain can handle it, the rest of the bike can too.

Sent by Motorola Moto G 4G

 

[bamamate]

I run stock and also swap to one tooth down in front and run 2 teeth up in rear. I run 150/70 rear tire so the 2 teeth up in rear gets me about back to stock. Stock length chain can barely handle 2 teeth up in rear. I should have gone with 1 additional link. The front sprocket is so small that changing 1 tooth doesn't really matter with chain length. I would play around with a sprocket calculator like here: Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator
1 tooth down in front make the bike a bit more responsive but isn't going to be enough for what you are looking for so I'd probably start the calculator with 1 down/3 up.
You are going to be limited to the available sprocket sizes.

 

[Captainbeaky]

I paid more attention today to the gearing while riding back from the workshop.
On some of the really steep slow corners, I found myself dropping down to first, but it was a bit too low.
Then on the faster stretches, I did the hooligan thing and reached about 150k ( 90mph) in 5th with revs left on one of the longer (3km) stretches of tunnel. Wouldn't pull in 6th though, as it was uphill run.

So I think that a serious reduction in the gearing would make it even better to ride.

Thanks for that gearing computer, I'll give it a go.
For now, I'm going to drop a tooth off the front, and see how that goes.
And maybe add a tooth on the back...
I'll see what I can get.

 

[Captainbeaky]

Yeah, there aren't many available sprockets for this,

It looks like going up a chain size might be the longer term answer.

 

[Deleted member 5383]

NC700X torque and horsepower curves:

 

[dduelin]

I paid more attention today to the gearing while riding back from the workshop.
On some of the really steep slow corners, I found myself dropping down to first, but it was a bit too low.
Then on the faster stretches, I did the hooligan thing and reached about 150k ( 90mph) in 5th with revs left on one of the longer (3km) stretches of tunnel. Wouldn't pull in 6th though, as it was uphill run.

So I think that a serious reduction in the gearing would make it even better to ride.

Thanks for that gearing computer, I'll give it a go.
For now, I'm going to drop a tooth off the front, and see how that goes.
And maybe add a tooth on the back...
I'll see what I can get.

Yes, with stock gearing and windscreen a manual version pulls about 90 mph in 4th, 100 mph in 5th, and if level and no headwind about 105-107 in 6th.

 

[turbodieseli4i6]

NC700X torque and horsepower curves:

Isn't that for the European NCX? I believe the USA version has around 51 horsepower.

 

[670cc]

Isn't that for the European NCX? I believe the USA version has around 51 horsepower.

That chart was published by Cycle World in this article: Honda NC700X Road Test Review- Specifications- Photos | Cycle World

 

[dduelin]

Isn't that for the European NCX? I believe the USA version has around 51 horsepower.

That graph shows horsepower and torque delivered to the ground by the rear wheel. Indeed, the 6 speed manual US market engine tested in that review delivered about 51 hp at the crankshaft and by the time it got through the parasitic losses of the transmission and chain drive it measured about 48.

Variables like temperature, humidity, and atmospheric pressure affect horsepower and the dynometers used to measure output have quality and calibration variables as well. The same engine tested at different times on the same dyno will show small variations in output never mind when tested on different dynos. This is the horsepower graph for my US market NC700X DCT:

 

[tngw1500se]

If you make 6th like 5th now is you've also lowered first enough that it's pretty much useless except for technical off-road stuff... So, either way you have 5 gears that are actually useful (unless you are doing the afore-mentioned off-roading)

I'd agree. Wife had a CB300F and it was geared to low. First was a "granny gear". Went up one tooth on the front and 1st was more useful. With the factory sprocket you'd only get a few feet before you'd shift to 2nd.

I'd agree also that the NC700X may be geared a little high for most riders. Seems like Honda wanted the R's low to improve mileage. My wife just uses 4th and fifth like the OP said. Sixth just goes along for the ride most of the time.

You may be happy with the change if you do it but some riders will hate what it does to 1st.

 

[Deleted member 5383]

If I was lowering gearing for Captainbeaky's purpose I'd try to find a set of sprockets that put 6th about halfway between where 5th and 6th are at currently... Seems like the NC's great torque curve allows one to upshift earlier in many cases, and ride a gear higher than they would on a higher-revving machine. But I guess habits built during much riding of higher-revving machines are hard to break. I myself use 6th a lot and it's not like we don't have lots of steep grades here at the Continental Divide. Ironically most of my motorcycle riding before last summer was on a machine that likes to be ridden up to 10,000+ RPM, but I had no trouble finding the NC's sweet spots which are so different than that...

 

[showkey]

^^^^^^^^^^^^Which then morphs this thread into ........what rpm is too low cruising in 4th ,5th or 6th......when is lugging ( which has hashed and rehashed a few times.).

I also use 6th a lot at 55-65 mph range and on my ST at 55-65 often look for 6th which in NOT there.

 

[Captainbeaky]

Work has been hectic here - much more so than I expected - I've got a line of classic cars to work on - so I've been keeping busy, and haven't been able to do anything to the NC, other than ride it, put fuel in it and fit the standard exhaust back on it for the regulatory import inspection!

No complaints about being busy whatsoever!

The NC is keeping me very entertained - even with the quiet standard exhaust- it's a good bike, and handles the mixed terrain here very well. The "frunk" is a massive bonus too!

What Madeira lacks in square miles ( it's about 65 by 45 miles) , it makes up for in altitude ( about 6000feet from memory) and many roads are what can be best described as rural in nature, are extremely twisting and steep, often needing to drop down to first gear on a hairpin bend descent or ascent. A shorter second would help somewhat here.

Supermotards and motorcrosser style bikes are very popular. I'm looking forward to fixing the carb on my XR250 and getting out on it.

In the U.K, 6th was the "cruise along at 80mph" gear, and it was fine, but here, with a 90kph (55mph) top speed, 6th feels a bit unused, and shorter gearing is definitely going to be the way forward for the hills.

I've ordered a -1 tooth front sprocket, and will be getting it in the next "care package" from my mum ( she collates non-urgent parts shipments for me, and adds in little care packages of cakes, bacon etc into the spare space!) and will see how this goes ( along with two he new turbo hoses for my Smart ForTwo!) in the next few weeks.

Wish me luck.

Mike.

 

[Johny_me]

Hi guys

If I were you.. I would try a 45ish rear sprocket. 15 in the front could be to small and make the chain touch too much the swingarm.

By the way, I have the 750, I will change the front sprocket from 17 to 16 teeth. Does anyone know if the speed/velocity sensor (VS) from the 750x is different to the 700x? I it is, would be good to take care of the speedometer error that will increase with the sprocket change.

Enviado do meu ASUS_Z00ED através de Tapatalk

 

[Captainbeaky]

Update.

The care package from my mum arrived yesterday, while I was away at a customers garage.
(Carburettor rebuild on a lovely Jag XK140)

I had some admin to do today, but made time to fit the -1 tooth front sprocket.
Made by JT sprockets, it was well made, and fitted the output spline perfectly, and there was plenty of chain adjustment available to take up the slack.

I took the bike for a test ride - all seems well.

I'll be using it this week to commute to the workshop, as I have two new patients to crack on with while I wait for the XK140 carb parts.

The first is a nice XK120 fhc that simply needs some mechanical TLC - fix oil leaks, repair oil level gauge, fix wiper motor mount, fox brake squeal, service and tune up etc,.
The second is major rebuild of a Land Rover Defender 90 - a rare 50th anniversary - needs a new chassis, and I've got three months to do it.

We will see how the NC feels with the new gearing - I'm going to be working hard.

I'm loving the bike, but I have to admit that when I really press on, and go into all-out bonkers mode, the suspension and brakes start to fray a little, and show their price... The handling gets a bit tatty, I can feel the forks twisting under very heavy braking, and it gets a tad unstable if I crank it all the way up to 180kph on a long downhill stretch.

But - at the price I paid, I am certainly not complaining - it's a very entertaining and economical bike.

 

[rippin209]

I went from a 43 to a 41 on the rear sprocket to get more top end without revving so high. I'm thinking the next sprocket set I buy I'll go down to a 39 and see how that works.