Question - changing sprockets

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Whilst I'm off Googling this, I thought I'd ask the learned forum members:

After reading an article recently on the R1, it’s been said that the first gear on my year (possibly before too) is very tall – I know for a fact it’ll do 102 as it hits the limiter; I found that out on an air strip by the way!

Said article listed one of the best improvements you could make to the bike is to change the front sprocket…

Whilst out on a group ride the other month, we were talking about modifications as you do and a friend of a friend said that by dropping a tooth at the front, you can up the revs, but keep the same speed; the sacrifice will come from losing top end speed. This sounded great, as I often have to feather the clutch for slow speed stuff, so if the revs are up, I can lose that chore!

I think this ties in with what I already read, and as front sprockets are fairly cheap, it seems like a pretty decent modification to try next – said FOAF also mentioned that by only changing the front, the existing chain can be re-used without having to remove links; just need to adjust the blocks again. Although he did say that changing the rear will result in a new chain, or removal (additon maybe) of links to the existing chain.

So OcUKers, might I trouble you for answers to these questions:

1. Will changing my front sprocket from the OEM 17 teeth to 16 help, if so how?
2. After making said change, will my existing 118 link chain be ok?

I understand that the speedo will be out, so I may invest in a speedo healer (how do they work by the way?) or at the very least get someone to pace me on a long straight road with sat nav and check the bike at 30, 40, 70 etc etc.

So yeah, answers, experience and pros/cons all welcome

 

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Thanks ShakenNstirred

From a few things I have just read, most people said they fit the OEM front sprocket from the 98-03 R1, as it has 16 teeth but also some rubber damping, which apparently reduces noise; can’t say I’ve ever noticed noise specifically from that area of the bike – the whole damn thing is noisy

As for the speedo, one guy said that after changing just the front on his 07 R1, the speedo was out by 13% - said it was out by 7% even before he’d started

 

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Cool, thanks

 

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General rule of thumb is go down a tooth on the front and up 2 teeth on the rear.

Aprilia RSV Mille gearing is 17/42 stock. I went up two teeth on the rear to a 44t Gold Renthal and was seriously amazed at the difference in grunt it afforded. It's a common mod. Then I went one tooth down on the front in combo with the 44t rear. Mindblowing.

It's like someone has bolted on an engine mod that gives another @50bhp. The difference is that noticeable. The RSV isn't exactly short of torque/low and mid range grunt from stock but the sprocket mods make it even better. Instant pickup in any gear for overtaking with instant power available on tap no matter where you are in the rev range. Mine now pops a wheelie with the slightest sniff of the throttle in 1st, 2nd and even 3rd gear easily. In short, best mod as far as "bang per buck" you can make. Drops off top speed a little but then again, who needs 175mph?. I'd rather have more urge in the "real world" on the road performance area.

As far as speedo accuracy, not sure about the R1 but Aprilia speedos are famous for being seriously accurate. Ape speedos take their pickup from a sensor at the rear which reads of the bolts on the rear disc in an optical kinda fashion. Very accurate although not particularly reliable. I've been through 3 speedo sensors since I have owned the bike. They seem to have quite a short lifespan for no reason at all.

So the -1 at the front will give me more revs for the same speed, what does the +2 at the rear do then; more torque?

I think if you have a speedo sensor on the wheel, as you do, then you don't have to worry about issues, as I understand it's when the sensor is at the engine.

 

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as most never use the top speed of there bikes
you may as well lower the gearing to give you better acceleration though the gears

Agreed, I wouldn't mind losing the top end, as I keep wanting to see what the limiter in 6th looks like (only saw an indicated 185 to date - but that's windy enough).

 

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I went 2 up on the rear of my GSXR 600 and loved it. Thing with that bike though and most 600s, is that they are revvy enough as they are so this takes that to the extreme and you have to shift even quicker. Great for a blast and power wheelies in second off crests, along with instant added pickup in any gear. However, it did get tedious cruising at a high speed with higher revs, especially on commutes where it kills economy even more. Yeah I know, nobody buys a sportsbike for mpg, but I'm just saying. To be honest if I did it again, I would probably go 1 up on the rear instead of 2. However, in the OPs position with an R1 I would totally go atleast either 2 up on the rear, or 1 down on the front. I wouldn't agree with the "general rule" being said to be 1 down plus 2 up, as that's a bit lairy tbh, especially on a mille! I know what you mean about the R1 and it's tall first. My mate used to get tired of riding his in traffic constantly feathering the clutch. I've ridden it and was amazed what speed/distance you are doing by the time you have simply let the clutch fully out. In a way it's nice to be able to go that fast lazily without changing gear, but as you know it's a bit wild with the torque of 1st gear, plus it can feel like you bog down compared to other stuff unless you slip the clutch.

So to summarise, yeah I would go 1 down on the front. You can re-use your chain, but think of it as a great time to replace it with an uprated one if it needs doing since it will all be apart. You will need a good chain breaking/joining tool. Worthwhile investment if you plan to do yours and your mates yourself form time to time. Got mine for about £30 I seem to recall off ebay actually. Be prepared if doing it yourself. Prep and take your time and be armed with correct and tight fitting socket for the front nut, preferably with a 6 sided impact socket and 2 foot breaker bar. I'm sure you can find a nice guide on an R1 forum but it's pretty easy if you have a good stand (I used to use an ABBA one and would recommend them) and use a good method to keep the rear wheel locked in place as you undo the front nut. i.e. get mate to apply brakes or my preferred one is to wedge something in between the wheel spoke and frame (without marking it).

The speedo will be affected. When I did mine I got a speedo healer and it was easy to adjust. I used your described method of satnav basically. I'd recommend you get it done rather than muck about guessing speeds. Put your mind at rest so you can enjoy it.

Don't get confused (you seem to be above?) that there is a different characteristic between front and rear sprocket mods. It's about the end result of the gearing in general. Does not matter which end you make alterations on. It's about altering the overall gearing. You'll notice it the instant you ride the bike having made the change. Where you used to need to kick down to overtake say (not that you would get that in an R1 much!) you can just roll on at the same speed as the revs will already be higher for the same given speed.

As for Aprilia speedos, I remember my RS125 speedo used to break on a monthly basis. I'd never buy an Aprilia again tbh! Parts were a nightmare to get hold of for me personally and they can be unreliable.

That’s an excellent reply jaybee, thank you Not that I’m saying the former weren’t mind you

It's a lot clearer from what has been posted in this thread, along with reading up elsewhere, I'm pretty keen on going -1 at the front and grabbing a speedo healer - a great mod (by the sounds of it) for about £100, not bad

I have a mate who’s a trained mechanic and has changed the sprockets on his K5 Gixxer 600, so has the tools to do it, and better still, a lovely Porsche main dealer’s workshop to use Failing that, he can bring his bits to mine and I’ll bump the bike onto the Abba stand (great stand by the way – got it for my Ninja before), then I’ll pay him in cash and beer tokens!

Ta muchly guys, been a right result

 

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I'd say the two best value mods you can do on a bike in my experience are sprocket change and a QAT (quick action throttle).

The latter has always crossed my mind, but it's rare I hit the stopper on the R1 - even at half throttle the thing is ballistic, and when I do hit the stopper and the YCCT decides to give the engine it's all; it's like Marty McFly hitting 88 mph

Scary ****!

 

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Thanks Flukester

My chain has done just over 12K now, still no problems with it, other than a little surface rust here and there.

 

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what year R1?

if its an early one the speedo drive may pick up off the front sprocket, if its a later fuel injected one i think there might be a sensor that picks up off the gearbox?

go down 1 on the front and you'll increase acceleration no end with a slight loss on top speed (but seriously where can you get to 150+ regularly!).

It's a 2007 model.

It would be nice on the TLGP not to have to feather the clutch all the time.... erm, I mean, commuting through town

 

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Thanks for the input everyone, I’ve ordered a 16 tooth front, was bidding on a speedo healer v4 on the bay, but it was heading towards almost new price money, so decided to just buy a new one – off to order that now

Looking forward to it now!

 

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Wel,, I did it, and here’s some random photos:

New sprocket

Old one in situ

Rear is looking ok

Most extreme work I've done before!

Speedohealer fitted

Bloody marvellous mod! The bike feels completely different now, more stable somehow, and far more comfortable around town now that I don’t have to feather the clutch so much, can even ride around town in third!

There were no air bases open to find out what the top speed was, but I do know that first gear has had about 20mph lopped off of it – does 85 now.

Only problem I have now is that the Acumen gear indicator doesn’t work, it wont learn the gears now for some reason, I’ve tried every combination under the tank – speed sensor > DG8 > SH > ECU and vice-versa, but it wont program Oh well, back to remembering what gear I’m in I suppose; did about 100 odd miles today and didn’t have many issues with 7th gear etc

 

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Not sure on that one Ghosteh, I'm guessing I'll have lost 20mph over all gears, but what it would be on yours..... ?