sprockets

[HarryHornby]

As some of you know from a thread further down the page I had my chain and sprockets changed last week, since then I've noticed that I don't have the same insane accelleration in lower gears that I had before and that where 70mph was always 6000 rpm it's now 5500 rpm.
 
I'm assuming that the bike has had either a bigger front sprocket, bigger rear or both fitted.  I've spoken the the garage that did the work and they said they just took the old ones off and put news ones on and didn't compare.  The chain is a DID chain and the sprockets are not Yamaha, just ones my local garage picked for the bike, when I spoke to them I asked if they were the correct ones for my bike and they said yes (I see no reason why they would lie) They did offer to change them if there was a problem.
 
I'm guessing that the sprockets they took off we not correct and were geared lower.
 
Should I be concerned?  It's a shame I'm not as quick when it comes to nipping round vehicles but I'm hardly slow.
 
Could this sprocket change affect anything else on the bike?
 
Is 5500rpm what everyone elses' bike is doing (using standard sprocket) at 70mph?
 
Cheers

[His Dudeness]

the number of teeth that the new sprokets have should be stamped on them or just count them. i think the standard ones have 15 on the front and 48 on the rear.

[Tefer]

As some of you know from a thread further down the page I had my chain and sprockets changed last week, since then I've noticed that I don't have the same insane accelleration in lower gears that I had before and that where 70mph was always 6000 rpm it's now 5500 rpm.
 
I'm assuming that the bike has had either a bigger front sprocket, bigger rear or both fitted.  I've spoken the the garage that did the work and they said they just took the old ones off and put news ones on and didn't compare.  The chain is a DID chain and the sprockets are not Yamaha, just ones my local garage picked for the bike, when I spoke to them I asked if they were the correct ones for my bike and they said yes (I see no reason why they would lie) They did offer to change them if there was a problem.
 
I'm guessing that the sprockets they took off we not correct and were geared lower.
 
Should I be concerned?  It's a shame I'm not as quick when it comes to nipping round vehicles but I'm hardly slow.
 
Could this sprocket change affect anything else on the bike?
 
Is 5500rpm what everyone elses' bike is doing (using standard sprocket) at 70mph?
 
Cheers

5500rpm, what gear?

[limax2]

It looks to me like your bike has higher gearing than standard. (Assuming this is your FZS600 and obviously top gear). The standard sprockets, as said before, are indeed 15 front and 48 rear. A larger front and/or a smaller back sprocket would give higher gearing. i.e. lower revs for a given speed.
On my FZS600 with standard gearing I think the revs are just over 6000.

[limax2]

Further to my earlier reply a calculation shows that standard gearing would give 5,500 r.p.m at 68.8 m.p.h. which with a bit of speedo error means it could be showing 70 m.p.h. Maybe your bike had lower gearing on before. The only way to be sure is to count the number of teeth on the sprokets.
Next time the sun shines  and I'm out on the bike I must take note of what mine does show?

[Andy]

I changed my sprockets and chain today and the sprockets were replaced with same, luckily the mental acceleration and top end is there still.

[Dead Eye]

I think mine may have lower gearing based on what you guys have said - 70MPH for me is at least 6,000RPM

Im heading out today so i'll check back. I have to do some work on the chain / sprockets anyways (see my other thread) so i'll check the teeth numbers then

[Captain Haddock]

I have '98 600 on standard gearing and had 60mph at 5000rpm and 70mph just under 6000rpm this afternoon, I counted the sprocket teeth just after buying it to see if it had been messed with.

[Dead Eye]

70MPH was basically 5900RPM for me - didnt get round to checking out the teeth on the sprockets though im afraid but have no reason to suspect they arent default

[limax2]

Well the sun was out on Saturday and I had a great ride to Hartside cafe for lunch. More to the point with standard gearing at 70 mph the revs were showing just under 6k, I would guess at 5,900.
Looks like we have general agreement on that figure.

[born to be mild]

Definately standard gearing , am I the only one then who forgets if hes in top or not and have to look at the tacho and speedo, 5k on the tacho is 60 mph and say, 6k on the tacho is 70 mph in top gear.  One of these days I'll end up in a ditch.

[HarryHornby]

Thanks for all the comments, I had a look this weekend when I was checking the bike over and I have 16 on the front and 49 on the rear, looks like it's not a standard sprocket set.  This would explain the slower acceleration.
 
The bike is still quick, but it's not hold on tight and grin quick, I'm in 2 minds about asking the garage to put standard ones on (which I thought they would have done in the first place).  It's not the end of the world and the bike is still quick, it's just a case of do I want the hastle of changing for the big grin......

[born to be mild]

They are geared that way at the factory for a reason, unless you plan to spend a lot of time on German autobahns or something I'd get the garage to put the right ones on. Bear in mind that you might find yourself overtaking at some point in the future and wishing you had the original power, equally you are going to have to change down more for bends etc.

[HarryHornby]

I agree "BTBM" I commute everyday and I do miss the power to blast round traffic, I'd rather have a quick bottom end than a quicker top end, I have my moments of going quick in a straight line but I use the quick acceleration of the bike a lot more than I do top end speed.
 
Just phoned the garage and they are going to "look into it", I don't think he was best pleased I was complaining but at the end of the day I asked them to fit chain and sprockets and I don't think it's wrong to expect the correct ones to be fitted.

[Andy]

16 and 49, I would go mad at them mate. You pay for the correct job and expect it to be done to correct spec.

[limax2]

Definately standard gearing , am I the only one then who forgets if hes in top or not and have to look at the tacho and speedo, 5k on the tacho is 60 mph and say, 6k on the tacho is 70 mph in top gear.  One of these days I'll end up in a ditch.

Many is the time when I've been in top and gone for another gear. Usually happens after toddling along in a 40 zone and then joining the motorway. After being at low revs for a while it then feels like the engine is reving to much for the speed.
 A couple of times I have gone the other way and found myself happily cruising down the motorway in 5th gear for a mile or two before realising it.

[Dead Eye]

Definately standard gearing , am I the only one then who forgets if hes in top or not and have to look at the tacho and speedo, 5k on the tacho is 60 mph and say, 6k on the tacho is 70 mph in top gear.  One of these days I'll end up in a ditch.

Im exactly the same, always end up forgetting which gear im in - end up just clicking up until I cant anymore :p

Back on topic though, im going to see if I can get round to attempting to wire in both headlights on mine. Hopefully today though if not perhaps sometime this week

[HarryHornby]

Bike shop are ordering in 15 front and 48 rear, will fit ASAP.