rear sprocket sport fit?

[Petrolhead]

Hi, will a sprocket from a tour fit the sport as there do not seem to be any sprocket kits in 15/43 for the sport.

I had my first ride out on the sport yesterday and it had difficulty pulling the top gear without snatching below 50mph. As I tend to ride in the mid 50,s on bends to the low 60,s on the straights I was thinking of lowering the gearing slightly to make it more lively....

[droy]

Sprocket will fit but your chain may need to be lengthen/shorted or adjusted depending on the number of teeth (sprocket diameter).

Lots of discussions on Bill's blog on sprocket gearing.

[Petrolhead]

Thanks, that fits in what Grahams shop said, they advocated getting a one tooth smaller front sprocket and with that I would not need to get another chain, just take up the extra on the tensioner....cheers

[DAVID THOMPSON]

15 is hard on the output shaft 16 on front and bigger on rear makes front last longer
dave

[Petrolhead]

Dave and others, would it be better to go for 15/43 or 16/45?

I want to cruise in top with no judder and pulling well from 45 to 60 in top? I'll be touching 60 for short periods, the B roads here are twisty with adverse camber!

Thanks for the help so far

[breakwellmz]

15 is hard on the output shaft 16 on front and bigger on rear makes front last longer
dave

I seen it mentioned several times that the smaller sprocket should be avoided for this reason.If so, why do Yamaha in their wisdom produce a sprocket this size?

[mincehead]

Yamaha care not, they`re just reacting to requests from dealers and owners. The least angle a chain runs at between sprockets, the longer it will last and the less load is applied to bearings.

[netguz]

I seen it mentioned several times that the smaller sprocket should be avoided for this reason.If so, why do Yamaha in their wisdom produce a sprocket this size?

Yamaha care not, they`re just reacting to requests from dealers and owners.

Many Raptor 660 owners use a 14 tooth sprocket, It may not be our motor but it's similar. Yamaha aren't stupid and if fitting smaller front sprockets caused breakage don't you think the Yam Forums would be full of complaints and that some enterprising young lawyer would have launched a Class Action by now?

Smaller sprockets are safe - not that I'd fit one.

15 is hard on the output shaft 16 on front and bigger on rear makes front last longer
dave

The least angle a chain runs at between sprockets, the longer it will last and the less load is applied to bearings.

I quite agree, it's just Maths. That's still not why I wouldn't use a smaller front sprocket.

Around about 3,700 rpm I, and I believe many others get chain rattle. If I fitted a smaller front sprocket then the chain would be even closer to the swinging arm ....

So, would I fit a larger rear sprocket - no.

In beautifully rural Dorset I spend a lot of my time on the backroads, B, C, and D roads - love 'em. But when I'm going somewhere, I use A and M roads, and on those M roads - or M ways - top is wonderful. Why lower the gearing, making first unusable, when I can enjoy myself in 3rd and 4th and change in to top when I need to get somewhere quick.

Being in top isn't important - being in the right gear is.

Right, back to the Cricket.

[Petrolhead]

Netguz I am sure you are right that it is important to get into the right gear for the situation ( as per Institute of Advanced Motorists best practice) but for me cruising with the engine revving in 4th is a no no. I want the engine to be in its quiet sweet spot currently at 65mph , lowered to about 56-8 mph. That way I'd feel happier riding it without dishing out rev happy abuse to my motor. Its a long termer with 2464 kms on the clock.

So 15/39 simply divided gives a ratio of 0.3846 - Sport standard sprockets
and 14/39 gives a ratio of 0.3589 - Sport smaller front
and 15/43 gives a ratio of 0.3488 - Traveller sprocket sizes.

Methinks I should go for the Traveller set up although just replacing just the front is the cheapest way.

[netguz]

I think I'm on standard Tour gearing and 4000rpm in 4th is about 55mph and 65ish in top, right in the sweet zone. Perhaps I'd best count some sprocket teeth to confirm.

Jon

[Petrolhead]

Netguz, I'd love to ride the lanes in sunny Dorset/Somerset but made to move to bare and often bleak Scotland in the north for the quiet life, few people and a laid back peaceful atmosphere. Would give a lot for your weather in summer, often cool and rainy here. Just the 5 degrees extra would help!

I've just bought a DID VX chain and afam sprocket kit with 15/43 Tour/Traveller gearing, my existing Sport gearing is 15/39......hope that will help in solving it.....BTW thanks a lot for the info

[netguz]

DAMN, DAMN, damn, damn ..... grrrr ....

Wandering down to La Tour this morning to give her a much needed clean, I thought - I must check on the gearing .... bloody short term memory ....

Netguz, I'd love to ride the lanes in sunny Dorset/Somerset but made to move to bare and often bleak Scotland in the north for the quiet life, few people and a laid back peaceful atmosphere. Would give a lot for your weather in summer, often cool and rainy here. Just the 5 degrees extra would help!

Tis nice down here, but one day I'd love to ride in Scotland, so much to see, so much to do.

I've just bought a DID VX chain and afam sprocket kit with 15/43 Tour/Traveller gearing, my existing Sport gearing is 15/39......hope that will help in solving it.....BTW thanks a lot for the info

While you've got it apart check the sprocket carrier bearings, cuz just a small bit of damage lets in the water leading to failure. Good luck.

Jon

[billr]

In beautifully rural Dorset I spend a lot of my time on the backroads, B, C, and D roads - love 'em. But when I'm going somewhere, I use A and M roads, and on those M roads - or M ways - top is wonderful. Why lower the gearing, making first unusable, when I can enjoy myself in 3rd and 4th and change in to top when I need to get somewhere quick.
Being in top isn't important - being in the right gear is.

Right, back to the Cricket.

2001 Traveller, 15 x 39
X2 on stirring the gearbox as needed. I commute on surburban streets, mostly 45 mph, 30-55 over the whole trip.
Appox 3.5-4k rpm, pick the gear for the speed limit.
If anything, I wish 1st was just a bit taller.

Bill R

PS: Hi, Jon!!

[netguz]

Hi Bill

I finally remembered to check 15 39.