should I or???

[roadstar06]

about to close this puppy up but need to know if I should do the 5th gear upgrade?? I bought a 32 tooth rear sprocket, is that enough or should I also do the upgrade to keep the rpm down on hwy?? I live in Jersey so its alot of 65mph and more.thanks... sorry if this is a double post, I thought i posted same q/ earlier but i cant find it

 

[gggGary]

Your info is sparse get the gearing too high and you'll be downshifting for every little bump and hill on the road.

 

[roadstar06]

Your info is sparse get the gearing too high and you'll be downshifting for every little bump and hill on the road.

very flay where i ride, I just don't want this thing screaming in 5th when i'm only doing 50-55 mph, also if someone can tell me since motor is already open when I turn star for shifter how easy or hard should it feel?? mine is inbetween it shifts but need a pliers to turn star, I can turn with fingers but alittle tough, thinking I should hit it with some oil as they arent super lubed up..

 

[gggGary]

They shift hard when the gears aren't turning. I run 60-70 all day with stock gearing. (17-34) You might be better with a 33 or 34 and the overdrive 5th but then a few have had issues with that gear.

 

[weekendrider]

I run 60-70 all day with stock gearing.

Ya know there are two others gears beyond third gggGary

 

[nj1639]

I'm beginning to think that the Yamaha engineers just may have known what they where doing.
I've been running 17/32 or 18/34 gearing for quite some time on my primary bikes. Yes, a little more clutch play starting out in first but rarely get over 4k rpm in 5th gear. From what I've read on the forum is that the slides on these carbs don't even start to lift until 4k, and max fuel efficiency is achieved after the slides come in to play.

Like Gary said, a lot of shifting with the 17/32.

I just got the '78 roadworthy with stock gearing 17/34. What a rip! I find that there's a lot less shifting and great throttle response from 2500 rpm to 4k rpm in 5th gear.......less shifting. Now, when I get her tagged and out on the highway screaming in 5th I may rethink about those engineers........lol

 

[azman857]

I run 17/32 and the OD 5th. I'm no lightweight either at 260lb. I'm not sure when I'm running 65 or higher because my speedo goes nuts and shows slower speeds the faster I go. I'm not sure of the tach either. It shows around 4k when I'm on the Hiway. I'm pleased with my build.

 

[peanut]

I'm beginning to think that the Yamaha engineers just may have known what they where doing.

I just got the '78 roadworthy with stock gearing 17/34. What a rip! I find that there's a lot less shifting and great throttle response from 2500 rpm to 4k rpm in 5th gear.......less shifting. Now, when I get her tagged and out on the highway screaming in 5th I may rethink about those engineers........lol

very good point nj1639 ..

The stock bikes were tested and set up to run at optimum with everything in combination ...fuel /air delivery ,compression,timing ,ignition, weight, wheel sizes etc .....
To take just one aspect, the gearing and change that substantially is bound to have a considerable influence on how the bike performs as a whole.

Having a 5th gear is a great option to reduce the gear ratio slightly for crusing but fitting a smaller rear sprocket and altering the gear ratios right across a 5 speed box is bound to impact performance against headwinds up hills and 2x up etc .

PamcoPete produced a nifty gear ratio calculator somewhere on here which will give you plenty of 'what if I changed that' scenarios to see if what you have in mind is feasible.

http://www.xs650.com/forum/showthread.php?t=43240&highlight=gear+ratio

ROADSTAR you might find this thread of interest.
I used Pamcopetes gear ratio calculator to guage whether it was worth fitting a 5th gear and found it only gave a rev reduction of 180 rpm (speed reduction of 2.5mph !) I concluded it wasn't worth the cost.
http://www.xs650.com/forum/showthread.php?t=28016&highlight=gear+ratio