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Discussion Starter #1 (Edited)
Hey everyone, I know this topic has been beaten to death, but something I havn't seen anyone suggest is changing the gears themselves in the transmission.

Would anyone be able to tell me if its possible to swap the actual gearsets in the transmission to get a lower 5th gear ratio? I thought maybe swap in a fourth gear set in with the input and output being reversed. This would give a 5th gear ratio of .858 instead of the .966 that comes from factory

The other thing is while I have seen that people say you cannot use the vstar 1100 or 1300 final drives, what about them does not work?
 

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Super Moderator "Loose Nut"
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The concept of your idea is great.. My question is what is the end results you are aiming for. While the 650 is a great bike, horse power will limit a 1.12% overdrive ratio you are suggesting. The cost of doing this swap would be high unless you had a donor bike. The 650 and 1100 engines have a higher cruise rpm than a lot of bikes due to their designed power band. With my 1100 I can cruise at 80 mph for hours without any issues. If you want a lower rpm cruising bike I suggest you get a larger bike. As far as final drives they are unique to each size bike. There are many 650 owners here and I'm sure they will chime in.
 

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I love the way my 650 cruises at 50 to 60mph. The bike feels like it would run forever at 55mph.

On the highway with the windshield on the bike at 80mph the throttle is really cranked. Pushing the RPMs lower at the same speed will give you less HP.

If you really want to ride the interstates look at a VS1300 or Roadstar size bike.
 

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Discussion Starter #4
I don't do a whole lot of highway driving, very little actually, just a short jaunt to work in the morning at 80km/h (posted limit, but we all know that isn't the speed I'm going :p)
The cost isn't a big deal, I have access to lots of wreckers and I'm sure I'd be able to find a ruined transmission, its just whether or not it'd be possible.

And as for the final drive, what makes them different? I did some searching and they appear to be the same, at least cosmetically. The four mounting bolts are in the same configuration and the shaft appears to be the same size. Is it the spline onto the wheel that differs? Or something else?
 

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Super Moderator "Loose Nut"
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And as for the final drive, what makes them different? I did some searching and they appear to be the same, at least cosmetically. The four mounting bolts are in the same configuration and the shaft appears to be the same size. Is it the spline onto the wheel that differs? Or something else?
The part numbers are all different, check web sites for oem parts. Manufacturers do use a lot of parts from one model to another, but part numbers stay the same. Here is a good link for part cross reference between the Vstar models, didn't see final drive but just about everything else is listed.

Fitment Chart
 

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Discussion Starter #6
The part numbers are all different, check web sites for oem parts. Manufacturers do use a lot of parts from one model to another, but part numbers stay the same. Here is a good link for part cross reference between the Vstar models, didn't see final drive but just about everything else is listed.

Fitment Chart
I get that the part numbers are different, but that only makes sense because the gear ratio is different. But if it mounts onto the frame without issue, and splines onto the wheel, I don't see why it wouldn't be a feasible option?
 

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If you have access to lots of wrecks I suggest taking a tape measure and micrometer to compare. If it's doable keep us informed. From my past experience at times the effort doesn't equal the results. That's why manufacturers make different models for sale.
 

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I get that the part numbers are different, but that only makes sense because the gear ratio is different. But if it mounts onto the frame without issue, and splines onto the wheel, I don't see why it wouldn't be a feasible option?
I highly doubt that the transmission components can be swapped over to a 650... it's transmission by design is smaller and lighter and doesn't have to be as beefy as the larger bikes to cope with the power and torque. I have yet to see any components swap so easily from one model to another and thats after decades of building frankenbikes. The one and only time I've seen such an easy swap is with the taller CB200 fifth cluster fitting into the CB175... but then they were basically the same motor/tranny.

Enjoy the 650 for what it is. It has a motor designed to be revved and will do so safely at greater than interstate speeds all day. If you want a low-revving road tractor then you should buy one.
 

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Look at the stock 650 HP curves on the website: https://www.pacificcoaststar.com/pcs/yamaha_dynos.htm

the stock engine produces 33HP at the tire from 5200 rpm to 6200 rpm, which is 75 to 89mph with the stock ratio in 5th gear.

If you put a higher gear ratio on 5th, you will shift that curve up (HP vs mph), giving you less HP in the jump between 4th gear and 5th.

To get the same acceleration between 55mph and 75, you would have to wind the bike out to its redline in 4th up ~70mph. Between 55mph and 70 you would be reving the hell out of the engine in 4th gear, so that you could have it spin a little slower in 5th gear. Every hill you hit you would have to kick it back down into 4th and hi-rev it again.
 
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