Im new to Japanese bikes as well as classic bikes. I recently inherited a 82cb750k. This thing needs new rubber in the worst way. I was going to change the chain and sprockets while i was in the neighborhood. Whats baffling me is that i cant find anyone going at least -1+2 on their sprocket conversion. Is there a reason why? I wouldn't do it on my hd because the redline is only 6k. But with this being significantly higher why not gear it down for some more torque? Forgive me if my reasoning is wrong but it sounds like an easy way to get a little more grunt out of her down low. Has anyone done a 530 or a 520 with a 16/50 or is that even possible with these bikes?
noob who wants some cheap go fast with a sprocket conversion.
- Thread starter thaglyde
- Start date
I'd clean it and service it and fit new rubber and if the sprockets or chain are worn, check out what others are doing, but stock gearing isn't bad. You could go up one or two teeth at the rear if you wanted but it will rev higher on the freeway and that might become annoying after a while.
i guess after riding a harley with loud pipes im not too worried about the noise. I know with the power from this 750 im not expecting any rolling burnouts. would the higher highway revs affect anything other than noise and a loss of gas mileage? How many mpg does this thing get anyway. My touring harley gets about 35 and i guess im not expecting much more than that. Ill sacrifice a little gas for a little more fun.
joeyputt
The green flag sets me free
Welcome to the site Brother theglyde, when you say -1+2 are you saying down one on the front and adding two to the rear? Just as a basic rule when figuring gearing one tooth on the front equals roughly four teeth on the rear so dropping one tooth on the front would be the same gear ratio as if you added four to the rear however combined it would be the same as adding six teeth to the rear gear ratio wise.
For example lets say stock gearing has a 15 tooth gear on the front and a 60 tooth gear on the front...
A 15/60 set of gears would be a gear ratio of 4.00
Drop one in the front...14/60 would be a gear ratio of 4.29
Or add four to the rear...15/64 which would be a gear ratio of 4.27 which is roughly the same and shows how dropping one tooth on the front gear is roughly the same as adding four teeth to the rear gear.
Say we use the same stock gearing of 15/60 and your example of -1+2...
The -1+2 would be 14/62 whis is a gear ratio of 4.43
Now start with the same stock gearing of 15/60 and add 6 teeth to the rear which would be 15/66 and a gear ratio of 4.40 which shows that the -1+2 gearing would be roughly the same as adding six to the rear gear.
So either way you gear it you will accomplish the same basic gear ratio however they will not pull the same...a lot of new builders may think that a 4.00 gear is a 4.00 gear which is simply not true. There is a lot more to gearing than what I will write here but again as a basic rule dropping a tooth on the front gear or adding teeth to the rear will generally give you more pull on the bottom or out of a corner while adding teeth to the front gear or dropping teeth from the rear gear will generally give you more pull on the top end.
As Brother Teazer already mentioned the gearing that you have mentioned will raise your rpm's at highway speeds and the stock gearing on the 750 is pretty good and should be enjoyable compared to most Harley gearing.
I know that most of the members here already know this information however I have noticed that we have a lot of new first time builders joining so I thought I would write this information for those that will read this thread.
For example lets say stock gearing has a 15 tooth gear on the front and a 60 tooth gear on the front...
A 15/60 set of gears would be a gear ratio of 4.00
Drop one in the front...14/60 would be a gear ratio of 4.29
Or add four to the rear...15/64 which would be a gear ratio of 4.27 which is roughly the same and shows how dropping one tooth on the front gear is roughly the same as adding four teeth to the rear gear.
Say we use the same stock gearing of 15/60 and your example of -1+2...
The -1+2 would be 14/62 whis is a gear ratio of 4.43
Now start with the same stock gearing of 15/60 and add 6 teeth to the rear which would be 15/66 and a gear ratio of 4.40 which shows that the -1+2 gearing would be roughly the same as adding six to the rear gear.
So either way you gear it you will accomplish the same basic gear ratio however they will not pull the same...a lot of new builders may think that a 4.00 gear is a 4.00 gear which is simply not true. There is a lot more to gearing than what I will write here but again as a basic rule dropping a tooth on the front gear or adding teeth to the rear will generally give you more pull on the bottom or out of a corner while adding teeth to the front gear or dropping teeth from the rear gear will generally give you more pull on the top end.
As Brother Teazer already mentioned the gearing that you have mentioned will raise your rpm's at highway speeds and the stock gearing on the 750 is pretty good and should be enjoyable compared to most Harley gearing.
I know that most of the members here already know this information however I have noticed that we have a lot of new first time builders joining so I thought I would write this information for those that will read this thread.
Thanks Joey,
I think this is the understanding that I needed. I think I'm going to treat the cafe build like the harley build: "Just take my time and let it develop" When i first got my hog i threw so many parts at it, I didnt have a chance to decide what it needed or didnt need, what i liked or didnt like. Then i ended up with a stockpile in the garage that i just got rid of. I will make sure it runs solid then take my time. I wont do any major upgrades before consulting with the gurus and thinking about it one more time. I have to decide what i want and at this point all I see is cafe bike. I need to do more research before i start making rash decisions and actually looking like a noob out on the road like the guys who saw that colorful mohawk thing and had to have one. I bet the next one is going to come out in rainbow.
Anyway, thanks again Joey and the rest of the crew....
I think this is the understanding that I needed. I think I'm going to treat the cafe build like the harley build: "Just take my time and let it develop" When i first got my hog i threw so many parts at it, I didnt have a chance to decide what it needed or didnt need, what i liked or didnt like. Then i ended up with a stockpile in the garage that i just got rid of. I will make sure it runs solid then take my time. I wont do any major upgrades before consulting with the gurus and thinking about it one more time. I have to decide what i want and at this point all I see is cafe bike. I need to do more research before i start making rash decisions and actually looking like a noob out on the road like the guys who saw that colorful mohawk thing and had to have one. I bet the next one is going to come out in rainbow.
Anyway, thanks again Joey and the rest of the crew....
joeyputt
The green flag sets me free
You are welcome Brother and we are all happy to have you here with us! I like to play with gearing a lot too so I understand what you want to do, change it around and see what you like! Most of all do not let anyone influence what you want to do, it is your bike so build it how you want it and we will support you man!
you wont get any grunt out of it. its not a torquey V twin... its a 4 cylinder. Keep the gearing stock, learn to slip the clutch and keep the revs high, and it will move plenty fast. you need to learn to ride the bike, not try and make it perform like your harley.
and believe me, where the fun stops on your harley (around 5k rpm) the fun is just beginning on your 750. rolling burnouts? sure... just get the revs up first.
and believe me, where the fun stops on your harley (around 5k rpm) the fun is just beginning on your 750. rolling burnouts? sure... just get the revs up first.
I've never delved into gearing much (my BMW is a shaft) but on my XS650, the stock gearing is 17/34 I think, and I just dropped it to 17/30 to improve highway comfort (vibrates like a stripper on coke). Bottom end grunt is still OK - not as fast off the line as it was, but I can still get it going plenty fast enough around town.
Odd thing is my SR500's stock gearing is 17/44.
I haven't ridden it yet, but I just don't quite understand how one bike can be geared at 17/34 and another at 17/44 for similar purposes.
Odd thing is my SR500's stock gearing is 17/44.
I haven't ridden it yet, but I just don't quite understand how one bike can be geared at 17/34 and another at 17/44 for similar purposes.
crazypj
Split personality, I fake being smart
As Rocan said, depends on internal ratio's
XS650 has too low a primary ratio so transmission has to be able to cope with torque multiplication and is larger/heavier than it would need to be with higher primary ratio, ('removing dogs from second gear is well known 'feature'
)
High ratio primary reduces torque transmission has to cope with and you use larger rear sprocket for the torque multiplier
If your not drag racing second usually lasts OK (almost 28,000miles on my650, not much compared to the 106,000miles on my CB550)
I've managed to find a 31 t crank gear, now need to source a clutch gear to match it (the high ratio primary from Australia has a 32t crank gear, but, cost $500.00 last time I enquired about it, I can't remember the clutch gear size though : )
Anyway, ;D back to the question.
It aint a Harley, it's not underpowered too bad and not too overweight, 750 is a 'better' motor than 900, especially when it gets a big bore kit :-X .
What do you intend to use bike for?
If it's just posing round town and BS at the cafe/pub/bar, go for it, will accelerate faster than a scalded cat
If you plan any 'long distance' trips, t will be buzzy and probably not very nice to ride
XS650 has too low a primary ratio so transmission has to be able to cope with torque multiplication and is larger/heavier than it would need to be with higher primary ratio, ('removing dogs from second gear is well known 'feature'
)High ratio primary reduces torque transmission has to cope with and you use larger rear sprocket for the torque multiplier
If your not drag racing second usually lasts OK (almost 28,000miles on my650, not much compared to the 106,000miles on my CB550)
I've managed to find a 31 t crank gear, now need to source a clutch gear to match it (the high ratio primary from Australia has a 32t crank gear, but, cost $500.00 last time I enquired about it, I can't remember the clutch gear size though :
)Anyway, ;D back to the question.
It aint a Harley, it's not underpowered too bad and not too overweight, 750 is a 'better' motor than 900, especially when it gets a big bore kit :-X .
What do you intend to use bike for?
If it's just posing round town and BS at the cafe/pub/bar, go for it, will accelerate faster than a scalded cat
If you plan any 'long distance' trips, t will be buzzy and probably not very nice to ride
