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TwoJugs
Excess XS
I feel that it might be easier to change the front sproket than the rear? You can go 18T max and keep your clearance against the motor case. Not sure at what point you need to ad links to the chain? Your tire selection will govern your final drive ratio more then the rim size if you vary from stock tires. Overall diameter is the factor, not rim size. Taller tires cover more ground.
^If you go to an 18 front it makes a tight fit for the chain between the sprocket and the shift shaft guard. In fact some have said you have to leave the guard off. Not worth it since you can get a same result for all practical purposes just messing with the rear.
Size of the wheel has nothing to do with chain length. A 104 link chain, (standard for 17/34 sprockets), should be able to be used for a reduction of 2 teeth, (32 tooth sprocket), on the rear and an increase of 2 teeth, (36 tooth sprocket), on the rear
have a look at Petes gear chart and compare the difference between a 17T and an 18T sprocket at 70mph
Alternatively read through this this thread where the options of changing the front sprocket are discussed and you'll see why it isn't an option .
I was talking about tyre clearance
I'd like to see you replace a 16" wheel with an 18" wheel and retain the same chain.
Look the op asked for advice regarding decreasing the rpm at 70mph and 75mph on a trip up CA on the freeway .
He doesn't need to change his bluddy wheel
or his front sprocket or his chain unless they are worn. All he needs to do is a simple quick cheap and totally effective change of his rear sprocket to reduce the revs from 5000+rpm down to a more comfortable 4300rpm or similar.You might find cruising at 5000rpm comfortable on a 35 year old twin but most of the rest of us wouldn't if there was a cheap alternative
I was talking about tyre clearance
I'd like to see you replace a 16" wheel with an 18" wheel and retain the same chain.
Look the op asked for advice regarding decreasing the rpm at 70mph and 75mph on a trip up CA on the freeway .
He doesn't need to change his bluddy wheel
You might find cruising at 5000rpm comfortable on a 35 year old twin but most of the rest of us wouldn't if there was a cheap alternative
By Petes chart the 18" rear is 3"/75mm longer along the ground than the 16", this is with the normal tyre that is recommended for those wheels. I have just measured the diameter of the 16" and 18" respectively and the 18" wheel is about 10mm bigger than the 16".
Swapping the sprocket from a 16" to an 18" and installing the wheel will retain the same chain. Just think of the distance from the axle to the outside of the sprocket and that doesn't change what ever size wheel is installed.
If using a standard 104 link chain (with a 34 tooth sprocket), then the same chain can be used with a 32/33/34/35/36 tooth rear sprocket without adding or subtracting any links
cafeguy
XS650 Enthusiast
also my bike has 23000 miles on it, never given me a problem, would you guys recoment taking a bike with that many miles across California?
From what I have found, at 55-60 mph, one tooth off the rear drops engine rpms about 100 rpms.
Adding one tooth to the front drops the engine rpms about 200 rpms.
As far as what I run I like the 17F/32R sprockets. Drops rpms about 200 at highway speeds and you don't lose too much low speed acceleration.
As far as vibrations at speed, proper engine and carb tuning works wonders. Properly trued wheels, good tires, and using Dyna Beads to balance, eliminates most of the vibes. Tires more than 5 or 6 years old are bad tires.
A good set of grips, not 30 plus year old hard rubber, new ones with a soft spongy feel. These absorb much of the vibration in the bars. Adding weight to the bar ends helps.
A good seat, the 30 plus year old foam in that old stock seat has seen better days.
Proper tuning of the suspension helps.
Leo
Adding one tooth to the front drops the engine rpms about 200 rpms.
As far as what I run I like the 17F/32R sprockets. Drops rpms about 200 at highway speeds and you don't lose too much low speed acceleration.
As far as vibrations at speed, proper engine and carb tuning works wonders. Properly trued wheels, good tires, and using Dyna Beads to balance, eliminates most of the vibes. Tires more than 5 or 6 years old are bad tires.
A good set of grips, not 30 plus year old hard rubber, new ones with a soft spongy feel. These absorb much of the vibration in the bars. Adding weight to the bar ends helps.
A good seat, the 30 plus year old foam in that old stock seat has seen better days.
Proper tuning of the suspension helps.
Leo
If the bike has been well maintained, serviced and tuned then it shouldn't be any problem.
Also depends on how long the bike has been in your possession, if not for long then regular servicing and general maintenance could have been lax in the past.
I have looked at your postings on here and there is no info about the bike to be able to get a good reading on it to be able to give an answer that would be informative and relevant to you and your bike.
At best i get the feeling that the bike is a recent purchase so any information given relating to the condition of the bike, (in the post at the top it sounds like you have had the bike from new and done the 23000mls), is conditional on a guess at best.
cafeguy
XS650 Enthusiast
have had the bike for three months now, bought it with 22,000 miles, and actually i did have an issue that only happened once, i was in fifth gear and it seemed to pop out for a second and then go back in?
That's not high mileage.
To put things in perspective, your grandpa did better, and without a cell phone. And if something goes wrong here it's an inconvenience at worst. At best an adventurous learning experience. Years ago my car broke down and the mechanic who towed it to his shop loaned me his personal truck for three days. Three speed on the column. Hard son of a bitch to drive.
