Change sprockets for more low end torque?

[pete]

Cool. I don't believe we ever got L's or T's over here, so to me they're rare beasties.

Mind you, I really would love to find a T seat pan still...

[djg42]

thanks everyone for the help! I ended up going 2 down in the fornt, and 2 up in the back-much faster now!

[pete]

Do you find yourself changing gears more often with that setup? Just curious...

[Flaming Chainsaws]

So this means quicker acceleration but less top speed?

[trackfiend]

I've been wondering about this for my 81 450E. Wondering what direction to go in if it's not trying to cruise highway speeds of 70-75? I don't want to hurt anything if I have to make an extended run down the highway.

[tkent02]

I've been wondering about this for my 81 450E. Wondering what direction to go in if it's not trying to cruise highway speeds of 70-75? I don't want to hurt anything if I have to make an extended run down the highway.

You won't hurt anything. These engines are made to spin.

[mighty13d]

You won't hurt anything.

Other than fuel consumption. But on an engine that small, it might be working less at a higher RPM at the same highway speed than it was at the lower RPM. Which would cause mileage to not suffer correct? I think I made that clear enough to be understood...



But going up 1 on back and down 2 on front will effectively be going up 7 in back.. that's a HUGE jump. Should really make it pull a lot harder from the lights and get up to speed a lot better. As was asked before though: How much more do you shift now?

[trackfiend]

Working on building the bike still so I have not rode it yet. Just worried about carrying high rpm's for extended rides at speed. Don't want to burn the motor up.

[tkent02]

Working on building the bike still so I have not rode it yet. Just worried about carrying high rpm's for extended rides at speed. Don't want to burn the motor up.

You can't burn up a stock 550 in good working order. It is one of the most bulletproof engines ever designed. It will last forever, no matter how hard you ride it. The key here is in good working order. If the valves are too tight, carburetion or timing wrong, etc. you can damage it, but not if everything is right.

Other than fuel consumption. But on an engine that small, it might be working less at a higher RPM at the same highway speed than it was at the lower RPM. Which would cause mileage to not suffer correct?

Chugging a 550 engine will not save gas, spinning it higher will not waste gas. It is a high RPM engine, it has big valves, short stroke, large bore, lots of carburetors, cam timing, lift and duration, intake and exhaust design and a lot of other factors are optimized for high RPM and power. The entire engine is designed that way. Max power for a given size. That's what sells bikes now, that what sold bikes in 1977. It runs most efficient at an RPM which allows the cam overlap and all these other factors to work. Running the engine slower is wasting gas, and hard on the engine.

It is not a tractor engine with no overlap, it does not have small valves and carburetor, it is not designed for maximum fuel efficiency at low power. If it was designed that way it would likely get 85mpg instead of 60 or so, it would be be slow as molasses, and they never would have sold very many...
Trying to run a small high performance motorcycle engine at low RPM is never going to work very well.

[mighty13d]

Chugging a 550 engine will not save gas, spinning it higher will not waste gas. It is a high RPM engine, it has big valves, short stroke, large bore, lots of carburetors, cam timing, lift and duration, intake and exhaust design and a lot of other factors are optimized for high RPM and power. The entire engine is designed that way. Max power for a given size. That's what sells bikes now, that what sold bikes in 1977. It runs most efficient at an RPM which allows the cam overlap and all these other factors to work. Running the engine slower is wasting gas, and hard on the engine.

It is not a tractor engine with no overlap, it does not have small valves and carburetor, it is not designed for maximum fuel efficiency at low power. If it was designed that way it would likely get 85mpg instead of 60 or so, it would be be slow as molasses, and they never would have sold very many...
Trying to run a small high performance motorcycle engine at low RPM is never going to work very well.

exactly what I was thinking but wanting verification!

[duaneage]

The L model probably has a 16 inch rear wheel and the others had an 18 or 17. The different gear compensates for what is a 1 -2 inch difference in wheel diameter.

If you can fit a larger diameter wheel on the bike you might be able to fiddle with the choices that presents. My yamaha came with a 16 but some xs400 bikes had 18 inch wheels. Same gearing on the rear but with a 15 tooth front, versus a 16 tooth. So dropping one in front gives a bigger change than 4 or more on the back.

I tried the 15 tooth on the xs400 and while the accelleration was spectacular, I actually overreved it in high gear a few times and topped out at 95. The vibration was a bit much, the change back to a 16 dropped the rpms about 1000 at 70 mph

So consider what your looking for and don't rule out going with stock gearing. They got it right for the most part when they chose the gears.

[djg42]

i do have to change gears more rapidly, I am out of 1st and into 2nd very quickly. It feels more intense/exciting riding with the new set up. If you dont like shifting and just want to cruise than maybe its not for you.
My 450L is a six speed, and I would say gearing it down 2 in front and 2 up in the rear eliminated the top gear-meaning driving on the highway in 6th gear revvs like 5th gear used to before i changed gears.
With that said, its awesome-im pleased with the results.

[ReTread]

You can't burn up a stock 550 in good working order. It is one of the most bulletproof engines ever designed. It will last forever, no matter how hard you ride it. The key here is in good working order. If the valves are too tight, carburetion or timing wrong, etc. you can damage it, but not if everything is right.



Chugging a 550 engine will not save gas, spinning it higher will not waste gas. It is a high RPM engine, it has big valves, short stroke, large bore, lots of carburetors, cam timing, lift and duration, intake and exhaust design and a lot of other factors are optimized for high RPM and power. The entire engine is designed that way. Max power for a given size. That's what sells bikes now, that what sold bikes in 1977. It runs most efficient at an RPM which allows the cam overlap and all these other factors to work. Running the engine slower is wasting gas, and hard on the engine.

It is not a tractor engine with no overlap, it does not have small valves and carburetor, it is not designed for maximum fuel efficiency at low power. If it was designed that way it would likely get 85mpg instead of 60 or so, it would be be slow as molasses, and they never would have sold very many...
Trying to run a small high performance motorcycle engine at low RPM is never going to work very well.

Years back I bought a Honda CB400F from a Honda mechanic.
He told me he used to race them back in the day. (Not the one I bought though, it was a garage find.)

I commented on the 10K redline and the guy says, "you do intend to ride this thing right"? "Go ahead and beat on it all you want because nothing is ever going to break".

I did. It did'nt. I still miss that little jewel too.

[Richharr]

my manual says

L=41
TX TXD 43
all others 45