rebuild gear selector box

[flynbulldog]

I trust that you first took note of the flywheel's preexisting timing-position, prior to it's removal from it's place on the crankshaft ?

Uhhh, nope.

(total loss system) Why, exactly ?

Weight, I suppose. lower rotating mass. The other guys who race with me are running their bikes that way and I guess they assumed I would be too.
Who am I to argue? Do you have another suggestion?

[DewCatTea-Bob]

" Uhhh, nope. "

____ So then had you assumed that it could simply be reinstalled randomly-attched, later ?


" Weight, I suppose. lower rotating mass. The other guys who race with me are running their bikes that way and I guess they assumed I would be too. "
Do you have another suggestion? "

____ I didn't realize that you were intending it for racing purposes. _ I guess that's fine for short-time race-periods.
I-myself can't justify any weight advantages in trading-off the heavy rotor for a heavy battery ! _ It dosen't make much since, especially when it's realized that a total-loss system produces weaker & weaker ign.sparks as the racing continues-onward, and a good/heathy spark could likely be of more use (towards winning a race) than any slight advantage which a ever so slightly lighter race-machine may provide !
It seems contradictory to build-up a race-motor with hot-running parts for obtaining higher performance, and then depend on a compromised ign.spark (with a total-loss system), yet then also still expect to have the engine running as a 'high-performace' machine.
The proponents of the 'total-loss' type ign.power-system can just call me 'nuts', I guess.


Dukaddy-DUKEs,
-Bob

[flynbulldog]

So then had you assumed that it could simply be reinstalled randomly-attched, later ?

No, I assumed it would not be reinstalled in this engine.

I didn't realize that you were intending it for racing purposes. _ I guess that's fine for short-time race-periods.
I-myself can't justify any weight advantages in trading-off the heavy rotor for a heavy battery ! _ It dosen't make much since, especially when it's realized that a total-loss system produces weaker & weaker ign.sparks as the racing continues-onward, and a good/heathy spark could likely be of more use (towards winning a race) than any slight advantage which a ever so slightly lighter race-machine may provide !
It seems contradictory to build-up a race-motor with hot-running parts for obtaining higher performance, and then depend on a compromised ign.spark (with a total-loss system), yet then also still expect to have the engine running as a 'high-performace' machine.
The proponents of the 'total-loss' type ign.power-system can just call me 'nuts', I guess.

It's not for over-all weight reduction, it's for lower rotating mass within the engine. I've also shaved and drilled the clutch basket and several internal gears all in the name of lower rotating mass.
There are several lithium A123 batteries that will run all day long with no reduction in output and they weigh about half of the weight of an acid or gel battery.

The engine will be running a 12.5 :1 Aries piston, an expertly ported head with ti valves, a massive megacycle cam, modern coil valve springs, roller rockers and more.
All of these mods have been tested on the track for many years and have proven to work quite well. Below are photos of the bikes that are running these build specs now.

I'm still open to a better way.

[Eldert]

more weight saving :

viewtopic.php?f=3&t=820

Eldert

[Rick]

I'd like to see a picture or supplier for your roller rocker arms- the valve tip end looks practical, but the rocker arm surface contacting the cam changes- hard to picture how a roller would work. Do you use a cam redesigned for the roller rocker?
Rick

[flynbulldog]

I'd like to see a picture or supplier for your roller rocker arms- the valve tip end looks practical, but the rocker arm surface contacting the cam changes- hard to picture how a roller would work. Do you use a cam redesigned for the roller rocker?
Rick

I should have qualified that, We replaced the rocker shaft bushing with needle roller bearings - the rocker is stock.

[DewCatTea-Bob]

By: flynbulldog...
" No, I assumed it would not be reinstalled in this engine. "

____ Well whatever engine it may end-up in, the rotor will need to be 'timed' to the crankshaft, and now it seems you've lost track of the originally done factory-set timing.


" It's not for over-all weight reduction, it's for lower rotating mass within the engine. "

____ Well of-course that reduction will make a somewhat noticeable RPM climb-rate while the motor is in neutral but, in 2nd.gear & higher, I'm quite sure that no obvious improvement in accellertion could be realized,, in fact, I'd have to see a side-by-side comparison (with the race-bikes of-course otherwise equal), to convince me that there's any worthwhile improvement even in 1st.


" There are several lithium A123 batteries that will run all day long with no reduction in output and they weigh about half of the weight of an acid or gel battery. "

____ Wow, I must've finally made it into the future,, it seems I've been ignorant of any such modern batteries.
Please excuse my dated-knowledge.


" The engine will be running
an expertly ported head
modern coil valve springs, "

____ Have you ever been made aware that such a combo of mods often leads to cracks in the head (around & under the coil-spring) ?


Dukaddy-DUKEs,
-Bob

[DewCatTea-Bob]

" We replaced the rocker shaft bushing with needle roller bearings "

____ I had sets of the 10x13x13mm caged needle-bearings installed in my-own race-engine since 1969 !
I've heard-tail that the needle-bearings ought not be so employed (in place of the stock bushings) unless the rocker-shaft/pins are first hardened. _ However I-myself never ran-into any consequences with those shaft/pins left as stock.


Hopeful-Cheers,
-Bob

[flynbulldog]

Have you ever been made aware that such a combo of mods often leads to cracks in the head (around & under the coil-spring) ?

I've seen the cycle world article from the 60's but that head was pretty severely over ported.
Like I said, all of these mods have been tested for years on bikes that are currently being raced. I think I'm in pretty good hands.

[Asphalt]

" Maybe some good mods? "

____I found such weaker coil-springs (otherwise just like stock), at a local spring-manufacturer, but before that, I'd simply cut-off a length of the stock-coil (making it a little shorter & weaker).

Dukaddy-DUKEs,
-Bob

This is my first post and it is not my intention to gain a reputation for being contrary but I have a question regarding tihs statement. But it is my understanding that when you cut a coil off a spring you make it stiffer. For instance when you cut a length out of a fork spring you make it firmer, not softer. If this is incorrect please enlighten me.