4t tuning thread

[TZ350]

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As well as valve lift, valve train acceleration and velocity are important design considerations.

http://www.google.co.nz/imgres?imgur...ed=0CBsQ9QEwBg

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[richban]

now why do that when you can fit a bigger carb and get more air flow all over ?????

Bad throttle response.

I am hoping that it will just open up a little at full throttle. It makes good power as it is, just playing really. I have designed the next engine for the bucket and it will be completely different to this one. Sleeved down and stroked up, short track torque.

[TZ350]

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4-Strokes

One.......... 0 - 180 Deg is the Power Stroke
Two...... 180 - 360 Deg is the Exhaust Stroke
Three.....360 - 540 Deg is the Induction Stroke
Four.......540 - 720 Deg is the Compression Stroke

4-Strokes = two revolutions of the crank, or 2 X 360 deg = 720 deg of crank rotation. The cam rotates at half the crankshaft speed.

Exhaust pipe tuning works in the “Over Lap” period just before 360 degrees, also the resonant tuned length of the inlet tract is arranged so a high-pressure pulse arrives at the back of the inlet valve, just as the inlet is opening. This helps in overcoming the inertia of the gas column, which is stationary in the inlet tract and gets it moving again.

The closing point of the inlet valve after 540 degrees is timed to close as the inertial driven flow of the now rapidly moving gas column in the inlet tract is being brought to a stop by the ascending piston and before any backflow occurs, thereby trapping the maximum amount of air in the cylinder. This over filling or supercharging of the cylinder can be quite high 20-25%.

The timing of the closing point of the inlet valve is critical to good performance.......

So when you go to buy that new superduper cam, not only do you have to check piston valve clearances to see if its going to bang the inlet valve into the piston or if its ramp profile is so savage that the exhaust valve will be left floating and get smacked by the piston, or tangled up with the inlet valve as it opens, there are a few timing things to think about too......

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[richban]

.

4-Strokes

One.......... 0 - 180 Deg is the Power Stroke
Two...... 180 - 360 Deg is the Exhaust Stroke
Three.....360 - 540 Deg is the Induction Stroke
Four.......540 - 720 Deg is the Compression Stroke

4-Strokes = two revolutions of the crank, or 2 X 360 deg = 720 deg of crank rotation. The cam rotates at half the crankshaft speed.

Exhaust pipe tuning works in the “Over Lap” period just before 360 degrees, also the resonant tuned length of the inlet tract is arranged so a high-pressure pulse arrives at the back of the inlet valve, just as the inlet is opening. This helps in overcoming the inertia of the gas column, which is stationary in the inlet tract and gets it moving again.

The closing point of the inlet valve after 540 degrees is timed to close as the inertial driven flow of the now rapidly moving gas column in the inlet tract is being brought to a stop by the ascending piston and before any backflow occurs, thereby trapping the maximum amount of air in the cylinder. This over filling or supercharging of the cylinder can be quite high 20-25%.

The timing of the closing point of the inlet valve is critical to good performance.......

So when you go to buy that new superduper cam, not only do you have to check piston valve clearances to see if its going to bang the inlet valve into the piston or if its ramp profile is so savage that the exhaust valve will be left floating and get smacked by the piston, or tangled up with the inlet valve as it opens, there are a few timing things to think about too......

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That's why designing an engine on paper first is the best way to go.

[bucketracer]

That's why designing an engine on paper first is the best way to go.

Hi Rich, TeeZee, I am not sure 4-stroke theory is the point of this thread, where do we buy hot up bits?

[SS90]

Now Teezee, get back to your blinged out GP125R...... the time you have spent researching and typing that useful info could have been better spent fiiting Cubic Zarconium plated fork tubes, or ruby clustered triple clamps.

I eagerly await your new dyno graphs!


And Speedpro's actually!

[richban]

Hi Rich, TeeZee, I am not sure 4-stroke theory is the point of this thread, where do we buy hot up bits?

Yes true, I will find a nice website with lots of shiny expensive stuff and post that soon.

[richban]

Now Teezee, get back to your blinged out GP125R...... the time you have spent researching and typing that useful info could have been better spent fiiting Cubic Zarconium plated fork tubes, or ruby clustered triple clamps.

I eagerly await your new dyno graphs!


And Speedpro's actually!

Don't listen to him. I am sure there is room for an ESE 4 stroke you know you want to.

[richban]

Now Teezee, get back to your blinged out GP125R...... the time you have spent researching and typing that useful info could have been better spent fiiting Cubic Zarconium plated fork tubes, or ruby clustered triple clamps.

I eagerly await your new dyno graphs!


And Speedpro's actually!

Don't listen to him. I am sure there is room for an ESE 4 stroke you know you want to.

[TZ350]

I eagerly await your new dyno graphs! And Speedpro's actually!

The game plan is; my new air filter should arrive next week, then we can take the "Flying Vacuum Cleaner" to MtWelly for Saturdays practice. If we can get it to carburate satisfactorily then the following week its off to the dyno at Johns place with Speedpro to test our bikes, if he hasn’t got sick of waiting and beaten me to it by then.

[TZ350]

Don't listen to him. I am sure there is room for an ESE 4 stroke you know you want to.

Supercharged 4-Strokes are my first love. When I was an apprentic I worked on a few racing units, Jaguar Ford BDA and BMC, some of which were supercharged. Although I have had a TZ forever, trying my hand at seriously tuning 2-Strokes is relatively new to me.

Yes I love 4-Strokes............

[TZ350]

A supercharged Honda would be fun. Cooling would be the big issue but I figure I could sort that....

[SS90]

A supercharged Honda would be fun. Cooling would be the big issue but I figure I could sort that....

Oh shit, here we go!

[richban]

A supercharged Honda would be fun. Cooling would be the big issue but I figure I could sort that....

Can I suggest a CBR125 re sleeved. Cooling sorted.

[speedpro]

Cooling "might" be a concern but in my personal experience it doesn't seem to make much difference how hot a 4-stroke gets. I had a CB360 with a few mods that turned the red paint on the barrel black with heat around the top. My turbo Z1 even after a cooldown lap at Puke still is hot enough to make oil on the head or barrel smoke once you get back to the pits. They both ran fine. I ran Mobil 1 in both.