ESE's works engine tuner

[Frits Overmars]

...the HRC blokes in the pit next door fired up the Honda six for a couple of demo laps on the oval. Blimey!!! I thought an earthquake was upon us!

Yeah, the 250cc Honda-six was loud but it was musical loud; still one of my favorite engine sounds. It had so little crankshaft intertia that one had to be careful not to let the revs drop too much, even during upshifting:
https://www.youtube.com/watch?v=hjZWrvUGAV8

The 125cc Honda-five, though with only half the engine capacitiy of the six, was offensively loud. It could make you feel sick to the stomach, and that's not just a figure of speech. From a distance, it was quite entertaining though. I tried to attach its soundtrack here, but the forum software wouldn't let me, so I zipped it for ye.
2xHonda125.zip

[Michael Moore]

My 216cc Honda twin vintage racer (based on a sloper CB175 engine) was measured at 130+ dB on open megaphones. There was no problem with people in the pits not getting out of the way when I was riding it to the grid.

The other people in the industrial park where the engine was built were used to the roar of race Z1 Kawasakis on the dyno and weren't bothered by that, but when the Honda was running one of the neighbors came over to find out what was making all the racket.

I'm not so keen on noise these days, and a friend's Zero e-moto is appealingly quiet.

[yatasaki]

How do you pick your final ratio for buckets?
One old karter around here told me to have max overrev on the final gear on the half of finish line.

..on the noise talk, once for carnival parade, I took the mufflers off my kr1s and fit megaphones one meter in length and 300mm exit diameter. The noise on the idle was really unpleasent 6m behind the bike.
When the bike was on the KIPS :cool: people from 7 km neighbour village were swearing hearing something like formula 1

[peewee]

determined to get this shit box running by summer so im sneaking to the garage every chance I get . a bit more grinding to do but im trying to have as much water around the passage as possible. extending it 2x the bore was a after thought, other wise I would of done things a bit different from the beginning but ill do the best I can with what I have to work with now without going backward to much

[karter444]

Thanks Richard , yea makes me laugh when all our opposition wreak gear by "tuning" on the stand.
I look at the Density Altitude on my phone and change jets 4 times a day, keeping the egt nailed at 650.
The C model insert can be cooled above the squish and around the plug only, by cutting a slot from front to rear in the cover.
If you think about it hard enough , you will see how not to be cooling the back of the chamber by doing this.

Hi Cheers for the reply , will try and work it out

[F5 Dave]

How do you pick your final ratio for buckets?
One old karter around here told me to have max overrev on the final gear on the half of finish line.

..on the noise talk, once for carnival parade, I took the mufflers off my kr1s and fit megaphones one meter in length and 300mm exit diameter. The noise on the idle was really unpleasent 6m behind the bike.
When the bike was on the KIPS people from 7 km neighbour village were swearing hearing something like formula 1

I start with max overrev at the end of the longest straight. But I don't stop there. I then consider my change points and relative acceleration compared with opponents as fastest lap time is not the entire picture although a good guide considering the first two points.

[_____]

determined to get this shit box running by summer so im sneaking to the garage every chance I get . a bit more grinding to do but im trying to have as much water around the passage as possible. extending it 2x the bore was a after thought, other wise I would of done things a bit different from the beginning but ill do the best I can with what I have to work with now without going backward to much

For the sake of science!
Could you make the exhaust port cooling seperated from the cylinder? So that you might use two different cooling circuits on the cylinder.
The idea of mine is you test the engine on the bench in two ways:
1. You cool the exhaust and the cylinder hereafter with coolant
2. You only cool the cylinder and leave the cooling circuit of the exhaust filled with air

Benefit: You'll see if it really is good to cool that much of the exhaust pipe or if it is just Ryger-ish snakeoil

Cheers
Chris

[Michael Moore]

yatasaki, it can be good to have the bike geared a little bit higher than you expect to use (not lose), so that you are able to go faster if you get a tailwind or a tow by slipstreaming a faster rider/bike.

[peewee]

For the sake of science!
Could you make the exhaust port cooling seperated from the cylinder? So that you might use two different cooling circuits on the cylinder.
The idea of mine is you test the engine on the bench in two ways:
1. You cool the exhaust and the cylinder hereafter with coolant
2. You only cool the cylinder and leave the cooling circuit of the exhaust filled with air

Benefit: You'll see if it really is good to cool that much of the exhaust pipe or if it is just Ryger-ish snakeoil

Cheers
Chris

i dont have a dyno for testing unfortunatly. i was going to use a larger shell around the exh passage but i thought that might cool the exh to much so i decided to use a smaller shell

[wobbly]

Plenty of work has already been done on this with no good results.
Firstly Jan filled in under the Ex duct to reduce the coolant flow - result deto city.
Secondly, I ceramic coated the duct inside surface , result lost power - deto city.
Third,Franco at TM tried the air gap shell idea, result - deto city.
Fourth,TM originally designed the KZ10 with all the coolant flow entering the cylinder under the duct.
This heats up ALL the water ,including that flowing over the transfer tops.
They later plugged the holes and directed all the water into the cylinder , from the side over the top of the duct.
This gave better power.
Lastly I bored a hole into the water jacket above the boost port , so all the cold water flowed over the transfers first.
Then added two 3mm holes thru the plugs under the Ex duct to help cool this area separately.
Result just over 1 Hp in 48 , with alot less deto level when under full power.
But the CIK and NZ techo guys would not allow this " additional " water circuit.
Moral of the ( long ) story is that cooling the duct first is bad , as is not cooling it at all , as you must keep the retained
mixture in front of the piston as cool as is possible to prevent the returning stuffing wave from pushing hot gas back into the cylinder.

[peewee]

Plenty of work has already been done on this with no good results.
Firstly Jan filled in under the Ex duct to reduce the coolant flow - result deto city.
Secondly, I ceramic coated the duct inside surface , result lost power - deto city.
Third,Franco at TM tried the air gap shell idea, result - deto city.
Fourth,TM originally designed the KZ10 with all the coolant flow entering the cylinder under the duct.
This heats up ALL the water ,including that flowing over the transfer tops.
They later plugged the holes and directed all the water into the cylinder , from the side over the top of the duct.
This gave better power.
Lastly I bored a hole into the water jacket above the boost port , so all the cold water flowed over the transfers first.
Then added two 3mm holes thru the plugs under the Ex duct to help cool this area separately.
Result just over 1 Hp in 48 , with alot less deto level when under full power.
But the CIK and NZ techo guys would not allow this " additional " water circuit.
Moral of the ( long ) story is that cooling the duct first is bad , as is not cooling it at all , as you must keep the retained
mixture in front of the piston as cool as is possible to prevent the returning stuffing wave from pushing hot gas back into the cylinder.

good info. my water routing has the duct cooled last. its not show in the photos but i was going to put a exit nipple at the end near where the exh spigot attaches

[yatasaki]

yatasaki, it can be good to have the bike geared a little bit higher than you expect to use (not lose), so that you are able to go faster if you get a tailwind or a tow by slipstreaming a faster rider/bike.

On our last moped race last year I had 10600 rpm on the end of finish straight. This year had new cylinder which gave 600rpm more ie 11200 but for this reason tried front sprocket 12 instead last years 13. Max speed was a bit less but laps 2 seconds better. My opponent had longer (13 instead 12 sprocket) final ratio and couldn't keep up but he was accelerating untill end of straight..
Our last shifter race
https://youtu.be/zP39jrMTOGA
Skip to 08:08, me at the lead
My shifting to fifth(final gear) 08:17
His shifting to final 08:24

[Frits Overmars]

On our last moped race last year I had 10600 rpm on the end of finish straight. This year had new cylinder which gave 600rpm more ie 11200 but for this reason tried front sprocket 12 instead last years 13. Max speed was a bit less but laps 2 seconds better.

There are no prices for top speed in road racing .
Yatasaki, you seem to be riding a Tomos with forced air cooling. I don't know about your regulations, but if it is permitted, removing the fan and the cowling could liberate another HP.

[Michael Moore]

As with so many things, gearing may often be a compromise. As long as your lap times decreased it sounds like you didn't do bad on your gearing choice. It all comes down to the bike/track and weather conditions.

For example, if you gear for max safe RPM in top on the back straight (which at almost 1/2 mile in length is very long on a small bike so you are flat out for quite a while) at Willow Springs in the morning when the air is still, you may find yourself closing the throttle some in the afternoon to avoid floating the valves if (very likely when in the spring) a 20-35 mph tail wind comes along out of the west.

You need to do what works and YMMV.

cheers,
Michael

[yatasaki]

There are no prices for top speed in road racing .
Yatasaki, you seem to be riding a Tomos with forced air cooling. I don't know about your regulations, but if it is permitted, removing the fan and the cowling could liberate another HP.

I could remove fan and cowling but cylinder head fins
Are to small for this move. Did another thing, as original bike spins around 6000 rpm, I cut every second fin on the fan. Heard from malossi scooter mechanic that every 5000 rpm fan takes around 1 hp.

Michael, on that track that very day we had some in-face excessive wind, when racing centrifugal clutch class. Than you shape yourself as a hedgehog..
Wind issues are more or less clear, but some theoretical/ideal gearing for given track I was wondering somebody has.