ESE's works engine tuner

[koba]

So here is some of the lines I've been making:

Blue Line: This was the Dyno curve of the bike in September, roughly; the first peak was slightly higher than the second. Standard Exhaust port, modified inlet and 28mm carb.

Red Line: This is the engine parameters as they are now with the attributes like combustion and scavenging efficiency and short circuit ratio adjusted to match close to what was seen on the dyno. I had to turn these down to the lower end of the scale which suggests my engine is handicapped in some or all of these areas.
This is what I've been racing with since Te Puke.
The difference between this and the blue line was raising the barrel 1.2mm, no leak from head and widening and Raising the exhaust port. Plus I cleaned up the inlet tract which was incomplete but there is still work to do on this.

Green Line: Plan A. This is the bike with the current (Still short) port timing and a conservative pipe. My pipe design needs more work.

Pink Line: Plan B. Port timing where it should be and a steeper pipe.

Both of these 'plans' don't fully take into consideration ignition timing curves and leaning off with a powerjet so hopefully I should see more range if I get that sorted.
The Ignition "curve I used was vary basic so once I map my ignitions changes I will see If in can refine them to that better in the sim.

One other thing I have noticed, which is why I haven't bothered changing the air/fuel curve is that the sim seems to have a distorted response to this, it's easy to make 40hp in the sim by cranking the A/F ratio up so I just picked an reasonable number and used that across the board.

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[F5 Dave]

Very awkwardly, not the sort of thing you want to do heading into a downhill hairpin.

Wonder where Ziff is nowadays? Obviously moved from Marton, had to seen him at Boxing day races, but not for, erm well over 10 years I guess.

Well talk about coiencidence! Last time I saw Ziffle was at the boxing day races as I said above. So who should step out of the crowd yesterday & shoulder tap me? Was n the same place as 10 years ago too. He live in Wangas, still doing plane stuff if anyone is interested

[wobbly]

Any sim you are using to design any part of a 2T engine, and dont take full account of the ignition timing regime - is a waste of time.
I can design a completely shit pipe, and with ignition tricks, make it work 1/2 way reasonable - in a sim and on the dyno.
But its impossible to design a really good pipe that will work well in reality, if you dont define exactly the ignition curve it will see when running.
You can change the temp in the header as seen by the egt probe, from 450 to 650C by simply taking away 4 degrees of timing when in the overev,so the pipe that before had a vertical power drop off
at 13500, now holds 50 + Hp out to 14500.
Same with having the solenoid powerjet scenario,you can easily make a pipe that will spin to 14,000 in the sim, but sadly it has no mid power to speak of at all.
Change the A/F ratio from 12:1 to 14:1 past torque peak, and a MUCH longer pipe, now has a ton of mid, then holds its torque up long enough for that " too long " TL to work at least another 1000 rpm than before,due to
the burning mixture now dumping a huge heat load out the port.

[koba]

Any sim you are using to design any part of a 2T engine, and dont take full account of the ignition timing regime - is a waste of time.
I can design a completely shit pipe, and with ignition tricks, make it work 1/2 way reasonable - in a sim and on the dyno.
But its impossible to design a really good pipe that will work well in reality, if you dont define exactly the ignition curve it will see when running.
You can change the temp in the header as seen by the egt probe, from 450 to 650C by simply taking away 4 degrees of timing when in the overev,so the pipe that before had a vertical power drop off
at 13500, now holds 50 + Hp out to 14500.
Same with having the solenoid powerjet scenario,you can easily make a pipe that will spin to 14,000 in the sim, but sadly it has no mid power to speak of at all.
Change the A/F ratio from 12:1 to 14:1 past torque peak, and a MUCH longer pipe, now has a ton of mid, then holds its torque up long enough for that " too long " TL to work at least another 1000 rpm than before,due to
the burning mixture now dumping a huge heat load out the port.

Cheers, I'd thought that would be the case based on what you have posted before.

It seems a little backwards designing the pipe to suit an ignition with a fixed curve shape but I'm going to have to go that way until I can afford to upgrade to an Ignitech or similar. That's going to have to wait for a long time though.
It would be great to able to change it but I have to make some compromises due to available resources.

Do you find the A/F ratio change in engmod close to reality? or do you just apply experience in that area?

Also I WILL be designing a completely shit pipe, relatively speaking, I just hope to get it less shit with the sim.

Using the Sim I've been able to compare different designs and I'm confident I can make more 'Simpower' than other pipes that I could be putting on the bike.
I would have thought the RG400 (I think it is anyway...) pipe I have on it now would be reasonably close but it appears miles off in practice and in the sim.

That is one thing about the 100 vs an Air Cooled 125; a random pipe of any old 125 seems to work OK compared to putting the same pipe on a 100.

[FastFred]

Ignition, I must make a basic map of the 'curve' on the KX125 ignition I'm running.
It would be great to be able to change it but I'm going to have to work within that box for a while.

KX80/125 Fixed ignition



KX80/125 Retarding igntion

This one can be converted to fixed by using a JayCar CDI blackbox replacement Kit.

Thats interesting Burt, if one had the stator part of a MX ignition they could follow the schematic and make the CDI part.



It would be worth looking at the Jacar CDI kit's

[koba]

KX80/125 Fixed ignition



KX80/125 Retarding igntion

This one can be converted to fixed by using a JayCar CDI blackbox replacement Kit.

Mine is the retard.

Actually possibly that exact one in the picture if Kel owned it at some point.

I'm going to try and map it with a rev counter and timing light.
I know it's unlikely to be perfect but I've gotta work with what I've got.
I'm dreading working out the timing marks, I have a few ideas but know it's going to be an arse!

[FastFred]

I'm dreading working out the timing marks, I have a few ideas but know it's going to be an arse!

It might not be that hard. There will be a line on the fly wheel that aligns with a mark on the stator. These are meant to line up at 2-3k rpm.

just set the piston at its BTDC firing point, 1.6mm BTDC ??? or whatever your engine is supposed to have. Then holding the flywheel on the stator with the marks lined up, align the flywheel key way with the crank key to see if the stator and pickup coil will sit somewhere convenient.

To check the timing when you have everything bolted up. Set the piston at its firing point before TDC and using a black marker pen make a line on the flywheel and stator plate and with the timing light check these line up when the motor is running about 3-4k.

You should also see some of the retard happening but most (cheap) timing lights give up when the reves get up a bit (its to do with the time it takes to recharge the capacitor that fires the flash).

[husaberg]

To check the timing when you have everything bolted up. Set the piston at its firing point before TDC and using a black marker pen make a line on the flywheel and stator plate and with the timing light check these line up when the motor is running about 3-4k.

The misses nail polish may show up better and gives the opportunity to use different colours.(for different timings) i doubt weather it will be accurate enough to pick up much. other than trends (in the timing rather than fashion).........

[koba]

It might not be that hard. There will be a line on the fly wheel that aligns with a mark on the stator. These are meant to line up at 2-3k rpm.

just set the piston at its BTDC firing point, 1.6mm BTDC ??? or whatever your engine is supposed to have. Then holding the flywheel on the stator with the marks lined up, align the flywheel key way with the crank key to see if the stator and pickup coil will sit somewhere convenient.

To check the timing when you have everything bolted up. Set the piston at its firing point before TDC and using a black marker pen make a line on the flywheel and stator plate and with the timing light check these line up when the motor is running about 3-4k.

You should also see some of the retard happening but most (cheap) timing lights give up when the reves get up a bit (its to do with the time it takes to recharge the capacitor that fires the flash).

Umm, not quite that simple.

It's a bit of a mis-match about the place, as it is the keyways don't line up so if/when I take the flywheel off I have to re-jig every measurement!

I'm going to (one day) re-rivet the centre of the flywheel in a different position so the two key-ways line up and them machine a key down do it will fit the 4mm slot in the crank and the 3mm slot in the flywheel. To do this correctly I must first be sure of where I want it because there is very limited room in the cases to move the external pickup backwards and forwards.

So far I've been using a relative measurement for timing, from the seating surface of the plug washer to the top-centre of the piston because it's easy to measure on the spot. 23mm is standard form memory.

It's relatively simple to extrapolate the actual linear position of the piston from this but to do it properly I'd like to make a fixture to use a dial guage on it.

I've got a good, but not great, timing light; it going to shit at higher revs could be a flaw in my plans!

[koba]

Right, I've had a few beers so it took a while to appreciate that last one properly.
Yeah I know what you mean, I can get the ignition lined up correctly as per standard KX125 but what I really want to know is the curve and absolute values. To work that out I need to figure out the position relative to a measured datum, something that isn't too hard but makes my head spin.
Added to that is the dubious accuracy of the timing light.
Still, Won't know until I try!

[husaberg]

Right, I've had a few beers so it took a while to appreciate that last one properly.
Yeah I know what you mean, I can get the ignition lined up correctly as per standard KX125 but what I really want to know is the curve and absolute values. To work that out I need to figure out the position relative to a measured datum, something that isn't too hard but makes my head spin.
Added to that is the dubious accuracy of the timing light.
Still, Won't know until I try!

You could always try a MB50 ignition they to have build in retard and pit straight on and the keys and timing marks suit?
I had the standard figures i posted somewhere.i could save some head spininng.

[TZ350]

There is a dark area over the Ex port, this implies the engine has crap scavenging and has alot of short circuiting, or the stinger is too small. The A transfer rearward radial angle may be too steep, allowing direct looping into the EX when at BDC

I had a look at a few performance and race water cooled cylinders laying about the place and they all seemed to have a more swept back angle than the GP.

Interestingly the angle on the water cooled performance and race cylinders seems to point more to the rear of the cylinder as the port approaches BDC. Its like the front of the A port is contoured.

- the stinger size is a little harder to optimise, being a very high specific output air cooled and very little anecdotal evidence to point you in the right direction.

As best as I can measure it, the RS pipe I am using has a little 22.5mm restriction in the end of the baffle cone and the stinger is 23.8mm ID.

[2T Institute]

Cheers, I'd thought that would be the case based on what you have posted before.

It seems a little backwards designing the pipe to suit an ignition with a fixed curve shape but I'm going to have to go that way until I can afford to upgrade to an Ignitech or similar. That's going to have to wait for a long time though.
It would be great to able to change it but I have to make some compromises due to available resources.

You will spend more time and money friggin round with the old unknown ignition just over a longer period than biting the bullet for a programmable.
I went through this with suspension, spent countless hours rebuilding shocks, buying shims and seal heads. Finaly bought a set, bolted them on set the rebound and have not touched them since. They work 100 times better than my best efforts.

MOTA is a massive compromise especialy on the ignition side. However it will provide some useful info on the return wave timing which is what you should concentrate on. As Wob has said probably 100 times and it's worth repeating "big depression/lowest pressure at BDC" and return wave arriving before the exhaust port closes. Get that right then look to get the rpm peak where you want it, finaly jiggle the TL length %'s to what Wob has already posted. Viola no more shit pipe.

[2T Institute]

TeeZed those transfer dividers apper to be the wrong way around, they are pointing AT the exhaust port.

[Buckets4Me]

Robert junior wants to know whats gone wrong with his crf250?



any clues as to why it locked up in top gear on him?