ESE's works engine tuner

[speedpro]

Other menus allow such things as firing a 180* twin off a single trigger by using a multi tooth rotor so that the ECU recognises cylinder 1 then 2 in turn - waste spark is dumb and unnecessary now we have this technology available.

All well and good. However unless your tandem twin is a 2T you still need some way of determining which cylinder is on compression and needs a spark this time around. The Ecotrons system uses MAP sensor fluctuations to determine where in the cycle one cylinder is.

[wobbly]

The Ignitech DC CDI P2 ( or RACE ) was designed for a 2T ( like a Rotax tandem for example ) using low ohm coils driven by a capacitor.
They make the usual 12V switching units as well, but both can be programmed easily for non waste spark on a 4T by using a cam sensor that identifies cylinder 1.
I have built both systems on old Ducati Bevels and running waste spark on a slow reving 4T works fine without the complexity of having to make a cam sensor setup, just two sensors
in the side cover at 90* with a single rotor lobe.
The CDI system makes identical power to the 12V on a dyno, but the riders swear ( alot ) that the cdi feels better on track re throttle response.
PS - never heard of a tandem twin 4T, enlighten me?

[Haufen]

Yes you can change angles and have an angle cut in the same place.
It doesnt affect the pipes performance at all, but sure as hell makes a huge difference to the form of the build.
Pipes look " dumb " needing a straight join,with angle cuts on each side, and it also means the other angle cuts have to be steeper to accomodate the straight piece.
Here is a cut and join exactly as described - the last diffuser joining the mid, to give a straight line on the bottom.
When the pieces are done in CAD the cone ends are lengthened a little, then the cut goes across the correct length on the centreline, no step and no area change at the joint of the two differing angled cones.

Thanks Wayne, good to know. When hammering, do you hammer before or after welding? Or both? I usually hammer after spot welding, then weld the entire circumference. The result turns out out pretty good, but it's sometimes hard to see the seam where to weld.

[speedpro]

- never heard of a tandem twin 4T, enlighten me?

Old Brit bikes are sort of a tandem twin being a 360 deg twin. Same ignition sequence, possibly. Your comment about the cam sensor to locate #1 is needless complexity if you already have a MAP sensor. MAP sensor fluctuations will determine which part of the cycle a cylinder is in. On a 4 stroke anyway. MAP sensors aren't so useful on a 2 stroke.

[wobbly]

Sure - its semantics but the Rotax is a tandem,one cylinder behind the other and they both fire together.
Brit bikes are parallel twins, both pistons moving together, but out of sequence on the firing strokes.
The old Ducati is a 90* parallel twin but fires sequentially at 270* apart.
Then you have a few essentially tandem V engines using knife and fork rods on the same pin,again the cylinders are longitudinally in line.
I agree, using the output of a MAP sensor to determine the crank position is one clever way to time for non waste spark.

[Dutch Fisher]

Wobbly Re:Ignitech .. What's your take on this reported problem http://www.pit-lane.biz/t3652p20-2-s...cc-development > post no.2

[wobbly]

There are several issues that I have worked thru to get the Ignitech to work its best.
Firstly is that they like low impedance coils - that is low DC resistance ( 0.2 ohm or less ) primary and a high inductance secondary.
The Suzuki RGV or Aprilia RS125/250 are the best common coils available, but I have used Crane PS92N cdi coils on Methanol burning Hydros where spark power is super important.
Stock Honda RS125/250 and CR250 coils are way too high resistance/low inductance to work well with this type of DC CDI.
Using both cdi to drive one coil doubles the effective energy available at the plug, and this is the way to get more power from say a RS125 Honda, especially if you swap out the coil.
Lastly using simply a battery alone isnt the go at all.
The voltage drops quickly under load with this setup, the DC CDIs work best when run with a battery that is being charged by the alternator at 14.2V continuously.
There is only one setup of MX rotor and stator that will drive sufficient current into an Ignitech for it to work best when using a cap instead of a battery.
The stator must have a 2 ohm winding and the rotor must be the later type with super strong magnets - you can feel them " clunk " over each pole as you rotate the rotor by hand.
You can see the voltage at the CDI drop ( on the computer screen ) during a dyno run - if the power supply isnt working as it should.
And as usual, the posts reveal that they werent using a resistor plug and cap as Seb4LO also pointed out, along with using the proper NGK race plugs.
So the spark would be all over the shop, not at the correct time to make power.
I dont know the exact calculation sequence the software uses, but I have found by trial and error that the best setup if possible,is to ensure that the addition of the base advance to the lobe duration
should be around the max advance used in the curve.
Having said that I have built several CR250 kart engines that have stock 6* of base and around 15* of lobe length, but the engine strobed exactly showing the 32* max advance as programmed.
And lastly I found that a lobe longer than around 20* length makes the calculations go haywire, and it will misfire badly at one rpm, then go perfectly well everywhere else.
There is a software button that says " wide lobe " and also one that says " no lobe length check ", but trying to translate from Czech what these actually do is impossible.
I simply cut the lobe length in 1/2 and it worked perfectly.

[chrisc]

Farmaken put me onto this.

Attachment 277602

Sioux model 5977 1/8" collet right angle precision pencil die grinder from Progressive tools - www.e-progressivetools.com E-mail jsgilbert1@msn.com ph. 336 933 9830 fax 336 993 9840

also

http://www.use-enco.com/1/3/pneumatic-pencil-grinder

also

http://www.browntool.com

The only problem with the Sioux is its head is too big to fit a 50mm bore with a cutter installed.

The best tool for the job is this, though more expensive initially its the only way to get the job done.

http://ccspecialtytool.com/182a-mc-s...dpiece-adapter.

The other issue is that even the 182 tool will not allow you to fit counter rotating burrs, by fitting them backwards into the head.

The only one that does this is the 1MC head, means you can rub the bur in both directions across the port roof to get equal cutting action on both sides of the cylinder.

http://ccspecialtytool.com/1mc-right-angle-handpiece

The 182 works fine in both directions with fine diamond cutters, or cotton polishing mops, but for hogging out tripple ports etc the 1MC is the best.

Whatever you decide you have to settle on 1/8 or 3mm cutters and stick with that for everything or buy expensive collets and change all the time - a butt pain, I know.

I'm at a point that I need a right angle head porting tool to cut the port openings in the GP125 cylinder I'm working on. Without sounding like a cheap bastard, is there a very cost effective way of doing this without paying $500+ for some nice tools from CC speciality tools?

I did a bit of digging in this thread and found the above two posts. I take a recommendation like that from Wobbly as a very good one but still wonder if there's a cheaper way for a low volume of porting. I mean I'm not exactly going to be doing it day in and out to justify spending lots on tools.

[twotempi]

Try this and let me know what you think

http://www.ebay.com.au/itm/Dental-Mi...item20d10daea2

[twotempi]

They have other models as well.

[husaberg]

Didn't F5 make/mod his own? it should be in his attached pics?

Well here's my latest project-ette.

I've borrowed RA dentist tools before & they can do the job but very slowly as they have micro bits.

I came across new old school (sorry I hate that expression) dentist drills that are lower speed but rotary driven & with bigger bits. Maybe I figured I could drive one from my dremel flexidrive & use these diamond bits I bought years ago in the chance that I could find something like this.

Good RA cutters small enough to fit in 50cc barrels or even 100s are more $ than I can justify. So how much for the dentist drill head brand new? Surely more? $25NZ landed to door. Yep that's right, free shipping ebay special.

OK so all was not simple dimple. How to interface the drive for a start. I made a fugly holder out of the end section of a diffuser & welded it to a bit of steel that was tapped (thanks Mike) to fit the dremel flexi (1/2" unf or some crazy tap I didn't have).

The other issue is the bits I'd bought were bigger shank than they said they were so I got a chap to turn them down (my lathe was too big), machine a retainer groove & a flat.

First try out tonight. It spins & is easy to use, but the bits aren't much chop, may have to sacrifice some tungsten dremel ones & the drive started slipping but I had a bent ended old bit to drive the coupling, I really need to weld a decent mating bit to slip into the coupling. Will update how sucessful this all is.

[chrisc]

Try this and let me know what you think

http://www.ebay.com.au/itm/Dental-Mi...item20d10daea2

There's a thought! Have you used these at all?

Heres a link to the burrs just to complete the post. Total of approx. AU$168 plus postage for burrs and machine

http://www.ebay.com.au/itm/10pcs-DEN...ffc43db&_uhb=1

[F5 Dave]

[QUOTE=husaberg;1130563152]Didn't F5 make/mod his own? it should be in his attached pics?



i can't believe I said simple dimple

[F5 Dave]

Well I finally got the igni base adjusting ok. Had to start the bike.

[Dutch Fisher]

Using both cdi to drive one coil doubles the effective energy available at the plug, and this is the way to get more power from say a RS125 Honda, especially if you swap out the coil.

So to use this method on a single crank V-Twin with separate triggers you need 2 ECU's ??