Baja 250cc Dirt ZS167FMM 2004

[Weldangrind]

Based on your pics, it is not a counter-balanced motor.

[oviking99]

Thanks again Weld. In thinking about the good performance, I got to wondering about the new CDI I installed. I also used a 150cc gy6 scooter 'Performance' coil I bought some time back from PCC Motor. The cdi is basically a voltage store/amplifier, but I wonder how it handles the advance curve. Curious to know if there is some kind of cpu controller or if it is just discrete components in the black box. Just thinking out loud.

[Weldangrind]

I've wondered the same thing. Humanbeing has pointed to a programmable CDI a few times, and it looks interesting. It has a USB port and software, and you can apparently program any curve you wish.

[oviking99]

I read about the programmable cdi/tci controller humanbeing pointed to. It is a PIC microcontroller that uses a lookup table to advance or retard ignition fire, for any given rpm. In order to re-program it, one would have to know the values. An engine analyzer, a dyno ,or a knock sensor would be needed to figure those values out, as far as I can tell.
If I were into racing, it might be worth the effort, but a bit complicated for most of us I think. Now, if someone had a table for a specific engine, that might to be easier to eek out some additional horses. For me, I'll leave the cdi programming to the pros.

[Weldangrind]

This has the makings of a terrific discussion over beers.

Why do you think one would have to know the values? With the provided software, what would stop us from simply plotting a curve and trying it? I would shoot for somewhere around 25 degrees for starters, and begin adding advance until it began to detonate. Do you think that's too risky? I don't know if the software allows you to tailor specific RPM points, but I'd love to find out if the curve could be extended so that it's all in by around 5000rpm, instead of the conventional 3500 (or so).

[bogieboy]

Throw another iron into this programable stuff discussion... What about a Microsquirt controller, and fuel injection....i am seriously tempted to look into that to see how much you can eek out of a china bike... In conjunction with that i have seriously considered a small turbo as well...i could se epushing 50-60hp from a 200 turbo/EFI china bike....

[katoranger]

I want to see the turbo china bike. Would you find a different piston to lower the compression ratio?

[oviking99]

Weld, I agree with the beers and the statement! The Pic microcontroller uses an Excel table and advances accordingly. The values can be reprogrammed into the table. If you could wire a knock sensor into the circuit, then back it off 2 or 3 degrees to maximize burn, store those values into the table I'd think it would make some easy horses.
Here's the link for the controller and the associated software.
http://www.sportdevices.com/ignition/ignition.htm#index

Another beer please!

[oviking99]

Or advance it until detonation, as you said and back it off a few degrees without a knock sensor. The only thing bad that could happen is loss of power, and some obvious knocking and pinging. Years ago as a young man, I used to illegally drag race my 66 Comet Cyclone 390. I had a friend who worked in a shop that had a dyno. It sure made performance tuning easy.

[oviking99]

As far as the turbo, I think MRP-Racing sells turbos for scooters. For fuel injection, it would require high pressure fuel pump, not to forget a controller. I think NOS might be easer, but I wouldn't try it on a high milage motor.

[oviking99]

Man I'm havin to clear out some cobwebs from my brain. There was a shop in oregon that I sent a honda dirt 74? 150 head to. (I cannot remember for the life of me the designation of the honda). At any rate, they installed roller bearings, and a hot cam. I overboard and installed a Wiseco piston and over sized Mikuni into it. I also installed an extended swing arm and better rims and tires. That thing felt more like a 400, and it was light as all get out. Sure love to have it now. That thing would leave my Baja x250 in the dust.

[oviking99]

All of our wishes answered;
http://www.chinese-parts-canada.com/...injection.html

Scratch MRP-Racing in my post below.

Just bring money!

[Weldangrind]

A 150 head? Wow! Was it an OHC engine? I'd sure like to learn more about the roller bearing coversion.

Got pics of the Comet? I bet it pulled like a train with a 390.

[katoranger]

Turbo Vento. Turbo Vento. You could test it on that XR.

[bogieboy]

Originally Posted by oviking99

As far as the turbo, I think MRP-Racing sells turbos for scooters. For fuel injection, it would require high pressure fuel pump, not to forget a controller. I think NOS might be easer, but I wouldn't try it on a high milage motor.

For efi i would use this as the basis of the kit, but probably use microsquirt for the controller instead of this one, since i am somewhat familiar with the mega/microsquirt platform http://www.ecotrons.com/Small_Engine_EFI_PNP_kit.html

And i would couple it with this turbo... http://pages.ebay.com/motors/link/?n...d=400537393173

Would probably mount the turbo in the location of the stock airbox, and plumb the exhaust and intake stuff accordingly...