Yamaha DT2 Build - Smoke if you got 'em...

Never much of a fan of the 250 as it's a bit porky (lot of gravity in there) a 360 or 400 drops right in and with minor port work plus exhaust you hav ea 120mph dirt bike 8) Those wheels maybe direct from the MX bike, none flanged alloy was stock on them. They can be re-shaped pretty easy, I've done worse and made them look like-new. Just loosen off all the spokes in the bad area and anneal with a propane blowlamp. Put some hand soap on the inside rim flange, when it turns black your good to go with a dead-blow mallet or 4lb 'lump' hammer and wood blocks
teazer said:
That's always a possibility but you need a pickup that can withstand hot(ish) oil.

Is there a later model DT250 that came with CDI that would bolt on? I did have a Hitachi single pickup system at one time (basically 1/2 a TZ system), but that had no lights. Not cheap but how about an HPI small rotor set up or maybe a powerdynamo/Vape large external flywheel system.

https://hvccycle.net/yamaha-dt-rt-dt250-dt360-dt400-cdi-ignition-12v-180w-7238799dc/

https://www.hpi.be/item.php?item=210K059
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The later MX (monoshock) had electronic ignition. Don't remember exact spec but advance curve was totally different on the DT400M<X and stock it was bit of a slug. Fit 250 ignition plus Franconi or similar pipe and it will out accelerate a Kawasaki KX400 then run away at top end, even with stock carb (I think 34mm?)
 
Sonreir said:
Started work on the stator for the DT2. Removed the coils for the lighting, charging, and ignition systems. We're going to a full 12V DC system, so all three coils will be rewound in series to create a single phase alternator.
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did that stator. kept the ac ignition because its stupid simple and I can run without a battery. ungrounded the headlight stator and ran 2 phase full wave for the lights and horn. did not need to use the tail stator with the taps. removed it.
 
Polaris - at least on some of their older sleds - ran AC to the lights and CDI ignition. They had a simple two wire regulator too - probably just a zener diode to dump excess volts to melt snow.
 
teazer said:
WOuld the rotating magnets in the flywheel not mess with the dyna pickups? I know that people fit DYNA's to RD350s with an internal rotor and they seem to work OK. I haven't tried one on an external flywheel. Cheap enough to try.
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Later DT250/400MX had electronic ignition
 
teazer said:
Polaris - at least on some of their older sleds - ran AC to the lights and CDI ignition. They had a simple two wire regulator too - probably just a zener diode to dump excess volts to melt snow.
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thats a common offroad setup. not just polaris, many dirtbikes and quads run ac lighting. the 2 wire ac regulator is a voltage clipper. I don't run this way because led's don't run ac. mark on the 2 stroke forum does. my kdx ran this way stock. rectified to half wave dc, regulated with a shunt regulator. (as opposed to floating ground to make street legal).

the rewound stator pic shows where this build is going. I just ungrounded the lighting coil and never looked back.
 
kept the ignition stator stock because it is full wave ac and works well. the headlight stator got ungrounded. I rectified the lighting coil 2 phase full wave. the 6v to12v conversion happens at the regulator. was able to run the stock headlight,stock horn, led tail and turn battery less with a big cap. getto repair but it works.



IMG-20180220-141256.jpg


this pic uses the same stator wired 3 phase for a different project (sig pic) but you can see what I did to the lighting coil on the dt. notice the missing o brass stator ground connectors.
 
I just remembered, Honda used ignition pick up on primary drive side on XR350~400 and probably a lot of others. The XR's run real hot so I think they would work well. I've also got some Suzuki ignition triggers off various SACS GSX's, they run in hot oil without a problem. If your removing oil pump you may be able to utilise the drive gear?
 
Or get a simple HPI.be alternator and CDI or grab one from Ignitech who sell a really cheap alternator with tiny/light external flywheel - no points needed.

Lots of possible upgrades.

It's amazing the choices we have today compared to a few years ago.
 
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