RZ/RD 350 & Misc. 2-Stroke Tech BBS

Shopping for new coils cause the originals bit the dust - suprised they lasted this long. Which have the best value: Dyantek miniture series or Banchee OEM? I was advised to stay away from racing Banchee coils. Note the cheap coils on Ebay but you get what you pay for when you have no spark in the middle of a ride.

Norbo sells some banshee coils and people seem to like em, its a budget option.

I have the Dyna.

Which version of Dyna and did you have to make a bracket to make them fit Jon?

I don't 100% know, but there are pics on my site, it was on my 421 build - It's here:
http://2smoked.com/Yamaha_RD350_LC_421c ... Frame.html" onclick="window.open(this.href);return false;

pic from there:


As for fitting: Not on an LC, it just bolted one. for an RZ John at Economy Cycle makes a fitting kit for the early RZs. Its very good.

Just ordered one and the mounting bracket too from Economy Cycle

Yet to fit it as I’m away working, Jon put me on to them

The coil and mounting kit from Economy fits and works great.

Got a response for a banchee coil for $202. Dyna tek mini series appears to be the the route to go but there are two offerings in the mini series: is it the 3.0 ohm - Single-Tower - Single Fire - Single Plug - DC3-2 or the 3.0 ohm - Dual-Tower - Dual Fire - Single Plug - DC1-3 needed ($159). Thinking dual is the answer. Couldn't see the lable Jon in your picture to confirm & looks like 5.0 ohms whereas the Economy Cycle (for RZ only) appear to be singles but not sure which ohms. Bit confusing.

The Dynatek coils for the RZ and Banshee are 0.5 ohms.

The Dynatek coil kit for the Banshee is the DCK7-4.

This Kit uses the DC11-2 coils.

I am currently running the DC11-2 coils on both my RZ's.

Folks, keep in mind that "ignition" is not equal to "ignition"

The most cars and youngtimers "ignition" is a points or TCI. The principle is to have a coil with a high number of windings that is put under 12V for a certain time (called dwell). If you suddenly switch off the current, you have a peak in primary voltage that causes the high voltage peak on the secondary (or HT) side because the coils act as a transformator.
The primary coils used here are in the 3-6 Ohm range and the thing that they're good at is "to defend themselves against the current being switched off". It's like a kind of high "electrical mass"

Now what are the RZ's using?
A CDI charges a capacitor to a few hundred volts and a thyristor is discharging this voltage through the primary side of the HT coil. Again working as a transformator causes a high voltage peak at the HT side which sparks at the plug.
The main difference here is that you need a coil that can bear a very fast changing current on the primary side (= a rather low "electrical mass") which is pretty much the opposite of what you want for the TCI
That's why a CDI only has a around 0.5 Ohms primary.

To make it a bit more complicated the resistance is not the element that really determines spark energy, it's the inductivity (as an easy picture: the number of windings or "the electrical mass").
If you use thin wire and a certain number of windings you end up with a certain resistance and an inductivity. Now if you increase the wire diameter it makes it easier for a current to go through (= lower resistance), but you may need too much space for the number of windings. So usually you reduce it which reduces the inductivity - good for a CDI, bad for a TCI.
That's why there is coils with different resistance and different inductivity in a wide range.

In a nutshell this rule applies: Stock CDI = use any coil in the 0.5 - 1 Ohm range. Do not use high resistance/inductivity coils.

Check out this page for a range of suitable products and spend attention to comments like not suited for original Japan ignitions.
http://ignitech.cz/en/vyrobky/accessories/ic/ic.htm" onclick="window.open(this.href);return false;

If you use a Zeeltronic or Ignitech the game is different. These can put out enough juice to feed a higher inductivity coil and enhace spark strength even more.
But even here you wouldn't use a 3 Ohm TCI coil!

Interesting stuff, what do you recommend for the Zeeltronic Martin?

For a Zeel you can use those with the higher inductivities like:
coil IC-CDI-S, Z43/431, IC-CDI-D

Regarding the Elsie, is the RZ's DCK7-4 Dynatek (using DC11-2 coils), the correct replacement choice Martin?

Are these the ones?

https://rover.ebay.com/rover/0/0/0?mpre ... 3607244052" onclick="window.open(this.href);return false;

0.5 Ohm sounds feasible.

Check the inductivity to be sure.
Ignitech states that 0.something mH would suit stock CDI's and 3.something mH wouldn't.

If unsure, why not buy a cheaper one from Ignitech?
They're in the 20-40 Eur range.
Personally I wouldn't spend 100 bucks or more on a bloody coil (are they gold plated or what?).

Contacted Jiri at Ignitech and his recommendation was thus:
"Suitable ignition coil for RD350 is IC-CDI-D (33 USD). This is similar features as original ignition coil. RD350LC has capacitive ignition. This type ignition should to use ignition coil with very low resistance (under 1 Ohm).
Only very old RD bikes with contact point ignition should to use coil with resistance 3-5 Ohm. Frerightage DHL is 38 USD." Measure the length - yep, 90mm fits. $71 Cnd - bought one as it almost half the cost of an OEM. How it preforms is another question. Other forms have highly recommend this product. Thx Martin for the suggestion.