These have been discussed quite a bit on this and other Yamaha forums, but until now, we did not have anyone who could attest to the product, it's quality, or it's ease of use. That appears to be old news

A friend of mine decided it was what was needed to get a DT400 with a bad pulsar going. So a about 4 days and a smidge over $200 and the product was in his hands. He invited me down to take a look. Mind you this is installment one, as the bike is not completely running yet, but that will be documented as soon as it does (which we are confident it will.)

First, what's in the box:



What you see is what you get.

• CNC Stator Backing Plate
• New sealed CDI control box
• Five assorted screws
• 4 aluminum spacers

That's it.

Next - remove your flywheel and stator, and remove the existing CDI box. Then you will be moving the source coil and lighting coils from the old stator to the new (good instructions with pictures included). You will end up with this:



Your old stator plate and pulsar are not reused. The new setup comes with one rubber tri-plug that plugs into the old harness. Where the other one comes off of the stator, it will only use two wires of the 4 and plugs into matching color wires off of the CDI box. The CDI box is virtually the same dimensions and fits perfectly into the old CDI perch on the bike:



Then you bolt the stator to the bike, and do an initial timing set of 4mm on one side of the mounting screw. That is close enough to get the bike to start after which you can use a timing light to set it perfectly. More on that when we come back for a running bike post.




The bike after a 45 minute job of moving things over, mounting them up and such, gave a good, fat spark when kicked over. This bike is not quite ready to run, so the final verdict is not in. The bottom line at this point is that the system seems like a great solution to the bad CDI setup we are so familiar with. Easy of installation is a second plus. And the cost is less than either a pulsar or a cdi box - assuming you could find one.! You will still have all stock lighting, so no battery fit issues, or bulb changes. (You won't get the great 12 volt benefits of the PowerDynamo system, but then if you bike is not running lights, or you are fine with the 6 volt stuff, this is a lot less money!)

We will be following this up with a running bike evaluation, but for now, the verdict is a Winner!

Link to the product page is: www.rexs-speedshop.com/epages/es143131.s...43131/Products/RMK-1

I have had some technical conversations with Rex's Speed Shop, and they have now joined the board! I am hoping they will weigh in on this as well as their upcoming new products!

Very nice fellow, and really seems to know his stuff.

We continue to attract the best and the brightest here on the site!

This system is the first of these we developed. We were given the idea by a chap who used to repair generators, he closed his business around 2001 and was happy to share the knowledge with us (although the idea sat unused for over 10 years). We have made the kit more user friendly as it plugs straight in to the bike's electrics. This kit is intended as a budget option to do away with the troublesome CDi and pulser, the CDi is poor design and so it the pick-up - its rare to find such poor ignition on Yamaha but these were the early days. We retain the standard flywheel as the engines vibrate a lot less with them and they are easier to keep running at low RPMs.

The new kit calculates timing in such a way it does give a slight boost in midrange performance and its a nice easy and easy to fit. We've been busy since we launched this kit and in the next few days there will be a new version that comes with a brand new source winding (UK manufactured in our own workshops) a racer CDi box plus a high output HT coil. We have adjustable CDi units waiting in the wings too.

Welcome to the site! I know there is a fair amount of interest in your products, so having the source available here to answer questions as they areise is fantastic!

Looking forward to seeing the other systems you have up your sleeve!

I have been looking and thinking of using the Rex's Speed shop version of the ignition system. it looks like a winner!

I inherited a Rex CDI box with the DT400 engine I bought of ebay, [ now installed in the 250D] its running the old pulser & soarse coils, running ok, I will buy the new updated system when available,

How compatible is this with the '77-'79 Dt400's? I know the years went up to '76, why I am asking.

Since the 77-78 units use a different CDI Rex's carries a different CDI box for those bikes. Apparently you don't need the full kit, just the box.

www.rexs-speedshop.com/epages/es143131.s...s143131/Products/DT4

You may want to contact them directly if you have questions about that application!

the 1977 and 1978 CDI on the DT400 is much more robust than what the 1974-1976 360 and 400 had. those are known to have the troublesome Pulsar on the early bikes. the 1977 to 1979 CDI have a much better pulsar setup. I bet the Rex's Speed shop CDI box has a better advance curve and might give a 1977-78 DT400 and a 1979 DT250 a nice little power boost. they promise better midrange power on the 1974 360 and the 75-76 400. a more modern ignition is always a good thing!

Has anyone any personal recommendations for this system or any other that is available, my pulser coil is damaged and the cdi looks like its been submerged in seawater for several years, whilst I'm rebuilding i would like to upgrade.

thanks