This is something me and my friend Paulo N. discussed for sometime now, we even took on all the troubles in comparing the old PR7’s wiring and ECU pinout to the new 2021 models wiring and ECU pinout, and… well there is no easy answer to this question. In fact, there is an additional question to ask – how much are you willing to pay and how much of the DIY you are willing to do?

In very short, yes it is possible, as bikes are not that much different and there are few ways to achieve that, however, is it worth the effort or no, well…that’s a good question.

1. One way, probably the cheapest way would be to get a new Athena ECU, a plug to fit old wiring, and a plug to fit a new ECU and make an adapter in between. But… there will be a need to make a lot of changes to the old wiring… and I mean a lot.
2. Another way would be to order a new complete wiring loom from AJP with a new ECU, change it, or let someone else change it, and the old PR7 will be as good as the new 2021 model. Obviously this one would be the easiest way, and the most expensive too as wiring, ecu, labour, and everything else will easily add up to…
3. The third way would be the “creative one”, probably as complicated as the first option, but not as expensive as the second, but, there is a big “but” there… there would be a chance to make changes on the way, even relocate ECU to a different place if wanted, and that’s while making your own wiring loom!

Making the adapter for pre-21 AJP PR7 to accept new Athena ECU

So let’s say we go ahead and try to make an adapter for an older PR7. Most of the wiring wouldn’t be a problem and could work as an adapter in between, however those extra bits and bobs that come in on 21+ PR7 what would cause the problem. When I compared the 2 wiring diagrams, from the first look these didn’t look that much different, but the closer I looked at them – less I wanted to mess with it as changes span all the way from one end of the loom to the other, on both Injection loom as well as the main loom. In the end, I decided to stop comparing the two, as it would be easier to make wiring loom from scratch than make changes to the old one.

Ordering a new complete PR7 wiring loom from AJP with a new Athena ECU

This wouldn’t be my preferred option mainly because of the costs involved, however Paulo N. sick and tired of fixing his old wiring that keeps breaking and burning out, decided to go ahead and source a new 2021 and ECU as in his case it makes sense not just to replace the wiring, but also to upgrade it at the same time. But even then, there still will be few things that must be done to make it work. Will be interesting to see the outcome.

Making your own wiring loom for AJP PR7

This is the option I’m personally considering myself. Cheaper – yes, parts available – yes, and most important can be done in whatever way is needed / wanted. It’s a big job, but after looking around, the most important plugs like the ECU plugs are available to buy, the rest of the plugs should be easy to source. ECU itself does not have to be directly from AJP, or for PR7 as the model AJP used is very generic and commonly found, hell, it doesn’t even have to be Athena, and (!) while making the wiring, all connections could be soldered properly to avoid problems like original PR7 wiring has! And if you think about all the benefits – dealing with 30+ wires and 100+ connections is not that bad as it might sound… a weekend project with a couple of months of preparations (being positive over here)! 

Let’s hope that AJP will come up with a factory solution for that and for a good price too, as I personally would like to spend more of my time riding the bike, then working on it, even though I enjoy both!

Just in case you are wondering:

Explore more!

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• Important things to know about your AJP PR7 – Torque Vales / Bearing / Seal Sizes / Manuals and Stuff.
• How I stored All my Trail Tools and Spares on my AJP PR7.
• AJP PR7 Tool Sizes.
• Cheap ways to make your motorcycles clutch lighter! (Part 2/3).
• How to make a Hydraulic clutch lighter on your motorcycle! (Part 3/3).
• Is it possible to fit the New Athena ECU on the old AJP PR7?

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• AJP PR7 Wheel Spacers.
• AJP PR7 Wiring Problem and how to fix it (random stalling problem).
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