What is an EPROM?
EPROM is an erasable programmable read-only memory. In other words – it is a chip with content that can be deleted. Or re-written with other content (after it has been deleted).

What does it contain?
In our case it contains the program that the injection computer needs to work. It also contains data needed for it to work properly.

What does it do?
ECU collects the data from several sensors, the program from the EPROM samples and recalculates those values using the data from the EPROM (the data from “maps”) so the right amount of fuel and the right moment for ignition are calculated. Then the ECU does just that – injects the correct amount of gasoline and ignites it just at the right time.

Why does the engine running a JayTune EPROM produce more power than the factory one?
Because the factory had to tune engines to conform the national standards for emmission and noise regulations. Sure there’s no problem in producing more power but emmissions would worsen – there would be more CO2 and CH’s in exhaust (with other words: more exhaust gases and more unburnt fuel), the exhaust system could be much better with a core design, but it would be more expensive (and 5 kilos lighter for that matter), and the bike would be much noisier. Aftermarket exhausts are aloud to be a little louder (so less restrictive), and usually there is no emmission test for homologation purpose. That way the user can ger better exhaust flow, but the need for gasoline even rises. By using a JayTune EPROM a user injects more fuel for given circumstances. Not only can torque and power improve, it even runs properly with sports exhaust and so produces even more power.

So does the consumption worsen?
Yes and no. “Yes” when you want the maximum of your bike – but in that case consumption doesn’t even matter, what matters is that the “maximum” is more powerful than the maximum with previous setup. And “no” when working in legal speed range because the “maps” are not changed much down there.

Do I lose my warranty?
Do you have a warranty?

I heard about “map 2″…
…yes, and that’s exactly what we use with our EPROMs. Every single EPROM is loaded with 2 DIFFERENT mapsets. Not 2 bikes are the same, and some exhausts are less restrictive than others. So every EPROM contains 2 similar mapsets, but with little differences in fuelling terms. One mapset is a bit richer and another is a bit leaner. A user has to try both and set the ECU to work with the proper map. That way the injection is optimally set for the given hardware.

How do I change from “map 1” to “map 2”?
Is is possible to switch between mapsets on the fly, using our Map 2 on the fly switch kit. The kit will soon be available in our shop. An article about map 2 will soon be added to the download section (that will soon be added to this page – yes, I know – this page is a mess at the moment).

I am not an expert. Can your products be installed by the bike shop?
Every product comes with Installation manual, and it is made to be installed by the non-professional people with basic know-how. That also means that they can easily be installed by professional mechanics. Just be sure to bring (and show) the installation manual when you visit the shop.

Can your product damage my bike?
What damages petrol engines is too poor air to fuel ratio. Our products do the opposite – the injection system produces richer AFR than the factory settings. That means lower combustion and exhaust temperatures and less chance to knock. On the other hand ignition timing is advanced (on all EPROMs), but not enough to cause damage to the engine. However improper installation and driving irresponsibly can damage your bike, we can not influence that.

How do I order your products?
Just click the “add to cart” button, check the content of your shopping cart and checkout via PayPal. No registration needed. You will get the order confirmation via email immediately, another email from PayPal, and we will get your shipping address from PayPal. You will get another email when the package will be dispached.

I didn’t get my item. What do I do?
Basically just wait, all products are sent via registered mail and can be tracked in real time on http://sledenje.posta.si/ (make sure to click “ENG” in the upper right corner). Anyway if you still have any request, question or complaint, don’t hesitate to contact us via email – info@jaytune.eu.

I didn’t get the correct item. What do I do?
That is very unlikely. However if it DOES happen, send us the picture of an incorrect item, and you will be able to keep the product and we will send you the correct item for free. If the item doesn’t work (which is also very unlikely), send it back undamaged in original box, we will send you a working product and refund you the amount of money that was paid for return shipping.

Were any mishaps or accidents with your equipment already?
There sure were. Not much, but there are more than 100 EPROMs on the road already, so no wonder there were. The most recent ones were our test bike Falco (wheeling out of the tarmac, rider OK) and a Mille R of customer that had installed exactly the same EPROM that was tested by the Falco at the time of crash (lowside, rider suffered a broken leg, few bruises and bumps).


Any other question? Don’t hesitate to contact us! info@jaytune.eu