e85 (ethanol) conversion. Should be possible, right?

Since i live in sweden were E85 is available just about everywhere, it is cheaper and eco-friendly. Therefore i quickly thought of converting my old 1981 XJ400 4v7 to running on E85, just like i prefer my cars. However, due to my inexperience with carbs in general and especially these CV carbs (the same as a 550) i am thinking that it might become an issue. I know i would have to replace all rubber seals, fuel lines and preferably coat the inside of the tank, but it is the carb part i am worried about. Maybe replacing the carbs with some other more easily managed carbs would be a good idea. There are some e85 compatible carbs for cars, does anyone know any reasonable ones for bikes?

Otherwise i will just have to convert it to EFI next winter.

 

In my experience with using e85 and or methanol in carbs, it really depends on how fresh the supply of e85 is and how long it sits around. When I was racing karts I had much better luck with a blended methanol, had some lubricant additives in it and I realize not practical for street use but same principals apply. Unless I found a station that went through enough e85 to always have at least semi fresh fuel it was ok. A little more finicky on the carb settings. Basically you would have to jet it a lot richer for alcohol (e85) replace as many rubber parts as you can in the fuel system. Viton is a much better alternative for alcohols in my opinion but could be difficult to source for xj carbs, not really sure. I am also unsure of how the timing would play in as we always advanced the timing on the kart motors not only for performance/rpm reasons but also for the alcohol fuel. It would be interesting to try it and I have even thought of it but really wouldn't know how the stock components would respond. I do know it is one heck of a lot harder on any fuel system, from the tank, lines, carbs/fuel injectors, and whatnot.

 

Compression ratio matters too. Carb work alone won't get you there, not with the best results anyway.
My suggestion would be to invest some time talking with somone who has converted engines to methanol for racing.

BTW, the fuel tank won't need to be lined; the inside is steel. If there is an old liner in there it might need to be stripped, depending on which liner was used.

 

Here in sweden many cars run e85, even daily drivers. Heck, i run my saab on e85, and that is stock. So quality e85 is readily available, it is actually easier to find e85 than higher octane rating, 95 octane is everywhere but 98 is more difficult and e85 is very rare not to find. I

Ignition timing should be slightly advanced in order to make more power, but should be decent with stock timing, the flame speed isn't all that different. Running a higher CR is definitively not necessary, but since e85 has a higher octane rating (about 105) you CAN run higher compression, i am not looking to much at power, if so i should just get a bigger engine.

To get the same power you need about 30-35% more fuel due to the lower chemical energy in e85 compared to petrol and that is my main concern.