I've had my Sporty Roadster for about 2 weeks. Runs like a champ and I love it. Haven't touched my other bikes since.......

Earlier this week I put in a few ounces of Lucas Gas treatment, mechanic swears by it. I just filled up yesterday and used 89 Octane, been using 91. A couple of times yesterday the engine started dieseling when I turned the bike off by the key.

Could it be the lower octane gas? Bad gas? Lucas treatment? Or something else?

Any thoughts welcomed.

Thanks,

RJ

 

I am going to assume you have a carb on an 05 since a FI bike closes the idle air off completely and should not diesel. Is it idleing too fast. Pull it down with the brake on and slipping clutch and turn it off. If it stops, it's the idle. If it's FI, go very easy on the additives and only proper amount per gallon and always ride after adding it, they will cause the fuel inlet sock to fall apart if you use too much. I personally do not think you need additives but I only base this for me on my experience of 50 years. It's not the 89 gas at idle. It should idle fine with regular. Mine runs fine on regular but I never WOT it and it's flat around here.

 

If you mean the engine carried on running after you switched off the ignition, that is caused by a hot spot inside the engine, like the spark plugs, or carbon build-up. It ain't good! Use better grade gas and if it still does it you need advise on sorting your bike out. I would visit a local indy or dealer, as your timing and fuelling could be way out.

 

Using less than 91 or 93 octane gasoline invites knocking and running on when you have a 10.5 to 1 compression ratio.

 

+1 - The Owners Manual for your bike calls for 91+ octane.

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I've had it happen half a dozen times last year. Sometimes I have to go out of my way to find 91, and even more so to find non-ethanol fuel. Most stations here have 87 and 89. The few times I've had dieseling always were after filling up with the 10% ethanol, and with the single line fuel pumps, who knows what octane I am getting. If I run out as much gas as I can and fill with 91 octane pure gas, I never had problems. Not sure if the 10% ethanol has any effect or not, but I stay away from it when I can.

 

Added a little fuel treatment to the gas last night. So far today I've started and stopped the bike 6-7 times and so far so good. Could have been less than desirable gas when I filled up yesterday. I did have new plugs and a complete service two weeks ago.

 

I wouldn't ever let ethanol touch your bike.

 

It's not the ethanol. All we have had here for last 15 years

 

this may sound strange, but try pulling out the plugs and dumping a tablespoon of automatic transmission fluid in the holes...let it sit overnight, put rags over the plug holes and turn it over a few times to blow out the extra ATF...reinstall the plugs..roll it outside and start it (it will smoke like crazy) .....Why this works....you may have a build up of carbon on the piston tops and this raises the compression and provides hot spots for ignition...ATF has a ton of detergents in it and will help dissolve the carbon, but will not dry the cylinder wall like solvents can...