My '97 ran great until the first tank of the local 'winter blend' with < 10% ethanol.

Are the carbed 4th GENs sensitive to having any ethanol in the gas? It idles great but misses while under a load (accelerating) and has no power. Is this a fuel issue or do I need to look at something else? If it is fuel is there an additive I can put in until the 'spring' blend comes back in February?
Thanks much.

 

Not that I know, I know from my experience that it runs very well with the good ole super in the tank. I have never ran any of the mixed blends. But.. to me it sounds like you have a vacuum leak. Check all the rubber connections and pugs. I had this very thing happen and it ended up being one of the rubber plugs for syncing the carbs had gone missing...

 

Turns out # 2 cylinder isn't firing-just a strange coincidence. No time to pull it apart until this weekend, anything I should look for beyond a bad plug?
Thanks for the help.

 

All of my local gas stations have been running 10% ethanol since this spring when fuel prices began to soar through the roof.

I have nto had one issue like you mentioned all summer (and I was 0.2 miles short of a 2,000 mile summer).

 

Check the cap on the plug. Make sure it is a good connection to the wire.
Check the carb, the solvent ability of the blend could have carried some junk over and plugged a small port.
If ign and carb are OK, do a compression test and or leakdown test to check for valve operation.

 

'97 running bad update:

For those that read the posts on maintenence and repair issues for future reference, it's running great. Confirmed #2 not running (wrap hand around exhaust while it was running. Pulled plug-fouled. Got new one, checked for spark against frame, still nothing. Pulled coil off, pulled plug wire and boot off, cleaned EVERYTHING (it wasn't dirty or corroded-bike now has 5400 miles on it) put it all back together-runs great. No idea what was wrong-or what I (inadvertently) fixed.


Thanks for the input (especially RVFR)-it's all good info..

 

Don'ts ya just love it when that happens, Now you will be wondering if it will happen again. It is good to hear, just chalk it up to Mr. Murphy doing his best. at least you know where to look if it comes back..

 

So you went through all the trouble to pull it apart to do one plug, but did you change all the rest while you were in there? Check the filters?

I'd also suggest if you are using 87 octane, that you stop; that stuff is barely gas at all. 92 octane may cost a little more but your bike will thank you for it and you should see a slight improvement in mileage.

 

Uhm, lower octane gasolines are MORE gasoline than higher octanes. It takes additives to increase the octane of gasoline. Higher octane ratings relate to the ability of fuel to resist detonation under compression. The flame front is SLOWER with higher octane.
If your engine is not detonating with lower octane, money spent on higher octane is wasted. (And better spent on farkles) Higher octane will not increase your fuel economy. (Less BTU's per lb.)

Mythbusters need to do some episodes on gas facts!

 

Mmm, thats ok, I'll spend the extra buck.