Is low octane gas causing my sputtering?

[gulliver]

My KTM 640 LC4 is sputtering at all RPMs; it cuts out and kicks in again shortly after. I've tried everything and currently have the carb out for a full cleaning - but seems pretty spotless as of the last time I tried it. The problem started right after I gassed up but the fact that I messed with jetting too has diverted my trouble shooting focus. Right now, I'm 100% stock and running out of options. I'm wondering if I accidentally filled my tank with low 87 octane gas.

Thanks.

 

[agitt73]

drain the tank and use 92 octane
if that dose not work then its a jetting problem

 

[Danny8785]

I hope, at the very least, you put in a new plug before all of this work.
The low octane fuel might make it spark knock but i REALLY doubt this is your problem, make sure the valves are in correct adjustment too. Little things will throw you, I always miss them.

 

[gulliver]

I brought my carb to a pro, right away he said that I was missing the
small spacer that goes right above the main jet. It holds the needle
jet in, and must have fallen out when I was changing jets.

User error (or loser error) on my part.

Now I have to locate one. Unfortunately, there is no part number for
it listed in my schematic. Hopefully my dealer will have good
resources to find it.

Thanks for your suggestions,

Martin

 

[JW]

Check H&H KTM www.ktmworld.com or call Letko Cycles I think is the name at 1-913-334-0881. They have both been around awhile and should be able to help if you have problems.
JW

 

[Pitts]

My KTM LC4 does this too. It has 170 miles on it. I run 100 Octane low lead aviation fuel in it. Sputters,quits,restarts,confuses me. I have not messed with the jetting at all. I'm about to let the dealer have a go at it. I think the vent tube for the fuel tank is routed under the tank and might be partially pinched at times. I have not seen any debris upon draing the float bowl. Mine has done this only after an hours ride time.I would be interested to know what you find.